Irrigation Feasibility Study Report

Vegetable Production and Irrigated Agriculture Project (RRP MON 51423-002)

Project Number: 51423-002 February 2020

Proposed Loans and Administration of Grant Mongolia: Vegetable Production and Irrigated Agriculture Project

Table of Contents

I. PROJECT CONTEXT AND RATIONALE 1 A. Need for investment 1 B. Objective 2 C. Subproject Selection 2 II. IRRIGATION SUBPROJECT DESIGN 6 A. General Design Principles 6 B. Subproject 1 – Tsakhir Irrigation and Drainage System Design 36 C. Subproject 2 – Yolton Irrigation and Drainage System Design 58 D. Subproject 3 - Erdeneburen Irrigation and Drainage System Design 84 E. Subproject 4 – Boomiin Am Irrigation and Drainage System Design 111 F. Subproject 5 – Khoid Gol Design of Irrigation and Drainage System 128 G. Subproject 6 – Tsul-Ulaan Irrigation and Drainage System Design 157 H. Subproject 7 – Ulaandel Irrigation and Drainage System Design 181 I. Subproject 9 – Khuren Tal Irrigation and Drainage System Design 203 J. Subproject 10 – Nogoon Khashaa Irrigation and Drainage System Design 224 K. Subproject 12 – Iven Gol Irrigation and Drainage System Design 245 L. Subproject 13 – Okhindiin Tal Irrigation and Drainage System Design 268 M. Subproject 14 – Sugnugur Irrigation and Drainage System Design 284 N. Subproject 16 – Dulaanii Tal Irrigation and Drainage System Design 307 III. TOTAL INVESTMENT AND FINANCIAL PLAN 327 IV. IMPLEMENTATION AND OPERATING ARRANGEMENTS 328 A. Implementation Schedule 328 B. Operation and Maintenance of Irrigation Systems 328 C. Capacity Building 331 V. PROJECT OUTCOME AND IMPACTS 332 A. Project Monitoring 332 B. Social Impact Assessment 332 C. Environmental Impact Assessment 332 VI. CRITICAL RISKS 333 A. Extreme Climate 333 B. Alignment with Interests and Expectations of Farmers and Other Stakeholders 333 C. Water Quality Especially Salinization 333 D. Operations and Maintenance 334

List of Tables

Table 1: List of Priority Irrigation Subprojects ...... 3 Table 2: Permitted Water Withdrawals as Percentage of the Long-Term Average Flow ...... 11 Table 3: Data Availability ...... 12 Table 4: Normal Range of Major Ions in Irrigation Water ...... 13 Table 5: Water Quality Classification ...... 14 Table 6: Crop Water Requirement Norm ...... 17 Table 7: Indicative Values of Conveyance Efficiency for Adequately Maintained Canals ...... 20 Table 8: Indicative Values of Field Application Efficiency ...... 20 Table 9: Number of Pump and Sprinklers, Drip in Command Area ...... 24 Table 9: Mean Monthly Climate Data for Tsakhir Irrigation Subproject ...... 39 Table 10: Soil Profile of Tsakhir Irrigation Subproject Area ...... 44 Table 11: Zavkhan River Water Resources for Tsakhir Subproject ...... 46 Table 12: Zavkhan River Percentage Change in Flow Due to Climate Change ...... 46 Table 13. Current and Designed Command Area and irrigation method...... 48 Table 14: Irrigation Scheme Efficiency ...... 49 Table 15: Irrigation Water Requirement for Tsakhir ...... 50 Table 16: Water Availability for Irrigation ...... 50 Table 17: Design Discharge from the Zavkhan River ...... 55 Table 18: Valves and Fittings for Tsakhir Subproject...... 57 Table 19. Bill of Quantities for Tsakhir Irrigation Scheme Modernization ...... 57 Table 20: Mean Monthly Climate Data for Yolton Subproject Area ...... 61 Table 21: Soil Profile ...... 65 Table 22: Ust-Chatsran River - Control Discharge Measurement (2019.6.18) ...... 67 Table 23: Water Resources for the Ust Chatsrana at Yolton Subproject Area ...... 67 Table 24: Current and Planned Command Area ...... 69 Table 25: Irrigation Scheme Efficiency ...... 69 Table 26: Irrigation Water Requirements for Yolton ...... 70 Table 27: Water Availability for Irrigation ...... 70 Table 28: Flow and Pressure Details for Pressure Pipes ...... 74 Table 29: Available Water Discharge from the Ust-Chatsran River ...... 80 Table 30: Flows and Pressure in System Pipes ...... 80 Table 31: Estimated Pipe, Valve and Filter Set Requirements ...... 82 Table 32: Bill of Quantities for Yolton Irrigation Scheme Modernization...... 83 Table 33: Mean Monthly Climate Data in the Erdeneburen Irrigation Subproject Area ...... 87 Table 34: Soil Profile of Erdeneburen Command Area ...... 92 Table 35: Water Resources in the Khovd River at Erdeneburen Irrigation Scheme ...... 93 Table 36: Khovd River Flow Sensitivity to Climate Change ...... 94 Table 37: Current and Planned Command Area ...... 97 Table 38: Scheme Irrigation Efficiency ...... 98 Table 39: Irrigation Water Requirements for Erdeneburen ...... 98 Table 40. Water Availability for Irrigation ...... 98 Table 41: Irrigation Design Option ...... 101 Table 42: Provisional Estimate for Annual Pumping Costs ...... 104 Table 43: Design Discharge from Erdeneburen River ...... 108 Table 44: Bill of Quantities for Erdeneburen Irrigation Scheme Modernization ...... 110 Table 45: Mean Monthly Climate Data in the Boomiin Am Irrigation Subproject Area ...... 114 Table 46. Soil Profile of Boomiin Am Command Area ...... 117 Table 47: Water Resources in the Bodonch River at Boomiin Am Irrigation Scheme ...... 118 Table 48: Current and Planned Command Area ...... 121 iii

Table 49: Scheme Irrigation Efficiency ...... 122 Table 50: Irrigation Water Requirement for Boomiin Am Irrigation Scheme ...... 122 Table 51. Water Availability for Irrigation ...... 122 Table 52: Irrigation Design Option ...... 124 Table 53: Bill of Quantities for Boomiin Am Irrigation Scheme Modernization ...... 127 Table 54: Mean Monthly Climate Data around Khoid Gol Irrigation Subproject ...... 134 Table 55: Soil Profile of Khoid Gol Irrigation Subproject Area ...... 138 Table 56: Discharge Measurement Results, Khusheet River, Darvi Soum, 2019-6-19 ...... 139 Table 57: Water Resources of the Khusheet River at Khoid Gol Subproject Area ...... 140 Table 58: Current and Planned Command Area ...... 141 Table 59: Scheme Irrigation Efficiency ...... 141 Table 60: Irrigation Water Requirements for KhoidgoI ...... 142 Table 61: Water Availability for Irrigation ...... 142 Table 62: Flow and Pressure Details for Pressure Pipes ...... 147 Table 63: Design Discharge from the Khusheet River ...... 153 Table 64: Proposed Valves and Fittings ...... 155 Table 65: Bill of Quantities for Khoid gol Irrigation Scheme Modernization ...... 156 Table 66: Mean Monthly Climate Data in the Tsul-Ulaan Subproject Area ...... 159 Table 67: Soil Profile and Analysis ...... 164 Table 68: Water Resources of the Khovd River at Tsul-Ulaan Subproject Area ...... 165 Table 69: Khovd River Flow Sensitivity to Climate Changea ...... 166 Table 70: Current and Planned Command Area ...... 170 Table 71: Scheme Irrigation Efficiency ...... 170 Table 72: Irrigation Water Requirements for Thus-Ulaan ...... 170 Table 73: Water Availability for Irrigation ...... 171 Table 74: Preliminary Canal Design Details ...... 175 Table 75: Irrigation Design (Open Canals) ...... 175 Table 76: Mean Monthly Irrigation Design Discharge ...... 178 Table 77: Bill of Quantities for Tsul-Ulaan Irrigation Scheme Modernization ...... 180 Table 78: Mean Monthly Climate Data in the Ulaandel Irrigation Subproject Area ...... 183 Table 79: Soil Profile of Ulaandel Irrigation Scheme...... 188 Table 80: Water Resources of the Sagsai River at Ulaandel Subproject Area ...... 189 Table 81: Khovd River Flow Sensitivity to Climate Change ...... 190 Table 82: Current and Designed Command Area and Irrigation Method ...... 192 Table 83: Scheme Irrigation Efficiency ...... 193 Table 84. Irrigation Water Requirements for Ulaandel ...... 193 Table 85: Water Availability for Irrigation ...... 194 Table 86: Irrigation Design Option ...... 196 Table 87: Provisional Estimate for Annual Pumping Costs ...... 198 Table 88: Design Discharge from Sagsai River ...... 200 Table 89: Bill of Quantities for Ulaandel Irrigation Scheme Modernization ...... 202 Table 90: Mean Monthly Climate Data in the Khuren Tal Subproject Area ...... 205 Table 91: Soil Profile ...... 209 Table 92: Water Resources of the Ider River at Khuren Tal Subproject Area ...... 210 Table 93: Khovd River Flow Sensitivity to Climate Changea ...... 211 Table 94: Current and Planned Command Area ...... 213 Table 95: Scheme Irrigation Efficiency ...... 214 Table 96: Irrigation Water Requirements for Khuren Tal ...... 214 Table 97. Water availability for irrigation...... 215 Table 98: Hydraulics Calculations ...... 216

Table 99: Irrigation Design Option ...... 218 Table 100: Design Discharge from the Ider River ...... 221 Table 101. Bill of Quantities for Khurental Irrigation Scheme Modernization ...... 223 Table 102: Mean Monthly Climate Data in the Nogoon Khashaa Irrigation Subproject Area ..... 226 Table 103: Soil Profile of Nogoon Khashaa Subproject Area...... 231 Table 104: Water Resources of the Sagsai River at Nogoon Khashaa Subproject Area ...... 232 Table 105. Khovd River Flow Sensitivity to Climate Changea ...... 233 Table 106: Current and Planned Command Area ...... 236 Table 107: Scheme Irrigation Efficiency ...... 236 Table 108: Irrigation Water Requirements for Nogoon Khashaa ...... 236 Table 109: Water Availability for Irrigation ...... 237 Table 110: Irrigation Design Using Open Canals ...... 239 Table 111: Design Discharge from the Chigestei River ...... 242 Table 112: Bill of Quantities for Nogoon Khashaa Irrigation Scheme Modernization ...... 244 Table 113: Mean Monthly Climate Data at Iven Gol Irrigation Subproject ...... 247 Table 114: Soil profile ...... 251 Table 115: Control Discharge Measurement, Iven Gol River (2019.06.11) ...... 254 Table 116: Water Resources in Iven Gol River for Iven Gol Subproject Area ...... 254 Table 117: Current and Planned Command Area ...... 256 Table 118: Irrigation Efficiency ...... 257 Table 119: Irrigation Water Requirements for Iven Gol ...... 257 Table 120: Water Availability for Irrigation ...... 258 Table 121: Flow and Details for Gravity Lined Canals ...... 261 Table 122: Available Water Discharge from the Iven Gol River ...... 264 Table 123: List of Various Gates, Valves and Fittings ...... 267 Table 124: Bill of Quantities for Iven Gol Irrigation Scheme Modernization ...... 267 Table 125: Mean Monthly Climate Data in the Okhindiin Tal Irrigation Subproject Area ...... 270 Table 126: Soil Profile ...... 275 Table 127: Selenge River Water Resources for Okhindiin Tal Subproject Area ...... 276 Table 129: Irrigation water requirements for Okhindoin tal...... 278 Table 130: Irrigation Design Option ...... 280 Table 131: Bill of Quantities for Okhindiin Tal Irrigation Scheme Modernization ...... 284 Table 132: Mean Monthly Climate Data for Sugnugur Irrigation Sub-Project ...... 286 Table 133: Soil profile ...... 291 Table 134: Sugnugur River Water Resources for Sugnugur Subproject Area ...... 292 Table 135: Sugnugur River Flow Sensitivity to Climate Changea ...... 293 Table 136. Current and planned command area ...... 296 Table 137: Irrigation Irrigation Water Requirements for Sugnugur ...... 296 Table 138: Water availability for irrigation ...... 297 Table 139: Flow and Details for Gravity Lined Canals ...... 299 Table 140: Available Water Discharge from Sugnugur River ...... 303 Table 141: Gates, Valves and Fittings to Regulate Flow from Canal to Irrigation Subsystem .... 305 Table 142: Bill of Quantities for Sugnugur Irrigation Scheme Modernization ...... 306 Table 143: Mean Monthly Climate Data in Dulaanii Tal Irrigation Subproject Area ...... 308 Table 144: Soil Profile and Analysis of Dulaanii Tal Irrigation Scheme ...... 313 Table 145: Water Resources of the Kherlen River at Dulaanii Tal Subproject Area ...... 314 Table 146. Kherlen River Percentage Change in Flow Due to Climate Change ...... 315 Table 147: Current and Planned Command Area ...... 316 Table 148: Scheme Irrigation Efficiency ...... 317 Table 149: Irrigation Water Requirements for Dulaanii Tal ...... 317 Table 150: Water Availability for Irrigation ...... 317 v

Table 151: Irrigation Design Option ...... 320 Table 152: Operating cost of pumps USD/ha/season ...... 321 Table 153: Design Discharge from the Kherlen River ...... 324 Table 154: Bill of Quantities for Dulaanii Tal Irrigation Scheme Modernization ...... 326 Table 155: Summary Cost Estimates ...... 327 Table 156: Summary Financing Plan ...... 328

List of Figures

Figure 1: Location of Subprojects ...... 4 Figure 2: Spatial Distribution of Annual Mean Temperature, 1961-1990 ...... 6 Figure 3: Spatial Distribution of Annual Precipitation, 1961-1990 ...... 7 Figure 4: Projected Summer Temperature with High Emission Scenario...... 9 Figure 5: Projected Summer Precipitation with High Emission Scenario ...... 9 Figure 6: Irrigation Subprojects and River Basins ...... 10 Figure 7: An Irrigation System Integrating Movable Central Pivots with Drip Irrigation ...... 33 Figure 8: Location of Tsakhir Irrigation Scheme ...... 37 Figure 9: Status of Tsakhir Irrigation Scheme ...... 38 Figure 10: Trends in Monthly Mean Air Temperature for Tsakhir Irrigation Scheme ...... 39 Figure 11: Trends in Hot Days with Daily Mean Temperature above 25oC and 30oC...... 40 Figure 12: Trends in Monthly Precipitation at Tsakhir Irrigation Scheme ...... 40 Figure 13: Trend in Days Without Precipitation at Tsakhir Irrigation Scheme ...... 41 Figure 14: Trend in Wind Speed and Direction at Tsakhir Irrigation Scheme ...... 41 Figure 15: Agro-Climate Characteristics around Tsakhir Irrigation Scheme ...... 42 Figure 16. Tsakhir Irrigation Subproject Soil Map ...... 43 Figure 17: Zavkhan River Basin: Location of the Tsakhir Irrigation Subproject and Taishir Hydrological Gauging Station ...... 45 Figure 18: Trend for Monthly Flow at Taishir Gauging Station on Zavkhan River ...... 46 Figure 19: Water Chemistry of Zavkhan River ...... 47 Figure 20: Suspended Solids in Zavkhan River Water ...... 47 Figure 21: Tsakhir Irrigation Scheme Layout ...... 51 Figure 22: Tsakhir Command Area and Sprinkler Arrangement ...... 54 Figure 23: Location of Yolton Irrigation Scheme ...... 59 Figure 24: Current Condition of Yolton Irrigation Scheme ...... 60 Figure 25: Trends of Monthly Air Temperature at Yolton Irrigation Scheme ...... 61 Figure 26: Trend in Hot Days with Daily Mean Temperature more than 25 oC and 30oC ...... 62 Figure 27: Trends of Monthly Precipitation at Yolton Irrigation Scheme ...... 62 Figure 28: Trend in Days with no Precipitation ...... 63 Figure 29: Trend in High Winds and Wind Direction ...... 63 Figure 30 Climate Characteristics ...... 64 Figure 31: Soil Map of Yolton Irrigation Scheme ...... 65 Figure 32: Ust-Chatsran River with Location of Headworks for Yolton Irrigation Scheme ...... 66 Figure 33: Ust-Chatsran River Flow Control Measurement ...... 67 Figure 34: Planned Layout of the Yolton Irrigation Scheme ...... 72 Figure 35: Plan for Yolton Lateral Move System for Command Area of Irrigation System ...... 78 Figure 36: Command Area with planned alignment of protection and outfall drains ...... 79 Figure 37: Current Situation for Erdeneburen Irrigation Scheme ...... 85 Figure 38: Location of Erdeneburen Irrigation Scheme ...... 86 Figure 39: Trend in Monthly Air Temperature at Erdeneburen Irrigation Scheme ...... 87 Figure 40: Trend in Hot Days with Daily Mean Temperature Greater than 25 oC and 30oC ...... 88 Figure 41: Trend in Monthly Precipitation at Erdeneburen Irrigation Scheme ...... 88 Figure 42: Trends in Days with no Precipitation ...... 88 Figure 43: Trend in High Wind and Wind Direction ...... 89 Figure 44: Agro-climate Characteristics...... 90 Figure 45: Soil Map of Erdeneburen Command Area ...... 91 Figure 46: Location of Erdeneburen Irrigation Scheme, Hydrological Gauging Stations and Meteorological Observation Stations ...... 93 Figure 47: Khovd River Flow at Erdeneburen Irrigation Scheme (1973 to 2017) ...... 94 vii

Figure 48: Water Chemistry of Khovd River ...... 95 Figure 49: Suspended Solids in Khovd River at Erdeneburen ...... 95 Figure 50: Erdeneburen Command Area...... 97 Figure 51: Erdeneburen Irrigation Scheme Layout ...... 101 Figure 52: Current Situation for Boomiin Am Irrigation Scheme ...... 112 Figure 53: Location of Boomiin Am Irrigation Scheme ...... 113 Figure 54: Trends of Monthly Air Temperature at Boomiin Am Irrigation Scheme ...... 114 Figure 55: Trends of Monthly Precipitation at Boomiin Am Irrigation Scheme ...... 115 Figure 56: Boomiin Am Irrigation Subproject Soil Map ...... 116 Figure 57: Bodonch River Basin, Hydrological Gauging Station ...... 118 Figure 58: Bodonch River Flow at Boomiin Am Irrigation Scheme (1983 to 2017) ...... 119 Figure 59: Water Chemistry of Bodonch River ...... 119 Figure 60: Suspended Solids in Bodonch River at Boomiin Am Irrigation Scheme ...... 120 Figure 61: Boomiin Am Command Area ...... 121 Figure 62: Boomiin Am Irrigation Scheme Layout ...... 124 Figure 63: Original Design Plan for Khoid Gol Irrigation Scheme ...... 129 Figure 64: Location of Khoid Gol Irrigation Scheme ...... 130 Figure 65: Current Condition of Khoid Gol Irrigation Scheme ...... 131 Figure 66: Proposed Upgraded Irrigation Scheme for Khoid Gol ...... 131 Figure 67: Preliminary Revised Layout for Khusheet River Diversion Intake for Khoid Gol ...... 132 Figure 68: Proposed Khoid Gol Irrigation Command Area Layout ...... 133 Figure 69: Trend in Monthly Air Temperature at Khoid Gol Irrigation Scheme ...... 134 Figure 70: Trend in Hot Days at Khoid Gol Greater than 25 oC and 30oC ...... 135 Figure 71. Trends in Monthly Precipitation around the Khoid Gol Irrigation Scheme ...... 135 Figure 72: Trend in Number of Days with no Precipitation at Khoid Gol Irrigation Scheme ...... 135 Figure 73: Trend for High Winds and Wind Direction at Khoid Gol Irrigation Scheme...... 136 Figure 74: Agro-climate Characteristics Around the Khoid Gol Irrigation Scheme ...... 136 Figure 75: Soil Map of the Khoid Gol Irrigation Subproject Area ...... 137 Figure 76: Khoid Gol Irrigation Scheme and Hydrological Gauging Station in the Khuisiin Gobi - Tsetseg Lake River Basin ...... 138 Figure 77: Khoid Gol River Flow Measurement ...... 139 Figure 78: Khoid Gol Balancing Storage ...... 143 Figure 79: Planned Irrigation Water Supply for Khoid gol Irrigation Scheme ...... 144 Figure 80: Overview of Upgraded Khoid Gol Command Area ...... 151 Figure 81: Current Situation for Tsul-Ulaan irrigation scheme ...... 157 Figure 82: Location of Tsul-Ulaan Irrigation Scheme ...... 158 Figure 83. Trends of Monthly Air Temperature at Tsul-Ulaan Subproject Area ...... 159 Figure 84: Trends in Hot Days with Daily Mean Temperature more than 25 oC and 30oC ...... 160 Figure 85: Trends of Monthly Precipitation at Tsul-Ulaan Irrigation Scheme ...... 160 Figure 86: Trends in Days with no Precipitation ...... 160 Figure 87: Trends in High Winds and Wind Direction ...... 161 Figure 88: Agro-climate Characteristics...... 162 Figure 89: Soil Map for Tsul-Ulaan Irrigation Scheme ...... 163 Figure 90: Khovd River Basin – Location of Hydrological Gauging Stations and Tsul-Ulaan Irrigation Scheme ...... 165 Figure 91: Khovd River Flow at Bayannuur Gauging station (1982-2017) ...... 166 Figure 92: Water Chemistry of the Khovd River ...... 167 Figure 93: Suspended Solids in the Khovd River Water ...... 167 Figure 94: Tsul-Ulaan Command Area Map ...... 169 Figure 95: Map of Tsul-Ulaan Irrigation Scheme ...... 172

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Figure 96: Current Situation for Ulaandel Irrigation Scheme...... 181 Figure 97: Location of Ulaandel Irrigation Scheme ...... 182 Figure 98: Trends of Monthly Air Temperature at Ulaandel Irrigation Scheme...... 183 Figure 99: Trend in Hot Days with Mean Temperature more than 25oC and 30oC ...... 184 Figure 100: Trends of Monthly Precipitation at Ulaandel Irrigation Scheme ...... 184 Figure 101: Trends in Days with no Precipitation ...... 185 Figure 102: Trends in High Winds and Wind Direction ...... 185 Figure 103: Agro-climate Characteristics...... 186 Figure 104: Soil Map of Ulaandel Irrigation Scheme...... 187 Figure 105: Khar-Us Lake-Khovd River Basin Showing Ulaandel Irrigation Scheme, Hydrological Gauging Stations and Meteorological Observation Stations ...... 189 Figure 106: Sagsai River Flow at Sagsai-Buyant Gauging Station (1965-2017) ...... 190 Figure 107: Water Chemistry of the Sagsai River ...... 191 Figure 108: Suspended Solids in the Sagsai River Water ...... 191 Figure 109: Ulaandel Irrigation System Layout ...... 196 Figure 110: Location of Khuren Tal Irrigation Scheme ...... 203 Figure 111: Current Situation for Khuren Tal Irrigation Scheme ...... 204 Figure 112: Trends of Monthly Air Temperature at Khuren Tal Subproject Area ...... 205 Figure 113: Trends in Hot Days with Daily Mean Temperature more than 25oC and 30oC ...... 206 Figure 114: Trends of Monthly Precipitation at Khuren Tal Irrigation Scheme ...... 206 Figure 115: Trends in Days Without Precipitation ...... 206 Figure 116: Trends in High Winds and Wind Direction ...... 207 Figure 117: Agro-climate Characteristics...... 207 Figure 118: Soil Map of Khuren Tal Subproject Area...... 208 Figure 119. Ider River Basin – Location of Khurental irrigation scheme, Hydrological Gauging Stations and Meteorological observation stations ...... 210 Figure 120: Ider River Flow at Ider Gauging Station (1965-2017) ...... 211 Figure 121: Water chemistry of the Ider River ...... 212 Figure 122: Suspended Solids in the Ider River Water ...... 212 Figure 123. Khuren Tal Irrigation Scheme Command Area ...... 213 Figure 124: Khurental Irrigation Scheme Layout ...... 217 Figure 125: Location of Nogoon Khashaa Irrigation Scheme...... 224 Figure 126: Current Situation for Nogoon Khashaa Irrigation Scheme ...... 225 Figure 127: Trends of Monthly Air Temperature at Nogoon Khashaa Irrigation Scheme ...... 226 Figure 128: Trend in Hot Days with Daily Mean Temperature more than 25oC and 30oC ...... 227 Figure 129: Trends of Monthly Precipitation at Nogoon Khashaa Irrigation Scheme ...... 227 Figure 130: Trends in Days Without Precipitation ...... 228 Figure 131: Trends in High Winds and Wind Direction ...... 228 Figure 132: Agro-climate Characteristics...... 229 Figure 133. Soil Map of Nogoon Khashaa Subproject Area ...... 230 Figure 134: Khyargas Lake-Zavkhan River Basin ...... 232 Figure 135: Chigestei River Flow at Uliastai Gauging Station (1965-2017) ...... 233 Figure 136: Water Chemistry of the Chigestei River ...... 234 Figure 137: Suspended Solids in Chigestei River Water ...... 234 Figure 138: Nogoon Khashaa Command Area Layout ...... 235 Figure 139: Proposed Nogoon Khashaa Irrigation Scheme Layout ...... 238 Figure 140: Iven Gol Canal Intake and Convoluted Path of Main Canal to Command Areas ... 245 Figure 141: Location of Iven Gol Irrigation Scheme on the North Side of Iven River Valley ..... 246 Figure 142: Trends of Monthly Air Temperature at Iven Gol Irrigation Scheme ...... 248 Figure 143: Trends in Hot Days with Daily Mean Temperature more than 25oC and 30oC ...... 248 Figure 144: Trends of Monthly Precipitation at Iven Gol Irrigation Scheme ...... 249 ix

Figure 145: Trends in Days with no Precipitation ...... 249 Figure 146: Trends in High Winds and Wind Direction ...... 250 Figure 147: Agro-climate Characteristics...... 250 Figure 148: Soil Map of Iven Gol Irrigation Scheme ...... 251 Figure 149: Iven Gol River Basin with Location of Irrigation Scheme, Gauging Station and Meteorological Station ...... 253 Figure 150: Iven Gol River Flow Control Measurement ...... 253 Figure 151: Concept Plan to Upgrade Iven Gol Irrigation Scheme at Sant Soum ...... 256 Figure 152: Proposed Iven Gol Command Area (240 ha) and Upgrading Infrastructure ...... 258 Figure 153: General Headworks Arrangement for Iven Gol Irrigation Scheme ...... 259 Figure 154: Plan of Proposed Upgraded Iven Gol Irrigation Scheme ...... 263 Figure 155: Location of Okhindiin Tal Irrigation Scheme ...... 268 Figure 156. Field Survey Work for Okhindiin Tal Subproject Area ...... 269 Figure 157: Trends of Monthly Air Temperature at Okhindiin Tal Subproject Area ...... 271 Figure 158: Trends in Hot Days with Daily Mean Temperature more than 25oC and 30oC ...... 271 Figure 159: Trend in Annual Mean Precipitation, 1966-2018 ...... 272 Figure 160: Trends in Days Without Precipitation ...... 272 Figure 161: Trends in High Winds and Wind Direction ...... 273 Figure 162: Agro-climate Characteristics...... 273 Figure 163. Okhindiin tal Irrigation Subproject Soil Map ...... 274 Figure 164: Confluence of the Selenge and Orkhon Rivers ...... 276 Figure 165: Selenge River Flow at Zuunburen Gauging station (1975 to 2017)...... 277 Figure 166: Water Chemistry of the Selenge River ...... 277 Figure 167: Suspended Solids in Selenge River Water ...... 278 Figure 168: Okhindiin Tal Irrigation Scheme Layout ...... 280 Figure 169: Sugnugur Canal Intake and Convoluted Path of Main Canal to Command Area .. 286 Figure 170: Sugnugur Irrigation Scheme Plan and Overview ...... 286 Figure 171: Trends of Monthly Air Temperature at Sugnugur Irrigation Scheme ...... 287 Figure 172: Trends in Hot Days with Daily Mean Temperature more than 25 oC and 30oC ...... 288 Figure 173: Trends of Monthly Precipitation at Sugnugur Irrigation Scheme ...... 288 Figure 174: Trends in Days with no Precipitation ...... 288 Figure 175: Trends in High Winds and Wind Direction ...... 289 Figure 176: Agro-climate Characteristics...... 289 Figure 177: Soil Map of the Sugnugur Subproject Area ...... 290 Figure 178: Sugnugur River Basin with Sugnugur Irrigation Scheme and Gauging Station ..... 292 Figure 179: Sugnugur River Flow at Sugnugur Gauging station (1989 to 2017) ...... 293 Figure 180: Water Chemistry of the Sugnugur River ...... 294 Figure 181: Suspended Solids in the Sugnugur River Water ...... 294 Figure 182: Planned Irrigation Water Supply for Sugnugur Irrigation Scheme ...... 300 Figure 183: Overview of Upgraded Sugnugur Command Area ...... 302 Figure 184: Location of Dulaanii Tal Irrigation Scheme ...... 307 Figure 185. Current Situation at Dulaanii Tal Irrigation Scheme ...... 308 Figure 186: Trends of Monthly Air Temperature at Dulaanii Tal Irrigation Scheme ...... 309 Figure 187: Trend in Hot Days with daily Mean Temperature More than 25oC and 30oC ...... 309 Figure 188: Trends in Monthly Precipitation at Dulaanii Tal Irrigation Scheme ...... 310 Figure 189: Trends in Number of Days Without Precipitation ...... 310 Figure 190: Trends in High Winds and Wind Direction ...... 311 Figure 191. Agro-climate Characteristics...... 311 Figure 192: Soil Map of Dulaanii Tal Irrigation Scheme ...... 312 Figure 193: Kherlen River Basin ...... 313

Figure 194. Kherlen River Flow at Kherlen-Buyant Gauging station (1965-2017) ...... 314 Figure 195: Water Chemistry of the Kherlen River ...... 315 Figure 196: Suspended Solids in Kherlen River Water ...... 316 Figure 197: Kherlen River Daily Flow Hydrograph for May 75% Exceedance ...... 318 Figure 198: Proposed Irrigation Scheme Layout ...... 319 Figure 199: Irrigation Management Institutions...... 331

CURRENCY EQUIVALENTS (as of 4 February 2020) Currency unit – Mongolian Togrog (MNT) MNT1.00 = $0.00036357 $1.00 = MNT2,750.50

ABBREVIATIONS ADB – Asian Development Bank FAO – Food and Agriculture Organization of the United Nations FC – field capacity FG – farmer group FGWU – farmer group for water users GCMs – Global Climatic Models GHG – greenhouse gas GPS – global positioning system HDPE – high-density polyethylene HWL – high water level IPCC – Intergovernmental Panel on Climate Change IWR – Irrigation Water Requirement JV – Joint Venture MAC – maximum allowable concentration MOFALI – Ministry of Food, Agriculture, and Light Industry O&M – operation and maintenance PIM – participatory irrigation management PWP – permanent wilting point RCPs – representative concentration pathways SAR – Sodium Adsorption Ratio THPP – Tsahriin Hydropower Station UNFCC – United Nations Framework Convention on Climate Change UNDP – United Nations Development Programme WR – water requirement WQI – Water Quality Index WUA – water user association WUG – water user group

WEIGHTS AND MEASURES °C – degree centigrade dB(A) – A-weighted sound pressure level in decibels cm – centimeter g – gram ha – hectare kg – kilogram km – kilometer km2 – square kilometer kW – kilowatt L – liter

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LAeq – Equivalent continuous A-weighted sound pressure level MW – megawatt m – meter m2 – square meter m3 – cubic meter m3/a – cubic meter per annum m3/d – cubic meter per day m3/s – cubic meter per second masl – meters above sea level mg/l – milligram per liter mg/m3 – milligram per cubic meter mm – millimeter t – metric ton t/d – metric ton per day t/a – ton per annum

GLOSSARY aimag – province soum – district

NOTE (i) In this report, "$" refers to United States dollars.

In preparing any country program or strategy, financing any project, or by making any designation of or reference to a particular territory or geographic area in this document, the Asian Development Bank does not intend to make any judgments as to the legal or other status of any territory or area.

I. PROJECT CONTEXT AND RATIONALE

A. Need for investment

1. The Mongolia agriculture sector comprises high potential for growth and livelihood opportunities. In line with the Government of Mongolia’s focus to accelerate economic diversification and job creation, agriculture has fast become a priority for growth.1 Mongolia has made strides over the past decade to become self-sufficient in mechanized cereal and potato production, but vegetable farming has been neglected and is not yet very productive. This perpetuates low income for vegetable farmers and high reliance on imported products, which in turn threatens national food security. On average, only about 51% of the country’s annual vegetable demand is met by domestic production (2008‒2016).2 Mongolia’s vegetable farming sector is typically characterized by smallholdings of up to 5 hectares (ha), fragmented farmland, lack of reliable access to water, and lack of value chain services and financial resources. There are about 300 cooperatives and 35,000 households across the country, growing vegetables on plots of up to 100 ha, totaling a land area of 7,200 ha.

2. Cooperatives and farming households lack access to high-value markets in urban centers due to the absence of value chain services. Only a small fraction of the added value is captured. Smallholder farmers only capture about 30%−60% of potatoes, carrots, cabbage, turnips, and onion retail value. Cooperative and farmer incomes are low, and opportunities curtailed not only because of lack of market access, but also because of poor agricultural practices with seasonally fluctuating supply and quality of farming outputs. Access to credit is hindered by high interest rates and collateral requirements which are major obstacles for small farmers’ access to financing. Short summers with frequent droughts limit the cropping season, resulting in seasonal vegetables, price fluctuations, and reliance on imported vegetables. The absence of irrigation systems and water- saving technologies results in high-risk production with frequent yield losses. In the absence of post- harvest and storage facilities, farming households mainly sell their vegetable produce to middlemen. Farmers have little access to wholesale price information and low awareness on value-added opportunities and marketing.

3. Irrigation services are supported by the Ministry of Food, Agriculture, and Light Industry (MOFALI), which owns most of the irrigation infrastructure and provides support for maintenance. There are currently more than 350 irrigation schemes in Mongolia, with most irrigation schemes found in the Kharaa River Basin and the downstream part of the Selenge and Orkhon River basins. Almost all irrigation systems are inefficient users of water resources, have outdated, poorly maintained, and often unworkable and unsustainable infrastructure. There is insufficient on-going support or investment for effective maintenance. Currently, about 54,000 ha are irrigated, out of a potential area of about 400,000 ha. The government is aiming to increase irrigated land up to 120,000 ha by 2030. Harmonized with Mongolia’s National Programme for Food Security (2009−2016), the government aims to develop and expand the country’s irrigated land with improved access to and management of scarce water resources. To achieve this, it is proposed that existing irrigation systems be upgraded and modernized, together with the establishment of stronger and effective participatory water management to improve system use and sustainability. The operational capacity of water users needs to be organized and strengthened, thereby reducing the vulnerability of farmers to system mismanagement and climate-induced disasters. However, this remains a challenge as most of the irrigation systems are old, have been neglected and

1 ADB. 2017. Country Partnership Strategy: Mongolia, 2017–2020—Sustaining Inclusive Growth in a Period of Economic Difficulty. Manila 2 Main vegetables that are produced in Mongolia are beat, cabbage, carrot, cucumber, garlic, onion, tomato, and turnip.

2 depleted of key assets, and need substantial investment to restore them to full and efficient functionality.

B. Objective

4. The project aims to upgrade and modernize existing irrigation systems with a primary focus of improving water management to enhance agricultural production in selected schemes. In particular, the emphasis is to increase vegetable production as part of the irrigated crop mix to meet increasing national demand and reduce reliance on imports. Annual vegetable production in 2018 was about 54% of requirements and, with population growth, this proportion is likely to decline without appropriate investment in improved irrigation and crop production technologies.

5. Mongolia has a history of developed irrigated agriculture, which is reported to have worked well under the old soviet style practices through to the end of the 1980s. With the decline of the soviet system, and introduction of democracy, the government opted to sell off the old collective irrigation farms to farmers (groups) and/or new enterprises forming post centralized management. Unfortunately, decentralization did not lead to stronger self-managed irrigated farms as expected. During the transition, the installed assets for many irrigation schemes were sold off for quick financial return rather than being retained and utilized for low value agricultural production. The outcome from this set of actions is that now irrigated agriculture is in serious decline, with many schemes stripped of physical assets (fixed and moveable) to the extent that most schemes have now ceased any meaningful crop production.

6. Under the proposed project, the Government of Mongolia (the government) aims to upgrade and modernize selected schemes that have since been returned to government ownership, working together with interested farmers to restore the schemes for increased and optimal production. Whilst the primary focus is to increase national and regional vegetable production, efforts will also be made to increase fodder and cereal production on suitable land to support the large livestock industry across Mongolia, and to offset the on-going need for import of livestock feed for the winter.

C. Subproject Selection

7. There are over 380 irrigation schemes of varying size in Mongolia all of which need modernization and upgrading. From this long-list of potential projects presented through the Ministry of Food, Agriculture and Light Industry (MOFALI) by soum and aimag governments, a short-list of 48 schemes was agreed between the Asian Development Bank (ADB) and MOFALI, assisted by the technical assistance (TA) consultant. These forty-eight schemes, located across the Western, Central and Eastern Regions of Mongolia, were assessed for further study, through a process of review and inspection during the early stages of project preparation.

8. The existing irrigation systems were designed in accordance with Soviet design standards, where crop water requirements were established as ‘Norms’ on the basis of providing a volume in m3 of water per hectare. These Norms are set based on climate, soils and crop for particular regions, and adopted as standard for particular crops. They do not allow for changed crop varieties and cultivation practice and are implemented to a fixed water supply regime rather than to fulfil crop water demand. Water is delivered in accordance with a defined schedule, from 4 to 6 times per year, rather than as required to maintain soil moisture in the root zone within pre-defined limits. Consequently, irrigation applications can be excessive (leading to water logging and deep percolation) or restrictive (causing crop stress) to crop growth and yield. Under the project and as

3 part of the operations more detailed irrigation scheduling will be developed in the basis of actual crop water consumption.

9. However, as most irrigation schemes are currently in poor condition, if working at all, then actual cropped area and yield are well down on the potential. In most cases, the available water resources are not restrictive to crop production, but because the irrigation infrastructure is dilapidated and often not functional, available water cannot be successfully and reliably delivered to the fields. This uncertainty for water supply and distribution to the land has led farmers to abandon irrigated cropping and seek alternative means to earn their livelihood.

10. Initially, MOFALI presented a long list of 384 subprojects for preliminary screening. By agreement, after review and inspection, this was reduced to 48 primary irrigation schemes for more detailed consideration, after which a short list of 17 priority schemes was agreed by the Government and ADB. The criteria for priority selection of irrigation schemes were: i. smallholder farmers’ access to irrigated land through a transparent and fair land lease distribution system, ii. public ownership of irrigation infrastructure with no resettlement issues (Cat C only), iii. reliable water source in terms of quantity and quality, iv. market access with at least 9% economic return on project investment, v. no significant or irreversible environment issues: (Cat B and C only) with sustainable water resource use

11. During preparation of this feasibility study report, four schemes were identified as being unsuitable for inclusion in the project and were therefore dropped. Three schemes, Ulaantolgoi in the Western Region, Tsagaan Tolgoi in the Central Region, and Kherlen Bayan-Ulaan in the Eastern Region were dropped due to social issues, specifically that the land is currently occupied by a few large companies, although in some cases it is rented to individual farm households on an annual basis, and there is no guarantee that the land will be available to for farmers following upgrading. One scheme, Ulaantolgoi in the Central Region, was dropped due to the very poor water quality, which impacts on vegetable quality and would trigger environmental concerns.

Table 1: List of Priority Irrigation Subprojects3 No Irrigation Aimag Soum Water Current Command Old Irrigation System source Crops area method Western Region 1 Tsakhiriin Govi- Jargalant/Taishir Zavkhan No 200 Sprinkler Tal Altai River cultivation 2 Yolton a Govi- Khaliun Well vegetables 30 Potable mini- Altai sprinkler 3 Erdeneburen Khovd Erdeneburen Khovd River No 2000 Sprinkler cultivation 4 Boomiin am Khovd Altai Bodonch No 300 Furrow River cultivation 5 Tsul-Ulaan Bayan- Bayannuur Khovd River No 161 Furrow Ulgii cultivation 6 Ulaan del a Bayan- Sagsai Khovd river No 400 Furrow Ulgii cultivation 7 Khuren tal Zavkhan Telmen Ider River Fodder, 195 Furrow vegetables 8 Nogoon Zavkhan Uliastai Chigestei Vegetables 64 Furrow khashaa River

3 Khoid Gol a scheme of projected 420 ha is not listed since it was agreed this would be removed due to lack of funds. However the feasibility study is still included in case priorities during the project implementation would change.

Central Region 9 Iven Selenge Sant Iven River Fodder, 240 Furrow fruit trees, vegetables 10 Okhindiin tal Selenge Zuunburen Selenge New 2170 Sprinkler a River irrigation scheme: no crops 11 Sugnugur Tuv Batsumber Sugnugur Vegetables 140 Furrow River Eastern Region 12 Dulaanii tal Khentii Kherlen Kherlen New 700 River irrigation scheme: no crops a Irrigation scheme nominated by MOFALI. Not visited during initial screening visits. Source: Agreed list by MOFALI, ADB and the Consultant

Figure 1: Location of Subprojects

Source: TA Consultant

11. Three of the prioritized irrigation schemes were defined as representative subprojects for which detailed feasibility studies and environmental baseline studies would be contracted to licensed companies during project preparation. Summaries of the results from these feasibility studies are included in this appendix and the full documents are available on request. The schemes are: (i) Boomiin Am irrigation scheme in Altai Soum of Khovd Aimag of the Western Region, an existing small scheme with a designed area of 300 ha out of a potential of 700 ha but no plan for expansion under the current project. The scheme is considered representative of small schemes that will be upgraded under the project.

(ii) Khuren Tal irrigation scheme in Telmen Soum of Zavkhan Aimag in the Western Region, an existing medium scheme with a designed area of 200 ha out of a potential 3,000 ha and with plans for expansion to 500 ha under the current project. The scheme is considered representative of medium to large schemes that will be upgraded under the project. (iii) Okhindiin Tal irrigation scheme in Zuunburen Soum of Selenge Aimag of the Central Region, a new large scheme for which 3,000 ha out of potential 12,000 ha is planned for development under the project. The scheme is considered representative of new schemes that will be developed under the project, of which there are three.

II. IRRIGATION SUBPROJECT DESIGN

A. General Design Principles

1. Climate

11. Temperature. The Mongolian climate is harsh and continental due to its unique geographical location in the center of the Eurasian continent, with high mountains and overall terrain well above sea level, and remote from the sea. The main climatic features are characterized by high seasonality with four very distinct seasons having wide temperature variation and low precipitation. Climatic variables are readily distinguished by latitudinal and altitudinal spatial distribution.

12. The annual mean air temperature is about -4oC in the Altai, Khangai, Khentei and Khuvsgol mountain ranges, -6 oC to 8oC in the depressions between mountain ranges, and within big river valleys, 2oC in the steppe-desert region and 6oC in the southern area. The warmest point is Ekhiingol where annual mean air temperature is 8.5oC (Figure 2).

Figure 2: Spatial Distribution of Annual Mean Temperature, 1961-1990

Source: Munkhbat, 2014. Current climate in Mongolia.

13. The warmest month is July when mean temperature is slightly less than 15oС in Altai, Khangai, Khuvsgol and Khentei mountain ranges, 15 oС to 20oС in the Great Lake depressions, in Altai, Khangai and Khovsgol mountain valleys and in Orkhon-Selenge river basins. It is 20 oС to 25oС in the eastern steppe and southern Gobi and desert regions. The highest air temperature recorded was 44.0oC (Darkhan city, 24 July 1999).

14. Precipitation. Mongolia has arid and semi-arid climate regions, where precipitation is generally low. Annual precipitation can be in the 300 mm to 400 mm per year range in the Khangai, Khuvsgol and Khentei mountains of the Central Region, and similar in the Khalkh river basin of the Eastern Region, from 250 mm to 300 mm per year in the Mongol Altai and forest- steppe; from 150 mm to 250 mm across the steppe and 50 to 150 mm in the Gobi and Desert

Region. On the southern inner side of the Altai Mountains, annual precipitation is less than 55 mm per year.

15. Spatial distribution of precipitation in Mongolia is very specific due to the varied landscape and altitude. Typically, precipitation decreases from north to south and from east to west. However, the altitudinal; variation significantly influences the spatial distribution of precipitation (Figure 3).

Figure 3: Spatial Distribution of Annual Precipitation, 1961-1990

Source: Munkhbat, 2014. Current climate in Mongolia

16. About 85% of total precipitation falls between April and September, and 50% to 60% of that usually falls in July and August in the subproject area.

17. Generally, precipitation is low but with high intensity – i.e. heavy storms of short duration. Since systematic, instrumental observations started in 1940, the highest maximum one-day rainfall was observed at Dalanzadgad, with 138 mm falling on 5 August 1956. The highest rainfall intensity records are in the range of 40 mm to 65 mm per hour.

18. Wind. Even though the mean wind speed for the growing months are moderate ranging from 1.2 to 4.1 m/s, the maximum wind speed can reach 30 m/s once a year. The number of days when wind speed exceeded 10 m/s has increased by 15 to 60 days over the last 25 to 50 years in the subproject area. The dominant winds and direction vary across the different subproject areas.

19. Sunshine. Total sunshine duration is about 230 to 260 days (2,600 hours to 3,300 hours) per year. Consequently, overall solar energy per year and particularly for the growing season is high.

20. Agro-climate transitions. When describing agro-climatic resources, special attention is paid to the growing season. The growing season is the period of a year when plant growth and active development under given climatic conditions is possible. The temperature at the beginning and end of crop growth is taken as the climatological characteristic that defines the growing

8 season. As described in the Mongolia agro-climate reference book4 for Mongolia and territory with a temperate climate, the growing season corresponds to the time period within a calendar year when the mean daily air temperature exceeds 10oC. The beginning of the late spring crop sowing corresponds to when damaging frosts cease and the daily mean temperature transitions above 10oC. Similarly, the end of the crop growth/production period with harvest coincides with when damaging frosts start and the mean daily air temperature drops below 10 oC,

21. The annual damaging frost-free period is generally quite short, at about 120 days. The cumulative temperature through the growing season in Mongolia ranges from 1800 to 3200ºС which is insufficient to support the production of many heat-tolerant crops5. The climate change study under this project shows that over the period from 1996 to 2018, significant climatic change has occurred in many of the subproject regions, with some positive benefits for agro-climatic characteristics. Over the study period, the growing season length has increased by about 10 to 25 days depending on the subproject region because the air temperature transition to above 10oC comes earlier in the spring and falls below 10oC later in the autumn. This has led to an increase in accumulated temperature to support a longer crop growth season, with more frost-free days, thereby favoring increased crop growth and production.

22. Climate change scenarios. During preparation of Third National Communication of Mongolia to UNFCCC6 climate change projection assessment was conducted for different greenhouse gas (GHG) emissions scenarios known as Representative Concentration Pathways (RCPs) developed for the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR5). Future projection of summer temperature and precipitation over Mongolia is estimated using the ensemble mean of 10 global climatic models (GCMs) from 2016 to 2100 under high (RCP8.5), mid (RCP4.5) and low (RCP2.6) GHG emissions scenarios. For this study, the RCP8.5 extreme case scenario that represents the highest levels of emissions with the most significant climate change impact, has been adopted, to avoid potential risks that lower emission scenarios, especially for water resources availability, may fail to cover.

23. The usual timeframes adopted for climate change assessment are: i) the previous 65 years from 1950 to 2015; ii) the near-term future from 2016 to 2035; iii) the mid-term future 2036 to 2065, and iv) the long-term future from 2081 to 2100. The design life of the irrigation scheme infrastructure would push into the mid-term timeframe, whilst most structures (lining, control gates, weirs, concrete works etc.), can, if installed and maintained to good standard, be expected to still be substantially functional into the long-term scenario. In terms of irrigation equipment functionality and performance, the more realistic projections would align with economic appraisal for the subprojects into the mid-term future. Also, as irrigation activities only occur through the warm/summer season, projections are made in relation to the summer season growth months from May to September.

24. Temperature projections. Summer temperatures are projected to increase by 1oC, 2.0o to 2.25oC, and 4.25o to 4.5oC in the Western region by 2035, 2065 and 2100 respectively, by 1oC, 2.0oC, and 4.25o to 4.5oC in the Central region respectively, and by 1oC, 2.25oC, and 4.25oC respectively in the Eastern Region (Figure 4).

4 Jambaajamts B. 1988. Mongolia climate and agro-climate reference book. Ulaanbaatar. 271p. 5 Jambaajamts B. 1988. Mongolia climate and agro-climate reference book. Ulaanbaatar. 271p. 6 MET, 2018. Mongolia Third National Communication of Mongolia to UNFCCC

Figure 4: Projected Summer Temperature with High Emission Scenario

Source: Ministry of Environment and Tourism, 2018. Third National Communication of Mongolia.

25. Precipitation projections. Precipitation in all subproject areas is projected to decrease by about 10% through to 2035 and decrease by a further 10% in most parts of the Central Region by 2065 (Figure 5). Conversely, the modelling indicates that by 2065, precipitation in the Western and Eastern Regions is projected to then increase by 10% from 2035 through 2065.

Figure 5: Projected Summer Precipitation with High Emission Scenario

Source: MET, 2018. Third National Communication of Mongolia

26. On the basis of this nationwide and regional assessment of likely climate change impacts through to 2065, further discussion on individual subproject areas has not been undertaken, as the climate change projections are generally the same for all of them.

27. The increased temperature would have positive impacts on agriculture production as the heat needed for plants and the number of frost-free days is projected to increase. Therefore, the current trend for any increased temperature and increased precipitation will bring positive impacts for crop production in Mongolia as the growing season is shot. On other hand, the number of hot days above 25oC, and days with high wind will impact negatively with increased evapotranspiration, increased risk for more severe soil erosion and more rapid depletion of soil moisture. However further increases to temperature and any decrease in precipitation increases the need for irrigation to sustain crops and increase production under more adverse climatic impacts.

28. Water Resources Scenarios: The impacts on water resources with climate change has been evaluated under 24 different hypothetical climate change scenarios. The impact of precipitation variance (+/- 20%) and temperature variance (from 0 to +5oC) sensitivity for source river flows has been considered for each subproject, and is described in the respective subproject feasibility study. Where available, river flow data for the period 1980 to 2010 or later have been used to establish the current baseline condition for climate change impacts assessment scenarios in the respective subproject areas.

2. Water Resources and Quality Assessment

a. Current

29. The main water source for the 12 identified priority irrigation schemes is surface water, mostly from the main national rivers and larger tributary streams. Rivers in Mongolia are divided into 29 water management basins and the irrigation scheme subprojects are located in 10 of these river basins. Details on each subproject, by aimag, soum and their respective water source river are given in Table 1. The location of the schemes across Mongolia is shown in Figure 6.

Figure 6: Irrigation Subprojects and River Basins

Source: TA Consultant

30. Time series data on water resources is available for the 12 irrigation schemes, with river discharge observations at hydrological gauging stations located mostly just upstream of the irrigation scheme headworks. The flow data time series used varies, the longest runs from 1959 to 2017, the shortest from 1999 to 2017. However, there is currently no available hydrological data for the Khusheet river for KhoidgoI irrigation scheme; the Ust-Chachran river for Yolton irrigation scheme; and the Iven River for Iven Gol irrigation scheme. As these rivers have no established gauging stations, some initial control measurements were made on these three rivers during consultant field surveys. Long-term water resources data for the irrigation schemes are given in Table 3

31. Environmental flow. After the severe drought at the end of the 1980s which caused many lakes to dry up, the government established strict thresholds for water abstractions from rivers and streams. This threshold depends on river flow and basin size. The updated estimates are

11 presented from the most recent publication of MET (20157) that show water withdrawal thresholds as a proportion of the long-term averages of river discharges that are allowed to be abstracted. The remaining water is considered as environmental flow to maintain aquatic as well as terrestrial ecosystems. The surface water resources available for irrigation use are based on the long-term average annual river flow of the river supplies water to sub-projects ) and the environmental flow requirements, given in Table 2.

Table 2: Permitted Water Withdrawals as Percentage of the Long-Term Average Flow River Permitted Withdrawal (%) Up- Mid- Down- stream stream stream 1 Rivers at the head water of Enisei like Guan, Khug, Sharga, 8 10 10 Shishkhed, Bus 2 Rivers in the Bulnai, Khangai and Khuvsgul mountains like Beltes, 5 10 10 Degermuren and Tes 3 Selenge, downstream from the point where the river gets the name 8 10 10 4 Rivers flow from Southern slope of the Sayan mountain like Uur, 5 10 10 uilgana, Arig and river inflow into Khuvsgul lake 5 Eg 5 10 10 6 Rivers flow from west and north-western slope of the Khangai 5 8 10 mountain like the Bogd, Chigestei, Ider 7 River flow from northern slope of the Khangai mountain like the 5 10 10 Orkhon, Chuluut, Terkh, Tamir, Khaui 8 River flow from southern and south-western slope of the Khangai 5 10 5 mountain like the Zavkhan, Badrag, Zag, Tsagaanuruut, Ulziit, Tui, 9 Taats, Ongi, Ar-aguit 2 3 - 10 River flow from the Khentii mountain like the Eree, Tsukh, Onon, Balj, 8 10 10 Kurkh, Barkh 11 Elz, and river in Mongolian north steppe 12 River flow from southern and south-western slope of the Khentii 5 10 10 mountain like the Tuul, Kharaa, Sharyin 13 River flow from southern and south-eastern slope of the Khentii 5 10 - mountain like the Kherlen, Gal 14 Khalkhgol - 5 10 15 River flow from eastern slope of the Mongol Altai mountain like the 3 5 5 Kharkhiraa, Turgen, Baruunturuun, Sagil, Torkhilog, Chigj, Namir, Zuil 16 River flow from northern slope of the Mongol Altai mountain like the 3 5 5 Khovd, Tsenkher 17 River flow from southern slope of the Mongol Altai mountain like 5 3 18 Rivers in the northern and southern depression of Gobi-Altai mountain 3 5 0 Source: MEGDT, 2015. Surface water regime and resources. (Editor: G. Davaa). Ulaanbaatar. Admon publishing

7 MEGDT, 2015. Surface water regime and resources.(Editor:G.Davaa). Ulaanbaatar. Admon publishing

Table 3: Data Availability No Irrigation Water source Gauging River flows Environmental System (River) station (m3/s) flow (m3/s) mean max min Western Region 1 Tsakhiriin Tal Zavkhan Taishir 7.19 86.9 0.11 6.47 2 Yolton Ustchachranga No gauging 0.56 1.64 0.38 0.54 3 Erdeneburen Khovd Bayannuur 61.9 361.0 23.9 55.7 and Myangad 4 Boomiin am Bodonch Altai 1.29 14.3 0.21 1.30 5 Khoid gol Khushuut No gauging 0.52 1.22 0.43 0.48 6 Tsul-Ulaan Khovd Bayannuur 63.1 358.3 26.4 56.8 7 Ulaan del Sagsai Buyant 15.1 112.0 8.11 13.6

8 Ulaantolgoi Kharkhiraa and Tarialan springs 9 Khuren tal Ider Ider 5.11 48.9 1.01 4.80

10 Nogoon Chigestei Ulistai 3.89 45.4 0.25 3.69 khashaa Central Region 11 Tsagaan tolgoi Orkhon Orkhon 12 Iven Iven No gauging 0.54 1.18 0.17 0.49 13 Okhindiin tal Selenge Zuunburen 242.4 2465.0 114.0 218.1 14 Sugnugur Sugnugur Sugnugur 1.73 16.8 0.34 1.64 15 Ulaantolgoi Khangal Jargalant Eastern Region 16 Dulaanii tal Kherlen Underkhaan 20.0 246.0 4.1 18.0 17 Kherlen Bayan- Kherlen Baganuur Ulaan Source: Consultant’s estimates

32. For normal and above average years flow in the river is far above the indicated environmental-flow requirements, and irrigation demand can be easily met. For extremely dry years (i.e. low precipitation/low runoff), the renewable water resources available for reliable irrigation may be insufficient to meet the irrigation water demand, but this is rare and mitigation measures are possible. A more detailed analysis of the river flows and irrigation requirement is presented in the feasibility studies.

33. Water quality. Irrigation and drainage are human impacts on the natural hydrological cycle in a river basin and depending on the scale of water use relative to the seasonal river flow, will vary in significance and potentially influence the movement of salts and various chemicals in soil and water. Unchecked irrigation, drainage and runoff can potentially adversely impact the water quality in rivers and streams. It will be critical to cautiously manage irrigation practice in conjunction with other agriculture inputs to manage adverse impacts on river water quality, the project design takes this into account. Using more advanced and modern irrigation application and management practices in the subproject areas will mitigate the risks for adverse consequences on streams and rivers.

34. Irrigation water enters directly the food chain it is used for the preparation of food, for recreation, for public water supply and even for drinking purposes. Therefore, many new

13 standards require the quality of the irrigation water as high as the quality of drinking water. Below is given the standard for irrigation and drainage water contributed water quality for agriculture.8

Table 4: Normal Range of Major Ions in Irrigation Water Water parameter Symbol Unit Normal range in irrigation water Sodium Adsorption Ratio SAR mEg/l 0-15 Calcium Ca2+ mEg/l 0-20 Magnesium Mg2+ mEg/l 0-5 Bicarbonate HCO3 mEg/l 0-10 Chloride Cl- mEg/l 0-30 Sodium Na+ mEg/l 0-40 Sulphate SO4 mEg/l 0-20 mEg/l = milliequivalents per liter Source: MNS irrigation systems O 16075: 2018. Guidelines for treated wastewater use for irrigation projects

35. Soil salinity. Salinization is the process of accumulation of salts in soils and is favoured by low leaching rates. Leaching rates are dependent on the water retention capacity of the soil, the hydraulic conductivity, the amount of precipitation and the irrigation water applied, as well as evapotranspiration. For the same rates of precipitation and evapotranspiration in a sandy soil, more water will move below the root zone than in a clayey soil. Preventing salt accumulation in clay and low-permeability soils is more difficult. Drainage is another important factor regarding salinization, as the dissolved salts have to be leached from the root zone9.

36. According the soil analysis the soils in the command area of the sub-projects are low to medium salinity (Table 1 of Annex 2).

37. The water salinity is caused by a range of salts made up of cations such as sodium, calcium and magnesium and anions such as chlorides, bicarbonates and carbonates. Thus the water quality of the water sources are presented by these parameters and concentration of these ions are well bellow the higher limit (Table 4) which proves the low salinity of the water.

38. Calcium and bicarbonates are the dominant ions in most of the rivers of Mongolia. The overall concentration of ions in rivers of the Basin is relatively low. In a vast majority of the rivers the order of abundance of cations is Ca2+ > Na-/K- > Mg2+ (Na- and K- ions can be dominant during - 2- - low water periods) and the order of abundance of anions is HCO3 > SO4 > Cl (even though concentrations of chloride can exceed the concentrations of sulphate). These ionic distributions for cations and anions are typical for pristine rivers and provide an indicator of the good condition of the rivers10.

39. The adsorbed ion and electrolyte concentration are the main causes affecting soil structure. It is customary, while examining the connection between cation composition in the soil solution and its hydraulic properties, to refer to the concentration ratios of sodium, calcium, and magnesium (which are the most common cations in the irrigation water and the soil) rather than the absolute concentration of sodium. Thus, the Sodium Adsorption Ratio (SAR) is one of the important measures for irrigation water requirement in addition to individual ions concentration 2+ + 2+ and calculated from the Ca , Na , and Mg reported in mel/l. The “sodium adsorption ratio” has been determined as follows:

8 MNS irrigation systems O 16075: 2018. Guidelines for treated wastewater use for irrigation projects. 9 MNS 16075-2018: Irrigation systems. Guidelines for treated wastewater use for irrigation projects 10 Batimaa P. 1998. Water chemistry and quality of the rivers in Mongolia. Ph.D. Thesis. Ulaanbaatar.

(Na) 푆퐴푅 = 1 √ (퐶푎 + 푀푔) 40. A threshold value for each combination2 of electrolyte and SAR is 15mEq/l. According to the chemical analysis for the last 6 years of rivers water, the concentrations of the SAR do not exceed 2.0 mEq/l.

Water quality index. River water quality in Mongolia is monitored at more than 160 gauging stations on about 120 rivers. The Water Quality Index11 (WQI) used in Mongolia is a simplified expression for a complex combination of five polluting parameters: (i) ammonium-nitrogen (NH4- N); (ii) nitrate-nitrogen (NO3-N); (iii) phosphate-phosphorous (PO4-P); (iv) permanganate value; and (v) suspended solids and serves as a measure for water quality. It is estimated by the following equation:

퐶푖 ∑푖 ( ) 푃푙푖 푊푄퐼 = Where, 푛 Ci is concentration of the pollutant, Pli is the maximum permissible level of the pollutant in accordance with the MNS 4586-98, and n is the total number of pollutants. The water quality of river is then classified based on WQI values, as shown in Table 5. below.

Table 5: Water Quality Classification Water quality Classification Water Quality Index classification I Very clean ≤0.3 II Clean 0.1-0.89 III Moderately polluted 0.90-2.49 IV Polluted 2.50-3.99 V Highly polluted 4.00-5.99 VI Extremely polluted ≥6.0 Source: MNE, 1998. Water quality monitoring guideline

41. Details of water chemistry and water quality of the rivers are presented under each subproject.

42.International Rivers. Two projects, Okhindin Tal and Ulaani Tal withdraw water from the Selenge and Kherlen rivers which are shared water with the Russian Federation (RF) and Peoples Republic of China (PRC) respectively. The article 7 of the transboudary agreement between Mongolia and RF and article 9 the transboudary agreement between Mongolia and PRC states that “any information in this agreement does not have to be shared with other”12,thus there is no need for any notification. The design of these projects took into consideration both the downstream transborder obligations as well as the potential downstream impacts. It was verified that the

11 MNE, 1998. Water quality monitoring guideline. 12 Discussion with MET

15 withdrawals leave sufficient water in the river as irrigation water requirement estimated to meet the environmental flow requirement.. Comparison with the pre-project conditions of existing upgraded irrigation areas indicate that water saving infrastructure, equipment, and management practices will actually reduce overall withdrawals. For the one new project it was verified that international agreements are honored and that withdrawals have a minimal impact on water flows.

43. Water quality protection measures will be taken through the reduction of agrochemical use effectively minimizing non-point source pollution, while waterlogging and salinization of the soil are avoided through appropriate drainage systems. Farmers will be trained in sustainably operating the new and modernized schemes.

b. With Project

44. The project aims to upgrade and modernize a number of existing irrigation systems in Mongolia that have fallen into disrepair. The functional deterioration for some of these schemes is substantial, to the extent that virtually all-new schemes have to be designed and built. The work required includes: (i) upgrading and/or reforming intake headworks and associated water storage and sediment management facilities; (ii) redevelopment of secure main and distributary canals and/or pipes with gated flow control structures/valves; and (iii) including the Community Grower Groups in planning and field water distribution and application systems (variously surface basin, furrow, sprinkler and/or drip systems) appropriate to the crops and command areas to be supported. Wherever feasible, use will be made of the existing infrastructure, with or without structural upgrade, to improve overall water flow and distribution management to the command areas. In the main, to secure water use efficiency in keeping with modernization, most irrigation system upgrades will be a transition to sprinkler, drip or combined sprinkler/drip systems, with/without some small-scale specialist vegetable greenhouses.

45. The objective will be to maximize the productivity of water and the areas to be irrigated, within the constraints of available seasonal water resources. If needed and possible within the available water resources, existing and/or new storage capacity will be included to store access water and facilitate improved access to water in accordance with crop water demand.. This would be done in conjunction with upgrading headworks, canals, flow control structures and field distribution and application systems to lift water use efficiency (conveyance and application) throughout the scheme. In general, this could mean improving current water use efficiency from less than 50% to perhaps greater than 80%.13 Whilst under surface application overall water use efficiency may remain at or below 60%, by converting irrigation areas to sprinkler and drip systems, potential water use efficiency will be substantially improved with better than 80% water use (conveyance plus application) efficiency.

46. In accordance with modern technology and practice, irrigation system reconfiguration and upgrading are premised on matching water supply to crop water demand, net at the field and gross at the irrigation scheme intake to cover for all projected conveyance and application losses that can occur with the adopted irrigation systems. The design principle to be adopted is to have access to water so that optimal root zone moisture regime can be maintained (nominally between 30% and 85%) for the various crops, with irrigation scheduling on a flexible basis to adapt to climate changes, and particularly maximizing the beneficial value of any rainfall. However, for excess rainfall, and to protect against runoff from hills and mountains adjacent to the irrigation scheme, consideration is

13 There are no available data on current irrigation schemes water use efficiency, and most irrigation is supplemental to rainfed agriculture. In general, most surface irrigation systems in poor condition would struggle to meet a 50% water use efficiency, whereas systems in good condition (upgraded/modernized) should be capable of reaching 60% efficiency or better, and certainly much higher if utilizing piped conveyance with controlled sprinkler or drip irrigation.

16 given to managing natural runoff towards, around or through the scheme, and for evacuating from the scheme area. This will include the provision of protection banks (or strengthening of existing banks), and improvements to any natural water courses or provision of drains through or around the scheme area. If and where beneficial, consideration is also given to catching and holding some runoff behind protection banks, so it can be accessed to supplement the irrigation water supply to the scheme.

47. To mitigate against headworks and main canal losses, it is proposed that relevant gated structures are incorporated to moderate flow velocities and maintain water levels at bifurcations into distributary canals and at outlets to field channels. As many canals are constructed through fragile sand/silt/gravel soils, they also need to be lined to mitigate the risk of erosion. Lined canals can handle water moving at higher velocity (up to 1.5 m/s in steeper terrain) whereas unlined earth canals are generally limited to a maximum of 0.8 m/s in easily erodible materials. The use of pipes can be considered for smaller flows, with higher velocities, but pipes are susceptible to frost damage if not properly drained ahead of the extended winter period. Pipes should also be graded so they can, when required, be freely drained.

48. Not all canals are located in steep terrain, where constraining flow velocity and erosion is important. In flatter terrain, the problem can be sediment deposition and deep percolation. To reduce deep percolation lining is needed, for reduction of sedimentation the use of some off-stream settlement sections that can be readily cleaned post each irrigation season should be included where sediment is likely to be recurrent and problematic.

49. The sediment management can also be included with the use of buffer storage tanks (if no dam and storage is available on the river/stream) to feed clean water to the irrigation intake. Whilst acting as a settlement basin, these storages would also fill when streamflow is plentiful, holding water until it is required in the irrigation system to meet crop water demand. Such storages should be designed to have ‘dead’ storage volume in which sediment is collected, and from which it is periodically removed (yearly as part of annual maintenance).

50. To the extent possible, canal and headworks intakes should be located on stable river sections, where flow from the river to the intake (gravity or pumped) is secure and can be maintained with minimal annual maintenance. Where a stable river section is absent, then the development of a stable section, with an in-river headed pool would be advantageous, and if the headworks intake is to be relocated for stability and security of flow diversion, then selection of a suitable river section where a small permanent pool can be established should be identified. The construction of a suitable and durable low-level barrier across the river may be required. Headworks and other structures, including pipes, frames and gate plates, should be designed and manufactured with high quality steel of sufficient thickness and strength that they can withstand both ice formation forces without distortion, and potential wear from sediment laden water.

c. With Climate Change

51. Climate change has for most schemes led to a reduction in available runoff from the source rivers and springs, and there is a continuing trend for further reductions signaled into the future. Whilst this will reduce the quantum of water available for effective irrigation, the upgrading and modernization should raise overall water use efficiency within the scheme, which will partly or even fully offset any decline in usable water volume. With some judicial water management, with storage of excess river water when available, or capture of rainfall runoff, it is expected that existing crop areas can be maintained or even increased. The major action needed overcome this prevalent downward trend in natural water supply will be to adopt diversified cropping with effective irrigation

17 practice to better match the water supply to the actual crop needs. The traditional practice of irrigating to a firm schedule and quantity X times per year does not always maximize the benefits from rainfall and can allow short term waterlogging to occur to the detriment of some crops.

52. Increasing temperature is also impacting water availability in the early spring, as snow melt, ice melt and glacier melt starts earlier, and the peak spring flow comes from 1 to 2 weeks earlier. This leads to a longer period between spring melt flows and the onset of summer warmth and subsequent rains (also sometimes reduced in occurrence and quantity), which can reduce potential water availability and lead to stress for established crops. To overcome this trend, additional consideration is given to enhancing irrigation scheme water storage, whether on-stream with existing dams, or off-stream with upgraded storage tanks, to ensure the risk for early summer crop stress can be minimized.

53. Irrigation operating principles need to be flexible, and this is made possible if there is a headworks reservoir (dam), or the main canal incorporates some buffer storage (on-stream or off- stream settlement basins/tanks) where water can be directed or held back, should climate changes occur. Similarly, such storages can provide the option to release additional water to susceptible crops during any extended drought periods. In the interests of managing water effectively, all schemes ideally will have some buffer storage capacity, whether necessary or not for sediment management.

3. Irrigation Water Requirement

a. Crop Water Requirement

54. The traditional Mongolian approach to determining irrigation (or crop) water requirements has been to adhere to established norms. The ‘norm’ initially was developed in 1982 and approved by the then Minister of Water. They were revised in 1995 and approved by the then Minister of Nature and Environment, and were most recently revised again in 201514. This ‘norm’ is applied for use in all sectors where water is used, and sets the standard for water utilization ‘norm’ per unit of production.

55. In previous agricultural planning, irrigation schedules and water delivery rates (volume/ha) were determined for the different crops grown across the five climatic/irrigation zones of Mongolia. The norms also show the potential for variance in volume of water required per growing season and per irrigation depending on the climatic conditions (high precipitation (wet) or low precipitation (dry)). For crop water requirement, the water utilization norm described in Table 6 is used.

Table 6: Crop Water Requirement Norm (Unit m3/ha) No Crop Region Altai-Khangai Central Western NorthernGobi Southern Gobi 1 Cereals 1,800-2,000 2,000-2,400 2,500-2,800 2,600-3,000 4,100-4,400 2 Corn 1,800-2,000 2,600-2,900 2,800-3,100 2,900-3,200 3,200-3,600 3 Fodder 2,400-2,900 3,000-3,300 3,500-4,000 3,600-4,100 3,800-4,200 4 Potatoes 2,000-2,400 2,500-3,000 3,100-3,400 3,200-3,600 4,000-4,500 5 Vegetable 2,200-2,500 2,600-3,200 3,500-3,900 3,600-4,000 n.a. n.a. = not available. Notes: The range depends on the precipitation in a particular year To convert to the depth in mm, divide the volumes by 10.

14 Ministry of Environment, Green Development and Tourism. Minister’ order No A/301 dated on 30 July 2015. Water use norm for unit product and service. www.mne.mn

Actual irrigation volumes depend on irrigation systems efficiency. Source: Ministry of Environment, Green Development and Tourism. 2015. Ministers order No A/301. Water use norm for unit product and service. www.mne.mn.

56. Crops need access to water from the soil within their root zone – which for the crops under consideration for the subprojects is typically in the range of 400 to 600 mm depth. To optimize crop growth, root zone moisture needs to be maintained between full capacity (soil saturation) and full depletion (taken as 30% remaining soil moisture content before crop water stress begins). The water holding capacity of soils in the scheme areas – sandy loams, with some gravel content – sits between 0% (dry) to 15% (saturated) whilst the usable root zone soil moisture ranges from 30% (depleted) to 85% (full capacity). Thus, in 500 mm depth of soil. this equates to (500 x 0.15 x 85%) minus (500 x 0.15 x 30%) = 41.25 mm of available water for the crop.

57. For many vegetables, the root zone depth is about 400 mm, so the maximum available water depth from a full irrigation is about 33 mm. To provide operational flexibility, without always testing the limits, a 25 mm water depth replenishment per irrigation cycle has been adopted. This may mean there is need for more irrigation cycles through the season, but in the event of any interruption to operations, there is a cushion for delay of about one day before the crop could incur stress. It is also assumed that minimal applied water is wasted each cycle through deep percolation as a result of overwatering, by using sprinkler and/or drip irrigation, which also ensures better overall uniformity of irrigation – something not easily secured with surface (flood) irrigation on relatively high permeability soils.

58. The local climate in April does not favor cultivation (i.e. it is insufficiently warm or free of snow), so irrigation will be undertaken from May through to August. This allows the snowmelt runoff to pass before irrigation can start, unless the system includes some buffer storage which can be filled during this time in readiness for the start of irrigation in May.

59. As compared to current surface irrigation, with an estimated average 36% overall efficiency, the upgraded and modernized irrigation systems are expected to substantially reduce future water requirements, with an improved operational efficiency in excess of 70% with no surface irrigation application, but some continued use of main canal supply up to the sprinkler or drip systems. All upgraded main and distributary canals will be lined, but bar any limited retention of field canals will be unlined. Modernized schemes will use overhead sprinklers, with some smaller area drip systems for potato/vegetable areas and any planned windbreaks. Whilst the overall irrigation systems layout and core infrastructure will remain the same, new irrigation equipment will be used to lift irrigation application efficiency and improve overall crop water application uniformity. Other key measures proposed for the new irrigation works to improve overall operational performance and water management efficiency will include lining (impermeable geomembrane sheet overlain with concrete slabs) for the main and distributary canals and improving overall flow control within the system to direct water to sprinkler and drip systems.

b. Conveyance and Application Efficiency

60. There is no background data on irrigation system efficiencies in Mongolia, but based on the current condition of systems, with limited if any effective water management facilities in place, overall water use efficiency is estimated to be quite low (36%, Table 7 and Table 8; 0.6*0.6). For pumped and piped sprinkler systems, and with good management, it should be possible to secure application efficiencies of up to 85% (sprinklers) to better than 90% (drip), leading to an overall efficiency above 70%. Where irrigation practice follows a fixed schedule and volume approach,

19 efficiency could be adversely impacted, so it is also planned that irrigation be undertaken in accordance with particular crop growth stage, understanding of the soil moisture profile, and with application rates/duration to ensure soil moisture management between the defined limits. Consequently, with irrigation systems upgrades and modernization, and the adoption of soil moisture monitoring practice, improved system operations and water use management should bring substantial water use efficiency gains. The assessment for maximizing the cropped land for a scheme should also be based on the assumption that reliable water supply will be available for diversion, at least 3 years in 4 (75% reliability).

61. The conveyance system handles all diverted water at the headworks, through any sediment basin(s) and storage tank(s), and through the main and distributary canals. There are inevitable evaporation losses in open canal and storage systems, which relate to the overall surface area of the storages together with the canals supply to field outlets. Losses also occur through the wetted perimeter of the canals, which can be reduced substantially with good quality canal lining. Operational losses occur when water cannot be retained within the canal network if not being used directly for irrigation (leakage and spills, escape flows). Irrigation design must aim, given the scarcity of water for some of the year, to minimize overall conveyance losses. Effective flow control (gated structures), lined canals with smaller overall section at steepest viable gradient, or pipes (smaller flows) are the obvious ways to minimize any critical water loss. In the case of storages, the better options are to limit overall surface area wherever possible, with deeper storage depth, to line the storage if natural seepage could be large, and if evaporative loss is significant, consider some form of cover or sealant on the water surface. In Mongolia, the only possible or viable options are for deeper storage tanks with possibly some form of lining – clay, concrete or plastic sheeting impermeable materials (geomembranes and/or plastic or rubber lining). .

62. Water application for crop growth across the land is much more variable depending on area to be irrigated and method of water application. Surface irrigation (basin, furrow) is generally much more difficult to control for uniformity (depth and coverage) and thus is inherently inefficient to get a uniform soil moisture profile across a basin or along a furrow. The usual outcome is some areas will be overwatered (saturated soil moisture profile) whilst others will be underwatered (insufficient time for adequate soil infiltration). Thus, the tendency is for overwatering and lower actual application efficiency, with probable uneven crop growth and yield. For water sensitive crops, this can be very noticeable (e.g. potatoes, carrots, turnip), whilst for crops tolerant to water shortage, the uneven water supply may be less critical (e.g. fodder, wheat).

63. To get more uniformity of water application, sprinkler and drip systems (or even micro-spray) are more effective, and the actual flow rate and application duration can be better controlled. Thus, the soil moisture profile can be managed more effectively, and kept within the optimal bounds of non-saturation (85%) and depletion (30%). Thus, if sprinkler and/or drip can be justified, then it should be the preferred application method, especially where water is scarce and needs to be used wisely. The choice between sprinkler and drip is then often related to both crop value (higher value helps justify use of drip) and areal coverage (large areas may be prohibitive for drip systems). Sprinkler tends to be used for fodder and cereal crops, and for potatoes, cabbage and similar large area crops, drip for more specialist vegetable crops (smaller areas or greenhouses) and fruit trees. That said, there is no clear distinction that defines which system should be preferred in any given situation, though the more limited the water resource, the greater the incentive to use drip. Similarly, in greenhouse situations, where water can be more precisely targeted to the plants, then drip or micro-spray systems – ground level or overhead – are likely the best choice.

64. As there are no background data on irrigation system efficiencies in Mongolia, the FAO15 irrigation efficiency is used for this feasibility study. Table 7 shows the indicative values of the conveyance efficiency for adequately maintained canals and Table 8 shows indicative values of the field application efficiency.

Table 7: Indicative Values of Conveyance Efficiency for Adequately Maintained Canals Canal length Earthen canals, efficiency by soil type (%) Lined canal Sand Loam Clay (%) Long (>2000) 60 70 80 95 Medium (200-2000m) 70 75 85 95 Short (<200) 80 85 90 95 Source: FAO, Annex I: Irrigation efficiencies at http://www.fao.org/3/t7202e/t7202e08.htm

Table 8: Indicative Values of Field Application Efficiency Irrigation methods Field application efficiency (%) Surface irrigation (border, furrow, basin) 60 Sprinkler irrigation 75 Drip irrigation 90 Source: FAO 56,Annex I: Irrigation efficiencies at http://www.fao.org/3/t7202e/t7202e08.htm

65. Assuming all water supply is through main canals, then conveyance efficiency is taken as 95%. The field application efficiencies stated by FAO are broad averages derived from assessment of many irrigation schemes and application systems. Where modern sprinkler irrigation (e.g. lateral move, center pivot) systems are deployed, then up to 90% application efficiency is regularly claimed, where applications can be programmed and linked to soil moisture monitoring probes across the irrigated area. If it is assumed that 90% application efficiency for manufactured sprinkler equipment with electronic setting and control systems is attainable, then with the lined canals for primary water supply, and overall irrigation efficiency of 85% is possible for sprinkler systems.

66. Similarly, for drip systems (or micro sprays) which more specifically place the water to individual plant or row root zones, an effective 95%+ application efficiency is possible. Therefore, with drip/spray systems, and particularly within closed environment greenhouses, it is now possible to get overall irrigation system efficiencies higher than 90%.

67. Therefore, where sprinkler and drip systems are adopted, the water use efficiencies adopted in this study are taken to be: Sprinkler Irrigation with lined supply canals: 0.95 x 0.90 = 85% system efficiency Drip/Spray systems with lined supply canals: 0.95 x 0.95 = 90% system efficiency

68. Whilst these may be high overall system efficiencies, in Mongolia with the semi-arid climate and scarce water available, especially during May and June, there is a strong incentive for farmers, and particularly if they are pumping water, to maximize overall water use efficiency. Additionally, to more effectively manage the conveyance and distribution of water, minimizing the loss of valuable water, there will also be an incentive to adopt piped rather than canal conveyance where this is cost effective or practical to do so (i.e. securing natural pressure from an elevated source to minimize need for pumping or reduce actual pumping requirements overall).

15 Annex I: Irrigation efficiencies at (FAO 56, Brouwer et al. 1989)

c. Key Irrigation System Design Rationale

69. Irrigation method and selection rationale: After examining the typical site conditions and soil chartacteristics, it is apparent that the use of surface irrigation has significant disadvantages, due to the natural topography (moderate to steep slopes at many sites) and the high permeability of sandy loam soils with varied gravel content. In such situations, it is difficult to get uniformity of irrigation coverage, and sufficient retention of volumes that need to be applied for surface irrigation to get adequate coverage of the command areas. Therefore, the general design rationale has been to adopt sprinkler and/or drip irrigation, despite abundant water availability in some rivers, to provide improved water use efficiency, more uniform coverage, and thus better equity of water distribution between participating farmers. Even if surface type irrigation were to be retained, improved water use efficiency, much needed where water sources are constrained, would necessitate adoption of some land levelling and irrigable block formations. The high permeability soils under surface irrigation would necessitate formation of fields (blocks) with short wetting front to minimize uneven watering. Over the medium to long term, this would create issues for ensuring effective maintenance of multiple channels subject to erosion, especially if they are not lined.

70. Innovation: The use of sprinkler and drip system technology allows for the adoption of innovative approaches to achieve more effective and water use efficient crop production. In some cases (Yolton and Khoid Gol), the natural terrain and high elevation of the access point for the source water above and distant from the command area, enables, together with balancing storage, to tap the natural energy to provide pressure for the sprinkler or drip systems, thereby negating any need for power for pumping. However, some power supply (electric – solar) may still be required for driving the mobile sprinkler units, unless the natural water flow can be utilized for hydraulic power driving a small generator. These details will need to be resolved at detail design stage in conjunction with potential equipment suppliers to examine what may be possible.

71. Power for Movable Irrigation machines: For sprinkler and drip systems where the water source and terrain do not provide sufficient water operating pressure, then power supply (grid electricity if in reasonable proximity – e.g. Erdenburen, Tsakhir) or diesel generator (e.g. Tsul Ulaan or centre pivots), or else a diesel engine/water pump/hydraulic pump (lateral move systems) will be required. In each particular case, appropriate O&M procedures will have to be defined to keep all components in working order, protected through the winter, and readied for each season. The main sprinkler systems will be either self propelled Centre Pivot systems up to 100 ha each, or self propelled lateral move systems also up to about 100 ha each. Modern systems can be programmed to travel at particular rates to apply a set among of water per pass, and to recycle for the next pass within a set period. Where Centre Pivot systems are used for multiple circles, then they would require quick connection/disconnection fittings at the circle centre and a suitable narrow straight road to move or be moved sequentially between a number (up to 4) circles in a group in both directions. T. All wheels on the irrigation machine should be rotatable between the circular move position and the lateral move position, with electric or hydraulic power.

72. Sprinkler Systems Coverage and Integrated Systems: Center Pivot systems cover only 78% of the square block containing each circle. It is thereofre proposed that non-irrigated areas between the circles could be irrigated, using water in parallel from the same buried pipes feeding the center pivots to supply either suitably arranged drip or fixed pipe and riser sprinkler systems, utilized by the smaller local farmers for vegetables or other selected crops. However, these drip and/or sprinkler systems would be movable so that initial cultivation and later harvest can proceed without damaging pipes. Farmers would also need to take up and/or empty such surface pipework to protect against winter frosts. The drip systems would have their own small ouput control station, with pump and filtration systems, feeding the main supply pipes to roll out lateral lines. The

22 pipe/riser sprinklers would similarly have fixed main supply lines with hydrants to which movable sprinkler laterals (or roll up drum rain guns) could be connected.

73. Water Supply to Sprinkler/Drip System Intake: The specific details for the particular subproject irrigation systems have not been fully determined. The main water supply to the command area for most subprojects, except for Yolton and Khoid Gol, will be by open lined canal, with or without any balancing storage to provide protection against low flow periods of the water source. It is proposed that all stream to main canal intakes would be upgraded to fixed and controllable installations, to provide a stable water pool from which the canals are fed, and to also provide greater certainty and reliability for the long term operation of the systems. These pools would also provide an immediate opportunity to settle out some of the coarse sediment entrained in the river water, and at low flow periods and/or at end of the irrigation season, pre-winter, some programmed removal of sediment deposited could be implemented (yearly or every two to three years as needed). The planned intake structures, with a settlement basin and overspill weir arrangement, operating within a limited head differential range, are also proposed to help further remove sediment, which can be flushed from the structure basin on a more frequent basis as required. The aim is to minimize sediment entering the lined canal, which could be detrimental to sprinkler and drip systems. At the detailed design phase, if it is determined any additional sediment settlement facility is needed, then this could be built into a suitable section of the main canal.

74. Irrigation Operating Pressure: All sprinkler and drip systems require a certain amount of hydraulic water pressure to function as design, suitably managed with control valves and pressure regulators between a minimum to maximum value to ensure uniformity of supply. Particular pressure variance can be managed with pressure compensating emitters (drip systems) or adjustable sprinkler nozzles. Where natural available pressure is to be utilized, open canals will be replaced with closed suitably pressure rated buried pipes (PE/HDPE/PVC-O) (e.g. Yolton and Khoid Gol). For other systems, where natural pressure is not available, then pump stations will be required. If the water is conveyed by open canal to the irrigation system (sprinkler or drip) intake point, then each system would require its own power source and pump (e.g. Iven Gol, Sugnugur). If it is possible to have a fixed pump station into a buried pipe network, to the various centre pivot or lateral move sprinkler connection points, then this has been adopted (e.g. Erdeneburen). For the larger pumping stations, these may be sited on the side of a balancing storage (e.g. Erdeneburen) and have national grid supplied power. For smaller schemes, with lateral move systems, these will have their own diesel powered pump and generator on board the machine (e.g. Tsul Ulaan). Other lateral move systems, such as Tsakhir, may have a diesel generator station, and power connection linked to the water supply hose from each supply hydrant position. Again, final details for each installation will require further consideration and selection at detailed design.

75. Power Supply: To the extent possible, it is anticipated maximum use will be made of connection to the national electricity supply grid. As many of the schemes are quite close to Soums, this should be viable, and would then be managed by Soum Government. For those sites where power is not readily available, then the choice will either be to install diesel motor driven generator sets, or to select equipment which is designed for and would include its own diesel power/pump/generator unit. The latter of course are more versatile for operating from multiple positions, or for travelling independently. Apart from grid supplied installations, provision will need to be made for fuel supply and management, and arrangements will be required to ensure financing and reliable supply for the full irrigation season.

76. Pipe Management: In all cases where buried fixed pipes are used, provision must be made to drain the pipes before any severe frost occurs. Therefore, all pipes must be fitted with lowest point outlet valves, discharging to natural or formed drains. These will also help to flush any fine

23 sediment that might potentially be deposited in the supply pipes. For some of the provisional scheme designs, an indication is given as to where such drain (or scour) outlet valves will be required.

77. Filtration Systems: to protect the sprinkler and drip systems from blockage and/or undue wear with risk for algal growth, each system should include at the pump station and/or intake before the first sprinkler nozzle or drip emitter of the system, suitable filtration systems to remove any remain ing fine sediment still entrained in the water supply. The choice of filter system – sand beds, discs, ceramic or mesh – should be suitable for the particular water quality and/or irrigation system. Ideally, the selected filter systems will also be either replaceable or more likely have a backwash control facility that activates once the pressure differential across the filter exceeds a pre-set value, as determined by the irrigation equipment supplier. With good management, these filter systems can operate successfully over multiple seasons, but the manufacturers guidance should be noted to allow for any periodic maintenance or replacement between seasons. If the filtration is of sufficient quality, then the risk for blocked sprinkler nozzles and/or drip emitters is greatly reduced, and such units will then operate successfully for longer.

78. Scheme Layouts: Following assessment of the priority subprojects, it is clear that whilst many of the existing schemes have similar key features, there are also some significant differences. Some are gravity supply from water source to command area and field application, some are pumped, and others have part gravity and part pumped. In two cases there is sufficient natural pressure, through use of gravity flow pipelines, that there is no need for pumping, even when using sprinkler and/or drip systems. Similarly, the command area layouts and/or available command area to be irrigated means that different irrigation systems are required for optimized land and water use. In some cases, the original form of irrigation is still applicable, but there are no cases where surface irrigation (flood, basin, furrow) will be retained, as these are relatively water use inefficient, and are difficult to justify when water available is scarce, particularly in the hot dry summer months of May, June and into July.

79. Summary of Key Features in all Schemes: though the schemes may have varied actual flow requirements based on their command area and crops, will include: (i) a stream flow diversion and intake structure, to feed a small section main conveyance canal of varying length, which needs to be lined due to the nature of the prevalent soils for construction and the typical grade for the alignment of the canal, the lining there to protect and maintain the integrity of the canal form, which would otherwise collapse and scour when in use if unlined; (ii) a small low-level barrier and weir across the source stream (typically 3 to 5 m high, variable overall length, with a central spillway weir) to form a headwater pool that will reliably enable water to be drawn into the canal intake structure; (iii) an intake structure with sediment separating and flushing compartment, coupled with an overspill weir for ‘clean’ water to enter the lined canal, this structure equipped with two vertical lift sluice gates, manually operated, to open the intake for water diversion, and the second to enable flushing of the sediment entrapment chamber; (iv) if needed and justified due to water availability, an onstream balancing storage (varying scale), to provide a disconnect between water source flow rate and actual irrigation flow rate, which will better enable irrigation water to be supplied when needed, as compared to using water when available; (v) escape structures with automatic overspill capability, at the intake point, the end of the main canal and/or from the balancing storage, before water is taken into the distributary canal or pipe system for conveyance to the command area (field canals or pipes) and at the lower end of the command area and drains;

(vi) outlets from the distributary canal to field canals or pipes to feed the irrigation equipment (lateral move, center pivot, drip or similar systems) for particular subareas within the command area; (vii) overspill outlets or scour valves from respectively field canals/pipes or distributary canals/pipes at either end points or low points in the network, with outflow to defined drains and/or drainage pathways; (viii) outlet points (hydrants) on pipe networks to connect irrigation equipment; suspended flow filtration units on pipe systems (or settlement sections in open canals) as may be required to protect the irrigation equipment from potential blockage (sprinkler spray nozzles, drip emitters), these filter systems to have appropriate gravity driven or pumped backwash facilities with discharge to drains; (ix) installation of protective windbreaks on the windward side of command areas to provide protection from wind erosion and wind drying of the topsoil; and (x) provision of various safety protection drains and banks against overland runoff and sediment flow, around command areas, alongside and occasionally over main canals or through command areas, or from the tail of canals and pipes as required, thereby reducing the risk for damage and interruption of installed water supply and irrigation operations (Table 9).

Table 9: Number of Pump and Sprinklers, Drip in Command Area No Irrigation Irrigated Pumped Gravity No of Sprinklers Drip Scheme Area (ha) Irrigated irrigated pumps Center Lateral move 5 ha 3 ha (ha) (ha) Pivot No No No No 1 Tsakhir 200 200 No 1 6 5 2 Yolton 320 320 2 2 19 3 Erdeneburen 2000 2000 5 4 30 2 4 Boomiin Am 237 237 2 5 5 Khoid Gol 420 420 - 2 30 1 6 Tsul-Ulaan 161 161 2 2 6 1 7 Ulaandel 400 400 1 1 13 1 8 Khuren Tal 500 500 3 4 10 1 9 Nogoon 64 64 - 3 13 1 Khashaa 10 Iven Gol 240 240 - 3 8 4 11 Okhindiin Tal 2780 2780 3 23 12 Sugnugur 140 140 1 3 10 13 Dulaanii Tal 700 700 4 4 4 9 Total 8,162 7,557 605 19 42 16 142 35 Source: TA Consultant

80. Additionally, depending on topography and alignment, measures should be included to moderate flow velocity in open canals, and/or moderate natural pressure and surge in main pipelines (pressure regulating valves and/or pressure surge chambers). In general, all equipment will have a safe operating pressure range. The command area layout and alignments are designed to use natural topography change to offset pipeline friction head losses, but where the situation requires, some additional pressure modulating valves and/or pressure surge chambers may be required to safeguard the pipes under varied operating conditions. Overall flow rates in canals and pipes will vary in accordance with the water demand and the scale of the overall scheme, from as little as 0.1 m3/s up to about 1.5 m3/s. Canals, structures and pipes are therefore scaled according to requirements as shown in each of the individual subproject studies and their works quantification.

d. Leaching Requirements

81. Whilst there are some where surface saline crusts have developed when ponded water evaporates, there does not appear to be any serious or regular occurrence of salinity in any of the irrigation areas. In most areas inspected, highly permeable free draining soils with no high groundwater presence were found. No severe or detrimental salinity was observed that could generate salinity limiting crop growth and require leaching. Soil test analysis show that soil in command area of the sub-projects are generally low salinity. Soil test results are provided under each sub-projects and detailed results are in the Annex 2 and 3.

82. Given that water availability for most schemes is limiting, the intention to irrigate any saline prone areas should be discouraged. Where irrigation operations lead to any build up of salinity, then some additional irrigation could be implemented at the end of each season to flush the soil, particularly for drip irrigated fields, as salts do tend to accumulate at the edge of the wetted soil near drip emitters.

4. Main Water Supply Systems

a. Headworks

83. Detailed headworks needs for the different schemes have many similarities in purpose, but varied means to achieve water capture and controlled supply. The primary principle is to have a stable water intake and water capture, and to manage water in a canal conveyance system, with or without a balancing storage, with or without any piped conveyance, to best match the irrigation system water supply to the crop water demand pattern. Generic design of the head work with sediment flushing is shown in Figure 1.2 of Annex 1.

84. Some schemes will depend on existing on-stream dams/reservoirs (e.g. Yolton, Khoid Gol), which may require some limited rehabilitation – predominantly repairing and upgrading the water intake structures for the irrigation systems and improve overall flow control. Depending on the age and condition, some repair and/or strengthening of the dam embankment and spillway may be required to ensure long term operational safety and performance, to guarantee water for the intake. The reservoir will also over time have accrued sediment, and to restore essential balancing storage capacity, some sediment removal and disposal (use or waste) will need to be undertaken. For some schemes currently without any balancing storage, this has been adopted where it is seen to be beneficial (e.g. Sugnugur, Iven Gol) by utilizing the available topography and introducing relevant flow control measures. The opportunity to install water level sensors and solar panel powered gate or valve controls should be further investigated, especially where distance between canal intake and storage is long.

85. For schemes without any existing on-stream storage dam, more specific attention will be given to ensuring the stability of the main canal intake channel and structure and the angle of river/stream flow relative to that intake. An assessment has to be made on what if any permanent water management infrastructure could be installed and what is actually required across the river channel(s), taking into account that some river fans are braided and volatile, so there is no long- term stable river channel. It may be necessary to build some flow deflection or diversion works (hard weirs or earthen/rock embankments (or gabion walls)) to more regularly direct water to the head of the main canal intake channel. In such situations, provision will be required for annual inspections and maintenance post the flood season, so that any late season runoff and spring snow/thaw can potentially be captured.

86. Besides the main canal intake structure, which may need to be repaired/upgraded with stronger gates, an assessment will be required in respect of main canal peak flow, cross-section, grade, flow velocity and flow control (additional check and/or drop structures) and whether the canal can be secure unlined, or will need lining. For most, it is expected lining will be essential to ensure long term main canal integrity and performance. The alternative for smaller systems is to consider the use of pipes (done previously) but whilst pipes offer improved conveyance efficiency, there are increased risks for damage if water ever freezes in the pipes due to the harsh winters. Pipes can also be problematic if there is major sediment entering the system, so effective sediment exclusion (the intake structure sluice and/or settlement sections in the open channel) are an essential inclusion. Pipes must also be fitted with scour valves (at ends or in low sections) to remove sediment and allow draining for winter.

b. Balancing Storage

87. If any off-stream storage is required, then the detail arrangements will need to consider the flow direction and control infrastructure to be installed to manage the inflow/outflow from the storage, as well as any emergency outlet (escape) to ensure the safety of the storage. In conjunction with including any storage (provision will be made to accommodate and manage sediment (variable load from the river source), with facilities to collect and/or exclude from the main canal reach (special wide section), so that sediment does not cause disruption to flow capacity and management of water distribution to the command area. The use of an on-stream balancing storage can also facilitate sediment removal.

88. To match irrigation water supply to crop water demand across the command area (mixed cropping, variable demand patterns per crop), some form of balancing storage is needed, creating a pool of water from which the irrigation supply can be drawn as required, irrespective of the highly variable river/stream flow through the crop growing season, except where water in major perennial rivers is being accessed. Previously, some dams have been constructed on smaller rivers/streams, but many have deteriorated over time and need remedial works to restore their capacity and ensure safety and performance. In some cases, the spillway structures have been undermined, so any remedial work could be extensive and costly to ensure long term dam wall and storage safety. The positive aspect for these dams is that typically, the overall storage is shallow and large in area, thereby providing optimal sediment settlement/exclusion to feed clean water to the irrigation schemes – particularly beneficial for the piped systems for sprinklers or drip irrigation.

c. Main and Secondary Delivery Systems

89. The main canal brings water from the intake location of the major water supply river or stream. Once at the irrigated command area, with various crop and watering requirements, there is need to have appropriate structures and bifurcation of flow into smaller distributary (secondary) and field (tertiary) canals (or pipes), subject to magnitude of flow and the proposed in-field water application systems (flood, furrow, basin, sprinkler, drip). The adoption of fixed or movable sprinkler or drip systems will reduce the number and extent of open canals to be used, leading to in general, higher overall conveyance efficiency. Similarly, with more specifically controlled water application through pipes, sprinklers and/or drip systems, field application efficiencies would also be higher. Given the serious constraints to water availability, the adoption of water conveyance and distributary systems that maximize water use efficiency should be favored, though based on crop economics, may not always be justified.

90. The diversion of water from the main canal, through controllable structures, into secondary and tertiary canal/pipe networks will subdivide the command area into manageable units suitable

27 for in-field O&M by WUGs. Depending on the size of each secondary or tertiary command area unit, there may be value to incorporate some localized storage facility, which could also double as a sediment settlement pond – particularly beneficial for the sprinkler and especially drip irrigation systems to be used. Even if they have primary source filtration systems, futher filtration is needed to remove fine suspended sediment, and not the medium to coarse sediment that may be entrained typically in open canal flow. If piped systems are to be adopted, feeding to the sprinkler/drip system pumps and filtration systems, then this will negate or significantly reduced the need for field distribution canals, and in the case of larger sprinkler systems, minimize the need for secondary canals – as the main supply pumps and pipes to such water distribution equipment could draw from the main canal, from a storage, or from supplementary on-farm water storage tanks. Actual needs will depend on the size of the irrigation systems and its particular layout.

91. For open canals, and well-designed structures with strong well-built flow control gates, the harsh winter, when open water freezes, should not present major O&M problems. The use of lining in canals could be at risk from frost heave, so an impermeable membrane is planned as part of the lining to prevent canal water seeping into the banks and bed of the canals. Without this, there is a high risk that lined canals will require frequent maintenance to replace dislodged lining slabs. Unprotected flexible lining can adjust more readily to frost heave without undue risk of damage. Generally, any rubber or geo-membrane lining installed without coverage by concrete slabs will tend to ripple with the flow of water, so a suitable arrangement is needed to prevent such membranes moving, wearing and fracturing. To hold them in place, the choice may be between using full slab coverage or suitable placement of concrete holding beams – longitudinally and transversely, together with proper turn in and burial of the membrane edge at the top of the bank..

92. The alternative, for reduced maintenance and conservation of water, is to use pipes in lieu of open canals, at least until such use becomes cost prohibitive due to the high volumes of irrigation water required, when larger lined canals are more cost effective. Today, manufacturing techniques, together with on-site installation technology, means that low weight and cheaper HDPE or PVC-O pipes can be used (pressure graded as needed) to provide a seamless conveyance conduit from water source to command area. With some flexibility in the pipe wall material, these pipes can follow the natural ground contour and be buried sufficiently deep to minimize potential frost risks. Annual O&M should include draining all pipes before the more severe winter sets in. Similarly, as well as using large diameter pipes to substitute for main open canals (in lieu of graded construction, with lining), smaller HDPE or PVC-O pipes can be used to supply field outlets and/or to sprinkler or drip subsystems. With good quality construction, where pipes are placed out of harm below ground, a major saving in routine and periodic maintenance, with sound operations practice, can be secured. Pipes will also save all (or a very high percentage) of the water in conveyance, thereby eliminating the typical 15 to 25% water losses that occur through open canals.

d. Field Distribution Systems

93. Many schemes still have the remains or even functional field distribution canals. For many upgraded schemes, the modernized irrigation system to be used will negate any need to update these works. Many field channels could be replaced by pipes for new sprinkler and/or drip schemes, but if surface irrigation is retained, then it would be up to CGG to undertake the required reconstruction/reforming of the in-field canals. If there is an identified need for some simple flow control structures (gated box outlets) then these could be pre-cast to a standard design and supplied to each site for rapid installation.

94. All field canals should preferably be aligned along the contour and be banked so as to maintain a steady water level, from which farmers can withdraw water to suit their requirements.

They can then be a readily available water source, fed from the major canal network, without recourse to excess flow and overspill.

e. Provision of Livestock Water Points and any Other Users

95. There are no definite requirements outlined to provide livestock water or supplies for other users. If such cases are identified, then these can be incorporated, subject to available water. Soums will need to identify where and how much water is required, and then a suitable controlled outlet can be provided to a standard design with or without any other canal, pipe and water storage (tank, trough, small pond) as relevant. There may also be opportunity to capture rainfall runoff, overspill water from escapes, and pipe water releases in drains/ponds adjacent to the command area.

f. Winter low temperature damage prevention

96. Open canals, pipes, and other equipment are subject to harsh winter conditions with low temperatures down below -40 celsius, which could potentially be damaging unless appropriate protection practices are adopted. To avoid such damage, water should not be left in the system during the winter. The effects on canals, gates, pipes, valves and pumps from freezing water can be destructive. Therefore, all designs should include suitable drainage outlets so that all water can be emptied from the canals, pipes and equipment before severe frost occurs. Such drainage water can, if required, be captured into locally formed and positioned livestock watering ponds.

97. Preventive measures to be included in the whole irrigation system planning, design, operation and maintenance cycles, would include: • Planning scheme layout to the extent possible that all pipes and canals terminate at the lowest point, where a gate outlet of valve can be placed; • Adoption of appropriate materials in open channel and pipework designs that are less vulnerable to deterioration under extreme temperatures (hot and cold), • Align and bury pipes to grade so they can fully drain out, or otherwise include additional drainage outlets at low points as necessary; • Ensure to the extent possible that no gated structures are left with water against them before the winter season begins; • Protect all fixed but fragile components (electronics, pipework, cabling, rubber hose, etc.) from adverse consequences of rain, dust, snow, snow melt and sunlight when not actually in use; and • If at all possible, protect sensitive parts of irrigation equipment (small pipes, nozzles, dripper pipes, pumps and other components) by relocating them, fully drained, to safe, secure and dry winter storage.

5. Irrigation Methods and Technologies

a. General

98. The project is to support mixed cropping in quite varied locations. The primary objective is to restore irrigated agricultural productivity and help mitigate the need for Mongolia to import agricultural produce – fodder, cereals and especially vegetables. Additionally, whilst land area may be plentiful, water resources, after allowance for environmental flows,16 are not, and all new

16 Ministry of Environment, Green Development and Tourizm, 2015. Surface water regime and resources. (editor:G.Davaa). Ulaanbaatar. Admon publishing

29 upgraded and modernized schemes need to maximize the use of this scarce resource. Therefore, basin and furrow irrigation methods were reviewed but the water use is too inefficient and these methods cannot be justified for modernized irrigation in Mongolia. Subsurface irrigation was considered as well, but concluded not to be suitable because of risks of frost damage or damaging by roots in case of trees.

99. The design and implementation of upgraded irrigation systems must generally be low cost, have low maintenance requirements (routine and periodic), and should be resilient to the harsh and variable climatic conditions found in Mongolia. Whilst fixed infrastructure must be strong and durable to survive being exposed to harsh winters and abrasive sediment loads in diverted water, it is also important that critical climate sensitive equipment (pipes, spray nozzles, electrical equipment, pumps, filter units) be mobile so that it can be placed into safe storage during the winter.

b. Center Pivot Sprinkler System

100. There is good experience for using center pivot type irrigation systems in Mongolia, with many actively in use, predominantly for fodder, wheat and cereal production, but also suitable for some vegetable cropping (e.g. potatoes, cabbage, turnips and onions). The use of pumps, pipes and movable irrigation equipment is well understood, with sensitive parts of the equipment removed in the winter for safe keeping. A major advantage for these systems is the overall efficiency from pump to spray nozzle, and the associated uniformity of water application over the crop. Where electricity connection is readily available, then these machines can be operated reliably and effectively, or else each unit may need its own engine and generator set. The major supply pipe infrastructure can be buried and safe from the winter frosts, provided the water can be drained out to a sump and evacuated once the irrigation season is over.

101. The major drawback for these irrigation units is the initial high cost, and the on-going maintenance costs for motors, hydraulic and pressurized water pipes, filter systems, and the sensitivity of the irrigation nozzles to water quality and sediment. Their overall size also means that they are not units which individual small farmers can use, unless they buy as a collective group, but they can be procured and operated by a CGG as an enterprise and/or Joint Venture (JV), with the necessary financial management structure to ensure continued funding to maintain the equipment and pay the power bills. Government can also assume ownership and responsibility for the installation, operation and maintenance of a Center Pivot unit, once there is agreement with participating farmers to meet relevant annualized charges to cover depreciation, operation and maintenance costs, sufficient for periodic unit upgrade or replacement, Typically this is beyond the scope of a CGG without Government or JV management support. Day to day operation is best done by the CGG based on actual irrigation needs and not a fixed schedule.

c. Lateral Sprinklers Systems

102. Sprinkler systems are widely used, from simple hand move pipes and risers through to the most sophisticated center pivot and lateral move machines. They can also range from fine spray multiple nozzle fine rain type units, putting a fine even application over a number of hours, through to the more aggressive long throw rain gun type machines, covering a large circle. The suitability of the various types depends on whether the irrigation is to be a heavy wetting, infrequent type approach, or a more moderate wetting like normal to light rain but applied more frequently. For the Mongolian sandy loam soils, the option that will provide the more uniform coverage and gradually soak the root zone evenly will be the sprinkler type approach rather than the use of a rain gun, though either can be used provide the machine is moving at the appropriate speed so that the net watering effect per pass matches the infiltration and water retention capacity of the root zone. Heavy

30 watering practice is not suitable for Mongolian soils, and this therefore goes against rain guns and also against the solid set pipe and riser or similar movable pipe and riser systems, due to their heavier demand for labor and regular shifting. The better solutions, which can be tuned to suit the various crops, are the lateral move and center pivot type machines, or the one that combines the benefits of both (lateral move – pivot end) which enables the machine to continue always moving on to fresh unirrigated land. In the situation where labor to operate irrigation systems is limited, these are the most attractive long-term options for broad area irrigation. In more confined or difficult shaped areas, then the use of hose reel boom and/or gun irrigators may be more suitable.

d. Moving Sprinkler Systems

All sprinkler systems require water pressure to be effective, and some also require and independent power source (electricity, diesel engine and/or diesel-powered generator set) to provide that pressure and also move the machine over its area – straight line path, circular path or a combination. The mode of irrigation, circular or longitudinal, can also influence how much manual input is needed to make hose-connections, correct any errors of alignment, and or set the machine up for the next parallel run. Hand move systems are moved sideways after X hours of irrigation to the next position, whilst solid set units are permanently installed, though risers and or water lines may be rotated between the fixed installed lines below ground. Overall, unless they need to be moved between circles, center pivots are the easiest to start up and use, as they follow a fixed circle and do a complete circle over several hours (variously up to about 72 hours (3 days). Moving them between circles takes time, though the more modern machines can now have rotatable wheels so they can be all reset so the machine can be towed in a straight line between circles. Each circle would have a base point for reconnecting the unit, and it is either towed between circles or in some cases may be able to drive itself to the next GPS controlled position, along an axis dividing all connected circles. Lateral moves are often fitted with an engine/generator so they can drive themselves, but older units could not reset for turning in a half circle so they can return on the other side of the water supply canal or pipe. Those that now combine the benefits of both Center pivot and lateral move are very useful for continuously irrigating long rectangular blocks. Most of the big irrigator units have electrically powered wheels (an individual small motor for each wheel or pair of wheels) and can utilize mains electricity supply. Where this isn’t readily available, then the choice is between a machine mounted power/generator set or a fixed based engine/generator that can then power several irrigation units simultaneously. The choice of configuration has to be determined based on mobility and irrigation command area situation. Any form of sprinkler irrigation system will need to be set out and/or commissioned/ decommissioned for each irrigation season. Any fragile components that could be susceptible to cold weather need to be fully drained and possibly stripped from the main machine frame for safe keeping until the next season starts.

e. Drip Irrigation

103. There are no drip irrigation systems currently used in any of the 17 priority subprojects, though there are small drip irrigation systems used in some small vegetable and greenhouse vegetable production enterprises in Mongolia. The systems are suitable for the small area developments for row crops, and more specifically the less mainstream vegetable crops that are grown in small areas. Potatoes, cabbage, beet, carrots and turnips are more regularly grown under furrow irrigation by small holders, or else under sprinkler irrigation in more commercial scale land holdings.

104. Drip systems are proposed for the infill areas not covered by centre pivots and for smaller vegetable, orchard growing, and windbreak areas in most of the schemes. It is assumed that the

Soum would own such systems and would provide support to the FG/WUGs who would be responsible to operate the systems. They would be strategically located for each group and would have a main supply canal or pipeline off the main canal or major distributary canal/pipe. The system would have a management station with filtration, pump and control systems to help distribute water in accordance with agreed process. A particular advantage of small drip systems is that they can be installed in difficult areas and are overall quite flexible for smaller irregular land areas. The main supply and distribution pipes would be laid out on a semi-permanent basis, only being removed, if necessary, for cultivation and harvest works, and aligned so they can freely drain when end stops are removed. Lateral lines, per row or group of rows, will be roll-out for 200 to 300 m length, generally down the slope, and would include in-line pressure compensating emitters to ensure even water outflow at all locations. Using in-line emitters means it easy to roll-out and roll-up the lines once planting is completed and just before harvest is undertaken. Attachment emitters are more difficult and can be damaged in this process.

105. It is important with in-line emitters that the water being used is clear of fine sediment, so filtration of the water, with scheduled filter backwash and disposal is essential, implemented when the pressure differential across the filter unit reaches a pre-set limit. This flushing can be a manually controlled operation, but today, with suitable inclusion of sensors and control valves, it can also be fully automated. Flushable filters (discs, ceramic cores, sand) will generally last several seasons before they need to be replaced, unless they are subjected to heavy sediment loads with coarse abrasive sand. It is therefore important to monitor water quality and may be preferable to also have some in-flow coarse screening or settlement basin capacity ahead of the intake to the drip system station. These drip systems operate quite effectively at relatively low water pressure – from as little as 2 to 5 m head – and as the water moves quite slowly in the pipes, there is relatively small friction head loss over substantial pipe length. The limits to lateral pipe lengths is more probably to do with pipe size, roll-up constraints and overall weight per length. For the winter, all pipes need to be fully drained, especially the emitters, to avoid potential frost damage. These systems are flexible in terms of adapting the layout to varied plot shapes, row length and number of rows, so they are well suited to small holder plots and for any changes in such plots made into the future. Unless there is adequate pressure in a supply pipe, each control station may require a pump and consideration can be given to this being solar powered with support battery for longer irrigation periods into and through the night.

106. Drip systems are also the ideal irrigation system for the proposed windbreaks, as drip lines and emitters can be set out according to the three lines (2 x tree, 1 x bushes) and the spacing between them along the lines (Figure A1.4 of Annex 1). The extended wind break lines can be set up, running down the slope, in blocks from 200 to 300 m long, similar to the vegetable areas, with either constant slow drip or for rotational operation between the blocks for up to 300 outlets per block. Again, the drip lines would need to be rolled out in the spring and rolled up before the winter. Figure of drip details e.g. one of the triangles or squares from the next system.

f. Greenhouses/closed chamber

107. In some irrigation scheme areas, greenhouses have already been established, mostly private units in household yards, but they may not have an organized irrigation system. It was noted that for some subprojects, there were small areas within the overall command areas that could potentially be developed with one or more greenhouses, and that these could readily access the main water supply canals or pipelines. This then provides the opportunity for interested CGG to set up one or more greenhouses to produce more specialists and sensitive vegetables production, such as lettuce, tomatoes, cucumbers or other vine growing types. They may also be able to diversify into ground cover fruits like strawberries. The greenhouses can also utilize alternative irrigation

32 methods, such as spray, mist or hydroponics, if they are set up with this in mind. They may operate with their own control systems or be a sub-set of a broader drip system control station for surrounding vegetable areas. The actual greenhouse irrigation system would need to be under autonomous control, as irrigation would need to continue within the greenhouses through the wet season. The possibility for recycling water within the greenhouse should also be considered, subject to nutrient and other chemical concentrations being safely managed with the inflow of sufficient new water, thereby minimizing any water losses within the relevant systems and production methods adopted within the greenhouse.

108. Establishment of some initial greenhouse operations may also be the catalyst to encourage other farmers to consider later investment in some greenhouse areas, and thereby encourage further crop diversification and reduction of water use. Drip systems are generally flexible, in that the layout and alignment of drip lines, with emitters or low-pressure spray, mist or outlets to feed hydroponic troughs can be amended within the overall capacity of the drip pump and control station. Drip systems also enable the input of relevant soluble fertilizer and other crop management inputs that ensures effective timing and uniform distribution throughout the system. It is expected that successful greenhouse developments will lead to more interest and uptake of such systems.

g. Integrated Systems with Mixed Designs

109. In larger areas, centre pivot systems are planned as shown in Figure 7. Center pivots are very effective sprinkler systems, but within an area, they only cover 78% of the square within which they operate. When several circles are side by side, then subject to their positioning in relation to each other, these unirrigated areas can be small to substantial (up to 30 ha with 100 ha center pivots set out on a square). There is then potentially some opportunity within a center-pivot dominated scheme to set up some smaller sprinkler or drip systems, tapping the main pressure pipelines to the center pivot, to support infill areas between the major crops, or otherwise to irrigate the full crop area sown with fodder, cereals or large area vegetables. The unirrigated areas will be utilized, using rollout drip systems, or other smaller satellite systems for the fringe areas.

110. To reduce initial investment costs, center pivot systems can also be movable, allowing one set of equipment to irrigate multiple pivot areas. This requires a center pivot system with rotatable main wheels, that can be mechanically turned (under electric or hydraulic power) through 90 degrees, such that then the machine can move like a long pipe, rather than sideways as it does for irrigation. It also requires an easily connected/disconnected head, to a prepositioned and fixed circle center base and water supply point. To move between circles, the unit, once disconnected, with all wheels realigned, can be towed longitudinally for connection to the center base for the next circle. For this to be most effective, all circles using such a towable center pivot unit arrangement would need to be in line, and it must be possible to tow the center pivot in both directions. A tractor would be required to tow the machine, once disconected, between the various circle positions, although some self propelling systems have also been developed. Once the general practice for moving the center pivot is established, relocation between circles would be expected to take from 2 to 3 hours, to be confirmed with potential equipment suppliers.

Figure 7: An Irrigation System Integrating Movable Central Pivots with Drip Irrigation

111. Soil test analysis shows that the soils in the command area of the subprojects are generally low in salinity. Soil test results are provided under each sub-project and the detailed results are presented in Annex 2 and 3. However, with irrigation salts always tend to accumulate, and appropriate irrigation practices need to be adopted to leach any excess salts periodically if there is insufficient normal irrigation or wet season rains to effect such management.

112. The adoption of an integrated irrigation system (sprinklers plus drip) is a more complex system with multiple pipe connections and variable flow rates. The operation of this will require due consideration of network flow rates and pressure distribution, with relevant operating procedures and control mechanisms. It is anticipated that the major flow in the systems would be for the operation of the large area centre pivots providing from 15 to 25 m of operating pressure. Other small area linked sprinkler and/or drip systems, requiring this or less operating pressure can draw from the same pipelines, which would be supplied through variable speed pumps/motors, responding to any pressure variance in the overall pipeline (using sensors at each center pivot head). At any given time, only one of four center pivot heads would be operating of the pressure pipeline, together with some of the smaller infill area sprinkler or drip systems. With relevant pressure regulation and control valves, and programming of sensor controls, the motor-pump can ramp speed up or down as needed depending on the actual water demand and pressure impacts in the operating line. A line for one center pivot (up to 4 circles) and associated sets of infill areas would be supplied through one pump set, but provisions at the pump house would allow for a spare pump to be activated in the event of any one pump failing, with suitable cross pipe and valves connection to enable from one to four separate pipelines being fed from the same overall pump station to be fully serviced through the season. Specific selection and adoption of pumps, motors,

34 pipelines and control systems to support the various irrigations systems will have to be discussed and finalized with eventual equipment suppliers.

6. Drainage

a. Drainage Requirement

113. Soil profile. Across the irrigation areas seen in Mongolia, none showed any specific requirement for soil profile drainage. The generally permeable soils of the root zone appear to be of sufficient depth that any properly managed irrigation should not create soil drainage problems. Most field investigations confirmed through discussion with local people that available groundwater in boreholes was typically at 20 m or more below the surface. No prevalent wetlands were observed in the inspected subproject areas.

114. Sub-soil. Based on review of earlier subproject investigations and designs, and on more recent field inspections with soil sampling and analysis results, there does not appear to be any underlying sub-soil constraints to effective soil profile drainage.

115. Drainage base. In general, most of the land presented for irrigation scheme upgrading and modernization has free draining soils and present no clear obstruction to the necessary periodic salt leaching. Artificial (sub-surface) drainage does not seem to be required (yet). Based on previous earlier work, it is assessed that most areas have to potential for a steady infiltration rate of about 8 mm per hour, but under heavier rainfall, runoff will occur. Concentrated flow from upland streams and springs will spill over the land in a fan until the drier months of the year, when overland flow in small braided streams tends to dry up.

b. Drainage Provisions

116. Surface drainage. The greater short-term problem is for surface drainage, particularly the safe management of upland runoff around irrigation infrastructure and for protection of the irrigated areas. In some instances, protective banks will be required to intercept and direct surface runoff around or safely across the main and distributary canals, into the existing natural drainage paths from the command area. In some cases, there may be opportunities and benefits to create upland ponding areas, where surface runoff is captured, and after due time for sediment settlement, clean water can be diverted from these upper ponds into the surface water canal system. The need for any associated intake and diversion infrastructure for this option will need to be assessed individually for each scheme and incorporated according to merit. An example is shown in Figure A1.4 of Annex 1.

117. The possible need for localized surface drainage from within the command area will need to be examined and assessed according to need. Generally, such drains would be aligned with locally depressed landforms and would flow downhill away from the major infrastructure. In forming field channels and/or aligning distributary canals, some natural ‘channels’ may be interrupted, in which case suitable provisions should be made within the field layout to safely direct and manage any surface water runoff through to natural flow paths downstream of the command area.

118. Sub-surface/Groundwater Drainage. No immediate need for any special subsurface or groundwater drainage interventions has been identified.

c. Winter Protective Drainage

119. Canals, pipes, pumps and other equipment need to have provisions in the system design to allow for drainage of residual water from the systems before the winter period to prevent damage caused by ice formation. All canal, pipe and drain alignments are designed to have free draining discharge points – gates or valves – that can be operated once the irrigation system requirements have been completed ahead of the winter. In this way, all critical infrastructure can be evacuated of water and protected from the risk of frost damage.

7. Tree Windbreaks

120. Various statistics show that 60% to 70% of Mongolia’s crop land is eroded to some degree. Soil physical properties affect the susceptibility of soil to wind erosion. Annually strong winds with gusts up to and over 15 m/s occur in: the Gobi region for 30 to 76 days per year; the steppe region for 30 to 76 days per year; the forest steppe region for 5 to 15 days per year; and in the Khangai, Khovsgol, Khentii alpine taiga regions for 1 to 5 days per year. Strong wind (tornado) records show that these can last for about 1 to 2 hours in the winter and summer seasons, and from 3 to 6 hours in the spring and autumn seasons.

121. A poorly structured, bare soil, recently tilled soil is highly susceptible to wind erosion even though the soil surface is rough. The effect of wind erosion on poorly structured soil is especially pronounced when the soil is dry. Moreover, climate change has already produced greater weather diversity and increased frequency storm events. More windstorms and periods of dry growing conditions are likely, and this will increase the occurrence of windstorms and the extent of erosive type wind damage.

122. Windbreaks (or field shelterbelts) have been found to increase crop productivity by 25%.17 It is therefore proposed that subprojects should include proactive protection measures against wind and storm erosion as part of overall project design and as a means to help protect and improve soil productive health. A resilient, well-planned field windbreak will mitigate soil loss and crop damage arising from the wind and associated harsh climate conditions.

123. A feasibility study undertaken by MOFALI on Tree Windbreaks shows that the most suitable trees to be used as windbreaks in all ecological zones of Mongolia are Ulmus Pumila and Padus asiatica. 18 The study result shows that these trees are more water tolerant and require less general maintenance once established. The feasibility study also outlined the possibilities for planting three species of Cargana, such as Cargana Korshinskii, Cargana Arborescens, and Cargana Spinosa L as tree wind breaks in semi-arid and arid regions.

124. Establishment. In recent years, companies and individuals have planted seedlings for the most popular trees in a region, as can be observed in most of the aimags. For example, there are 10 companies and 20 individuals undertaking this work in Darkhan-Uul aimag. Based on these developments and experience, it is recommended that trees adapted to the subproject region’s climatic should be used for tree windbreaks. The cost of seedlings is very similar across all regions, about MNT3,500 to MNT35,000 per plant.

17 Molla Mekonnen Alemu. Ecological Benefits of Trees as Windbreaks and Shelterbelts. 2016. United Nations Development Programme. International Journal of Ecosystem 2016, 6(1): 10-13 18 MOFALI and University of life science, 2018. Feasibility study to plant shelter belt/tree windbreak around the crop land area (TTOZ/2018/01/TEZU). Ulaanbaatar.

125. Monitoring. There are little to no tree windbreaks in the priority subproject areas. Where windbreaks have been observed, they are often incomplete, or have been largely left untended to the extent they no longer fulfill the purpose of an effective windbreak. Some have been cut down and the timber used for fencing and to create barriers to protect irrigated areas against the predation of livestock. Where specific windbreaks are established to protect irrigated areas, the farmers/CGG will need to maintain and manage.

126. Windbreaks will be newly planted, using those tree varieties that are particularly tolerant of drought conditions. To ensure the effective establishment of a uniform and effective windbreak, the new seedlings will be well tended, irrigated and maintained with sufficient soil moisture during the growing season, to ensure good root growth and survival of the young seedlings. Part of the management and monitoring activities will include ensuring adequate protection of new seedlings against the predation of wild animals, particularly rabbits and mice, which are difficult to control in Mongolia. Windbreaks are an integral and essential part of the irrigated farming activities. The windbreaks will need regular Maintenance.

8. Bill of Quantities

127. The preparation of the Bill of Quantities (BoQ) was based on the “Estimator Pro” software that was certified by the Minister of Urban Development and Construction on 23 February 2008. This software has been developed based on the Building Norm and Standards:81-10-13 for Preparation of Budget for Construction Works. The software is updated regularly to take into account most recent relevant official rates such as salary, transport, fuel, and equipment hire. An example of the estimation of BoQ with unit rate is given in Annex 4.

B. Subproject 1 – Tsakhir Irrigation and Drainage System Design

1. Site Description

a. Area and Scheme Description

128. Tsakhir irrigation scheme headworks is located in Taishir Soum, but the irrigated command area is located in Jargalant soum, both in Govi-Altai aimag. But the Jargalant soum is responsible for whole Irrigation system i.e there no any involvement of the Taishir soum. The irrigation scheme sits along the left bank of the Zavkhan river (Figure 8). The irrigation scheme intake is fed directly from the river through a short, constructed diversion channel, which feeds a 3.6 km long graded (and previously lined) main canal. The canal bifurcates to distributaries through the command area that sits north of the main canal (which continues a further 4.3 km) and falls gradually towards the river. The main canal alignment is still well defined, but requires protection from upland runoff, especially in the section immediately downstream of the headworks intake. The field distribution system was set up for tracked sprinkler boom machinery.

Figure 8: Location of Tsakhir Irrigation Scheme

Legend: headworks, main canal, fields Source: Based on google map

129. Jargalant soum government owns the irrigation scheme. The original irrigation scheme was developed in 1969 with simple open canal diversion for the production of fodder and wheat. No specific details on scheme production and performance from this period are available. The command area design was, and remains, 206 ha although there is potential for this area to be increased. There is no active irrigation today, and any past investment was limited to restoration rather than upgrading of the original scheme. The scheme had two travelling boom sprinkler systems (soviet style), now removed, and these are no longer available. The boom sprinklers drew water by suction from a full distributary canal, at approximately 100 l/s. Each irrigation unit would cover 100 ha in a cyclical pass across multiple field blocks. The old field blocks layout is still visible in Google imagery, though many of the distributary canals are filled with sediment and overland wash-off. The scheme area is highly suitable for fodder or cereal crops, but as there is some distance to a reliable or large market for potatoes and vegetables, the preference is to grow produce for livestock consumption.

130. Today, with no active irrigation use, this scheme could be classed as virtually a green field site. Whilst the field layout would enable the reintroduction of modern and efficient travelling spray boom irrigation equipment, the opportunity now exists to modernize with more efficient and larger lateral move systems. With large travelling irrigation equipment, it is possible to grow a variety of crops in the irrigated area although, in Tsakhir irrigation scheme, the dominant need is to produce fodder for livestock security during the harsh winters that prevail in the region. Other crops, such as potatoes and vegetables, could be grown in suitable areas (field blocks) with lighter soils. It may even be feasible to consider the inclusion of some greenhouses to boost vegetable production for local consumption in Jargalant and Tsahiriin Soums, or for some of the many small herder settlements in the area. With clear water in the main canal, it would be feasible to consider adopting drip irrigation systems for greenhouse and vegetable plots, or otherwise grow vegetables using the broad area sprinkler systems across selected blocks. The main adjustments required for modernization would be in revising the irrigation methods, application schedules and rates, and determining the optimal irrigation cycle best suited to more crop varieties. The area would also need to be fenced from livestock intrusion and be protected with windbreaks from wind travelling through the wide Zhavkhan river valley.

131. Figure 9 shows the existing intake structure (upper left) and main canal (lower left) that divert and convey water to the irrigation scheme command area (lower right and Figure 8). The condition of the main canal/distributary canal bifurcation structure is highlighted (upper right) and

38 confirms that significant reconstruction or replacement is needed. Concrete lining in the main canal has been mostly removed, whilst the lining in distributary canals is largely buried and damaged. If the existing system layout was to be upgraded, much repair or replacement of damaged gates and canal sections would be required.

Figure 9: Status of Tsakhir Irrigation Scheme

Source: TA consultants from site visit

132. Given the development of Tsahriin Hydropower Station (THPP) in recent years, there is less need to manage sediment from the water supply, but eroded sediment from upland runoff is problematic, especially for the main canal. Though the main canal has some constructed protection bank to potentially keep runoff and sediment in-wash from the canal, this has not been fully successful, and the protection bank and canal have been breached at several locations. For long term sustainability, an appropriate revised approach is required to safeguard the main canal, and to safely manage and divert overland runoff around the western end of the command area, in line with the general fall of the river though the valley. Whilst this irrigation scheme remains inactive, it was confirmed during a field visit that the soum government had recently commissioned the preparation of a preliminary upgrading plan, but this was not made available for review.

b. Climate

133. Meteorological observations, started in 1985 at Jargalant Soum where Tsakhir irrigation scheme is located, provide a 33-year time series (1985 to 2018) on monthly mean air temperature, wind speed and monthly precipitation. The meteorological station at soum level observes agro- climatic parameters such as when the air temperature exceeds 10oC in spring or falls below in the autumn. The days when frost occurs is also recorded. Data sets were obtained from the Altai aimag

39 center meteorological station covering the period 1999 to 2018, which has been analyzed to inform this study.

134. In Tsakhir irrigation subproject area, the day-time temperature in mid-summer has been recorded at 38.3oC (daily maximum) in June. Annual rainfall is approximately 88.5 mm, with about 80% of this rainfall occurring in the three months from June to August. Very little rain falls in the vegetative season, necessitating a heavy reliance on irrigation water for effective crop production. The average wind speed is moderate throughout the year, peaking in the spring and early summer. Mean monthly climate data for the project area is given in Table 10.

Table 10: Mean Monthly Climate Data for Tsakhir Irrigation Subproject Month Average Absolute Absolute Humidity Wind Precipitation Temperature Maximum Minimum (%) speed (mm) (oC) Temperature Temperature (m/s) (oC) (oC) January -22.6 4.0 -43.9 71.2 3.0 0.8 February -18.6 12.5 -43.8 68.2 3.1 1.2 March -8.20 19.0 -39.4 59.5 4.4 1.5 April 3.90 30.0 -21.5 51.3 5.2 2.3 May 11.4 38.0 -9.4 48.9 5.1 6.9 June 17.6 38.3 -1.2 52.8 3.9 16.7 July 20.0 37.6 0.0 55.1 3.5 24.5 August 17.5 35.3 1.5 56.9 3.6 23.3 September 10.3 29.4 -9.0 54.6 3.9 6.3 October 1.00 22.0 -24.5 60.4 4.2 2.4 November -11.0 17.0 -32.8 67.5 3.8 1.4 December -19.0 8.5 -38.4 70.4 3.1 1.3 Average 0.19 24.3 -21.9 59.7 3.90 88.6 Source: National Agency for Meteorology and Environment Monitoring

135. Air temperature. Figure 10 shows the trend for change in monthly mean air temperature from April to September. In April, the mean temperature is 5.9oC (lower than 10oC), whilst the minimum can be as low as -21oC (Table 10). This means there is insufficient warmth to support crop growth, and there is a serious risk for damaging frost to occur. Therefore, no irrigation is undertaken in April.

136. Trends in air temperature. Figure 10 also shows the trend for monthly mean air temperature between April and September, which is the crop growing season. The April mean air temperature has increased by 2.8oC in June, by 2.6oC in July, by 1.8oC, and by 0.8oC in August, but for May, the mean air temperature has decreased by 0.4oC. The significant increase in temperature in June to August is highly beneficial for crop production, whereas in April, it remains too cold and risky for crop planting.

Figure 10: Trends in Monthly Mean Air Temperature for Tsakhir Irrigation Scheme

Source: National Agency for Meteorology and Environment Monitoring

137. Duration of hot days. An important climate factor for effective irrigated crop agriculture is the occurrence of hot days in excess of 20oC. Figure 11 shows that the number of days with a daily average air temperature above 20oC has increased by 33, and the number of days above 30oC has increased by 3 over the last 20 years. Whilst this is beneficial for crop growth, it also implies that irrigation water demand will increase due to increased evapotranspiration.

Figure 11: Trends in Hot Days with Daily Mean Temperature above 25oC and 30oC

Source: National Agency for Meteorology and Environment Monitoring

138. Precipitation. Figure 12 shows that monthly precipitation has increased through the growing season for all months except June: In April, May, July and August, precipitation has increased by 3.5 mm, 3.6 mm, 11 mm, and 10 mm, respectively, while June precipitation has declined by 2 mm on average over the past 33 years. While more precipitation in the growing season is welcome, the pattern of occurrence, and the relatively meagre amounts (rarely above 60 mm in June or July, and generally much lower) means that rainfall, on average provides limited sustenance for crop production. For effective crop growth, managed irrigation is an essential requirement optimizing the benefits of infrequent precipitation.

Figure 12: Trends in Monthly Precipitation at Tsakhir Irrigation Scheme

Source: National Agency for Meteorology and Environment Monitoring

139. Increased precipitation in most months of the growing season can be explained by a decrease in the number of days (from 2 to 4 days) in each month without precipitation between May and August (Figure 13).

Figure 13: Trend in Days Without Precipitation at Tsakhir Irrigation Scheme

Source: National Agency for Meteorology and Environment Monitoring

140. Wind. The monthly mean wind speed during the growing season ranges from 2.4 to 3.8 m/s (Table 10) while the maximum wind speed can reach 30 m/s on average twice a year. The number of days through the growing season when wind speed exceeds 10 m/s has increased by 26 days over the last 30 years (Figure 14%), where it can be seen that 36% of the wind comes from the west, and 15% comes from each of the southwest and southeast. The most marked trend is in the windspeed that exceeds 10 m/s, whilst the trend for speeds greater than 15 m/s is not significant.

Figure 14: Trend in Wind Speed and Direction at Tsakhir Irrigation Scheme

Source: National Agency for Meteorology and Environment Monitoring

141. Agro-climate. On average, the start of the frost-free period is coming 10 days earlier, whilst the start of autumn frosts is coming 10 days later, increasing the overall average frost-free period from about 100 to 120 days per year. The cumulative value of temperature (sum of daily values greater than 10oC) in the Tsakhir area ranges from 1,900 to 2,200ºС, but the average trend over 33 years has remained steady at about 2,000oC. On balance, over the period from 1985 to 2018, significant climatic warming has occurred around the subproject area, and this has beneficial agro-climatic characteristics. During the study period, the growing season has lengthened by about 15 to 20 days, largely due to the shift in air temperature to above 10oC earlier in spring and later in autumn. The accumulated temperatures to support crop growth have increased slightly whilst the number of frost-free days has increased markedly, by up to 20 days per year, thereby supporting crop growth and overall production (Figure 15).

Figure 15: Agro-Climate Characteristics around Tsakhir Irrigation Scheme

Source: National Agency for Meteorology and Environment Monitoring

142. Projections. Under climate change scenarios (UNFCC) it is projected that summer temperatures could increase by another 1oC by 2035 and 2.0oC by 2065 in the Tsakhir subproject area (Figure 4), while there could be up to a 10% decrease in precipitation by 2035 through 2065 (Figure 5).

143. Increased temperatures with extended warm-period duration will be beneficial for irrigated agriculture production but conversely the increased number of hot days above 25oC, and increased days with high windspeed can be detrimental with increased evapotranspiration, soil erosion and more rapid reductions in soil moisture. The current trends for increased temperature and increased precipitation have positive impacts for irrigated agriculture, but further temperature increases coupled with projected precipitation decline will necessitate increased irrigation water requirements.

144. The increase in the number of days where windspeed is high increases the necessity to plant windbreaks (ordered rows of suitable fast-growing trees and bushes). With the dominant winds coming from the west and southwest, the windbreak, comprising a shelter belt of two lines of trees and one line of bushes (Annex 1), needs to be aligned on the west and south-west sides of the command area.

c. Soils

145. The soil map for Tsakhir Irrigation subproject (Figure 16) shows the command area consists of predominantly light Kastanozem with some small areas of Aluvial meadowish soil, suitable for cultivable crops and vegetables/potatoes. Soil was riparian area’s alluvial meadow soil and meadow yellow brown soils dominated. By World Reference Base soil classification, the command area soil is grouped Light leptic Kastanozems. Kastanozems are potentially rich soil, its need to irrigation for high yields. Leptic means having continuous rock coming between 40-80 cm. Secondary carbonate accumulated in surface layer and soil pH is slightly above 8.0. Kastanozems have relatively high

43 levels of available calcium ions bound to soil particles. These and other nutrient ions move to downward with percolating water to form layers of accumulated calcium carbonate or gypsum. Kastanozems are principally used for irrigated agriculture and grazing.

Figure 16. Tsakhir Irrigation Subproject Soil Map

Source: Institute of Geography and Geo-ecology

146. For the soil particles texture is Sandy clay loam and 50-70 percent of soil is sand fraction. ‘B’ horizon has more porosity because texture was sandy loam and lots of gravel. Stone and gravel more than 2 mm fraction was less than 20% of the soil in the ‘A’ horizon (Table 11). The soluble nitrogen contents are lower, around 8-9 mg/kg, plant available phosphorus levels are lower, around 8-10 mg/kg, and exchangeable potassium levels are 75-85 mg/kg which means a sufficient level of nutrients (Annex 2).

Table 11: Soil Profile of Tsakhir Irrigation Subproject Area Soil Depth, Characteristic horizon m 1 A 0.0-0.2 Sandy clay loam, yellow brown soil. Gravel more than 2 mm = 20 %, High carbonate content 2 E 0.2-0.4 Sandy loam and high carbonate content. 3 B >0.4 Sandy loam with lots gravel. Lower carbonate content 4 C >0.7 Sandy soil with gravel

Source: Integrated agricultural laboratory

147. Soils are weakly developed with low organic matter (1.5%) and meadow yellow brown soil. Soils have sufficient nutrient levels. Soil profile is not so deep because at 40 cm riverbed stone gravels appear. Each horizon is high reacting with 10% hydrochloric acid, which means weak alkaline or near to neutral. Carbonate contents around 1%, secondary carbonate sediment collected to soils. Soil pH=8.6 and EC= 180-200 μS, which means there is low salinization effect to the crops.

148. Soil cation exchange capacity is high, around 33-35 meq/100g, which meaning cations are binding with clay particles and indicating soil will good enough to deliver nutrients to plant root. Calcium contents are highest of the various cations (Annex 3).

d. Water Sources

149. The Tsakhir irrigation scheme lies on the left bank of the Zavkhan river, which has a large catchment and therefore abundant available water. The catchment supports the THPP power station just over 40 km to the east and upstream from the Tsakhir irrigation scheme. Zavkhan river is formed by the confluence of the Buyant and Shar-Us rivers, that are replenished by runoff from the south-west slopes of the Khangai mountains. The river flows into the THPP reservoir, which regulates the river flow through the need for environmental flow releases and power generation releases. Consequently, whilst the THPP reservoir provides a substantial water storage reserve, the flow releases from it will be irregular, driven by timing for hydropower generation.

150. The main water source for irrigation is the Zavkhan River, and the overall river basin is shown in Figure 17. There is 22 years (1996 to 2017) of river flow data available from the Taishir

45 gauging station which has been used to assess the available water resources for the Tsakhir irrigation scheme.

Figure 17: Zavkhan River Basin: Location of the Tsakhir Irrigation Subproject and Taishir Hydrological Gauging Station

Source: TA Consultants based on National Atlas

151. Table 12 shows that the monthly mean flow at Taishir gauging station ranges from 10.4 m3/s to 19.0 m3/s during the crop growing season. The environmental flow allocation is 6.47 m3/s. as 90 percent of the long-term average of 7.19 m3/s (Table 2 and Table 3) of the Zavkah river at Taishir gauging station. After satisfying the environmental flow, there is at least 3.9 m3/s of water available for use during the months from May to September. Monthly high flows have reached 40.6 m3/s, 63,6 m3/s, 86.9 m3/s and 55.7 m3/s respectively for May, June, July and August. Now, with the THPP and reservoir, there are improved regulation of flows in the Zavkhan river, which helps ensure there is sufficient water available for irrigation. However, considering the 75% exceedance flow values, there is a high risk that insufficient water will be available for irrigation after allowing for the environmental flow allowance. Analysis of river basin catchment yield with average mean discharge values, and after allowing for stated THPP capacity, indicates that even with flow storage, THPP can only operate at full capacity for short periods, and that overall capacity is limited to less than 20% of capacity over an average year. THPP is therefore concluded a ‘peaking power’ station, and releases to the river downstream will potentially be irregular due to short-term peak period operations. This could necessitate a need for some additional flow regulation in proximity to the Taishir irrigation scheme intake to provide access to a more stable water supply in dry years.

Table 12: Zavkhan River Water Resources for Tsakhir Subproject

Net Water availability Mean Mean Environ- Mean % of Annual Maximum Minimum mental Month Discharge Discharge Discharge Discharge Flow (m3/s) (%) (m3/s) (m3/s) (m3/s) (m3/s) m3/month

April 10.2 0.06 4.66 6.47 5.40 - May 40.6 0.11 10.4 6.47 12.09 3.96 10,618,984 June 63.6 0.15 11.5 6.47 13.3 4.99 12,939,260 July 86.9 0.21 19.0 6.47 22.0 12.59 33,459,134 August 55.7 0.30 17.4 6.47 20.20 10.9 29,350,190 September 25.5 0.17 10.4 6.47 12.06 3.93 10,183,968 October 16.4 0.15 6.47 6.47 7.50 - November 15.7 0.02 3.23 6.47 3.75 - December 0.6 0.01 0.25 6.47 0.28 - January 13.2 0.00 1.04 6.47 1.20 - February 10.4 0.00 0.85 6.47 0.99 - March 9.2 0.00 1.09 6.47 1.26 - Source: National Agency for Meteorology and Environment Monitoring

152. Zavkhan river flow during the irrigation period, from May to August, at Taishir has been in decline since 1996. However, river flow has been slowly increasing since 2010, following the commissioning of THPP, which is now providing some regulation of the river flow. Thus, irrigation water availability will depend more on THPP water use than on the annual flow in the river, which can be attenuated and managed through the THPP storage reservoir.

Figure 18: Trend for Monthly Flow at Taishir Gauging Station on Zavkhan River

Source: National Agency for Meteorology and Environment Monitoring

153. The flow sensitivity of the Zavkhan River to climate change is shown in Table 13 below. As shown in Figure 5, if the temperature were to increase by 1oC and precipitation decrease by 10% over the period 2035 to 2065, as has been projected, there is a risk that the Zavkhan river flow could decrease by more than 20%.

Table 13: Zavkhan River Percentage Change in Flow Due to Climate Change Temperature changes Precipitation changes (%) o ( C) -20% -10% 0% +10% +20% 0 -40.4 -22.1 26.0 56.0 1 -45.4 -28.6 -8.3 15.6 43.5 2 -50.3 -35.1 -16.7 5.1 30.6 3 -54.8 -41.0 -24.3 -4.4 18.9 5 -61.7 -50.1 -36.0 -19.2 0.7 a Percentage change in average river flow Source: TA consultant

154. Water quality. Water chemistry analysis for 2013 to 2018 is presented in Figure 19. The overall chemical composition assessment shows good balance and concentrations (Figure 19). 2+ 2+ - of Ca , Mg , SO4 and Cl which do not exceed the irrigation water standard thresholds (Table 4). The sodium adsorption ratio (SAR), a critical factor for durable irrigation, is also below 15 mEg /l which is within the accepted standards for long term use on the land. It is therefore concluded that the Zavkhan River water is suitable for irrigation.

Figure 19: Water Chemistry of Zavkhan River

Source: Central Laboratory of Environment and Metrology

155. Suspended solids in the Zavkhan River water range from 1.0 to 33 mg/l (or 0.001 to 0.03 kg/m3), but do not exceed 20 mg/l (0.02 kg/m3) in most cases (Figure 20). Therefore, the quality of water in the Zavkhan river is classified as “clean” to “very clean”, based on completed water quality analysis and the relevant water quality index (WQI).

Figure 20: Suspended Solids in Zavkhan River Water

Source: Central Laboratory of Environment and Metrology

156. Impacts on Groundwater Quality. During field surveys, 80% of responders stated that the depth of water in wells is generally more than 20 m. With such depth to the water table, it is concluded that with moderated irrigation practice, in keeping with water use efficiency, adverse impacts from irrigation on the groundwater adverse unlikely.

e. Existing Irrigation System and New Proposed Design

157. The existing scheme, which is in disrepair, originally consisted of a gated intake structure off a branch loop in the Zavkhan river, and this gated intake is still in relatively good condition. The main canal is in two parts – the main conveyance to the command area (3.7 km) and the command area head canal (3.8 km). There are 6 distributary canals totaling 3,200 m, ranging from 300 m to 840 m long. Within the command area, there are a 26 field canals, set approximately 125 m apart and totaling about 17 km. All of these canals, to serve an area of 206 ha, would need to be reconstructed and improved for more effective and efficient irrigation if a similar irrigation method/arrangement were to be maintained. However, the general landform and command area shape can be remodeled to better suit the use of newer lateral move irrigation systems. This provides an opportunity to revise the irrigation system layout within the existing command area to achieve effective use of the travelling irrigators – i.e. adopt more uniform field channel length, reform the field blocks into more uniform size and alignment etc. Whilst a similar layout may eventually be adopted, it could also be reorganized for effective operational use of the planned travelling irrigators. A combined lateral move/pivot irrigator is proposed that can follow the line of the supply canal, or pipe and hydrants, and can irrigate both sides of the supply canal and rotate around the end point, thereby working to a continuous cycle.

158. An example of such a system can be found at : https://www.tlirr.com/products/ultra-linear- irrigation-system/ and given center pivots can now be up to 800 m long, it is assumed that such a lateral-pivot type machine can be obtained with a 250 m wide span, and be able to rotate at each end and not need to roll back on area just irrigated. It would then operate in a continuous cycle, once every ten to 12 days, drawing water from a supply pipe aligned along the center of the command area.

2. Irrigation Water Requirement

159. To estimate the irrigation water requirement (IWR) the water utilization norm19 (Annex 1) has been used, pro-rated for 85% fodder (Lucerne, Alfalfa), 7.5% potatoes and 7.5% vegetables. However, fodder requires about 25% less water than potatoes, and about 35% less than vegetables in the Govi-Altai region. To allow for this, either there has to be some overwatering of fodder in proximity to potatoes and vegetables or these more water hungry crops need to be grown in specific areas where the irrigator speed can be adjusted to provide additional water. Typically, this variance in water need is accomplished by undertaking fewer irrigations in a season for fodder, where from 400 to 500 m3/ha of water is applied per irrigation cycle. With a lateral move sprinkler system, the typical application is about 250 m3 per pass, but the irrigation is done more frequently. This moderates the amount of water lost each cycle to deep percolation, as smaller volumes delivered more frequently are retained more effectively in the root zone. The current and designed command area and irrigation methods are presented in Table 14.

Table 14. Current and Designed Command Area and irrigation method Crop type Current Allocation of Irrigation Planned Allocation Irrigation command area method of command area method Potatoes, ha Currently no crop is Used 15 drip Vegetables, ha cultivated as there is Furrow 15 drip Cereals, ha no is canal to the Fodder, ha command area 170 sprinkler

19 Water utilization norm, Order no A/310 by Minister of Environment, Green Development and Tourism dated on 30 July 2015.

Fruit trees and wind break, ha 5 drip

160. If fodder is planted in all fodder blocks, it is not so difficult to manage irrigation for a mix of two or more crops. Where less water is required, the speed of travel can be increased proportionately. As fodder is good for fixing nitrogen in the soil, potatoes and vegetables usually follow in rotation between seasons. The programmable lateral move irrigation machine will be set to operate with GPS, so that each cycle can be completed without too much operator demand. The main concern however is that when using pipes/hydrants rather than an open channel, periodic connection of the roll out hose will be required for about every 300 m of travel. If an irrigation cycle is about 6 days, then up to five cycles could be completed per month, providing up to 125 mm (1,250 m3/ha) can be applied each month, which is greater than any particular crop would require over a 3 to 4 month growing period. Therefore, the irrigation equipment will have some periodic downtime.

161. To provide protection against strong winds, 2,400 deciduous trees and 2,400 fruit/nut bushes are proposed to be planted along the southwest, west and northwest boundaries of the command area. The specific detailing will be based on the prevailing wind direction, and the extent that protection is needed within this open river valley aligned southeast to northwest. At planting and in the early years, a purpose installed drip system is proposed, with locally available electric power for low pressure pumping from the main canal at the command area boundary. The protective tree lines could 4.7 km long.

162. With modernization, the overall irrigation operations efficiency is expected to increase from 36% (low, open channel system, poor condition) to 86% (Table 15) [new lined main canal (3.7 km), new effective flow regulation from a new intake structure and low level river pool, and high efficiency sprinkler application equipment – lateral move-pivot]. This means that only half of the total water volume would be required for the improved irrigation system, and there would be sufficient water and capacity to increase the irrigated command area at a later stage. The water use efficiency gains are based on modernizing the irrigation scheme through new and more durable lining of the main canal, with a single distributary pipe through the middle of the command area along the longitudinal axis, which would feed, through spaced hydrants, a single efficient lateral move – pivot end sprinkler system, thereby providing improved uniform land coverage, to increase fodder, potato and vegetable production. A localized and specific drip irrigation system, off the end of the main canal, is proposed to sustain the planned windbreak during establishment through to maturity, and this same system could be used to irrigate small areas of vegetables.

Table 15: Irrigation Scheme Efficiency Characteristics Field irrigation Percentage Conveyance Field The scheme application of total efficiency application irrigation command (%) efficiency efficiency area (%) (%) Current for total Surface irrigation 100.0 60 60 36 command area (border, furrow, basin) Designed fodder Sprinkler 85.0 95 90 86 area, 170 ha Designed potatoes Drip 15.0 95 95 90 and vegetable, 30 ha Average for designed Combined 100.0 95 91 86 command area sprinkler and drip Source: TA Consultant

163. As it remains cold in April, cultivation for irrigated crops starts in May with overall crop growth through to August. The estimated total water use for the irrigation season, based on irrigation water utilization norm (Table 6) with the planned crops is 1,241,057 m3 (0.47m3/s) with-project and 1,268,041 m3 (0.48m3/s) with climate change (Table 16). This Irrigation water amount is 1.28% of the net available water in the irrigation season in the river or 0.33-1.16 percent of the river flow of the given month (Table 17). Therefore, even after meeting the environmental flow of 6.47 m3/s, there is still plenty of water available to meet the irrigation needs. The operations of the THPP will influence actual flows in the river at the headworks, so it is recommended that the diversion intake and main canal have a peak design capacity of up to 0.5 m3/s, which whilst greater than the steady flow needed by the lateral move irrigator (0.12 m3/s) under continuous operation, would facilitate at a later stage any expansion of the command area and/or use of more than one irrigator.

Table 16: Irrigation Water Requirement for Tsakhir Irrigation period Item Total May June July August September Allocation of command area Potatoes (ha) 15 15 15 15 15 Vegetables (ha) 15 15 15 15 15 Cereals (ha) 0 0 0 0 0 Fodder (ha) 170 170 170 170 170 Fruit trees and wind break (ha) 5 5 5 5 5 205 Water requirement with project Gross irrigation norm (m3/month) 255,582 292,308 271,924 175,436 72,059 Irrigation efficiency (%) 0.86 0.86 0.86 0.86 0.86 Total irrigation water requirement (m3) 297,189 339,893 316,191 203,996 83,790 1,241,057 Water requirement with project with climate change Increase in ET, (m3) 25 206 575 266 41 Projected crop water requirement (m3/month) 264,184 295,738 275,929 179,133 75,531 Irrigation efficiency (%) 0.86 0.86 0.86 0.86 0.86 Projected total irrigation water requirement (m3) 307,191 343,881 320,848 208,294 87,827 1,268,041 Source: TA Consultant

Table 17: Water Availability for Irrigation Projected total Percentage of Monthly Environ- irrigation water irrigation water Irrigation River ment Net available flow in requirement with use from net river period Discharge, Flow, the river project flow m3/s m3/s m3/s m3/month m3/s m3/month % May 10.4 6.47 3.96 10,618,984 0.11 307,191 1.10 June 11.5 6.47 4.99 12,939,260 0.13 343,881 1.16 July 19.0 6.47 12.49 33,459,134 0.12 320,848 0.63 August 17.4 6.47 10.96 29,350,190 0.08 208,294 0.45 September 10.4 6.47 3.93 10,183,968 0.03 87,827 0.33

Total 96,716,315 1,268,041 1.28 Source: TA Consultants

3. System and Layout

a. Area Topography

164. The Tsakhir scheme command area sits alongside the left bank of the Zavkhan river, set slightly to the south where the soils are more suitable for fodder and small areas of vegetable and

51 potato. The current expectation, to be confirmed at detail design, is for 170 ha of fodder, 15 ha for potato, 15 ha of vegetable, and 4.8 ha of windbreak, making about 206 ha in total. As there is no clear guidance on area breakdown between crops at this time, there will be some discrepancy in these numbers. The proposed scheme layout is shown in Figure 21.

Figure 21: Tsakhir Irrigation Scheme Layout

Source: TA Consultant

165. The landform slopes in the direction of the river flow to the northwest. The existing intake is at approximately 1,566 masl, and the main canal meets the command area in the southeast corner, at 1,560 masl. The existing main canal continues northwest to end at 1,548 masl, and the land falls away towards the river, to 1,546 masl in the northwest. The area will drain generally in a northwest direction from the main canal intake towards the river. On the south side of the area, a protection bank has been constructed to direct upland runoff (from the south) along the southside, westwards and around the western end of the scheme. However, this protection bank has been breached and part of the main canal has been washed away and/or filled with sediment. More particular attention will need to be given to protection of the main canal and effective drainage around the command area.

b. System

166. The original scheme was developed for using lateral move sprinkler boom machines (old soviet crawler tractor mounted type). The existing layout is specifically arranged therefore to suit

52 the use of these now obsolete machines. The land layout is irregular and does not easily lend itself to substituting center pivot or lateral move systems, nor does the intended dominant crop type warrant the use of drip systems.

167. Given there is no firm boundary for redeveloping this scheme, the demarcated subproject command area is proposed to be reconfigured to suit the optimum use of a modern lateral-move, pivot-end sprinkler system, with a 250 m wide sprinkler span, linked to a four-wheel moving pivot head that tracks along the line (3.7 km) of a buried distributary pipe, with 11 interspaced hydrants (each 300 m apart) for the connection of a roll up hose (300 m long) (Figure 22). This approach is taken as there is a 10 m elevation change in the distributary line (As currently configured, the 4 land blocks vary between 15 ha and 44 ha, with most close to 40 ha. The balance is split into two smaller blocks of 27 ha and 15 ha each. Given the scheme is currently unused, the opportunity exists to fully grade out all canals and drains and start afresh with a layout maximizing the beneficial use of sprinkler machines for the various crops. On the highly permeable soils, it is proposed that no surface irrigation be retained, but for smaller vegetable and potato areas, as well as for the windbreaks, suitable drip systems might be adopted.

168. In the event of making a major transition from the existing layout to something new, the options for machine selection and supply canal/pipes are more plentiful. However, as a basis to develop costs at this preliminary stage, use of a lateral-move pivot system is proposed, which enables a single unit to cover the area at an effective application rate of 8 mm/hr. applying 25 mm per unit area per pass (3 hr. of irrigation per unit area). Modern control systems on these and other types of overhead sprinkler system mean that actual spray can be controlled and isolated on the machine such that non-cropped areas are not irrigated, This machine operates as a lateral move on one side of the water supply pipeline when running straight, but the anchor/water intake trolley can be anchored at each end whilst the spans turn around the anchor like a center pivot, completing a half circle before then being released to travel laterally to irrigate the other side of the pipeline. In this way, the sprinkler machine operates on a continuous cycle, covering about 35 ha per day, and completing the cycle in 6 days. Machinery options and control systems should be more fully assessed before making a final selection and completing the scheme layout and design.

169. The north and west boundaries of the command area will be protected by a windbreak (4.8 ha) to the standardized arrangement – 2 lines of trees and one of fruit/nut bushes. To sustain these from the initial seedlings and to nurture through to maturity, a small low-pressure drip system with inline drippers will take water from the western end of the main canal to a filter and control station at the northeast corner of the command area. From there, the water will be filtered and pumped though a system of main, header and lateral pipes to implement drip irrigation to each tree and the row of bushes on a rotation basis. The control station will need a power supply (available mains or a link to the power generator for the main sprinkler system). Filter backwash will be discharged to the main canal escape drain.

c. Irrigation Scheme Layout

170. Irrigation Equipment. The use of any form of mechanical irrigation system has positive and negative characteristics. Positive characteristics include that improved precision of placing water directly at the crop, coupled with electronic monitoring and control systems, can greatly improve not only water management (reduce wastage) but contribute quite significantly to crop production and yield. Most modern irrigation systems can now be procured in conjunction with various climate, weather and soil water monitoring systems, that enable the operators to adjust schedules based on crop water needs and/or to halt operations for a period following rain. These are programmable features that enable scarce water to be used more wisely. Negative characteristics include that

mechanical systems define irrigation field shape—length, width, diameter—and the maximum run length possible for lateral moves or sprinkler lines. These details have to be considered when designing canal alignments, field channel length and spacing, position and buried runs for pipes, necessity for drainage outlets from the land (surface runoff) or for draining pipes and equipment pre-winter close down. Type of equipment can also be critical in power—consumption, type and thus costs—and possible operational constraints or need for power access points if machines are using a trailing power line. If electric power is not readily available, the lateral, pivot or drip systems will need diesel motors and pumps, whether as a fixed diesel power generator set providing electricity, or as a machine mounted engine/generator. Many of these requirements cannot be finalized until detailed design when all the specific criteria and constraints can be fully assessed with design options prepared for comparison. The general layout of the scheme components as described below are shown in Figure 21 and Figure 22.

171. River Diversion Wall and Intake. The planned modernized scheme will need to include a low barrier wall with a central overspill weir across the Zavkhan river to create a header pool to feed the intake structure as in the general design (Annex 1) with an inlet box and sediment trap, sluice gated outlet to flush sediment, and an overspill wall/weir of sufficient length to spill water to the outlet into the main canal. The exact position of the barrier wall/weir and width of the final weir will be finalized following detailed site survey prior to detailed design. However, it is expected to be reasonably close to the position of the existing intake, 3.6 km upstream of the command area. If the intake structure needs to be moved, preference should be to locate it closer to the command area, assuming a suitable alignment for the barrier wall/weir can be identified. The weir will be a rock-fill structure, with an impermeable core, and a central reinforced concrete-faced walled-weir set about 0.75 m below the top height of the rock wall. Under extreme but short periods, the rock wall should be able to withstand shallow overspill though the upstream THPP will moderate any river peak flows. For most regular and annual cyclical flows, any overspill should be able to pass over the spillway weir. Intake level is taken to be 1,566 masl whereas riverbed level is about 1,564 to 1,565 masl. The objective for the barrier wall is to control river water level under regular flow to 1,566 masl, and thereby provide assured opportunity to divert the required water for irrigation. Top level of main barrier wall should be no more than 1,567 masl, whilst abutments at intake and left/right banks of the river should be set at about 1,568 masl, or sufficient to ensure peak flow will pass over the weir and at worse the central section of the rock wall without passage around the abutments.

172. Main Canal. Given the fall between the intake and the command area is about 6 m over 3.6 km, or 1 m per 600 m, use a pipe is assessed as too costly although this can be more fully evaluated during detailed design. The pipe option has a distinct advantage in that it can be buried below ground level and would not need much, if any, protective embankment and diversionary protective drainage. Previous experience has shown that the main canal, even when lined, is particularly vulnerable to wash off from the nearby southern high ground. Similarly, if the intake from the river could be closer to the command area, there would be a reduced length for a lined canal and associated protection measures. It is not possible at this time to be firm on this aspect, so current quantities and costs are based on retaining the existing intake structure position with upgraded intake and 3.6 km of open lined canal.

Figure 22: Tsakhir Command Area and Sprinkler Arrangement

Source: TA Consultant

173. Distributary pipe. At the command area (Figure 22), the main canal will terminate with inflow to a single distributary pipe for a further 3.6 km through the middle of the revised command area. The pipe will need to be about 350 mm diameter to ensure net positive head in the pipe up to 3 m when flowing, but up to 10 m static head, thus PN 2, HDPE, ID 375 mm (400 mm OD). The pipe will be fitted with 11 outlet hydrants (up to 200 mm diameter) at 300 m centers, starting 600 m from the start of the former main canal. The pipe intake will have a closure valve, and an overspill weir will be required from the main canal for water to go back to the river, via a constructed channel, in the event main canal flow exceeds to flow being withdrawn from the pipe. The peak pipe discharge assumes the irrigation equipment will be operating a 24-hour day, moving steadily, with hose connection, disconnection and reconnection between successive hydrants, at a speed sufficient to irrigate 35 ha per day, applying 25 mm depth of water per pass (at 8 mm/hr.). The pipe would require an end (west) scour outlet to drain it of sediment and/or for the winter. A shallow and wide outlet drainage channel should be formed which under normal operations will not impede the turning of the lateral move – pivot on the half circle at the western end of the command area.

174. Hydrants. The hydrants will have snap fit connectors for the hose reel, with swivel heads for easy alignment and connection as the travelling irrigator moves along the length of the pipe. The hose reel, after connection, will gradually unwind behind the irrigator head, moving in its controlled path. At completion of a section (hose fully extended) the machine would shut down awaiting the operator to decouple the hose, rewind it in the irrigator, and then recouple it to the next hydrant before commencing the next section (300 m). These short interruptions to continuous irrigation can be accommodated within the overall irrigation cycle, provided the operator(s) are on hand and attentive, monitoring and implementing actions as required. A change of hose connection will be required every 7.5 ha (about once every 5 hours) on the straight run, and after 25 ha (about 17 hr.) at each end. The natural fall of the land does not readily allow for including an open canal rather

55 than a pipe from which the irrigation machine can suck the water, so this discontinuity for hydrant connection is required.

4. Design Discharge

175. The headwork’s maximum capacity is 0.53 m3/sec, the water flow in the main canal is 0.53 m3/s and in the distributary canal 0.11 m3/s (Table 18). The water needed for irrigation is from 0.03 m3/s to 0.13 m3/s. These amounts are only 0.33 to 1.16% of the excess flow at the river after meeting the environmental flow (Table 12). Also, the irrigation scheme is downstream of THPP, which regulates river flows and operates for varied periods each day, without some regulation downstream, there could be periods during the day where available irrigation water could be limited. This needs further investigation at detailed design to understand what, if any, compromise may be necessary for irrigation water demand to be fulfilled during irrigation operating hours.

Table 18: Design Discharge from the Zavkhan River Irrigation Net Average Water extracted from Capacity of irrigation scheme period Available Water, river for irrigation canals and pipes (m3/s) (m3) m3/s % Main Distributary Field May 3.96 0.11 1.10 0.53 0.11 June 4.99 0.13 1.16 0.53 0.11 July 12.49 0.12 0.63 0.53 0.11 August 10.96 0.08 0.45 0.53 0.11 September 3.93 0.03 0.33 0.53 0.11 Source: TA Consultant

176. Pumping costs. Assuming water is accessible in the distributary main with no residual head ,although a small net positive head needed to ensure no suction problems for the pump, for a flow of 0.101 m3/s over 140 hours per cycle and 12 cycles per season, the total pumping cost, at MNT130/kWh, is MNT10.76 million.20

5. Civil Works

177. The main civil works for the diversion headworks from Zhavkhan River, and conveyance of water to irrigation sprinkler/drip systems in the command area will include: (i) construction of a rockfill barrier wall (up to 3 m high, u/s slope 2:1; d/s slope 2.5:1, top) with impermeable core, about 250 m across the Zhavkhan River channel between natural abutments (east and west), at a location to be confirmed downstream of the existing intake structure and start of the main canal; (ii) incorporation of a reduced level (-0.75 m) reinforced concrete spillway section, up to 10 m wide, to control pool water level upstream, and pass moderate excess flows back to main river, over an armored spillway on the rockface of the barrier wall; (iii) construction of a new intake structure in the barrier wall at the head of the existing intake channel, with vertical screw lift sluice gate, with free release of the small flow (up to 0.5 m3/s) into the main canal; (iv) construction of a sediment sluicing channel in the box section of the new intake structure, with a sluice gate (0.5 x 0.4 m) to the right side of the new barrier wall, for periodic sediment sluicing; base of sediment collection chamber to be formed for effective guidance of sediment under flow toward sluice outlet;

20 Using the cost estimation model developed for Erdeneburen irrigation scheme.

178. At this stage, the design and related details are preliminary, and as detail design and operational requirements are clarified, some additional works may be identified (e.g. additional protection measures for pipes, construction of field covered and protected valve boxes, minor earth checks in drains to support windbreaks).

6. Equipment

179. Within the civil works, required equipment will be limited to gates, low pressure distributary pipe (HDPE) and associated fittings to the sprinkler system connection hydrants. The following specific equipment, some of which was mentioned for installation with civil works are: (i) Water intake – one vertical lift sluice gate with preliminary 1.0 m wide and a 0.6 m lift; (ii) Intake sediment sluice – vertical lift sluice gate, provisionally 1.0 m wide with 0.6 m opening, sufficient to flush rapidly at up to 0.5 m3/s, details to be finalized around operational and physical levels at site; (iii) A low-pressure pipe (375 mm diameter) intake control valve, with box protection to facilitate closure of the pipe intake; (iv) Provision and installation of various valves and fittings (Table 19);

(v) One self-propelled lateral-move pivot-sprinkler set, 250 m spray width, single sided with flexible hose connection to field hydrants (100 mm diam) to track up and down the line of the distributary pipe, all inclusive of power supply, flow controls, and associated spare parts, spray nozzles and drop pipes suitable for particular crops, all details to be discussed with potential suppliers before confirming detailed specifications (specifics of lateral drive to be discussed and agreed based on local electricity power available, and the operational convenience of available options); (vi) One low pressure drip filtration, pump and control station, with sufficient associated main and connecting drip pipes, for up to 4.8 ha; and (vii) Provision of relevant power supply infrastructure, whether connection to main national or local electricity grid, inclusion of diesel power and generator sets, or provision of diesel power to drive irrigation systems (pumps, self-propulsion, etc.). There is an expectation that adopted sprinkler equipment would include suitable on- board power controls and drive mechanisms if electric power supply and cabling is not viable.

Table 19: Valves and Fittings for Tsakhir Subproject Pipe Intake Valve Outlet Valve Scour Valve Filter Set a Emitters b Distributary 1 1 x 375 1 x 200 1 x 375 Drip 1 1 x 200 with pipe 1 x inline inline a Inline filter set with control station to process all drip flow, specific details and arrangements to be discussed with suppliers. b Pressure compensating steady flow rate emitters installed in the rollout drip lines during manufacturer at specified intervals as required. Source: Consultant’s estimates

7. Bill of Quantities

180. The cost estimation for Tsakhir irrigation scheme construction and equipment (Table 20) summarizes the cost for key components for the upgrading and modernization of the gravity supply and pumped sprinkler and drip irrigation systems for 206 ha. The estimated cost is MNT4,800.50 million, equivalent to MNT24.00 million/ha.

Table 20. Bill of Quantities for Tsakhir Irrigation Scheme Modernization Budget No Item Unit Quantity (MNT million) Unit cost Total Civil Works Headworks Sluicing structure with intake sluice channel and 1 piece 1 72.68 72.68 outlet flushing channel Rockfill Barrier and Water level Control Weir, Wall L = 250 2 m 250 2.77 693.73 m, h = 1.5 m, Weir L = 10 m, h = 1.0 m 3 Headworks protection embankment m 500 0.04 18.48 4 Main Canal – reforming and lining m 4730 0.13 604.46 5 Header Canal – reforming and lining, in take sluice m 4,500 0.07 335.32 7 Drains – reforming and grading m 1,000 0.004 4.41 8 Bridge piece 9 Roads – forming and grading m 10,000 0.00 32.70 10 Windbreaks – prepare land and install ha 5 44.41 222.04 11 Drain and protection bank m 4,500 0.03 143.38 12 Fence km 10 7.00 70.00 13 Pump station 1 100.00 100.00 Subtotal 2,297.20 Equipment

Budget No Item Unit Quantity (MNT million) Unit cost Total Head work Control Sluice Gate, Width 1.0 m x Height 0.6 m, 14 piece 2 1.68 3.36 vertical screw 15 Distributary PE: PE100, SDR11, 1,0mpa, DN355mm, PN10 piece 4,500 0.27 1,194.75 17 Self-propelled lateral move - pivot sprinkler set set 1 210.55 210.55 17 Water Efficient Drip Watering Advanced System (5 ha) set 7 43.47 304.32 18 Trees, number piece 15,000 0.004 60.00 19 Pump, VTP-300/0.5-0.12 piece 1 15.00 15.00 20 Universal Excavator for O&M piece 1 168.60 168.60 Subtotal 1,956.58 21 VAT % 0.00 425.38 22 Environmental baseline assessment number 1 42.67 42.67 23 Environmental impact assessment number 1 42.67 42.67 24 Design cost ha 200 0.18 36.00 Subtotal 546.72 Grand total 4,800.50 Source: Consultant’s estimates

C. Subproject 2 – Yolton Irrigation and Drainage System Design

1. Site Description

a. Scheme Background

181. The Khaliun Soum owns the Yolton Irrigation Subproject. The original irrigation scheme was developed in 1980, with a first step to take water down the slope (6.8 km and 140 m lower) in an open lined roughly shaped main canal from the Ust-Chatsran River (1,38 masl) to an intermediary balancing storage (346,000m3, 1.606 masl), which then fed a closed concrete pipe to the command area, 3.3 km away and 80 m lower (1,615 masl), all operating under gravity flow. The command area then had installed subsurface pipe with risers to sprinkler heads to irrigate the land, all operating under pressure from the balancing storage.

182. The pipeline however has been dug up and is no longer functioning. The irrigation scheme design was for a command area of 315 ha to grow fodder, barley, vegetables and potatoes. For the upgrade design, the command area remains unchanged and the crop mix will change under rotational agriculture. Currently, there is limited production in the command area based on use of groundwater.

b. Area and Crop Maps

183. Geomorphology. The project area, at 1590 to 1827 masl, sits in valley of Khaliun and Usdt-Chatsran River. Bounded to the south by Undur Tsakhir mountain (2358 m) and Seer Mountan (2510 m) of the Mongol-Altai Mountain range, to the north by the Uvuljuu Mountain (1950m). The area is located south of the Main Mongolian Lineament (Figure 23), which represents the main tectonic boundary separating the Neoproterozoic domain in the north, affected by early Paleozoic orogenic event, from the early Paleozoic domain to the south.

Figure 23: Location of Yolton Irrigation Scheme

Legend: head work, main canal, fields Source: Based on Google Map

184. The Yolton Irrigation Scheme is located about 29 km east from the Khaliun soum of Govi- Altai aimag. The water intake from the Ust-Chatsran ephemeral river lies just over 10 km due south, emerging from the foothills of the southern Nnuruu mountain chain. The project area sits on the opposite side of the valley, and the available pressure from the intermediate reservoir (80 m head) is sufficient to push the water down across the valley and up the other side, whilst retaining sufficient operating head (30 to 40 m) to drive the installed sprinklers. However, at this time, the reservoir remains and is kept full, but the supply pipeline and sprinkler system in the fields has been removed. Current irrigation is done with movable sprinkler lines and groundwater.

185. The photographs provide a good indication of the poor state of the main canal to the reservoir, and the poor condition of the remains of the underground main canal pipe, that in combination bring water to the command area, via the central balancing storage. To restore reliable water supply to the Irrigation Scheme, these key infrastructure works need to be reconstructed, and to ensure long term durability, it is recommended a full piping option be considered, with a suitably revised intake off the Ust-Chatsran river that would provide more reliable and clean water intake. The physical operating levels between water source and command area will mean the pipeline would be under pressure, necessitating suitably rated pressure pipes. The use of HDPE pipes, fuse welded, up to PN16 (160 m head) would have to be considered, but the pipe could then be buried and protected against any migrating overland runoff and erosion. The intermediate storage would be a break point in the pressure line, but the additional intake for the lower pipe would need an appropriate trash and sediment trap to mitigate risks for blockage in the remainder of the piped system through command area. An on-stream (in pipe) fine sediment filter would be needed immediately prior to water entering the command area sprinkler network, which with an appropriate piping and valves arrangement, can use the line pressure to effectively backwash the filter to an outlet scour valve and drain. This would then protect the sprinkler heads from potential blockage.

186. Currently, the ongoing irrigation is limited to about 30 ha using water taken from a groundwater well, with the use of a movable mini sprinkler system called “Namiraa”, imported from China (Figure 24). The current cropping under this system is fodder.

Figure 24: Current Condition of Yolton Irrigation Scheme

Upper Left: Intake Canal from River Source to Storage reservoir. Upper Right: remains of Pipeline from Storage to Command Area Lower Left: Current Irrigation with Hand Move Sprinkler Lines. Lower Right: Groundwater Well for Irrigation Water Source: TA Consultnat from site visit

c. Climate

187. Meteorological observations started in 1986 at the Khaliun soum at the Yolton Irrigation Scheme site. This provides 32 years of time series data (1986 to 2018) of monthly mean air temperature, wind speed and monthly precipitation. The Khaliun soum meteorological station does not make observations of agro-climatic parameters such as when days when air temperature crosses the 10oC threshold in spring and autumn, or on the days when frost occurs. This type of data has been obtained from the Altai aimag center meteorological station for which the time series is from 1999 to 2018.

188. At Yolton irrigation subproject, the day-time temperature in mid-summer can reach to about 38.3oC (maximum daily) in June. Annual rainfall is approximately 88.5 mm, with about 80% of this rainfall occurring in the three months from June to August. Very little rain falls in the vegetative season, meaning there is a very heavy reliance on irrigation water. Average wind speed is moderate throughout the year. Mean monthly climate data of the project area is given in Table 21.

Table 21: Mean Monthly Climate Data for Yolton Subproject Area Month Average Absolute Absolute Humidity Wind Precipitation Temperature Maximum Minimum (%) speed (mm) (oC) Temperature Temperature (m/s) (oC) (oC) January -17.5 6.5 -42.8 44 3.1 2.5 February -11.3 10.8 -38.2 48 3.2 2.2 March -3.9 20.6 -31.5 42 3.9 3.9 April 6.1 29.4 -16.2 38 4.8 4.3 May 12.1 34.3 -7.6 33 4.3 7.4 June 16.6 40.7 -3.8 37 3.8 15.4 July 18.5 39.3 0 47 3.4 16.8 August 15.1 37.8 1.9 42 3.4 15.7 September 9.3 33 -7.2 45 4.0 11.4 October 3.8 28.6 -21.5 45 3.9 6.5 November -7.2 17.9 -29.4 47 3.7 3.5 December -14.0 7.9 -38.8 50 3.6 3.0 Average 2.3 40.7 -42.8 33 3.8 92.6 Source: National Agency for Meteorology and Environment Monitoring

189. Air temperature. Figure 25 shows the trend for change in monthly mean air temperature from April to September. As the April mean temperature is 6.1oC or lower than the 10oC crop growth threshold, and the minimum temperature can fall to -16oC (Table 21), the air temperature is too low to support crop growth for most of that month. However, snow and ice melt will occur, and this can be captured to fill up the intermediate storage reservoir.

190. Air temperature trends. Air temperature trends (Figure 25) illustrate that monthly mean air temperature change for the months from April to September. All months demonstrate an increasing temperature trend, though in May and September, the trend is less marked, in fact almost no change. April mean temperature has increased by 2.6oC, June by 1.6oC, July by 1.7oC and August by 1.6oC. On balance, it is perhaps reasonable to assume there has been minimal significant shift in the mean annual growing season temperature, though there are some shifts that could impact crop production. With increased temperatures in June, it is likely some increased irrigation would be required. Figure 25: Trends of Monthly Air Temperature at Yolton Irrigation Scheme

Source: National Agency for Meteorology and Environment Monitoring

191. Duration of hot days. One important climate factor that influences irrigated crop production is that of hot days. Figure 26 shows the number of days each year with daily average air temperature above 25oC has increased by 35 days over the last 20 years. The number of days where air temperature has exceeded 30oC has increased by 18 days over the last 20 years. This has a clear implication that additional water will be needed, with some increased irrigation application

62 necessary for sustained crop production (as crop evapotranspiration need and evaporative loss from the reservoir will both be higher).

Figure 26: Trend in Hot Days with Daily Mean Temperature more than 25 oC and 30oC

Source: National Agency for Meteorology and Environment Monitoring

192. Precipitation. Monthly precipitation has increased during the growing season, in June by 20 mm and in August by 0.6 mm (Figure 27). Precipitation in other months has either decreased, in July by 10 mm, or is virtually unchanged.

Figure 27: Trends of Monthly Precipitation at Yolton Irrigation Scheme

Source: National Agency for Meteorology and Environment Monitoring

193. The increase in precipitation during June and August may be explained by the decrease in the number of days when there was no precipitation by 3 days, whereas the number of days with no precipitation in July remained the same (Figure 28).

Figure 28: Trend in Days with no Precipitation

Source: National Agency for Meteorology and Environment Monitoring

194. Wind speed. The monthly mean wind speed in the growing season has increased from 3.6 to 5.1 m/s (Table 21) while the maximum speed can exceed 30 m/s on average twice a year. There are more than 100 days per year when wind speed exceeds 10 m/s, and this has increased by 50 days over the last 30 years (Figure 29). The number of days when the wind speed exceeds 20 m/s has increased by 25 days over the last 30 years. Figure 29 shows that 30% of the wind comes from the west and southwest, and 20% from the northwest. Therefore, windbreaks are needed along the west and southwest sides of the scheme.

Figure 29: Trend in High Winds and Wind Direction

Source: National Agency for Meteorology and Environment Monitoring

195. Agro-climate. Due to the change in the time when air temperature transitions above 10oC (earlier in spring, later in autumn), the overall temperature and duration has increased and provides extended support for crop growth. The number of frost-free days has increased by 20 days over the past 33 years, which greatly favors increased crop growth and yield (Figure 30).

Figure 30 Climate Characteristics

Source: National Agency for Meteorology and Environment Monitoring

196. Climate Projections. Summer temperature is projected to increase by another 1oC and 2.0oC by 2035 and 2065, respectively (Figure 4), while it is projected there could be about a 10% decrease in precipitation by 2035 and 2065 respectively (Figure 5). Further increase in temperature and decrease in precipitation are the most likely projections that will lead to increased irrigation water demand in the future.

d. Soils

197. The soil map for Yolton Irrigation Scheme (Figure 31) shows that the dominant topsoil type in the command area is Semi-desert brown and Aluvial Meadowish.

198. Six soil samples were collected during the field survey. Analysis indicated a uniformly similar type of soil. Texture is sandy clay with density of soil around 1.35 g/cm3 which meaning not so compacted and good physical condition. The ‘A’ horizon of soil depth is around 0.4 m below the surface. But ‘A’ and ‘B’ horizons are completely merged, hard to determine differences. Coarse gravel more than 2 mm is 1-2% of soil (Table 22). Sandy clay loam soil need frequent irrigation and fertilization to maintain healthy growth.

Figure 31: Soil Map of Yolton Irrigation Scheme

Source: Institute of Geography and Geo-ecology

Table 22: Soil Profile Soil Depth, Characteristic horizon m 1 O 2 A 0.0-0.4 Sandy clay loam, high carbonate content -0,5%, low organic matter in yellow sandy soil 3 E 0.4-0.6 Sandy loam layer, higher carbonate content and color going to white. 4 B >0.6 Carbonate with loamy layer going to till 1 m down. More compacted soil horizon. Source: Integrated agricultural laboratory

199. Agrochemical test results show that the soluble nitrogen content is about 15 mg/kg, which is within the acceptable limits for crops, but the phosphorus available for the plants is very low at around 4.5 mg/kg, the exchangeable potassium concentrations, at 50 to 60 mg/kg, shows there is a low level of nutrients. Soil cation exchange capacity is high at around 35 meq/100g, which means cations will bind with the clay particles confirming the soil is suitable to provide nutrients to the crop roots (Annex 2).

200. Soils have a low organic matter content (less than 1%) and they are highly affected by wind and water erosion. Each soil horizon has been tested with hydrochloric acid (10%) and the soils were found to have low alkalinity, a carbonate proportion of 0.5 to 0.7%, a pH>8 and an EC of 125 to 130 μS. This indicates there is a low risk for any salinization impact on the crops. Detailed assessment of fertilizer requirements is in Annex 3.

e. Water Sources

201. The primary irrigation water source is the ephemeral Ust-Chatsran River, which is fed from snow and ice melt in the spring, and summer rainfall runoff. In May-June, before the summer rains, there is high risk for this river to run dry. The Yolton Irrigation Scheme headworks are located in the natural river cutting where the river exits the foothills of the Nuruu Mountain range on the northern slopes. The headwork is now in disrepair but is located in the left bank of the main but unstable Chatsran river basin (Figure 32) and is one of many streams discharging to and evaporating from the Govi Altai plain and lakes. There is no gauging station on the Ust-Chatsran River and therefore no clear picture of how the river flows (peaks, low period and droughts) through the years. However, by tapping the river flow when available, it has been possible to maintain the balancing storage pond just 3.3 km south of the Yolton command area.

Figure 32: Ust-Chatsran River with Location of Headworks for Yolton Irrigation Scheme

Source: TA Consultants

202. A control measurement of the river flow was made during the field survey on 18 June 2019 (Figure 33) and findings are presented in Table 23.

Figure 33: Ust-Chatsran River Flow Control Measurement

Source: TA Consultant’s-field survey

Table 23: Ust-Chatsran River - Control Discharge Measurement (2019.6.18) Chatsran Coordinates H F B V H Q Remarks River at m m2 m m/s m m3/s Yolton Headworks Ust- 45o 48‘ 84.9” 1820 0.45 3.68 0.12 0.85 0.39 Water is clear, no Chatsran 96o 27’ 39.2” smell, no odor, pH=7.9 Source: Integrated agricultural laboratory

203. The Ust-Chatsran river originates from the foot of the Burkhan Buudai mountain in the Nnuruu range at elevation of about 3,500 m. The river basin is located within the Khuisiin Gobi- Tsetseg Lake Basin. The catchment area is approximately 403.5 km2 with a river length of 34.8 km (Figure 32).

204. To estimate the specific runoff for the Chatsran river, the relationship between basin mean elevation and specific runoff (M= f(H)) derived for Gobi Altai mountain region21, has been adopted. The annual runoff distribution for the river has been estimated according to the Gobi-Altai regional reference ratio for monthly percentage runoff. Table 24 provides estimated monthly mean flow on the basis of control measurement, which ranges from 0.85 m3/s to 1.64 m3/s during the growing season. The environmental flow calculated as 95% of the annual mean flow estimated based on control measurement.

Table 24: Water Resources for the Ust Chatsrana at Yolton Subproject Area Mean Environme Net Water available a % of Annual Month Discharge ntal flow 3 Discharge 3 (m /month) (m3/s) (m3/s) (m /s) April 0.38 0.54 5.6 - May 0.85 0.54 11.9 0.31 821,733.1 June 0.86 0.54 12.4 0.32 821,145.6 July a 1.64 0.54 24.9 1.10 2,937,669.1 August a 1.47 0.54 22.4 0.93 2,482,341.1 September 0.88 0.54 12.9 0.33 872,985.6 October 0.43 0.54 6.1 -

21 Ministry of Environment, Green Development and Tourizm, 2015, Surface water regime and water resource of Mongolia, [Editor G.Davaa]. Ulaanbaatar. Admon Publishing.

November 0.09 0.54 1.3 - December 0.04 0.54 0.6 - January 0.00 0.54 0.0 - February 0.00 0.54 0.0 - March 0.14 0.54 2.1 - Source: TA Consultants a Excess Water has to be tapped to refill the on-stream storage; other monthly flows close to IWR.

205. Water quality. As there is no hydrological gauging station, water quality for this Irrigation Scheme has not been monitored. During the field visit, the Ust-Chatsran river water was observed visually and measurements were taken. The pH was found to be 7.9, which is within normal expectations,22 and the electrical conductivity value was 169 μS/m3.

206. Impact on ground water quality. During the field survey, 80% of responders advised that the water level in developed groundwater wells was at least 20 meters deep. On this basis, it is estimated that irrigation in the area will have no negative impact on the ground water.

f. Existing Irrigation System and Design Maps

207. The existing (original) Yolton Irrigation Scheme was a natural pressure operated sprinkler system, with buried supply pipelines and riser pipes to sprinkler heads. The main buried pressurized water supply pipe from the reservoir ran along the lower side of the command area and branched to 4 No. field distributaries (buried pipes) with riser hydrants to which a lateral irrigator could connect. These irrigators ran up and down the slope to each irrigate 72 ha. None of the pipes or equipment remains, so a new ‘green field’ layout can be proposed to optimize the use of new technology. The water supply, sourced under gravity from the reservoir, has a minimum pressure head of 66 m rising to 90 m across the command area. This is more than enough, with suitable pipe sizing, to provide a modern lateral system operating pressure of 25 to 30 m. Pipes can be sized to absorb some of the static pressure head through dynamic friction resistance, but the pipe network should include some pressure regulation valves to ensure pressures remain within an acceptable working range in the field pipes.

208. In the original design, windbreaks were proposed running north-south between each of the irrigated blocks (4 x 72 ha). However, there is no remnant of these windbreaks remaining, if they were ever installed. The command area topography slopes diagonally from northeast to southwest, with a total fall of 40 to 45 m (average 1 in 80, or i = 0.0125). On this slope, it would not be possible to adopt surface irrigation without a high risk for erosion, hence the use of sprinklers with application rates in keeping with natural soil infiltration rates. Additionally, because of the slope, crop rows should ideally be transverse the slope rather than up and down the slope, so as to mitigate against erosion damage during both irrigation and rainfall.

209. The existing scheme is now almost non-operative, and any original drainage channels and protection banks have been infilled or washed away. The area has the natural drainage gulley (wide, not readily defined) along the southern edge of the command area, but there is no defined drainage channel constructed along the northern edge of the area. As there are at least three abraded runoff fans coming from the northern hills (Figure 23) running towards the command area, a drain will be needed along the northern side of the area to intercept these flows and direct around the western end of the command area. It may be possible to use these natural flows to partly sustain any planted windbreaks along the northern and western sides of the command area.

22 MNS-Irrigation SchemeO-16075: Project development for irrigation.

210. Whilst the irrigation is operated using naturally harnessed water pressure, there is still a need for power to move the machines. It is not clear how this was done previously but is possible the installed machines were self-propelled with diesel power. Electricity is provided to the site, as it is used to pump groundwater. This power may be sufficient to provide the motive power for slow moving irrigation machines whilst pumping is not required.

2. Irrigation Water Requirement

211. The specific irrigation water requirement (IWR) for Yolton irrigation scheme has been developed from the declared Mongolian water utilization ‘norm’ (Table 6). These ‘norms’ define the crop water requirements for various crops and locations in Mongolia, and specify per growing season CWR, but provide no breakdown for monthly or daily CWR. Therefore, an approximation is adopted to define a monthly IWR demand pattern. Improved irrigation operations efficiencies will help reduce actual water requirements for effective crop production.

212. The designed command area is 320 ha out of which 50 ha for potatoes, 45 ha - vegetables, 100 ha – cereals,120 ha – fodder and 5 ha- fruits. There is 5 ha for tree wind break. It is proposed to plant leafy trees at two rows and one row bushes to the west and west-northern boundary of the command area according to the wind direction data Table 25.

Table 25: Current and Planned Command Area Crop type Current allocation Irrigation Planned allocation of Irrigation of command area method command area method (ha) (ha) Potatoes, ha 80 Used Furrow 50 drip Vegetables, ha 3 45 drip Cereals, ha 100 sprinkler Fodder, ha 120 sprinkler Fruit trees and 5 5 drip wind break, ha Source: TA Consultants

213. Overall efficiency (Table 7) will be raised to 75% by using closed pipe systems from the balancing storage, modern controllable linear move sprinkler irrigation machines for 220 ha of fodder and cereals, and low pressure drip systems for potatoes, vegetable, fruits and windbreak (Table 26).

Table 26: Irrigation Scheme Efficiency Characteristics Field irrigation Percentage Conveyance Field The scheme application of total efficiency application irrigation command (%) efficiency efficiency area (%) (%) Current for total Surface irrigation command area (border, furrow, 100.0 60 60 36 basin) Designed fodder area, Sprinkler 70.3 95 220 ha 75 71 Designed potatoes, Drip vegetable and fruit, 100 29.7 95 90 86 ha Average for designed Combined sprinkler 100.0 95 79 75 command area and drip Source: TA Consultants

214. As it remains cold in April, cultivation for irrigated crops starts in May with overall crop growth through to August. The estimated total water use for the irrigation season, based on irrigation water utilization norm (Table 6) with the planned crops if potatoes, vegetables, cereals and fodder is 2,142,254 m3 (0.12 m3/s) with-project and 2,145,221 m3 (0.12 m3/s) with climate change (Table 27). Total irrigation water requirement accounts for 21% of total net available water in the growing season or about 0.7-9.2 percent of the river flow of the given month, after meeting the environmental flow of 0.54 m3/s thus there is sufficient water available to meet the irrigation needs (Table 28).

Table 27: Irrigation Water Requirements for Yolton Item Irrigation Period May June July August September Total Allocation of command area Potatoes, ha 50 50 50 50 50 Vegetables, ha 45 45 45 45 45 Cereals, ha 100 100 100 100 100 Fodder, ha 120 120 120 120 120 Fruit trees and wind break, ha 5 5 5 5 5 320 Water requirement with project Cross water norm, m3 418,631 418,758 378,302 283,313 107,687 Irrigation efficiency, % 0.75 0.75 0.75 0.75 0.75 Total irrigation water requirement (m3) 558,175 558,343 504,403 377,750 143,583 2,142,254 Water requirement with project with climate change Increase in ET, (m3) 188 962 444 1,526 66 Projected water requirement (m3) 418,820 418,758 378,746 284,839 107,753 Irrigation efficiency (%) 0.75 0.75 0.75 0.75 0.75 Projected total irrigation water requirement (m3) 558,426 558,343 504,995 379,785 143,671 2,145,221 Source: TA Consultants

Table 28: Water Availability for Irrigation Percentage of Projected total irrigation water use Monthly Environ- irrigation water from net river flow Irrigation River ment Net available flow in the requirement with period Discharge, Flow, river project m3/s m3/s m3/s m3/month m3/s m3/month % May 0.85 0.54 0.31 821,733 0.08 558,426 25.4 June 0.86 0.54 0.32 848,517 0.08 558,343 24.6 July 1.64 0.54 1.10 2,937,669 0.06 504,995 5.3 August 1.47 0.54 0.93 2,482,341 0.01 379,785 1.2 September 0.88 0.54 0.34 902,085 0.05 143,671 6.1 Total 7,992,346 2,145,221 21.2 Source: TA Consultants

3. System and Layout

a. Scheme Topography

215. Whilst the water intake is at a very high elevation (1,820 to 1,840 masl depending on where the eventual new intake is located), the irrigation command area is much lower (the high point is about 1,630 masl; the low point at 1,585 masl). Thus, there is a total fall from water intake to command area high point of 190 to 210 m, whilst the fall across the command area is diagonally across the area about 45 m over a distance of 3,350 m, east to west. The huge elevation difference in the main water supply canal and pipeline means there is more than enough pressure

71 available to operate low to medium pressure lateral (linear) move systems, and in fact much of the physical head is dissipated by having the mid-point balancing storage (Figure 34). For the lower part of the system, any excess pressure head can be dissipated by adopting small diameter conveyance pipe with high friction loss for the peak flow rate required of 0.17 m3/s (to be verified and possibly adjusted to irrigation equipment operating schedules and flow rates).

216. The irrigation scheme has been selected to restore irrigated agricultural to support the Soum vegetable needs and provide support to the local herders. The development will secure the water supply through a complex river flow diversion, canal, balancing storage and pressure pipeline to support the use of two linear move irrigation machines over up to 280 ha. Up to a further 30 ha will be irrigated by drip systems fed from the pressure pipeline, variously for a mix of potatoes and vegetables, with or without some limited greenhouses. Drip systems will also be supplied from the main pressure pipeline to nurture the proposed windbreaks on the west, southwest and exposed northern sides of the command area.

Figure 34: Planned Layout of the Yolton Irrigation Scheme

Source: TA Consultants

b. Overall System

217. The existing and planned upgraded and modernized Irrigation Scheme has the following key components which make effective use of the topography and opportunity to tap pressure in the pipelines from the significant change in elevation from water source intake to irrigated command area.

218. Water Intake and Barrier Wall: The existing water intake is now nothing more than a regularly reconstructed low bank in the river channel, which readily washes away in floods and disrupts water diversion. A more durable and effective solution is needed, so it is proposed to construct a low rockfill wall with a central weir (see generic design, Annex 1Annex 1), up to 250 long (subject actual location adopted) to form a permanent shallow pool (2 to 3 m deep) which will then feed a new permanent intake structure. The barrier wall will have an impermeable core, and incorporate a low central weir (concrete faced with armored spillway (gabion baskets) to pass up to 5 m3/s. The rockfill wall, if constructed with appropriate rock size and layout, could also withstand any short-term shallow overtopping if the flood flow is greater than 5 m3/s. The barrier wall will need to be uniform in height to ensure a reasonably even shallow discharge across the width of the wall on those rare occasions when this may happen. The bank height in proximity to the left bank intake structure (a new standardized design solution with coarse to medium sediment exclusion facility) would be set 1 m higher than the barrier wall across the river, in order to protect it from wash out.

219. The intake structure will be new, in accordance with a standardized approach proposed for all schemes (see generic design, Annex 1) where such type of structure is required and feasible. There is ample river channel grade to make it possible to utilize hydraulic head (the pool behind the barrier wall) to flush sediment in the trap/exclusion chamber of the structure through an outlet sluice back to the river section. Hydraulic head will force the cleaner water over an internal weir wall, after which it can enter the open channel (or pipe) as appropriate.

220. Main Canal The existing main canal is a relatively rough and small open U section, lined with coarse concrete. The canal runs almost directly down the hill – originally 6.8 km, future perhaps 5.5 km – to discharge into a natural storage ponds in the hills, south and roughly 70 m above the command area. The main canal is in poor condition, though it is still functional. The most damaged section is the initial 1,500 m, which has been washed away due to rainfall runoff and river flow from the southerly mountains. It may be worth considering adopting an initial pipe section for this canal and making some suitable protective banks to direct any runoff over the buried pipe. The gradient for the main canal is about 1 in 50, which means any large flow would travel at high velocity and could do significant damage to a fragile lined canal. Roughness and very shallow flow in the section means that flow velocity can be kept in check, but it may still be difficult without some check/drop structures to moderate the peak flows. Some preliminary analysis however shows that something like a 250 to 300 mm diameter pipe would be needed to carry a steady flow of about 170 l/s, As this discharges into the balancing storage, then it should be possible to set up a modernized canal or pipe with steady flow from the newly created river pool to the established balancing storage. The required flow does need to peak to match irrigation demand, as the existing balancing storage has sufficient capacity to facilitate any fluctuations require on the supply side through the connecting pressure pipeline. The layout of these primary infrastructure components is shown in Figure 34.

221. Balancing Storage. The existing storage requires no additional work and is ready for use. It is suggested that a permanent outlet structure be built on the end of the inflow canal, closer to the pond low level, so that the end of the canal is secured, and washout of the storage bed from uncontrolled discharge (and thus disturbance for sediment in the storage) is minimized.

222. Pipeline Intake. The pressure pipeline needs to be controlled by a sealable gate (penstock type) or valve so that in winter, water is retained in the storage, and the pipe can be emptied through a scour valve, located at the bottom where the pipe crosses the southern drain. This crossing point and outlet scour valve will need to be suitable protected from any erosion/washout that could damage the pipe and its operation. The intake to the pipe should also include a concrete intake wall and wings, with the inclusion of rake cleared coarse and medium trash gratings, to prevent the ingress of any windblown and floating trash in the storage. The inlet can be relatively narrow, but will need to be sufficiently deep that the storage could, if necessary, be almost fully drained in the event of a long drought period. It is not known how deep the storage is where the original pipe exited, nor whether there is any pipe left or if so, whether it is buried under sediment. This will have to be investigated prior to detail design and determining where and how deep the pressure pipeline intake should be set.

223. The pressure pipeline will be a replacement for an original steel pipe of which most has been removed thereby stranding the command area. It is suggested that a replacement pipe, 3.75 km long, of HDPE (PN 6 to PN 10 subject to safe operating pressure requirements), capacity 780 m3/hr. (217 l/s), and 375 mm in diameter be adopted. The maximum static head on the pipe (across southern drain) is about 83 m, whilst the static head at distributary 1 is 81 m and at Distributary 2 it is 72 m. Due to friction loss in the pipe, of about 30 m, the dynamic head at these three locations is reduced, but still exceeds the 20 to 25 m required to operate the lateral move and drip systems. In order to ensure there is no excessive pressure in the sprinkler and drip systems, pressure regulating valves should be installed to check the actual pressure for sprinkler and drip systems to a maximum of 25 m and 20 m respectively. A check should also be made to evaluate whether it will be necessary to include a pressure surge chamber, probably close the backwash filter arrangement before the offtake for the vegetable drip system. Initial guideline pipe and pressure information is given in Table 29.

Table 29: Flow and Pressure Details for Pressure Pipes Pipeline Length Static Diameter Dynamic Discharge Material Pressure (m) Head (mm) Head Loss m3/hr. Rating (m) (m) (x10 m) Main 3,750 up to 375 27 to 30 780 HDPE PN6 to PN10 Distributary 2 x 3,000 25 m 250 23 to 27 350 HDPE PN 6 Drip Main 800 Up to 20 160 4 to 5 72.5 HDPE PN 4 m HDPE = high density polyethylene Note: PN X means 10 times X m maximum head. In most cases the estimated dynamic head loss is compensated for through the physical drop in level along pipe. In the case of distributary and drip main, the start pressure in the pipe off the main will need control valve set to the required operating pressure for the sprinkler or drip system. Source: TA Consultants

224. There will be two drip systems with initial flow filtration banks and a suitable aligned network of pressure pipes – primary main flow; secondary header pipe; and multiple lateral pipes from each header running downslope to maximize head. The lateral pipes will have inline pressure compensating drippers, so can operate at constant flow under significant pressure variance in the pipes. Manufacturers/suppliers will be able to provide test data to confirm the performance of their products to meet the required performance specification. The first drip system will service the 30- ha potato and vegetable area, which would also have sufficient capacity to include 1 or more greenhouses if they need to be developed. The second system will feed from the top end of the 2nd Distributary (at 25 m head) and irrigate, through a system filter bank, the 4.5 ha of windbreak, consisting of blocks of up to 300 m long with 3 lateral lines each. Specific details for the final layout and pipe sizing can be obtained from the contracted supplier.

225. Sprinkler Irrigation. The original irrigation system involved linear irrigators moving from fixed position hydrants on four buried water mains, feeding from a main supply pipe along the southern side of the command area. Each field pipeline served 72 ha. The proposal now is to revise the approach but use similar but larger and more advanced linear move irrigation machines. There will now be two buried pressure lines in the command area running east-west, fed from the upper end of the main pressure supply pipe. Subject to the eventual choice of irrigation machine and its operating parameters, it could be necessary to include a pressure regulation valve at the start of the buried field supply pipes so that pressure at the connection hydrant for the irrigation machine matches the manufacturers specification. The pressure distributary pipeline is aligned down the slope, so the dynamic head loss is compensated for by the drop-in level. Thus, at all hydrants (8 No.) on the line the dynamic operating pressure will be almost the same, but static pressure will be up to 28 m higher (about 50 m) at the western end. When operating at peak flow, there will be close 25 m of friction head loss in each of the 350 mm diameter pipes over 3000 m. It is recommended that an inflow regulation valve be included with the sprinkler unit, to help manage any pressure variance.

226. Lateral move irrigators can be operated over a wide range of pressure, from about 15 m head up to 30 m head, However, the higher pressures need stronger pipework, and also lead to less accurate uniformity, as it is more difficult to get unified pressure balance throughout the length of the machine. The proposed units would be about 230 m long, to cover a total width of 250 m. It is therefore recommended that the adopted operating pressure be in the order of 20 to 30 m head at the command area, with a preference towards the lower pressure.

c. Irrigation Scheme Layout

227. Sprinkler Systems: The Yolton Irrigation Scheme will be a pressure piped combined sprinkler and drip system. The main command area block of 280 ha will be primarily for fodder and wheat, irrigated as two blocks with tow lateral move sprinkler systems running east-west on a circular loop. Initial assessment has assumed they will operate on a 15-day cycle, irrigating for at least 15 hours per day. The start of each cycle will depend on the necessity for the next application, and the machines can be halted in the cycle should rain occur. For Yolton, the lateral move irrigators will be connected to the buried pressure pipeline through a flexible hose, that will need to be reconnected to each of the 8 hydrants on each distributary pipeline as the machine progresses from start of the cycle to the other end and back again – a total of 16 reconnections per cycle. As only one hydrant of the buried pressure line is used each time, and as the pressure in the pipe is compensated by the gradient of the pipe (east to west), each hydrant will have an almost equal operating pressure to the others (which was not the case in the original design). By adopting a revised layout, it is also then possible through pressure regulation/control at the inlet of these field distributary pipes, to use a common size and pressure rating through their full length. Each distributary pipe will have 8 hydrants, one inlet pressure regulating/compensating valve, and an end scour valve to enable the pipe to be scoured and emptied pre-winter, with discharge through a controlled channel to the nearby drain (or to the line of the windbreak).

228. By way of example to illustrate likely peak irrigation application rate/day for predominantly high permeability sandy soils to sandy/silt loams: (i) Irrigation application rate: a. Rootzone – say rootzone b. Assumed water holding capacity (WHC) – say 8% c. Depth to be applied (100%) = 32 mm

d. Assume 75% spread between permanent wilting point (PWP) and field capacity (FC) – depth needed = 24 mm e. Adopt an application depth per pass of 24 mm. (ii) Assume irrigation cycle for 150 ha (per machine) takes 12 days23 = 12.5 ha/day (iii) Volume required per day (net) = 12.5 ha x 10,000 m2 x 0.024 m = 3,000 m3. (iv) Allow for operational efficiency – spills, flushing, backwashing, over irrigation, then overall system losses in order of 5 to 8%, take system efficiency to be 92.5%. (v) Overall system water requirement per irrigation machine = 3,000 / 0,925 = 3,250 m3. (vi) Assume 12.5 ha irrigation completed in a 15-hour day, then flow rate required is: 3,250 / (15 * 60 x 60) = 60 l/s or 217 m3/hr.

Thus, for the main fodder/wheat irrigated area, possibly interspersed with some potatoes (not recommended as difficult then to balance the different crop IWR norm if crops are intermixed), a flow of 217 m3/hr. is required.

229. Besides the use of lateral move sprinklers for the main irrigation command area, there are two smaller peripheral areas at the eastern end, on the south side of the sprinkler block, which could readily be developed for mixed vegetable and potato production. This is close to a natural drain where the soils would be fine and fertile, just downstream of where the main supply pipeline crosses from south to north. It is proposed that, subject to further interest, this area be developed with a roll out drip irrigation system, taking water through a spur pipe from the main pressure supply pipe, with a pressure regulating valve and drip filtration system to ensure suitable overall water quality for small diameter drip systems with inline emitter pipe. There could if required be a supply from this system to any greenhouses that are developed. The total area is about 30 ha, so a combined flow rate for 100 l/s (i.e. 3.3 l/s/ha) should be sufficient to satisfactorily irrigate these crops over 100 days. That is: 100 days x avg. 15 hours per day x 60 mins x 60 secs at 95% efficiency = 18,750 m3. The peak flow rate for the whole vegetable and potato block (30 ha) will be about 80 m3/hr. with flow rotated between sub-blocks on a 5- to 6-day cycle. Irrigation water can be provided on a needs basis over the growing season, taken to be 100 days, and it has been assumed that the systems would operate for at least 18 hours per day up to 24 hours for peak demand. The remaining block header and lateral in-line dripper sizing and flow rates will need to be determined with the potential equipment supplier.

230. Drip Systems. Drip system 1 will be set up specifically for vegetables and potatoes in the south east corner of the command area, covering 30 ha outside of the coverage under the sprinkler system. Again, the detail for how this would operate will need to be determined with the equipment supplier, but water demand is established based on uniform irrigation over the whole area on at least a 15-hour day. Pressure will always be available in the main water supply pipe. The tee for the drip system of the supply pipe should be located on the downstream side of the supply pipe with backwashing fine sediment filter,24 which when operating discharges to the nearby southern drain. The drip systems will also have filtration elements to trap any finer sediments that could otherwise over time clog the in-line emitters suggested for this drip system. In-line emitter constructed pipe is much easier to roll out and rollup once the crop is established or once irrigation stops for the season.

23 Based on 2 irrigators making a circular cycle around each of two buried field pipes with 8 hydrants on each, 400 m apart. Actual details will need to be checked and adjusted at detail design stage. 24 The back washing filter includes additional pipework and valve controls so that in the section of pipe where the filter is located, and through which all irrigation water will flow, periodically, valves can be activated to enable the flow to go through the filter in the reverse direction, so as to wash entrapped sediment out through a scour valve to the nearby drain.

Downstream of the filtration set, there will be a main low pressure (up to 2 MPa) header pipe, about 150 mm diameter and 800 m long, which then supplies subsystems consisting of 100 mm diameter, 200 m long section distributary pipes, feeding multiple lateral drip lines, running down the slope (to offset pressure head loss when flowing). Drip emitters can be chosen for the appropriate flow rate, through reference to manufacturer design guidelines. Typically, these can work at rates from 0.5 to 3 l/hr., and actual application rates can be matched by adopting appropriate spacing. Higher flow rates will saturate soil over a larger area but may be less efficient due to percolation loss. Closer inline spacing can be adopted to suit the plant spacing and minimize wetting areas away from the effective plant roots.

231. Drip system 2 will be for the 5,000 m long (total length on the north and west of the command area) by up to 10 m wide windbreak (5 ha) depending on how the two tree lines and 2 fruit/nut bushes are spaced (see generic design, (Annex 1). The arrangement for tree spacing and fruit/nut bush positioning to form an effective windbreak will determine how the drip main line, spur lines and laterals can be laid out, and the supplier will need to determine the appropriate layout to optimize pipe sizing, maintenance of effective operating pressures, taking water from the tail of the main pressure supply pipe. Suitable pressure regulating and filtering will be needed to ensure long life for the dripper lines, which will likely be installed and remain permanently in place. Pipes would be fitted with end stops so they can effectively be drained before the winter rollup. The windbreak layout might also include land forming to capture rainfall runoff (a drain) and consideration could be given to including small checks in the drain to retain water for nurturing the trees and bushes.

232. Figure 34 shows the overall layout of the upgraded Yolton Irrigation Scheme, Figure 35 provides an overview of the proposed irrigation command area. The command area is protected by formed banks on the downstream side of drains cut to run water around and/or away from the command area (see generic designs, (Annex 1). If at the detail design it is assessed that there is some advantage to incorporate the windbreak with the drain, thereby entrapping runoff to sustain the trees, then this will need to be more fully assessed and detailed prior to construction.

Figure 35: Plan for Yolton Lateral Move System for Command Area of Irrigation System

Source: TA Consultants

233. Drainage: will be needed to protect the area against the risks of large overland flows, coming from the south and east for the southern drain (Figure 36) or from the north for the northern drain. These should be formed as relatively wide natural earth channels, with material pushed up on the low side to prevent any risk for water to spill across the drain and into the command area. The pushed-up material will generally be won from the formation of the drain, that will follow the natural fall alongside the command area until it can be freely released to the natural drainage systems at no risk to the command area or any other system infrastructure.

Figure 36: Command Area with planned alignment of protection and outfall drains

Source: TA Consultants-Based on Google Map

234. Any exposed infrastructure may also need to be protected, including pipes, canals, cropped area, windbreaks, roads and associated structures from the uncontrolled risk for erosion from overland flow or any infrastructure failure. The main form of protection would be pushed up earth banks suitably position and shaped to deflect any runoff around the key infrastructure and cropped area. The only structures specifically foreseen to protect infrastructure from runoff risks are: (i) Rock armored protection in the bed and sides of the drain in proximity to crossing the installed pressure pipeline where it crosses the southern drain; and (ii) Possible installation of a short piped section in the upper main canal (from 100 to 200 m) to facilitate, with flow management banks, the safe passage of runoff flows from the foothills over the line of the main canal, and thereby mitigate the risk for disruption of diverted water from the Ust Chatsran river.

4. Design Discharge

235. The head work’s maximum discharge capacity is 0.20 m3/sec, the water flow in the main canal is nominally 0.20 m3/s (0.17 m3/s needed on a steady basis), in the main pressure pipeline up to 0.19 m3/s and in the distributary pipelines is 0.09 m3/s. The maximum volume of water stored in the off-river balancing storage is 346,000 m3. Under the new design, it is proposed that the intake structure to supply water from the river to the balancing storage be position in a barrier wall across the Chatsran River in the foothills, to be located at the most suitable position between riverbed level of 1810 m to 1830 m. This barrier will create a reliable pool from which water can be diverted via a stable and secure intake structure, feeding the old main canal, with some sections reformed and lined, and a section between km 1.0 and 1.2 possibly piped to provide a protected section for overland flow to pass without damaging the canal.

236. The river water flow available to maintain the balancing storage for irrigation varies from 0.3 m3/s to a maximum of 1.10 m3/s, with the peak flow available in July. The water extracted from the river for irrigation will be taken from a pool formed by a barrier across the Ust-Chatsran river. The pool depth would be between 2.5 and 3 m at the wall face across the river. Peak flows would be free to pass over and included and armored weir (concrete or rock-filled gabion baskets), with under extreme conditions the possibility for some shallow flow over the full width of the weir. The barrier wall will include an impermeable core to weir level. The left abutment would contain the intake structure, where the barrier wall height would be 0.5 to 1.0 m higher through to the abutment, thereby keeping water on the river side of the main canal.

237. The average potential discharge flow in the main canal can vary through the months from 0.11 to 0.18 m3/s. These flows range from 0.7% to 9.2% of the net river flow (Table 30). Following discussions with local people during the field survey, it was understood that the Ust-Chatsran river can run dry during droughts. The development of the secondary but permanent intake pool will be a positive safeguard against such conditions except where the drought extends over multiple years.

Table 30: Available Water Discharge from the Ust-Chatsran River Irrigation Net Off-river Water extracted from Design Discharge for Main Water Supply period Available water the river for irrigation Infrastructure a m3/s Water from pond Main Pressure Distributary river, m3/s m3 Main Canal Pipe Pressure Pipe m3/s % m3/s m3/s m3/s May 0.31 346,000 0.08 9.2 0.17 0.19 0.09 June 0.32 346,000 0.08 9.1 0.17 0.19 0.09 July 1.10 346,000 0.06 3.5 0.17 0.19 0.09 August 0.93 346,000 0.01 0.7 0.17 0.19 0.09 September 0.88 346,000 0.05 6.1 0.17 0.19 0.09 a Design discharge capacity does not mean that this flow is taken all the time or at the maximum rate. Source: TA Consultants

238. The broad operating parameters for the proposed pressure systems taking advantage of the natural topography from water source to field application are summarized in Table 31. The high available hydraulic head from the balancing storage means that the all the sprinkler and drip systems can be reliably pressurized and operate under acceptable pressure range without any pumping. Final design may lead to some adjustments to these numbers, but even if flows have to be adjusted the head can be managed successfully through prudent pipe sizing. Where the available pressure in the system is too high, then some regulation (flow control valves) will need to be included in the layout.

Table 31: Flows and Pressure in System Pipes Pipe Section ha Length (m)Static Level Head Gain Start CommentFlow Pipe Diam Friction Head Net Head at Start Finish m Press m m3/hr m3/s mm m end Main 322.5 3,700 1696 1624 69 3 water in pond 782 0.1866 350 36.5 35.5 Distributary (2 No.) 144 3,000 1624 1596 28 25 regulated 350 0.0972 275 21.6 31.4 Drip 1 30 800 1612 1607 5 20 regulated 73 0.0264 200 5.6 19.4 Drip 2 4.5 250 1624 1631 -7 25 regulated 11 0.0031 80 1.3 16.7 Source: TA Consultants

5. Civil Works

239. The main civil works for the diversion headworks from Ust-Chatsran River, and conveyance of water to irrigation sprinkler/drip systems in the command area will include: (i) construction of a rockfill barrier wall (up to 5 m high, u/s slope 2:1; d/s slope 2.5:1, top) with impermeable core, about 250 m across the Ust-Chatsran River channel between natural abutments (east and west), at a location to be confirmed downstream of the existing but broken intake channel; (ii) incorporation of a reduced level (-1 m) reinforced concrete spillway section, up to 10 m wide, to control pool water level upstream, and pass moderate excess flows back to main river, over an armored spillway on the rockface of the barrier wall; (iii) construction of a new intake structure in the barrier wall at the head of the existing intake channel, with vertical screw lift sluice gate, with free release of the small flow (up to 0.2 m3/s) into the main canal; (iv) construction of a sediment sluicing channel in the box section of the new intake structure, with a sluice gate (0.5 x 0.4 m) to the right side of the new barrier wall, for periodic sediment sluicing; base of sediment collection chamber to be formed for effective guidance of sediment under flow toward sluice outlet; (v) construction as necessary (cutting, forming, shaping and protection) of a channel to carry sediment back toward the river on the downstream side of the barrier wall, away from the toe of the embankment; (vi) to the west of the main canal and intake structure, formation of a revised Soum road alignment, that goes up and over the left abutment of the barrier wall and around the edge of the water pool formed by the barrier wall; (vii) reformation and re-lining/repair of the main canal to balancing storage (about 5,500 m, subject to actual start and finish location); suggested inclusion of a 100 to 200 m buried pipe section with inlet and outlet transition structures, this section to allow for the high risk for overland flow that can pass over the main canal alignment, inclusive of any necessary water guidance and protection earth embankment (to be detailed later);main (viii) main canal discharge structure into the balancing storage (southern end) to calm inflow velocity from the main canal, and to minimize scour when the balancing storage is low, this should be set close to the low water level in the storage (it can be submerged without issue); (to be detailed, assume lump sum provision in the costs for the main canal); (ix) intake structure to main pressure pipeline, inclusive of secure penstock gate or closure valve, to enable full sealed closure, with rake actioned pre-intake coarse and medium screens (trash racks) for control and removal of windblown and washed in trash and sediment, pre-entry to pipe, or else some other durable form of filtration to mitigate entry of trash and debris; ensure design includes access to the structure, which must be positioned to enable water withdrawal down to the dead storage level of the storage (perhaps 2 to 3 m below high water level (HWL)); (x) main pressure pipeline from header canal (2,557 m long, 375 mm diameter, pressure rated PN 6 to PN10 as static and dynamic head combined) to feed the 2 main distributary pipes and two drip irrigation systems; (xi) main pressure line backwash filtration unit with associated flow control valves and pressure surge vessel to ensure clean water operations for irrigation systems; (xii) 2 distributary pressure pipelines (6,000 m, 275 mm diam., PN 6) to be installed, completed with 8 No. vertical 200 mm diam riser pipes (1.5 m long), each with a blanking cap and butterfly valve, on each 3 km long distributary, total no risers 16;

(xiii) reforming or building new U-shaped earth drains (up to 8.5 km to protect the canals and command area, and enable clear drainage of rainfall runoff and any canal overspills; (xiv) installation of various flow control, pressure regulation and outlet structures in the main pressure and distributary pipes (est. 5 x 350 mm; 4 x 275 mm, and 16 x 200 mm); (xv) development of the windbreaks (4.2 km) on the north and west sides of the command area.

240. At this stage, the design and related details are preliminary, and as detail design and operational requirements are clarified, some additional works may be identified (e.g. additional protection measures for pipes, construction of field covered and protected valve boxes, minor earth checks in drains to support windbreaks).

6. Equipment

241. Within the civil works, required equipment will be limited to gates, HDPE pressure pipes HDPE and associated fittings to the sprinkler system connection hydrants. The following specific equipment, some of which was mentioned for installation with civil works are: (i) The Water Intake – one vertical lift sluice gate with preliminary 1.0 m wide and a 0.6 m lift; (ii) Intake Sediment Sluice – vertical lift sluice gate, provisionally 1.0 m wide with 0.6 m opening, sufficient to flush rapidly at up to 1 m3/s, details to be finalized around operational and physical levels at site; (iii) A pressure pipe (350 mm diameter) intake control valve or penstock gate, with long spindle for the release of water from the balancing storage into the main pressure pipe; (iv) Provision and installation of various valves and fittings (No. and open diameter (mm)) as per Table 32; (v) Two self-propelled lateral move sprinkler sets, 250 m spray width, single sided with flexible hose connection to field hydrants (200 mm diam) to track up and down the line of the distributary pipes, all inclusive of power supply, flow controls, and associated spare parts, spray nozzles and drop pipes suitable for particular crops, all details to be discussed with potential suppliers before confirming detailed specifications (specifics of lateral drive to be discussed and agreed based on local electricity power available, and the operational convenience of available options; (vi) One low pressure drip filtration, pump and control station, with sufficient associated main and connecting drip pipes, for up to 5 ha; (vii) Provisionally, one or more sets of low-pressure micro spray and/or drip systems for installation in greenhouses (size and number to be determined), should the option to develop such facilities at the eastern end of the header canal be approved; (viii) Provision of relevant power supply infrastructure, whether connection to main national or local electricity grid, inclusion of diesel power and generator sets, or provision of diesel power to drive irrigation systems (pumps, self-propulsion, etc.) [there is an expectation that adopted sprinkler equipment would include suitable on- board power controls and drive mechanisms if electric power supply and cabling is not viable].

Table 32: Estimated Pipe, Valve and Filter Set Requirements Pipe Intake Valve Outlet Valve Scour Valve Filter Seta Emitters b Main 1 x 350 1 x 350 1 x inline

Distributary 1 1 x 275 8 x 200 1 x 275 Distributary 2 1 x 275 8 x 200 1 x 275 Drip 1 1 x 200 with pipe 1 x inline inline Drip 2 1 x 80 with pipe 1 x inline inline a inline filter sets process all flow, and include provisions with their installation for local flow management (valves) to use the line pressure for backwashing the filters, Specific details and arrangements to be discussed with suppliers. b These are pressure compensating steady flow rate emitters installed in the rollout drip lines during manufacturer at specified intervals as required. Source: TA Consultants

7. Bill of Quantities

242. The cost estimation for Yolton Irrigation Scheme construction and equipment is given in Table 33.Table 78 The table summarizes the cost for key components required for the upgrading and modernization of the Yolton irrigation scheme. The estimated cost is MNT7,425.58 million, equivalent to MNT23.20 million/ha.

Table 33: Bill of Quantities for Yolton Irrigation Scheme Modernization Budget No Item Unit Quantity (MNT million) Unit cost Total Civil Works Headworks Sluicing structure with intake sluice 1 piece 1 72.68 72.68 channel and outlet flushing channel Rockfill Barrier and Water level Control Weir, Wall 2 m 420 2.87 1,207.47 L=420 m, h=3.75 m, Weir L= 13 m, h=1.0 m 3 Headworks protection embankment m 500 0.04 18.48 4 Main Canal m 5,620 0.14 772.30 5 Main pressure pipe m 3,300 0.07 230.73 6 Distribution pressure pipe m 6,400 0.08 534.91 7 Balancing reservoir m3 14,000 0.03 420.00 8 Drain well no 10 3.02 30.20 9 Bridge piece 3 4.06 12.18 10 Roads – forming and grading m 10,100 0.00 33.03 11 Windbreaks – prepare land and install ha 4.7 44.41 208.72 12 Drain and protection bank m 9,200 0.03 293.13 13 Fence km 10.1 7.00 70.70 14 Pump station no. 1 100 100 Subtotal 4,004.53 Equipment Head work Control Sluice Gate, Width 1.0 m x 12 piece 2 1.68 3.36 Height 0.6 m, vertical screw 13 PE400, SDR17, 1,0mpa, DN400mm, PN10 m 3,300 0.18 604.26 14 PE400, SDR17, 1,0mpa, DN250mm, PN11 m 6,400 0.08 510.62 15 Culvert for bridge (0.75x0.75 m) piece 3 1.48 4.43 Lateral Move Sprinkler sets install, commission, 16 – set 2 210.55 421.09 train, with x years parts 17 5ha Water Efficient Drip Watering Advanced System set 19 43.47 826.02 18 3ha Water Efficient Drip Watering Advanced System set 19 Trees, number number 14100 0.004 56.40 20 Pump, piece 2 15.00 30.00 21 Excavator for O&M piece 1 168.60 168.60 Subtotal 2,624.78 21 VAT % 37.91 662.93 22 Environmental baseline assessment number 1 42.67 42.67 23 Environmental impact assessment number 1 42.67 42.67 24 Design cost ha 320 0.15 48.00

Sub-Total 796.27 Grand total 7,425.58 Source: Consultant’s estimates

D. Subproject 3 - Erdeneburen Irrigation and Drainage System Design

1. Site Description

a. Scheme Background

243. The Erdeneburen Soum owns the Erdeneburen irrigation scheme. The original irrigation scheme was developed in 1985, with an open main canal from the Khovd River to supply water for up to 2,000 ha of fodder production, to partly fulfil the large demand for fodder in Khovd aimag. However, since the transition to democracy in the early 1990’s, the original irrigation scheme, with pumping, pipes and irrigation sprinkler machines (center pivots), has been stripped of almost all assets. There remains about 50 ha of partial low technology irrigation for fruit trees and some vegetables, with some occasional irrigation of grassland near the trees. A settlement had been established when the scheme was developed and operational, but this has now disappeared. Due to the topography and the source of water, the scheme required mostly pumped sprinkler systems to cover the design command area, with only the small existing area able to operate, as now, under gravity. The main canal and an off-stream storage pond are still in place, though in poor condition due to siltation and low maintenance, but there are some fruit trees and windbreaks still supported where the scheme starts, before the main irrigation area that had been planned and partly developed for up to 22 center pivots.

244. In the absence of reliable irrigation, the scheme area is now used for mostly grazing, but it has been assessed as having good fodder production potential with irrigation. The overall objective for development (upgrade and modernization) is to help reduce the dependency that the aimag now has for importation of fodder to the region to support the growing livestock herds through the winter. Erdeneburen Soum does have other small areas developed for the production of some limited vegetable crops, potatoes and fodder, but the Soum desperately needs both additional vegetable production for self-sufficiency, and fodder production to satisfy the local regional market.

245. The existing Erdeneburen irrigation scheme is in serious decline (Figure 37), and major investment is needed to upgrade and modernize the primary water supply from Khovd River and the irrigation infrastructure and operations. The overall irrigated area is currently about 50 ha, but the intention is to increase this to 2,000 ha of mostly fodder. At the present time, the main part of the scheme is inoperable. Water passes through the existing main canal, but there is no means to control the flow down the slope from the river intake headworks. Limited effective use is made of the uncontrolled flow in the command area.

Figure 37: Current Situation for Erdeneburen Irrigation Scheme

Upper left: small off-stream storage pond (frozen); Upper right: water pond head work structure; Lower Left: remnant fruit orchard and windbreak; Lower Right: main canal and unused command area Source: TA Consultants-site visit

b. Area and Crop Maps

246. Geomorphology. The project area, at 1,203 to 1,220 masl, sits within ranges of the Mongolian Altai Mountains, with elevations from 2,100 to 3,360 m around the soum area. The project area is bounded on the north by Tsambagarav mountain (3,060 m), to the east by Altankhokhii mountain (3,351 m), to the north and east by the Khovd river, and to the west by the Khagiin Khuush mountains (2,141). The valley of the project area is formed from stream alluvial, proluvial and alluvial-proluvial accumulative fans, which remain active and will need to be managed with effective drainage to protect the developed command area and water supply infrastructure.

247. The Erdeneburen irrigation scheme is located 15 km north-west from Erdeneburen Soum center, Khovd Aimag, and lies adjacent to the right bank of a branch of the Khovd River (Figure 38). The intake is about 2 km upstream from the command area and continues for about another 5.7 km along the southwest side of the command area with a pumped and pipe system to then branch into groups of planned center pivots. Each group will consist of four center pivots with a supply pipe size sufficient to provide water to irrigate one center pivot circle at a time. The pipe capacity may also be enhanced to provide water to supplementary irrigation systems that water the void areas between the circles and at the boundary of the command area. Whilst the center pivots deliver the main cropped area watering, these supplementary systems could deliver targeted water to none circle zones, either for crops grown through and across the circles, or for

86 alternative crops such as potatoes in the larger rectangular 25 ha blocks, or perhaps fruit or vegetables (possibly with some greenhouses) in the smaller 12.5 ha triangular blocks. The use of movable pipe sprinkler systems, spray (boom and rain gun) systems, or drip options can be selected based on the required cropping. If the primary water is satisfactorily filtered at the pump station, then no additional filtration would need to be installed for these small scattered systems.

Figure 38: Location of Erdeneburen Irrigation Scheme

Legend: Headwork, Main Canal, Field Source: TA Consultants-based on google map

248. There used to be a settlement when the scheme was working with part surface canals and some pumped sprinkler systems, but all the equipment and most signs of what used to be associated with the irrigation scheme has now gone. The main canal and a what appeared to be a small system balancing pond, which does not show clearly on Google Earth imagery, remain, but both are filled with sediment and windblown sand. The only remnants of the irrigation scheme that remain are some fruit trees and partial windbreaks near the head of the irrigation area (western side).

c. Climate

249. Meteorological observations at Erdeneburen soum began in 1985, and there are now 34 years of time series data (1985 to 2018) of monthly mean air temperature, wind speed and monthly precipitation data. Analysis shows that the climate is sharply continental like many other regions of the Altai mountains. It is characterized by dry air, with relatively low rainfall throughout the year, and has significant weather variability for both individual seasons and between years.

250. In Erdeneburen irrigation subproject area, the daily temperature throughout the growing season will exceed 30oC (maximum daily) between May and August, and humidity is typically in the 40 to 50% range. Average monthly precipitation varies from: 10.4 mm in May, 25.6 mm in June, 30.4 mm in July, and 23.4 mm in August, with an overall annual average of 137.1 mm. Typically 40% of this rain falls in June and July, and 75% falls in the period May to August. The average wind speed for the year is 3.1 m/s, with peak wind speed experienced at the beginning of the crop growing months. As the April mean temperature is 5.5oC, and below the 10oC crop growth threshold, there is insufficient natural warmth in the air to support crop growth for most of that month, so irrigation is not implemented. Mean monthly climate data for the Erdeneburen project area is given in Table 34.

Table 34: Mean Monthly Climate Data in the Erdeneburen Irrigation Subproject Area Average Maximum Minimum Humidity Wind Precipitation Temperature Temperature Temperature % speed mm oC oC oC m/s January -24.7 3.7 -45.3 80.2 2.33 1.9 February -19.3 9.2 -45.2 74.8 2.58 2.5 March -6.8 21.3 -35.9 57.1 3.22 5.4 April 5.5 28.5 -21.5 44.1 3.90 7.1 May 13.1 32.5 -6.3 42.0 3.85 10.4 June 19.0 38.5 0 47.0 3.27 25.6 July 20.2 38.9 2.2 52.5 3.19 30.4 August 18.0 38.8 -1.5 52.6 3.00 23.4 September 11.8 32.0 -9.6 51.0 3.18 13.5 October 2.6 26.5 -17.8 54.1 3.09 10.3 November -9.9 15.6 -33.3 66.4 3.00 3.4 December -19.8 10.1 -44.2 77.9 2.43 3.0 Average 0.8 38.9 -45.3 58.3 3.1 137.1 Source: National Agency for Meteorology and Environment Monitoring

251. Air Temperature Trends. Air temperature trends are shown in Figure 39, which shows that monthly mean air temperature change for the months from April to September has been more-or- less consistent. April mean temperature has increased by 6.0oC, May by 2.4oC, June by 4.4oC, July by 6.4oC and August by 3.6oC, and September by 1.2oC. On balance, it is perhaps reasonable to assume there has been a significant shift in the mean annual growing season temperature, though there are some shifts that could impact crop production. With increased temperatures in the crop growing months, it is likely increased irrigation would be required.

Figure 39: Trend in Monthly Air Temperature at Erdeneburen Irrigation Scheme

Source: National Agency for Meteorology and Environment Monitoring

252. Duration of hot days. This an important climate factor that influences irrigated crop production is the duration and number of hot days. Figure 40 shows the number of days each year where the daily average air temperature exceeds 25oC has increased by 32 days over the past 34 years. Despite this, the average number of days where air temperature has exceeded 30oC has only increased by 8 days.

Figure 40: Trend in Hot Days with Daily Mean Temperature Greater than 25 oC and 30oC

Source: National Agency for Meteorology and Environment Monitoring

253. Precipitation. Annual average precipitation is 137.1 mm. Figure 41 shows that monthly precipitation change for the months of April to September has not occurred consistently. For May and July, precipitation has decreased by 8 mm and 22 mm respectively, while for April, June and August, precipitation has increased by 1 mm, 6 mm and 3mm respectively. The major loss in monthly precipitation has occurred during the hottest month of July, signaling the irrigation is especially critical then for effective crop production.

Figure 41: Trend in Monthly Precipitation at Erdeneburen Irrigation Scheme

Source: National Agency for Meteorology and Environment Monitoring

254. Though there is an increase in precipitation for most months in the growing season, the number of days occurring with no precipitation has seen only a small decrease for May and July, but a more substantial decrease in June by 9 days, and 6 days in August (Figure 42).

Figure 42: Trends in Days with no Precipitation

Source: National Agency for Meteorology and Environment Monitoring

255. Wind. The monthly mean wind speed in the growing season tends to be slightly higher than for other months (Table 34). Even though the mean wind speed for the months of April (3.9 m/s), May (3.8 m/s), June (3.3 m/s), July (3.2 m/s) and August (3.0 m/s) are low, the number of days when the wind speed has exceeded 10 m/s has increased by 29 days over the last 34 years (Figure 43). Thirty percent of the wind comes from the northwest, and 20% from the southwest (Figure 43). To protect the irrigated area against strong winds, a windbreak should be developed mainly to shield the command area from the strong northwest and southwest winds.

Figure 43: Trend in High Wind and Wind Direction

Source: National Agency for Meteorology and Environment Monitoring

256. Agro-climate. Changes in agro-climatic characteristics (Figure 44) indicate that over the period from 1985 to 2018, the growing season length has increased by about 20 days due to a shift in when the daily air temperature transitions above 10oC (earlier dates in the spring) and falls below 10oC (later dates in autumn). The accumulated temperature that supports longer crop growth with frost free days has increased by about 10 days in the spring to about 8 days in the autumn, giving an increased number of growing days by 18 days per year, thereby favoring greater crop growth.

Figure 44: Agro-climate Characteristics

Source: National Agency for Meteorology and Environment Monitoring

257. Projections The summer temperature at Erdeneburen irrigation scheme is projected to increase by 1oC, to 2.0oC (Figure 4), and annual precipitation to increase by 10% (Figure 5), during the period from 2035 to 2065. A continued increase in temperature with a slight increase in precipitation are the most likely combined future impacts that will necessitate increased irrigation applications over time.

d. Soils

258. The Erdeneburen irrigation subproject soil map is shown in Figure 45. The predominant crop root zone soil types in the command area are weak developed sandy kastanozem and light kastanozem (silt loam).

Figure 45: Soil Map of Erdeneburen Command Area

Source: Institute of Geography and Geo-ecology

259. Soil-particle analysis indicates the texture is sandy loam and 60-70% of soil is sandy. The ‘B’ horizon is more compacted, no roots in this zone and more sandy clay loamy soils (Table 35). Stone and gravel of more than 2 mm fraction accounts for about 10% of the soil, located river side as riparian area soil. Soluble nitrogen contents are low, about 9-10 mg/kg; plant available phosphorus levels are very low, about 4-5 mg/kg; and exchangeable potassium levels are 35-40 mg/kg, which means not insufficient nutrients for adequate plant growth (Annex 2).

260. The soil surface is affected by wind erosion. Soils are high organic matter 3.4% dark brown and high nutrient levels. The ‘A’ horizon was low reacting with 10% hydrochloric acid and ‘B’ and ‘C’ horizons showed no reaction, indicating that the soils are weak alkaline or near to neutral. Carbonate contents are around 0.1%, secondary carbonate sediment collected to soils. Soil pH=8.3 and EC= 60-80 μS, which means there is low salinization effect to the crops (Annex 3).

Table 35: Soil Profile of Erdeneburen Command Area Soil Depth, Characteristic horizon m 1 A 0.0-0.3 sandy loam, very low organic matter, grey brown color. middle carbonate content and high-density soils 2 E 0.3-0.6 Sandy clay soils. No carbonate 3 B >0.6 Sandy loam. No react with carbonate content 4 C >1.8 Gravel and sandy loam.

Source: Integrated agricultural laboratory

261. Soil cation exchange capacity is very good, around 7-8 meq/100g, meaning cations bind with clay particles and indicating soil will able to deliver nutrients to plant roots.

e. Water Sources

262. The main water source for irrigation is the Khovd river (Figure 46), with water trapped by a low barrage across a branch of the river. To assess the water resources available for Erdenebuuren irrigation scheme, 44 years of time series data (1973 to 2017) from Bayannuur and Myangad gauging stations have been used. The Bayannuur gauging station is located well upstream of Erdeneburen whilst Myangad gauging station is located downsteam of the irrigation scheme.

Figure 46: Location of Erdeneburen Irrigation Scheme, Hydrological Gauging Stations and Meteorological Observation Stations

Source: TA Consultants-based on National Atlas

263. Table 36 shows monthly mean flow data from Khovd-Bayannuur river gauging station, which ranges from 62.4 m3/s to 180.3 m3/s during the growing season. The monthly environmental flow requirement is set at 55.7 m3/s as 90 percent of the long-term average 61.9 m3/s (Error! Reference s ource not found.). This means that the Khovd River, just upstream of Erdeneburen, has an average monthly mean flow of at least 20.1 m3/s after meeting the environmental flow requirement in May, and more in other months through to August. Even then, the monthly mean high flow can be 111.8 m3/s in May up to 361.0 m3/s in July, while the low discharge can fall below the environmental flow requirement in all months except July. In general, there is more than enough water for reliable irrigation at Erdeneburen during the growing season, though some prudent storage management in May and June would be beneficial for potential dry years.

Table 36: Water Resources in the Khovd River at Erdeneburen Irrigation Scheme

Mean Mean Environ- % of Net water available for use Mean Maximum Minimum mental Annual Month Discharge Discharge Discharge 3 flow Discharg (m /s) 3 3 (m3/s) (m3/s) (m3/s) e (m /s) m /month April 50.1 7.64 28.0 55.7 3.77 - May 111.8 23.9 62.4 55.7 8.40 6.69 17,918,496 June 272.0 53.9 154.2 55.7 20.8 98.49 255,286,080 July 361.0 63.4 180.3 55.7 24.3 124.59 333,701,856 August 238.0 51.1 126.1 55.7 17.0 70.39 188,532,576 September 127.9 26.8 70.4 55.7 9.48 14.69 38,076,480 October 105.1 17.9 44.1 55.7 5.94 - November 38.7 9.65 26.5 55.7 3.57 - December 28.2 7.01 16.9 55.7 2.28 - January 22.8 4.22 12.2 55.7 1.65 - February 30.1 3.30 10.3 55.7 1.38 - March 32.1 3.27 11.3 55.7 1.52 - Source: National Agency for Meteorology and Environment Monitoring

264. The Khovd river flow during the irrigation period from May to August has been increasing by 22 m3/s and 15 m3/s since 1973 in April and May while is decreasing by 30 m3/sin June, 60 m3/s in July and August (Figure 47). It should be noted that since 2010 the river flow has increased in all months. Figure 47: Khovd River Flow at Erdeneburen Irrigation Scheme (1973 to 2017)

Source: National Agency for Meteorology and Environment Monitoring

265. The Khovd River flow sensitivity to climate change is shown in Table 37. If precipitation remains unchanged and average temperature increases by 1°C, 2°C, 3°C or 5°C, then it is projected that the river flow could decrease by 3.4% (+1oC) to 15.3% (+5oC). The impact of precipitation declining by up to 20% is substantially more marked than if precipitation increases by 20%, but an increase of 5oC would almost eliminate any gains expected from additional precipitation. If precipitation has declined by 20%, then the reduction in river flow from increased temperature is relatively small. Overall, river flow is highly sensitive to reduced precipitation, but with unchanged or increased precipitation, the impact of increased temperature is more significant in moderating river flow.

Table 37: Khovd River Flow Sensitivity to Climate Change Temperature Projected Percentage Change in Precipitation Increase (oC) -20% -10% 0% +10% +20% 0 -62.1 -38.2 25.8 33.9 1 -63.4 -40.4 -3.4 20.8 26.7 2 -65.1 -42.4 -6.6 15.7 19.2 3 -64.8 -44.5 -10.0 10.6 11.7 5 -69.1 -47.4 -15.3 2.1 8.7 Source: TA consultant

266. Water quality. Water chemistry analysis for Khovd river from 2013 to 2018 is shown in Figure 48. The overall assessment is that the chemical composition of water in Khovd river is 2+ 2+ - good, where the concentration of Ca , Mg , SO4 and Cl do not exceed the irrigation water standards thresholds. The sodium adsorption ratio (SAR) that is a critical factor for sustainable irrigation is also found to be within acceptable limits, so it is concluded that water from the Khovd River is well suited for irrigation use.

Figure 48: Water Chemistry of Khovd River

Source: Central Laboratory for Environment and Metrology

267. Suspended solids in the Khovd River water range from 4.6 to 106 mg/l (or 0.004 to 0.1 kg/m3), but do not exceed 25 mg/l (0.02 kg/m3) most of the time (Figure 49). There is no clear seasonality to suspended solid concentrations, but there are periodic and short duration increases as a result of peak snow melt flows and summer flood flows when intense rainfall can lead to excessive runoff and peak river flows and water levels. There is therefore a need for careful management of water diversions from the river to contain suspended sediment discharge into the intake and canal/irrigation system, which may require additional sediment management measures at intake or through settlement and flushing basins aligned with the main canal.

Figure 49: Suspended Solids in Khovd River at Erdeneburen

Source: Central Laboratory for Environment and Metrology

268. Water quality in the rivers of the Khar Lake - Khovd River basin is classified “very clean”, based on water quality analysis and assessment against the Water Quality Index (WQI). Particularly, around Erdeneburen the WQI is 0.28 (Table 5).

f. Existing Irrigation System and Design Maps

269. The Erdeneburen Irrigation Scheme was originally designed to irrigate a command area of up to 2,000 ha. It is not clear from obtained information if the scheme had previously been developed to full capacity, with 22 center pivot circles, as available mapping and imagery does not show sufficient detail. However, it is clear there is adequate land and water available to safely irrigate 2,000 ha if the scheme is redeveloped.

270. Water for the scheme is obtained from the right bank of a branch stream of the Khovd River. This branch already has a low-level weir installed that maintains a water pool in the branch at about 2010 to 2011 masl. An intake structure is sited immediately upstream of the weir right abutment, from which there was originally a lined canal, now in poor condition, that conveys water 2 km to a small off-stream storage and/or the intake headworks for the schemes main canal. From the main canal that runs along the high (south western) side of the command area, the original design shows pipe intakes to distributed pump stations (6 no.) down the slope, which would supply water to groups of center pivot areas (3 x 62 ha; 19 x 86 ha). None of these pipes and pump stations remain, if they were in fact ever installed, so it is now possible to undertake a wholly new approach and design for this scheme. However, as there is only a small head difference in water level between the river pool and the command area, and as surface irrigation would be inefficient on highly permeable soils, the primary solution for irrigation of this sloping land (s = 0.004416 or 1 in 225) is pump, pipe and sprinkle water over the land. This could then lift irrigation efficiency to the low 90%, with minimal additional water loss in the open canal and balancing storage.

271. What remains of the existing Erdeneburen irrigation scheme is limited to about 50 ha of fruit trees and vegetables for the soum, which lies 10 km south of this small area, and sits 50 m higher. It is proposed that as part of the redevelopment of this scheme, a small drip system could be installed to provide more reliable irrigation for the trees and vegetables, controlled from the same pump station needed for the modernized main command area. The overall command area of the scheme is shown in Figure 50. To get water reliably to the irrigation scheme, an improved intake and main canal will be required, adequately sized and protected, together with development of a larger and more reliable water balancing storage from which the pumped schemes will draw water. Currently the main command area receives no water, and there is only irrigated crop production from the small tree and vegetables area at the start of the command area. Following discussions with local government, it is understood that the modernized irrigation scheme command area will be allocated to grow approximately 100 ha of potatoes, 200 ha of vegetables, 1,150 ha of fodder, and 500 ha of grains. This will then enable the soum to provide fodder to not only the soum but also to fulfil some of the demand in other parts of the aimag.

Figure 50: Erdeneburen Command Area

Source: Ta Consultants

2. Irrigation Water Requirement

272. The designed command area is 2000 ha out of which100 ha for potatoes, 200 ha - vegetables, 500 ha – cereals, and 1195 ha – fodder. There is 5 ha for tree wind break. It is proposed to plant leafy trees at two rows and one row bushes to the west and west-northern boundary of the command area according to the wind direction data (Table 38).

Table 38: Current and Planned Command Area Crop type Current Allocation of Irrigation Planned Allocation of Irrigation command area method command area method Potatoes, ha 10 Furrow 100 drip Vegetables, ha 19 200 drip Cereals, ha 500 sprinkler Fodder, ha 1195 sprinkler Fruit trees and windbreak, ha 2.2 5 drip Source: Consultant’s estimates

273. Overall efficiency (Table 8) will be raised up to 73% using lined canal systems, pressure pipes, modern sprinkler irrigation machines for at least 85% of the area and low pressure drip systems for rest of the area and windbreak (Table 39).

Table 39: Scheme Irrigation Efficiency Characteristics Field irrigation Percentage of Conveyance Field Scheme application total efficiency application irrigation command (%) efficiency efficiency area (%) (%) Current for total Surface irrigation 100.0 60 60 36 command area (border, furrow, basin) Designed fodder area Sprinkler 85.0 95 75 71 Designed potatoes and Drip 15.0 95 90 86 vegetable Average for designed Combined sprinkler and 100.0 95 85 73 command area drip Source: TA Consultants

274. This irrigation season water requirement has been calculated based on the irrigation water utilization norm (Table 6) applicable for the region and planned crops. Following analysis for the future upgraded and modernized irrigation system development, the estimated total water use for the irrigation season, based on irrigation water utilization norm (Table 6) with the planned crops of potatoes, vegetables, cereals and fodder is 14,470,408 m3 (1.10 m3/s) with project and 14,792,938 (1.13 m3/s) with climate change (Table 39). This irrigation water accounts for 1.7 percent of total net available water in the growing season or about 0.6-2.0 percent of the river flow of the given month (Table 41), after meeting the environmental flow of 55.7 m3/s thus there is water available to meet the irrigation needs.

Table 40: Irrigation Water Requirements for Erdeneburen Irrigation period Item Total May June July August September Allocation of command area Potatoes, ha 100 100 100 100 100 Vegetables, ha 200 200 200 200 200 Cereals, ha 500 500 500 500 500 Fodder, ha 1,195 1,195 1,195 1,195 1,195 Fruit trees and wind break, ha 5 5 5 5 5 2005 Water requirement with project Gross irrigation norm (m3) 2,494,122 2,900,386 2,618,244 1,742,647 807,999 Irrigation efficiency (%) 0.73 0.73 0.73 0.73 0.73 Total irrigation water requirement (m3) 3,416,606 3,973,131 3,586,636 2,387,187 1,106,848 14,470,408 Water requirement with project with climate change Increase in Evapotranspiration, (m3) 673 4394 6222 3840 1734 1811 Projected irrigation Water Use (m3) 2,580,556 2,934,690 2,658,771 1,780,791 844,037 Irrigation efficiency (%) 0.73 0.73 0.73 0.73 0.73 Projected total water requirement (m3) 3,535,008 4,020,123 3,642,152 2,439,440 1,156,216 14,792,938 Source: TA Consultants

Table 41. Water Availability for Irrigation Projected total Percentage of Monthly Environ- irrigation water irrigation water Irrigation River ment Net available flow in the requirement with use from net river period Discharge, Flow, river project flow m3/s m3/s m3/s m3/month m3/s m3/month % May 62.4 55.7 6.7 17,918,496 1.27 3,535,008 2.0 June 154.2 55.7 98.5 263,795,616 1.52 4,020,123 1.0 July 180.3 55.7 124.6 333,701,856 1.33 3,642,152 0.7

August 126.1 55.7 70.4 188,532,576 0.89 2,439,440 0.7 September 70.4 55.7 14.7 39,345,696 0.42 1,156,216 0.6 Total 845,360,240 14,792,938 1.70 Source: TA Consultants

275. If the overall norm per season is 2,800 m3/ha for cereals, then the net irrigation depth per ha is 280 mm per year. To deliver this, at 28 mm per irrigation, and a flow rate in the irrigator of 8 mm/ha (about 100 l/s for a 100 ha center pivot), the irrigator will take 3 days to complete a circle, and 12 days to irrigate 4 circles, plus up to 2 days in total for moving the irrigator between circles. Thus, the irrigator can apply 250 mm in 10 cycles in 3.5 to 4 months, with some time lag between the 1st and last of 4 circles in each group. It can be assumed that water is being applied at any time at about 2 mm per day over the whole scheme. Thus, with 2,000 ha, the total volume of water required is 40,000 m3/day, equivalent to 1,667 m3/hr., and 0.463 m3/s, when operating 24 hrs. per day.

276. If an allowance is made for flow variance from the river, and for overall efficiency, then the peak flow required in the canal might be 2 to 3 times that required for irrigation. Thus, in way of a provisional conservative approach to scale the main canal, it is assumed that the required flow should be multiplied by 3. Therefore, the provisional maximum discharge capacity required at the headworks (intake from Khovd river) is estimated at 1.4 m3/s. This presumes that at peak demand, the irrigation work will continue 24 hrs. per day, except when irrigators are being moved between circles. The design command area is 2000 ha of mixed cropping, with 100 ha potatoes, 200 ha vegetables, 500 ha cereal, 1,195 ha – fodder and 5 ha fruit. There will also be about 11.5 ha for tree wind breaks to the northwest (2,300 m), and south-west (9,200 m). The planned irrigation demand for 2,000 ha of mixed cropping is estimated to require a peak pumped flow from storage of 0.515 m3/s (90% overall sprinkler system efficiency when operating 24 hrs. per day). For the purposes of preliminary design, assume a peak pumped water requirement of 0.6 m3/s, or 0.15 m3/s for each irrigation subset of 4 circles. Therefore, for the center pivot irrigators, 4 operational pumps (with an additional on standby) will be required, each capable of delivering up to 0.15 m3/s against an operational head (static plus dynamic pipe head) of 40 m.

3. System and Layout

a. Area Topography

277. The existing intake from the Khovd River pool is located at elevation 1,214 masl (riverbank level), at 48.35.44N and 91.25.20E, and the nominal river pool level is 1,213 masl (these positions and levels to be confirmed at detail design). This intake will have a closure sluice gate, but if feasible it would be optimal to have the TWL in the new balancing storage equal to the storage level in the river pool. The existing storage is relatively small and on the north side of the main canal, and partly filled with sediment. This has a relatively low level but can currently gravitate to the existing (50 ha) fruit and vegetable area.

278. The boundary of the main fodder/cereal/potato command area, starting 2.0 km downstream from the headworks sits at elevation 1,211 masl, at 48.34.53N and 91.26.21L (southwest corner of the center pivot area). To the north/northwest of this point is the existing fruit and vegetable surface irrigation (50 ha) – sloping to the north and the Khovd River. The north western corner of the command area is 2,300 m to the northeast at elevation 1,207 masl, with a slope of 1 in 575. The eastern side of the command area is 5.75 km away on a slight upward slope (1 in 525) to the southeast corner at 1,222 masl, and from there it falls to 1,200 masl in the

100 northeast corner over 4.6 km, with slope 1 in 210). The overall land slope is about 1 in 200 to 1 in 250.

279. The existing main canal was originally trapezoidal; but there is no information on the size. This canal to an existing small off stream storage with gated outlet is about 1.8 km long, with a grade of about 1 in 1,000. Detail survey will be needed if this is to be upgraded as part of the new system, though a wholly new main canal might be easier to construct on the required alignment to a new balancing storage that will act as a sump for the planned new multiple pumping station. The existing gated control structures near the start of the command area would no longer be required. There are no parts left of the originally designed pipe and pump irrigation system for up to 22 center pivots. The remaining fruit tree and vegetable area to the west side of the area is poorly serviced with an open channel (field ditch) supply.

b. New Irrigation System

280. Headworks Weir. The planned new irrigation system will include a revised gravity water supply system from source (Khovd River) to the start of the existing command area boundary, approximately 2 km from the river (Figure 51,Table 42). The gravity part of the system will include an upgraded and strengthened barrier across the river, with a weir length equal to the width of the river plus the addition of abutments to both banks, at a minimum level 1,214 masl. The abutments will blend into any additional embankments that may be needed alongside the river to at least contain a peak river pool water level up to 1,214 masl without overtopping. It is currently considered that under normal flood flows, the water level with flow passing over the weir (at river width) would rarely exceed (if ever) the indicated top of bank height, but a detailed check for this should be undertaken, and the abutment and bank design height should be raised if necessary.

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Figure 51: Erdeneburen Irrigation Scheme Layout

Source: TA Consultants

Table 42: Irrigation Design Option № Irrigation Scheme: Components and Value and Units Details 1 Gross irrigation scheme Area 2,100 hectares 2 irrigation scheme Command Area 2,000.0 hectares 3 Land Use Coefficient (1/2) 0.95 4 Main Canal (lined) Capacity and Q = 1,400 l/s, L = 1,350 m, d = 0.6 m, Dimensions Depth = 0.6 m, h = 0.8 m, m=1.5 5 Main Canal Intake Structure and Q = 1,400 l/s, see Annex 1 Sediment Sluice 6 Balancing Storage (water surface V = 100,000 m3, L = 250 m, W = 150 m, dimensions) d = 3.0 m, Top Bank = 1,214 masl, m = 1.5 7 Storage Inlet Structure and Escape see Annex 1 Outlet 8 Drains around Command Area up to L = 10,000 m, b = 1.0 + m, m = 1.5 9 Protection barriers around Command Up to L = 10,000 m, b = 2.0 m top, m = 1.5, h = up to 2 m Area 10 Pumping station intake pipework and see Annex 1 filtration units 11 Pump Station, 5 pumps (one standby), Details to be developed Power Supply and Control Panels 12 Drip Irrigation System for Windbreaks Q = 25 l/s, L = 7,000 m, A = up to 80 ha and Orchard/Vegetable Area 13 Pipes (HDPE or equivalent) to Center L = 24480 m, Diam (ID) = 500 mm, Pivot Irrigators (16 No.) L = 4600 m, Diam (ID) = 450 mm,

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№ Irrigation Scheme: Components and Value and Units Details L = 5690 m, Diam (ID) = 355 mm, etc. Diameter will be to standard available, OD or ID, best next size 14 Center Pivot Machines (4 No.) A = 100 ha, Radius = 565 m, App Rate = 8 mm/day 15 Road 10000 m, with surface area of 3 ha 16 Windbreak / Forest Strip L = 8,000 m, b= 10 m, with area of 8.00 ha 17 Small Sprinkler Equipment sets Up to X sprinkler units - to be used in multiple areas 18 19 Fence Length Up to 20.000 m Source: TA Consultants

281. Headworks Intake. With the weir upgraded and strengthened so water pool level can be maintained, a new gated intake and sediment sluicing arrangement (see schematic in Annex 1) should be installed at the right abutment, with two sluice gates, suitably sized to pass the design peak flow for the canal (1.4 m3/s). This intake structure would be rectangular in general form and embedded as an integral part of the embankment in the right abutment. It would include: (i) An intake sluice gate of appropriate size for flow with minimal head loss when fully opened; (ii) A sediment trap chamber with a suitable alignment and formed floor to guide flow and encourage sediment removal when the flushing sluice gate is opened; (iii) An outlet sluice of sufficient size to engender high velocity discharge and flushing to an external channel that runs back to the river downstream of the river barrier/weir; (iv) An internal obliquely aligned side spill weir wall (to get length) where clean water (without the settled sediment) can flow over into the outlet chamber, be steadied in a pool area and released steadily into the canal (or pipe) [the indications are an internal weir wall length of 4 to 6 m is required to pass the design flow at 0.4 m to 0.5 m depth over the weir wall]; (v) An outlet basin to steady the flow prior to it exiting into the lined canal; (vi) The outlet canal to be set at a level (making use of level differential) to facilitate installation and functionality of the sediment excluding intake structure. The original intake had no sediment exclusion feature, so sediment entered the open main canal and this sediment either settled in the canal, reducing section and capacity (going hard over time) or else was discharged either into any balancing storage (gradually reducing capacity) or passed through to settle in distributaries and/or field canals. Where pipes, pumps and mechanical sprinkler and drip systems are used, sediment is the enemy, and everything should be done to exclude sediment from the water before it enters into any closed pipe system.

282. Balancing Storage. The main canal discharges into a planned 250 m long x 150 m wide, up to 3 m deep balancing storage, which will be sited about 700 m to the west of the command area. The balancing storage will have an approximate volume of 100,000 m3, and water withdrawal from the storage will be by suction of the main irrigation pumps, sited southeast of the storage. This storage will be the sump for the pumping station to supply all the planned irrigation systems. It will receive a regulated flow from the river, at a rate commensurate with water available from the river pool, whilst extraction will be in accordance with the needs of the irrigation systems. The balancing storage will require an inlet structure from the main canal, to carefully discharge water into the storage, minimize scour from high velocity of entry, and limit sediment disturbance and turbidity in the storage. There will also be an escape structure to a spur drain that will flow eastwards to the main western drain, which in turns then flows down between the existing orchard/vegetable area and the new command area to the north and the Khovd river.

283. To operate the storage, two possible options are considered:

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(i) The storage is constructed with a bank height equal to the enclosure bank at the river intake (1,214 masl – approx. 3 m above local ground level) and the balancing storage and river pool can equalize at full capacity; or (ii) The storage is a cut and fill balance at the local site, and inflow is regulated with controlling sensors and solar powered operated automatic control of the intake sluice gate to reduce or cease flow when the balancing storage is full. Alternatively, the balancing storage can be managed manually by the pump station operator, who can be provided with warning alarms to signal if and when action is needed. Details for final operations practice will be finalized at detail design, but with the generally small difference in level between river water level and storage full level, the option to have a closed and self-controlling system might be the safest approach.

284. No matter which water level management system is adopted, the storage should still be equipped with an overflow spillway (bellmouth and pipe intake or weir over wall – options to be compared and selected at design stage) to protect the storage against any possible risk for overtopping. To have a common level between river pool and balancing storage, both the canal and storage banks will need to be at least 0.75 m above the expected top water level in the river pool under peak river flow. If matching storage and pool levels is not possible, or requires inordinately high banks (say greater than 3 m), then an alternative means of controlling the outflow at the intake, with an adequate overspill capacity at the balancing storage to the escape drain down the western side of the command area will be required. An alternative could be to establish a solar panel and battery storage at the intake headworks to remotely operate the flow control gate from the pool, with a balancing storage sensor to detect increasing water level and correspondingly reduce the flow, eventually to zero once the balancing storage is full. However, if the system were to fail (gate jams, fails to operate, sensor or communications cease working) then there should still be a storage escape outlet for controlled discharge to the drain.

285. Pumping Station: Due to the local topography, there is no natural hydraulic head available from the river for the operation of piped sprinkler and drip irrigation systems. It is therefore essential, if adopting these types of systems, to include sufficient pumping capacity to deliver water to the irrigation machines/systems at the required operating pressure. Water can be pumped using suitable centrifugal or combined axial/centrifugal pumps. Choice should depend on operational efficiency for the particular flow and capacity and costs. It is assumed that, for complete operational independence, there will be four separate center pivot systems, where each supplies water, on rotation to a movable center pivot with four operating positions (circles). The required flow rate is assumed at 8 mm/day equivalent across the 100-ha center pivot circle. Each pump would also be supplying water at the same rate to 25% more area, this being the infill areas between/around the circles, which will use smaller specific types of irrigation equipment. Thus, each pump is supplying sufficient water to irrigate 125 ha at 8 mm/day. It is also supposed that all four pumps might be connected at the pump station with common inflow and/or outflow manifolds, which would then also provide flow for the windbreak and orchard irrigation systems, and by virtue of connection, can equalize pressure and flow to all parts of the command area. The specifics for linking or not linking the separate irrigation systems from a common pumping arrangement, with valves and manifolds, will need to be discussed and finalized at detailed design. By linking the pumps and comparing combinations to meet expected output and pressure requirements, there may be possibilities to moderate overall equipment, energy and operating costs. For this analysis, it is assumed there will be four separate center pivot pump systems with outflow capacity of 125 to 130 l/s against an overall operating head up to 50 m (conservative as may need only about 40 m depending on pipe length, size and hydraulic friction loss).

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286. A provisional estimate has been made for pumping costs, based on the arrangement outlined above (Table 43). A cost range has been developed utilizing a net ‘Norm’ on the assumption less water is needed when using sprinklers than if using surface irrigation, as is the general basis for derived ‘norms’. These are also allowing for the water losses that occur in the open canal systems, whereas with pumping, the costs are attributable to the net water actually pumped inclusive of direct on-field application losses, taken as 10%. On this basis, to operate four pumps to service the four central pivot units and other ancillary irrigation systems, the annual electricity costs (subject to actual applicable tariff) are in the order of MNT15.6 million to MNT17.56 million per season.

Table 43: Provisional Estimate for Annual Pumping Costs Amount Amount Item Unit (norm 1) (norm 2) Unit Factor Potatoes norm 2,400 3,000 m3/ha/season (net) if net, then gross norm 3,429 4,286 at Y% efficiency Y = 70% efficiency Assume X irrigations a 286 357 m3/ha/irrigation X = 12 irrigations Gross Depth (mm) 29 36 mm/irrigation b 10 factor % of root zone depth 7.14% 8.93% within 5-15% range root zone 400 mm

Assumed System Irrigated Area 80 100 ha Total Volume Water Required 22,857 35,714 m3/cycle Over X hour cycle 0.09 0.14 m3/s X = 72 hrs Peak flow rate 88.2 137.8 l/s 1000 factor 317.5 496.0 m3/h 3600 factor Supply pipe Diameter 193.45 241.81 mm at flow rate 3 m/s say OD 225 280 mm OD 2000 factor c 3.142 Pi

Operating pressure psi 40 30 Converted to kPa 275.8 206.8 1 psi = 6.89476 kPa

Pump efficiency d % 75% 78% Pump hydro power kW 24.3 28.5 3,600,000 factor Pump shaft power kW 32.4 36.5

Pumping Hours/cycle 72 72 Pumping Energy kWh 2,335 2,631 Pumping Costs MNT/cycle 303,515 342,002 Energy Cost 130 MNT/kWh No of Cycles No. 12 12 Total Yearly Cost MNT000 3,642 4,104

Add to this the costs of energy to drive the actual irrigation machine (it isn’t driven hydraulically but through electric motors) - say an additional 10%. MNT000 4,006 4,514 per season a Typical quoted rate of delivery for CP machines is 8 mm/day. b This is a high rate; really need more irrigations per year 20 to 25 mm per pass. Have to do smaller applications but more frequent for central pivot and lateral move. c Radius to diameter, m to mm d Typical modern pump efficiency up to 87% Source: Consultant’s estimates

287. The pump station should also include a water filtration system, to remove any suspended sediment that could otherwise be harmful to and might collect in the pipes, valves, sprinklers and

105 drip emitters. Whilst some coarse screening to trap vegetative matter and other large items can be included as a strainer on the intake side of the pumps, the fine sediment filtration should be located on the pressure side of the pumps. Then, by suitable pipe and valving arrangements, the pump pressure can be used to backwash filters periodically (programmed or when the operate observes significant pressure differential across the filters) and thereby protect the irrigation equipment from any sediment induced problems. The layout for the pumps, pipes and filtration are shown in Annex 1.

c. Irrigation Scheme Layout

288. Distributary/Field Canals. The original irrigation system design was based on the use of center pivots ranging from 62 to 86 ha each. A total of 23 circles were defined. The general land form is well suited to the use of center pivots, and as the soils are highly permeable with a sandy silt topsoil, low in organic matter, overlying a more permeable sand transitioning to gravelly sand at depth, it is best to use an irrigation system that more uniformly distributes and limits the depth of water application per path. This is not possible with surface irrigation, where much of the water would be lost to deep percolation close to the canal, limiting effective overland flow runs. By using center pivots, water can be spread more evenly, and can be applied at rates within the general water holding capacity of the topsoil, and thereby constrain overall loss of scarce water through deep percolation. Therefore, the prime means of distributing water over the land for the crops will be center pivot sprinklers, and this will be enhanced within the substantive blocks between the pivot circles that cannot be readily irrigated, by also deploying some smaller localized sprinkler/spray/drip solutions, supplied from the center pivot buried supply pipes, to suit particular cropping requirements in those smaller areas. In this way, whilst 1,600 ha is covered directly by the required 4 100-ha center pivots, up to another 400 ha will be covered by these smaller subsidiary systems.

289. Up to 3 drip systems are proposed to be supplied directly from the pumping station, to irrigate up to 8 ha of windbreak, and to upgrade the irrigation for the existing fruit orchard and vegetable growing area, that has survived the decline of the overall Erdeneburen irrigation scheme.

290. Drains. The Erdeneburen command area is large and lies on the alluvial flood plain slopes formed over many years. These slopes still carry runoff water from rain and snowmelt, and the route of this runoff can be seen in Google Earth across the command area. Once the irrigation systems are in place, it will be preferable to ensure there is no overland flow crossing the cultivated areas and causing aggressive erosion, as such washouts are disruptive to both cultivation and the passage of the irrigation equipment. To avoid such risks, it is proposed that a combination of surface drains and raised banks are installed around the southeastern, southwestern and northwestern boundaries of the center pivot command area.

291. The drains and banks are needed to intercept and reliably direct excess runoff water and any overspill from the balancing storage, and filter backwash water, safely around and away from the command area. The drains will discharge to the Khovd river. The estimated length for drains required within and around the command area is about 10,000 m. They will have a minimum width of 1.0 m, and a side slope of 1.5 to 1. They will be earth channels open to livestock, traffic and general runoff, and will therefore require periodic inspection and maintenance to ensure adequacy for purpose.

292. In constructing and forming the drains, this will provide material that can be used to form the protective banks that are needed on the lower side of the drain. These banks would be nominally 2 m wide at the top, follow the grade line of the drain and be up to 2 m high across any localized

106 depressions. Their purpose is to prevent runoff from crossing over the drain line and help redirect any major runoff along the line of the drain. These banks could if required duplicate as part of the access road network. Some specific arrangements may have to be made to safeguard access to the command area, with appropriate locations to cross the drains and the banks without disrupting flow in the drain or weakening the effectiveness of the banks. Where the drains are to cross the main pumping main from the pump station, special attention will need to be given to set the pipe well below the drain bed level and provide added rockfill or concrete protection for the pipe and the drain banks.

293. Command Area Fence. A fence will be installed around the command area to protect the cropped area, forest strips and seedlings from livestock and other outside interference. The fence will be up to 20 km long. It will include 4 lines of galvanized steel wire between wooden posts 5 m apart.

294. Access Road. Roads to the site and headworks, and within the irrigation command area, will be formed with a minimum width of 3.0 m and total length of up to 30 km and will be routinely maintained. These will run alongside or on the protection banks, alongside the main canal and storage, and between the central pivot connection hydrants. They will be earth roads, suitably elevated where necessary, in conjunction with the pipe, canal, drain, protection bank and windbreak network.

295. Windbreak/Forest Strip. Windbreaks will be used as a means of checking aggressive winds locally to protect dry soils from erosion. These windbreaks will be located in suitable alignments adjacent to the command area or canals, on the windward (approach) side. For Erdeneburen, the dominant wind direction is from the northwest and southwest. It is proposed that windbreaks be installed on the northwest side of the command area, to the west of the existing orchard (2,300 m) and also along the southwestern side (up to 6,000 m) adjacent to the main pipeline, road, protection bank and command area.

296. The windbreak will consist of two rows of trees and 1 row of shrubs/bushes (for fruit and/or nuts). The distance between each tree will be 4 m, and between each bush 1 m. The distance between the tree lines will be 4 m and the shrub line will lie a further 3 m away from the second tree line. The general arrangement for setting out the windbreak lines is shown in Annex 1. At the initial development stage of these windbreaks, it is proposed that they be supplied with water via permanently installed dripper lines, with the intake located at and using filtered water from the main pump station. Specific design of drip systems – pump, filters, control valves, main supply lines, and dripper pipes to tree and/or bush base should be completed at detail design stage. It is assumed that up to 7,500 m of main supply pipe, and at least 24,000 m of small diameter in-line emitter drip pipe will be required to reach all trees and bushes. It is assumed for water demand estimation purposes, that the effective wetted area is the length of the treelined x an effective 10 m overall width. Alignment of the main pipes will, wherever possible, be downslope to provide some partial pressure recovery over distance. However, where lines run uphill, sufficient initial pressure can be provided from the pumping station to ensure operating lateral lines (there will be some rotation between blocks) will have sufficient pressure to ensure minimum outflow pressure at the furthest outlet.

297. Irrigation Method. For Erdeneburen, the modernized design retains the use of center pivot irrigation machines. With 16 circles for 1,600 ha, the area can be covered by 4 100-ha units (560 m radius) working on a 72 hour irrigation period per circle, On the assumption that each machine can deliver an equivalent of 8 mm per day over the circle, but take three days to complete the circle, the irrigation depth would be 24 mm per cycle. Given that the root zone soil depth is

107 about 400 mm, and the water holding capacity (replenishment) is a minimum of 5%, then 24 mm represents 6% of the water holding capacity of the soil. This application rate reduces the risk of any excessive deep percolation, with a 12- to 15-day period between irrigations. Taking this approach, then within the 12- to 15-day period, the center pivot can be used sequentially on up to four circles, with relevant disconnection, moving and reconnection of the machine for each successive circle estimated to take from 3 to 4 hours. On this basis, four 100 ha center pivots are required to service four circles each, 16 in total. They would complete between 8 and 10 cycles each per season.

298. Additionally, it is proposed that the shortfall of 400 ha (i.e. the aggregated corner areas in the square for each circle) in the main command area could also be irrigated with small subsystem sprinkler or drip as suited, either covering the main crop, or otherwise for smaller pockets of potatoes and/or vegetables, or even fruit trees. The water would be source via connection from the main center pivot pressure lines, with strategically placed hydrants and movable irrigation infrastructure – pipelines and risers, rain guns or drip roll out. A four-corner block between four center pivots is effectively 28.9 ha of potentially unused land (say 25 ha), so there is merit in considering how to utilize this as a small subunit, or as a supplementary area attached to the center pivot circles. In total, this could be 10 subunits totaling 250 ha. Similarly, there are 10 double corner blocks at about 12.5 ha each, which would provide another 125 ha or irrigated land. Thus, whilst the center pivot s are the main irrigation machines, it would still be feasible to arrange infill irrigation for up to another 375 ha.

299. Besides the main center pivot sprinkler systems, and any additional sprinkler or drip systems tapped to the center pivot pressure supply pipes, there is also need for drip systems for up to 11.5 ha of windbreak on the southwest (long side) and northwest (short side) of the command area. There would also be a benefit from upgrading the existing fruit trees and vegetable area (up to 80 ha) with a purpose arranged drip or fixed sprinkler system, all to be fed directly from the main pump station. The drip systems would also include a filtration unit on the main feedline, which would backwash through control valves and discharge to the escape drain from the balancing storage. These systems would operate on a rotational basis under lower pressure, with pressure compensating in-line emitters or otherwise higher head movable sprinkler/riser lines.

4. Design Discharge

300. The estimated maximum discharge capacity from the river intake headworks is taken to be 1.35 m3/sec, which at 86% overall conveyance and application efficiency, equates to a net applied average water application rate of 1,161 m3/s or 0.58 l/s/ha for 2,000 ha. The peak water flow in the main canal can be designed to be up to 1.5 m3/s, though with the effective use of the balancing storage, the peak flow rate is less critical.

301. Under the without-project scenario, the water extraction from the river for irrigation ranges from 0.69 m3/s in September to 2.46 m3/s in June, with an operational efficiency of 45%. These flow requirements are well below the mean monthly flow available (net of environmental flow) in the river at just 1.0% to 30.6% respectively (Table 44). In the with-project scenario, and with a projected overall improved irrigation water use efficiency of 86%, the water to be extracted from the river is about 50% of the without-project requirement, at 0.38 m3/s in September up to 1.35 m3/s in June.

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Table 44: Design Discharge from Erdeneburen River Month Net Average Water extracted from Irrigation scheme Canal and Pipe Capacities Available river for irrigation with m3/s Water project m3 Main Pipe Main Distributary Distributary m3/s % Canal Pipes Pipes May 6.69 1.27 2.0 1.4 0.13 0.13 June 98.4 1.52 1.0 1.4 0.13 0.13 July 124.6 1.33 0.7 1.4 0.13 0.13 August 70.4 0.89 0.7 1.4 0.13 0.13 September 70.4 0.42 0.6 1.4 0.13 0.13 Source: TA Consultants

5. Civil Works

302. The main civil works for the diversion headworks on Khovd River right anabranch will include survey, detail design and strengthening/raising the cross river barrier to maintain a river pool level at 1,213 masl, for the diversion and conveyance of water to a balancing storage, pump station and irrigation sprinkler/drip systems. The works can be summarized as: (i) improvement, raising and strengthening of the existing rockfill barrier wall (with impermeable core) across Khovd River anabranch channel, immediately downstream of the existing intake channel, to raise the pool water level to a reliable 1,213 masl; (ii) construction of a new intake structure at the head of the existing intake channel, with inlet sluice gate, internal flow control weir for discharge to the main canal, and a shaped sediment collection basin, with outlet sluice gate for flushing sediment back, via a formed channel, to the river below the river barrier [this internal weir acts like a side spill weir and has to be a minimum 5 m long to ensure depth of water over the weir does not exceed 0.4 m; assume with 0.1 m headloss through sluice gate and sediment settlement chamber, the weir sill level will be set at least 0.5 m below the set river pool water level]; (iii) construction of a safety protection embankment from the barrier wall, incorporating the intake structure and along the anabranch right riverbank until it meets ground level (west end) at a top height of at least 1,214 masl [hydrology to be checked at detail design]; (iv) reformation, realignment and lining of the main canal (1.65 m long), to discharge through a constructed protection drop into the balancing storage, with bank height and canal bed level sufficient to contain and deliver water safely between upstream river pool and the balancing storage; (v) construction of a balancing storage with possible top water level of 1,213 masl, with earth embankment, 1:1.5 side slope, storage depth up to 3 m, and overall surface water area of 250 x 150 m, including an outlet control spillway (to spur drain to western main drain) with sill level (bellmouth via pipe or bank overflow concrete weir) of 1,213 masl; (vi) provision of piped/culvert outlet from the balancing storage to the pump station, to a suction sump, with coarse trash and sediment strainers on the inlets, whether one only inlet or several inlets, one per pump; (vii) provision of a pump house, to house up to 5 pumps, inclusive of suitable water filtration unit(s), pipe connections, valves and monitoring/control systems, and power connections, to supply the 4 center pivots, and all associated small irrigation systems outlined for the orchard, windbreaks and infill areas between the center pivots;

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(viii) installation of main and subsidiary pressure pipes to deliver water from the pump house to all irrigation systems (center pivot, sprinkler/spray, drip) for the complete 2,000 ha command area, inclusive of pressure monitoring and warning systems for fault management; (ix) reforming and/or new drains (about 10.0 km) to protect the canals, associated infrastructure, windbreaks and command area, with clear effective drainage of rainfall runoff and any canal overspills to Khovd river; (x) formation of relevant protection banks around the command area and other infrastructure, in conjunction with the development of drains and windbreaks; (xi) development of the windbreaks on northwest and southwest sides of the command area; (xii) construction/formation of up to 30 km of access road; (xiii) construction of up to 20 km of fence for stock proofing the command area. At this stage, the design and related details are preliminary, and as detail design and operational requirements are clarified, some additional works may be required (e.g. crossing points on the main canal at headworks, or at start of the command area). The detail of whether the balancing storage could be constructed at the same level as the river pool needs early checking and confirmation, else there will also need to be more detailed consideration for regulating flow in the main canal to the storage and management of the storage water level.

6. Equipment

303. Within the civil works, required equipment will be limited to gates to be installed for: (i) The water intake – vertical lift sluice gate with preliminary 1.2 m wide and a 0.6 m lift; (ii) Intake sediment sluice – vertical lift sluice gate sufficient to flush rapidly at up to 1 m3/s, details to be finalized around operational and physical levels at site; (iii) Provision of up to 5 no. pumps and associated pipes, with up to 40 m operating head and output of at least 125 l/s, to supply all planned irrigation systems (central pivot, sprinkler/spray, drip) to cover the full 2,000 ha in a maximum 15-day cycle; (iv) Provision of all required pipework – HDPE or other as suitable – to distribute all pumped water around the command area to the designated center pivot anchor stations and other required offtakes for minor system; (v) Provision of 4 100-ha center pivot sprinkler sets, with 560 m boom, inclusive of propulsion power supply, operating control, and associated spare parts, spray nozzles and drop pipes suitable for particular crops, all details to be discussed with potential suppliers before confirming detailed specifications; (vi) Provision of three drip system controlling stations and all associated low-pressure drip pipework, with sufficient associated connections and control valves for up to 8.0 ha of windbreak and up to 80 ha of upgraded and revitalized orchard; (vii) Provisionally, one or more sets of low-pressure micro spray and/or drip systems for installation in greenhouses (size and number to be determined), should the option to develop such facilities be adopted; (viii) Provision of relevant power supply infrastructure, whether connection to main national or local electricity grid, inclusion of diesel power and generator sets, or provision of diesel power to drive irrigation systems (pumps, self-propulsion, etc.). The sprinkler equipment would include suitable on-board power controls and drive mechanisms if electric power supply and cabling is not viable.

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7. Bill of Quantities

304. The cost estimation for Erdeneburen irrigation scheme construction and equipment (Table 45) summarizes the cost for key components required for the upgrading and modernization of the Erdeneburen gravity supply and operated irrigation scheme.

305. The preliminary estimated cost for Erdeneburen irrigation scheme is MNT24,253.95 million, equivalent to MNT12.13 million/ha.

Table 45: Bill of Quantities for Erdeneburen Irrigation Scheme Modernization Budget

No Item Quantity (MNT million) Unit Unit cost Total Civil Works Headworks Sluicing structure with intake sluice 1 piece 1 76.55 76.55 channel and outlet flushing channel Rockfill Barrier and Water level Control Weir, 2 m 200 2.87 574.98 Wall L=200m, h=2 m, Weir L= 13 m, h=1.0 m 3 Headworks protection embankment m 500 0.04 18.48 4 Main Canal, reforming and lining m 3,540 0.14 486.47 5 Main pipe m 18,420 0.08 1,473.60 6 Distribution pipe m 16,300 0.04 1,141.00 7 Balancing reservoir m3 14,000 0.03 420.00 8 Drain well piece 42 3.02 126.94 9 Roads – forming and grading m 10,000 0.003 32.70 10 Windbreaks – prepare land and install ha 7.5 44.41 333.06 11 Drain and protection bank m 6,000 0.03 191.17 12 Pump station number 1 100.00 100.00 13 Fence km 10.0 7.00 70.00 Subtotal 5,044.96 Equipment Head work Control Sluice Gate, Width 1.0 m x 14 piece 2 1.68 3.36 Height 0.6 m, vertical screw Main PE: PE100, SDR11, 1,0mpa, DN500mm, 15 m 18,420 0.40 7,368.00 PN10 Distributary PE: PE100, SDR11, 1,0mpa, 16 m 6,060 0.40 2,424.00 DN500mm, PN10 Distributary PE: PE100, SDR11, 1,0mpa, 17 m 4,550 0.34 1,531.08 DN450mm, PN10 Distributary PE: PE100, SDR11, 1,0mpa, 18 m 5,690 0.27 1,510.70 DN355mm, PN10 19 Culvert for bridge (0.75x0.75 m) piece 3 1.48 4.43 20 Central pivot sprinkler set 4 303.88 1,215.54 10ha Water Efficient Drip Watering Advanced 21 set 30 79.00 2,370.00 System 3ha Water Efficient Drip Watering Advanced 22 set 2 28.36 56.72 System 23 Trees, number piece 22500 0.004 90.00 24 Pump (diesel) piece 5 15.00 75.00 25 Excavator for O&M piece 1 168.60 168.60 Subtotal 16,817.42 25 VAT, 10% % 53.75 2,186.24 26 Environmental baseline assessment number 1 42.67 42.67 27 Environmental impact assessment number 1 42.67 42.67 28 Design cost ha 2000 0.06 120.00 Subtotal 2,391.58 Grand total 24,253.95 Source: Consultants’ estimates

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E. Subproject 4 – Boomiin Am Irrigation and Drainage System Design

1. Site Description

a. Scheme Background

306. Altai Soum owns the Boomiin am irrigation scheme. The original irrigation scheme was developed in 1976, with an open main canal from the Bodonch River to supply water for up to 270 ha of fodder production, to partly fulfil the large demand for fodder in Khovd aimag. However, since the transition to democracy in the early 1990’s, the original irrigation scheme, with pumping, pipes and irrigation sprinkler machines (center pivots), has been stripped of almost all assets. There remains about 27 ha of partial low technology irrigation for fruit trees and some vegetables, with some occasional irrigation of grassland near the trees. A settlement had been established when the scheme was developed and operational, but this has now disappeared. Due to the topography and the source of water, the scheme required mostly pumped sprinkler systems to cover the design command area, with only the small existing area able to operate, as now, under gravity. The main canal and an off-stream storage pond are still in place, though in poor condition due to siltation and low maintenance, but there are some fruit trees and windbreaks still supported where the scheme starts, before the main irrigation area that had been planned and partly developed for up to 5 center pivots.

307. In the absence of reliable irrigation, the scheme area is now used for mostly grazing, but it has been assessed as having good fodder production potential with irrigation. The overall objective for development (upgrade and modernization) is to help reduce the dependency that the aimag now has for importation of fodder to the region to support the growing livestock herds through the winter. Boomiin am Soum does have other small areas developed for the production of some limited vegetable crops, potatoes and fodder, but the Soum desperately needs both additional vegetable production for self-sufficiency, and fodder production to satisfy the local regional market

308. The existing Boomiin am irrigation scheme is in serious decline (Figure 52) and major investment is needed to upgrade and modernize the primary water supply from Bodonch River and the irrigation infrastructure and operations. The overall irrigated area is currently about 27 ha, but the intention is to increase this to 362.9 ha of mostly crops. At the present time, the main part of the scheme is inoperable. Water passes through the existing main canal, but there is no means to control the flow down the slope from the river intake headworks. Limited effective use is made of the uncontrolled flow in the command area.

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Figure 52: Current Situation for Boomiin Am Irrigation Scheme

Upper: Head construction and water source of the irrigation system Bodonch river and Vertical direction of highway of western region will be constructed along the Bodonch river’s bank, Lower: Main canal, and Water regulation balancing storage/water accumulation. Source: Hydro-Us Co. Ltd.

b. Area and Crop Maps

309. Geomorphology. The irrigated field is located on Mongol Altai mountain region, 1500m over the sea level and has harsh severe climate.

310. The Boomiin am irrigation scheme is located beside the Altai Soum center, Khovd Aimag, and lies adjacent to the right bank of a branch of the Bodonch River (Figure 53). The intake is about 4.5 km upstream from the command area and the command area with a pumped and pipe system to then branch into groups of planned center pivots. Command area will consist of five center pivots with a supply pipe size sufficient to provide water to irrigate one center pivot circle at a time. The pipe capacity may also be enhanced to provide water to supplementary irrigation systems that water the void areas between the circles and at the boundary of the command area. Whilst the center pivots deliver the main cropped area watering, these supplementary systems could deliver targeted water to none circle zones, either for crops grown through and across the circles, or for alternative crops such as potatoes in the larger rectangular 111.8 ha blocks, or vegetables (possibly with some greenhouses) in the smaller 10.6 ha triangular blocks. The use of movable pipe sprinkler systems, spray (boom and rain gun) systems, or drip options can be

113 selected based on the required cropping. If the primary water is satisfactorily filtered at the pump station, then no additional filtration would need to be installed for these small scattered systems

Figure 53: Location of Boomiin Am Irrigation Scheme

Source: Hydro-Us Co.Ltd.

311. There used to be a settlement when the scheme was working with part surface canals and some pumped sprinkler systems, but all the equipment and most signs of what used to be associated with the irrigation scheme has now gone. The main canal and a what appeared to be a small system balancing pond, which does not show clearly on Google Earth imagery, remain, but both are filled with sediment and windblown sand. The only remnants of the irrigation scheme that remain are some fruit trees and partial windbreaks near the head of the irrigation area (western side).

c. Climate

312. Meteorological observations at Altai Soum began in 1985, and there are now 9 years of time series data (2009 to 2018) of monthly mean air temperature, wind speed and monthly precipitation data. Analysis shows that the climate is sharply continental like many other regions of the Altai mountains. It is characterized by dry air, with relatively low rainfall throughout the year, and has significant weather variability for both individual seasons and between years.

313. In Boomiin am irrigation subproject area, the daily temperature throughout the growing season will exceed 34oC (maximum daily) between May and August, and humidity is typically in the 40 to 50% range. Average monthly precipitation varies from: 4.8 mm in May, 11.7 mm in June, 11.8

114 mm in July, and 13.8 mm in August, with an overall annual average of 73.6 mm. Typically 70-80% of this rain falls in June and July, and 75% falls in the period May to August. The average wind speed for the year is 1.8 m/s, with peak wind speed experienced at the beginning of the crop growing months. As the April mean temperature is 5.5oC, and below the 10oC crop growth threshold, there is insufficient natural warmth in the air to support crop growth for most of that month, so irrigation is not implemented. Mean monthly climate data for the Boomiin am project area is given in Table 46.

Table 46: Mean Monthly Climate Data in the Boomiin Am Irrigation Subproject Area Absolute Absolute Average Wind Maximum Minimum Humidity Precipitation Month Temperature speed Temperature Temperature (%) (mm) (oC) (m/s) (oC) (oC) January -25.41 -3.78 -30.44 60.5 0.73 1.09 February -19.03 -0.17 -34.58 53.8 1.16 0.64 March -4.85 15.1 -24.98 44.7 2.03 2.28 April 5.5 22.33 -12.3 36.44 2.65 1.51 May 10.87 25.69 -5.86 34.5 2.88 7.59 June 17.03 29.68 2.99 36.89 2.29 25.77 July 19.44 31.9 6.97 37.63 1.94 13.98 August 17.13 30.9 3.63 39.8 2.34 17.99 September 10.49 26.1 -5.51 38.7 2.37 5.61 October 2.06 18.73 -14.45 41.7 1.89 4.80 November -9.66 8.91 -25.47 49.2 1.49 0.36 December -20.4 -1.99 -33.95 58.4 0.86 0.93 Source: Hydro-Us Co. Ltd.

314. Air Temperature Trends. Air temperature trends are shown in Figure 54, which shows that monthly mean air temperature change for the months from April to September has been more-or- less consistent. April mean temperature has increased by 0.7oC, May by 1.8oC, June by 2.0oC, July by 3.0oC and August by 1.0oC, and September by 0.5oC. On balance, it is perhaps reasonable to assume there has been a significant shift in the mean annual growing season temperature, though there are some shifts that could impact crop production. With increased temperatures in the crop growing months, it is likely increased irrigation would be required.

Figure 54: Trends of Monthly Air Temperature at Boomiin Am Irrigation Scheme

Source: Hydro-Us Co.Ltd.

315. Precipitation. Annual average precipitation is 61.4 mm. About 70-80% of annual precipitation falls in the warm period of a year. Figure 55. shows that monthly precipitation change for the months of April to September has not occurred consistently. For May and July, precipitation has decreased by 6 mm and 6 mm respectively, while for April, June and August, precipitation has increased by 3 mm, 14 mm and 10 mm respectively. The major loss in monthly precipitation has

115 occurred during the hottest month of July, signaling the irrigation is especially critical then for effective crop production.

Figure 55: Trends of Monthly Precipitation at Boomiin Am Irrigation Scheme

Source: Hydro-Us Co.Ltd

316. Projections The summer temperature at Boomiin am irrigation scheme is projected to increase by 1oC, to 2.0oC (Figure 4), and annual precipitation to increase by 10% (Figure 5), during the period from 2035 to 2065. A continued increase in temperature with a slight increase in precipitation are the most likely combined future impacts that will necessitate increased irrigation applications over time.

d. Soils

317. The Boomiin am irrigation subproject soil map is shown in Figure 56. The predominant crop root zone soil types in the command area are weak developed steppes alluvial meadow soil and meadow yellow brown soils dominated. By World Reference Base soil classification, Soil grouped leptic Kastanozems. Kastanozems are potentially rich soil, its need to irrigation for high yields. Leptic means having continuous rock coming between 40-80 cm. Secondary carbonate accumulated in surface layer and soil pH is slightly above 8.0. Kastanozems have relatively high levels of available calcium ions bound to soil particles. These and other nutrient ions move to downward with percolating water to form layers of accumulated calcium carbonate or gypsum. Kastanozems are principally used for irrigated agriculture and grazing.

318. Soils are weak developed, low organic matter (1.2 %) and meadow yellow brown soil. Soil has not sufficient nutrients level. Soil profile made not so deep because from 50 cm riverbed stone gravels to be come out. Each horizon was high reacting with 10% hydrochloric acid, which means weak alkaline. Carbonate contents around 0.5%, secondary carbonate sediment collected to soils. Soil pH=9.0 and EC= 180-200 μS. Which means there is low salinization effect to the crops.

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Figure 56: Boomiin Am Irrigation Subproject Soil Map

Source: Institute of Geography and Geo-ecology

319. For the soil particles texture is sandy loam and 60-70% of soil is sand fraction. B horizon has more porosity because texture was sandy loam and lots of gravel. Stone and gravel greater than 2 mm fraction are around 12% of the soil in A horizon (Table 47). Soil chemical properties will tell soil nutrients level. For soluble nitrogen contents are lower which around 14-15 mg/kg, plant available phosphorus levels are lower which around 5-6 mg/kg and exchangeable potassium levels are 110-120 mg/kg which means a sufficient level of nutrients (Annex 2).

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Table 47. Soil Profile of Boomiin Am Command Area Soil Depth, Characteristic horizon m 1 A 0.0-0.3 Sandy loam, yellow brown soil. Gravel more than 2 mm = 10 %, High carbonate content

Source: Integrated agricultural laboratory

320. Soil cation exchange capacity is high level around 26-28 meq/100g which meaning cation are binding with clay particles and indicating soil will good enough to deliver nutrients to plant root. Calcium contents higher between other cations. Wind and Water erosion affected to the soil surface. Clay particle and stones are appearing top surface.

e. Water Sources

321. The main water source for irrigation is the Bodonch River (Figure 57).To assess the water resources available for Boomiin am irrigation scheme, 34 years of time series data (1983 to 2017) from Altai gauging stations have been used. The Bodonch gauging station is located well upstream of Boomiin am irrigation scheme.

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Figure 57: Bodonch River Basin, Hydrological Gauging Station

Source: Information and Research Institute of Meteorology, Hydrology and Environment

322. Table 364 shows monthly mean flow data from Bodonch river gauging station, which ranges from 1.87 m3/s to 2.91 m3/s during the growing season. The environmental flow requirement is set at 1.25 m3/s as 97 percent of the long-term average 1.29 m3/s (Table 48) at the Altai gauging station that is located in the most downstream of the Bodonch river basins. This means that the Bodonch River, just upstream of Boomiin am irrigation scheme, has an average monthly mean flow of at least 1.03 m3/s after meeting the environmental flow requirement in May, and more in other months through to July. Even then, the monthly mean high flow can be 7.77 m3/s in May up to 14.3 m3/s in July, while the low discharge can fall below the environmental flow requirement in all months. In general, there is more than enough water for reliable irrigation at Boomiin am during the growing season, though some prudent storage management in May and June would be beneficial for potential dry years.

Table 48: Water Resources in the Bodonch River at Boomiin Am Irrigation Scheme

Mean Mean Environ- Net water available for use Mean % of Maximum Minimum mental Month Discharge Annual Discharge Discharge 3 flow (m /s) Discharge 3 3 (m3/s) (m3/s) (m3/s) (m /s) m /month April 4.77 0.14 1.23 1.25 7.92 - - May 7.77 0.44 2.28 1.25 14.7 1.03 2,749,721 June 12.1 0.29 2.79 1.25 18.0 1.54 3,982,923 July 14.3 0.49 2.91 1.25 18.8 1.66 4,447,359 August 10.4 0.20 2.34 1.25 15.1 1.09 2,926,273 September 13.2 0.21 1.87 1.25 12.1 0.62 1,600,060 October 13.0 0.16 1.33 1.25 8.62 0.08 214,222 November 4.80 0.05 0.51 1.25 3.33 - - December 1.58 0.00 0.09 1.25 0.60 - -

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Mean Mean Environ- Net water available for use Mean % of Maximum Minimum mental Month Discharge Annual Discharge Discharge 3 flow (m /s) Discharge 3 3 (m3/s) (m3/s) (m3/s) (m /s) m /month January 0.01 0.00 0.00 1.25 0.00 - - February 0.03 0.00 0.00 1.25 0.01 - - March 0.50 0.00 0.12 1.25 0.77 - - Source: National Agency for Meteorology and Environment Monitoring.

323. The Bodonch river flow during the irrigation period from May to August has been decreasing by 0.4 m3/s in April, 2.0 m3/s in May, 2.0 m3/s in June, 2.8 m3/s in July, 1.8 m3/s In August and 0.8 m3/s in September since 1983 (Figure 58). It should be noted that since 2010 the river flow has increased in all months. Data was not sufficient to conduct a sensitivity analysis.

Figure 58: Bodonch River Flow at Boomiin Am Irrigation Scheme (1983 to 2017)

National Agency for Meteorology and Environment Monitoring.

324. Water quality. Water chemistry analysis for Bodonch river from 2013 to 2018 is shown in Figure 59. The overall assessment is that the chemical composition of water in Bodonch river is 2+ 2+ - good, where the concentration of Ca , Mg , SO4 and Cl do not exceed the irrigation water standards thresholds. The sodium adsorption ratio (SAR) that is a critical factor for sustainable irrigation is also found to be within acceptable limits, so it is concluded that water from the Bodonch River is well suited for irrigation use.

Figure 59: Water Chemistry of Bodonch River

Source: Central Laboratory for Environment and Metrology

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325. Suspended solids in the Bodonch River water range from 2.0 to 15.2 mg/l (or 0.002 to 0.01 kg/m3), but do not exceed 20 mg/l (0.02 kg/m3) most of the time (Figure 60). There is no clear seasonality to suspended solid concentrations, but there are periodic and short duration increases as a result of peak snow melt flows and summer flood flows when intense rainfall can lead to excessive runoff and peak river flows and water levels.

Figure 60: Suspended Solids in Bodonch River at Boomiin Am Irrigation Scheme

Source: Central Laboratory for Environment and Metrology

326. Water quality in the rivers of the “very clean”, based on water quality analysis and assessment against the Water Quality Index (WQI). Particularly, around Bodonch the WQI is 0.23 (Table 5).

f. Existing Irrigation System and Design Maps

327. The first detailed design for Boomiin Am irrigation system was developed by the Water Exploration, Design and Scientific Institute in 1976, and the field survey was carried out on 270 ha, of which 237 ha with suitable soil was designed for an irrigation scheme. The detailed design involved water flows to the irrigated area through a 6.5-km concrete open canal by own head and the irrigation scheme operated with 3 transporting pump stations SNP 50/80, MA-200 sprinkler 1 unit, 3 units of sprinkler DKSh Voljanka, of which 1 unit covered 72 ha and completion of physical works was started in 1978. In the same year a state resolution was approved to extend the irrigated area to 1,000 ha to support 3 gobi soums located beyond the Altai mountains. A detailed design was developed for an extension of the irrigated area on 376 ha without any field survey or investigation. In 1978, a field survey was carried out on 144 ha, which was constructed in 1979 and handed over for operation of an irrigation system with total area of 757 ha. Since handing over of the irrigation system the irrigated area has ranged between 530 ha and 720 ha. In 1987, 530 ha was irrigated with a transporting pump station SNP 50/80, and 10 units of DKSh 64/800 Voljanka. Harvested yields were low, ranging from 0.5-1.43 tons/ha. Reasons of this poor performance include: (i) construction of the system without any investigation or survey; (ii) lack of consideration of agro-technical requirements; (iii) periodic shortages of fuel and diesel; and (iv) lack of proper management of irrigation requirements. In 1987 the Water Exploration, Design and Scientific Institute carried out an exploratory survey and determined that 412 ha (54%) of the area was not suitable for irrigation and removed from the command area. Using some land outside the command area, a revised scheme was developed with an area of 500 ha (Figure 61).

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Figure 61: Boomiin Am Command Area

Source: Hydro-Us Co.Ltd

2. Irrigation Water Requirement

328. The designed command area is 262.94 ha out of which 74.4 ha is for potatoes, 10.6 ha for vegetables, 111.8 ha for cereals, and 55.9 ha for fodder(Table 49). There is 10.24 ha for tree wind break. It is proposed to plant leafy trees in two rows and one row of bushes to the west and west- northern boundary of the command area according to the wind direction data.

Table 49: Current and Planned Command Area Crop type Current Allocation Irrigation Planned Allocation of Irrigation of command area method command area method Potatoes, ha 1.2 Furrow 74.4 sprinkler Vegetables, ha 0.3 10.6 sprinkler Cereals, ha 111.8 sprinkler Fodder, ha 55.9 sprinkler Fruit trees and windbreak, ha 10.24 drip Source: Hydro-Us Co.Ltd

329. Overall efficiency will be raised up to 72% using lined canal systems, pressure pipes, modern sprinkler irrigation machines for at least 96% of the area and low pressure drip systems for rest of the area and windbreak (Table 50).

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Table 50: Scheme Irrigation Efficiency Characteristics Field irrigation Percentage of Conveyance Field Scheme application total efficiency application irrigation command (%) efficiency efficiency area (%) (%) Current for total Surface irrigation 100.0 60 60 36 command area (border, furrow, basin) Designed fodder area Sprinkler 96.1 95 75 71 Designed potatoes and Drip 3.89 95 90 86 vegetable Average for designed Combined sprinkler and 100.0 95 76 72 command area drip Source: TA Consultants.

330. Irrigation season water requirement has been calculated based on the irrigation water utilization norm (Table 6) applicable for the region and planned crops. Following analysis for the future upgraded and modernized irrigation system development, the estimated total water use for the irrigation season, based on irrigation water utilization norm with the planned crops of potatoes, vegetables, cereals and fodder is 1,640,421m3 (0.12 m3/s) with project (Table 51). This irrigation water accounts for 10.5 percent of total net available water in the growing season or about 6.86- 14.6 percent of the river flow of the given month (Table 52), after meeting the environmental flow of 1.15 m3/s thus there is water available to meet the irrigation needs

Table 51: Irrigation Water Requirement for Boomiin Am Irrigation Scheme Irrigation period Item May June July August September Total Allocation of command area Potatoes, ha 74.4 74.4 74.4 74.4 74.4 Vegetables, ha 10.6 10.6 10.6 10.6 10.6 Cereals, ha 111.8 111.8 111.8 111.8 111.8 Fodder, ha 55.9 55.9 55.9 55.9 55.9 Fruit trees and wind break, ha 10.24 10.24 10.24 10.24 10.24 262.94 Water requirement with project Gross irrigation norm, m3/month 289,379 343,816 272,871 196,017 79,021 Irrigation efficiency measures, % 0.72 0.72 0.72 0.72 0.72 Total water requirement,m3 401,915 477,522 378,987 272,246 109,751 1,640,421 Source: TA Consultants

Table 52. Water Availability for Irrigation Percentage of Projected total irrigation water Monthly Environ- irrigation water use from net Irrigation River ment Net available flow in the requirement with river flow period Discharge, Flow, river project m3/s m3/s m3/s m3/month m3/s m3/month % May 2.28 1.25 1.03 2,755,270 0.15 401,915 14.6 June 2.79 1.25 1.54 3,988,310 0.18 477,522 12.0 July 2.91 1.25 1.66 4,442,662 0.14 378,987 8.55 August 2.34 1.25 1.09 2,915,974 0.10 272,246 9.36 September 1.87 1.25 0.62 1,603,670 0.04 109,751 6.86 Total 1,640,421 10.5 Source: TA Consultants

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3. System and Layout

a. Area Topography

331. The existing intake from the Bodonch River is located at elevation 1,554 masl (riverbank level), at 46° 2'10.50"N and 92°32'15.83"E, and the nominal river pool level is 1,554 masl (these positions and levels to be confirmed at detail design). The existing storage is located on the northwest side of the headwork, and partly filled with sediment.

332. The boundary of the main fodder/cereal/potato command area, starting 4.5 km downstream from the headworks sits at elevation 1,515 masl, at 46° 0'6.00"N and 92°29'50.07"E (north corner of the center pivot area). The north western corner of the command area is 1500 m to the northeast at elevation 1,515 masl, with a slope 0.0071.

333. The existing main canal was originally trapezoidal. Main channel length is 4.87 km. Slope 0.008. The total area of the irrigation system is 362.94 ha, of which 262.94 ha are irrigated (Figure 61).

334. Water would be transferred through the head construction and /Typical head construction GVS-2,0х2,5х1,2 / main canal to the regulation reservoir. Intake capacity of the head construction is Q=1.2 m3/sec; capacity of the drain construction is Q=5.4 m3/sec.

b. New Irrigation System

335. Capacity of the regulation balancing storage is 18,000 m3, length of the balancing storage is 98 m, width 62 m, depth 2.5 m. Capacity of the water balancing storage was estimated on the base of water consumption and river water flow with 75% provisions. The current balancing storage would be rehabilitated. Estimated flow volume would be discharged through the current concrete lined main canal with length 4,933 m is Q=0.555 m3/sec; slope m=1.5; bottom width b=0.8 m, water depth h=0.7 m. Water would be discharged from the balancing storage by a pumping station and flow through the underground pipeline to the central pivot sprinklers. Underground grid of the Irrigation System: diameter of the main pipe is 450 mm, total length is 1,453 m. Diameter of the dispatching pipe is 360 mm, length 824 m, diameter of partial pipe is 280 mm, total length is 1,640 m. Diameter of the draining pipe is 100 mm, total 889 m. Pipes would be HDPP (Figure 62 and Table 53).

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Figure 62: Boomiin Am Irrigation Scheme Layout

Source:Hydro-Us Co.Ltd

Table 53: Irrigation Design Option № IS Details and Components Value and Units 1 Gross IS Area 327.7 hectares 2 IS Command Area 262.9 hectares 3 Land Use Coefficient (1/2) 0.77 4 Main Canal (lined) Capacity and Q = 1.2 l/s, L = 4933 m, Depth = 0.8 m, h = 1.0 m, Dimensions m=1.5 5 Main Canal Intake Structure and Q = 1.2 l/s, Sediment Sluice 6 Regulation pond (water surface V = 18000 m3, L = 98 m, B = 62 m, dimensions) depth = 3.0 m, Top Bank = 4, m = 1.5 7 Pump Station, 2 No. Pumps (one Details to be developed standby), Power Supply and Control Panels 8 Well /distribution/ 5 9 Pipes (HDPE or equivalent) to Center L = 640 m, Diam (ID) = 450 mm, Pivot Irrigators (16 No.) L = 824 m, Diam (ID) = 355 mm L = 813 m, Diam (ID) = 450 mm, L = 1275 m, Diam (ID) = 280 mm, L = 369 m, Diam (ID) = 280 mm, L = 404 m, Diam (ID) = 100 mm, L = 485 m, Diam (ID) = 100 mm 10 Center Pivot Machines DYP 7 and DYP S = 55.9 ha, Radius = 425 m, App Rate = 8 mm/day 8 S=42.5 ha Radius = 369 m 11 Road L=8854 m, with surface area of 2.6 ha

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12 Windbreak / Forest Strip L = 7970 m, b= 11 m, with area of 8.76 ha /3 row/ /around irrigation field/ L= 4933 m b=3, with area of 1.48 ha /2 row/ alone main channel 13 Fence Length 13000 m Source: Hydro-Co.Ltd

336. Headworks Intake. With the weir upgraded and strengthened so water pool level can be maintained, a new gated intake and sediment sluicing arrangement (see schematic in Annex 1) should be installed at the right abutment, with two sluice gates, suitably sized to pass the design peak flow for the canal (1.2 m3/s). This intake structure would be rectangular in general form and embedded as an integral part of the embankment in the right abutment. It would include: (i) An intake sluice gate of appropriate size for flow with minimal head loss when fully opened; (ii) A sediment trap chamber with a suitable alignment and formed floor to guide flow and encourage sediment removal when the flushing sluice gate is opened; (iii) An outlet sluice of sufficient size to engender high velocity discharge and flushing to an external channel that runs back to the river downstream of the river barrier/weir; (iv) An internal obliquely aligned side spill weir wall (to get length) where clean water (without the settled sediment) can flow over into the outlet chamber, be steadied in a pool area and released steadily into the canal (or pipe) [the indications are an internal weir wall length of 4 to 6 m is required to pass the design flow at 0.4 m to 0.5 m depth over the weir wall]; (v) An outlet basin to steady the flow prior to it exiting into the lined canal; (vi) The outlet canal to be set at a level (making use of level differential) to facilitate installation and functionality of the sediment excluding intake structure.

337. The original intake had no sediment exclusion feature, so sediment entered the open main canal and this sediment either settled in the canal, reducing section and capacity (going hard over time) or else was discharged either into any balancing storage (gradually reducing capacity) or passed through to settle in distributaries and/or field canals. Where pipes, pumps and mechanical sprinkler and drip systems are used, sediment is the enemy, and everything should be done to exclude sediment from the water before it enters into any closed pipe system.

338. Balancing Storage. The main canal discharges into a planned 98 m long x 62 m wide, up to 2.5 m deep balancing storage, which is located beside the command area. The balancing storage will have an approximate volume of 18,000-20,000 m3, and water withdrawal from the storage will be by suction of the main irrigation pumps, sited east of the storage. This storage will be the sump for the pumping station to supply all the planned irrigation systems.

c. Irrigation Scheme Layout

339. Distributary/field canals. The original irrigation system design was based on the use of center pivots ranging from 42.5 to 55.9 ha each. A total of 5 circles were defined. The general land form is well suited to the use of center pivots, and as the soils are highly permeable with a sandy silt topsoil, low in organic matter, overlying a more permeable sand transitioning to gravelly sand at depth, it is best to use an irrigation system that more uniformly distributes and limits the depth of water application per path. This is not possible with surface irrigation, where much of the water would be lost to deep percolation close to the canal, limiting effective overland flow runs. By using center pivots, water can be spread more evenly, and can be applied at rates within the general water holding capacity of the topsoil, and thereby constrain overall loss of scarce water through deep percolation. Therefore, the prime means of distributing water over the land for the

126 crops will be center pivot sprinklers, and this will be enhanced within the substantive blocks between the pivot circles that cannot be readily irrigated, by also deploying some smaller localized sprinkler/spray/drip solutions, supplied from the center pivot buried supply pipes, to suit particular cropping requirements in those smaller areas. In this way, whilst 362 ha is covered directly by the required 3 sprinklers for 55.9 ha each center pivot, 2 sprinklers for 42.5 ha each center pivot will be covered

340. Up to 3 drip systems are proposed to be supplied directly from the pumping station, to irrigate up to 10.8 ha of windbreak.

Command Area Fence. A fence will be installed around the command area to protect the cropped area, forest strips and seedlings from livestock and other outside interference. The fence will be up to 13 km long. It will include 4 lines of galvanized steel wire between wooden posts 5 m apart.

341. Access Road. Roads to the site and headworks, and within the irrigation command area, will be formed with a minimum width of 3.0 m and total length of up to 8.9 km and will be routinely maintained. These will run alongside or on the protection banks, alongside the main canal and storage, and between the central pivot connection hydrants. They will be earth roads, suitably elevated where necessary, in conjunction with the pipe, canal, drain, and protection bank and windbreak network.

342. Windbreak/forest strip. Three lanes of the forest protection from wind and evaporation for the irrigated area and also 2 lanes of the forest protection for main canal will be irrigated by the drip system covering an area of 8.76 ha (7,970 m long by 11 m wide) around the command area, and an area of 1.48 ha (4,933 m long by 3 m wide) along the main canal.

343. Irrigation Method. One DYP-7 sprinkler will be installed to irrigate two center pivot areas and one DYP-8 sprinkler will be installed to irrigate the remaining three. A drainage canal will be constructed at the end of the main canal to drain off any excess water.

344. During the growing season, the area will need 1.6 million m3 of water and Table 51 illustrates the actual water demands. Both sprinklers will work at the same time.

345. During the low flow with 0.75 per cent provision the water discharge rate is 0.69 m3/sec or the accumulated volume of water in the balancing storage will 59,616 m3/day. From mentioned total volume 50% would be used for irrigation and almost 29,808 m3 water will be accumulated daily. In this case the accumulated water source for irrigation is sufficient and covers irrigation demand.

346. Besides the main center pivot sprinkler systems, and any additional sprinkler tapped to the center pivot pressure supply pipes, there is also need for drip systems for up to 10.9 ha of windbreak on the southwest (long side) and northwest (short side) of the command area. Sprinkler system, all to be fed directly from the main pump station. The drip systems would also include a filtration unit on the main feedline, which would backwash through control valves and discharge to the escape drain from the balancing storage. These systems would operate on a rotational basis under lower pressure, with pressure compensating in-line emitters or otherwise higher head movable sprinkler/riser lines

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4. Civil Works

347. During the winter period the underground grid of the irrigation system should be protected from freezing. The water in the grid should drained through underground pipeline and draining well relatively. On the top points of the grid would be installed three automatic air-drainers, which drain air pressure from the pipe grid. Five observation wells are planned to be installed for the maintenance and services of the underground pipeline. As a result of the re-construction of the irrigation system the old, damaged, ruined main canal, dispatch canal and regulation construction would be reassembled and buried. 2 crossing bridges with 10-m length will be constructed over the water canals for citizen, animals and other facilities including vehicles. Earth road with width 5 m was designed within the irrigated area and as connecting road between the head construction, canals and other civil constructions. Total length of the ground road is 8.9 km.

5. Equipment

348. Required equipment will be limited to: (i) Pumping Station: 2 pumps (1 reserve pump with building) (ii) Two center pivot irrigation machines DYP-7 2 for 85 ha, (iii) Three center pivot irrigation machines DYP-8 3 for 167.7 ha; and (iv) Two drip for 5 ha.

6. Bill of Quantities

349. The cost estimation for Boomiin Am irrigation scheme construction and equipment (Table 54) summarizes the cost for key components required for the upgrading and modernization of the irrigation scheme.

350. The preliminary estimated cost for Boomiin Am irrigation scheme is MNT4,320.55 million, equivalent to MNT14.40 million/ha.

Table 54: Bill of Quantities for Boomiin Am Irrigation Scheme Modernization No Item Unit Quantity Budget (MNT million) Unit cost Total Civil Works 1 Headworks protection- Rockfill protection L=250 m, t=0.4-0.5 m 250 1.81 452.50 m, d<4000 mm 2 Main Canal, reforming and lining m 540 0.03 16.20 3 Outlet canal /earthworks/ m 930 0.2 186.00 4 Drain well piece 6 3.02 18.12 5 Bridge m 5 4.06 20.30 6 Roads – laying of new roads /width 4 m/ m 13000 0.03 390.00 7 Pump station /with 2 pump and building/ number 1 100 100.00 8 Tree /Forest Strip. Prepare land and install ha 10 0.60 6.14 9 Green are for leisure activities beside pond ha 1 0.6 0.60 10 Regulation pond- rehabilitation work m3 1600 0.08 128.00 11 Earthwork /install main and distributary pipes m3 4810 0.08 384.80 12 Move and installing electrical line from irrigate area m 1970 0.2 394.00 Subtotal 2,096.66 Equipment 13 Main PE: PE100, SDR11, 1,0mpa, DN450mm, PN10 m 640 0.34 215.36 14 Distributary PE: PE100, SDR11, 1,0mpa, DN450mm, PN10 m 813 0.34 273.57 15 Distributary PE: PE100, SDR11, 1,0mpa, DN355mm, PN10 m 824 0.27 218.77 16 Distributary PE: PE100, SDR11, 1,0mpa, DN280mm, PN10 m 1,644 0.11 180.84 17 Distributary PE: PE100, SDR11, 1,0mpa, DN100mm, PN11 m 889 0.02 17.96

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18 Central pivot sprinkler, DYP-7 set 1 88.84 88.84 19 Central pivot sprinkler, DYP-8 set 1 102.1 102.10 20 Trees, number piece 9201 0.003 27.60 21 Bush, number piece 7970 0.002 15.94 22 Pump piece 2 15.00 30.00 23 Geo-membrane pond liner m2 8400 0.05 420.00 24 Excavator for O&M piece 1 168.60 168.60 Subtotal 1,759.59 25 VAT, 10% % 53.75 385.63 26 Environmental baseline assessment number 0.00 27 Environmental impact assessment number 1 42.67 42.67 28 Design cost ha 300 0.12 36.00 Subtotal 464.30 Grand total 4,320.55 Source: Consultant’s estimates

F. Subproject 5 – Khoid Gol Design of Irrigation and Drainage System

1. Site Description

a. Scheme Background

351. The Khoid gol irrigation scheme is located in Darvi soum of Govi-Altai aimag in the natural upland runoff fan of the Khusheet river. The scheme is now owned by Darvi Soum and whilst it is now operating on an ad hoc basis, without any formal irrigation system, the Soum wants to re- introduce systemized irrigation, recovering and improving some of the remaining infrastructure, and adopting new command area development with modernized irrigation systems.

352. Runoff water has in the past gone to the left and right of the command area, but in more recent times has also gone into and across almost the entire command area. Whilst there is still some temporal surface irrigated farming (opportunistic), all remnants of the original scheme command area development, bar some sections of the main canal, have been destroyed due to system neglect and breakup, and the impacts of uncontrolled overland flow. When examining the Google Earth images, it is difficult to fully understand the changes in river flow pattern that have occurred over time. The current direction of the Kusheet river flow as it approaches the command area and new highway from the south appears to turn westwards to flow along the southern side of the new highway. However, there are also indications that some flow, currently or in the recent past, has also gone eastward to the depression located east of the command area but on the northern side of the highway.

353. This scheme was first developed in 1985 with a water intake approximately 16 km to the south and 300 m above the command area, drawing water from the Kusheet River just before it exits the foothills onto the wide and steep sloping fan (gradient 1 in 50) of a flood plain in the high Altai. It has a 10.1 km long open main canal to a water storage tank (4 ha, 100,000 m3) located 6 km from the command area. The current water supply is now solely the river due to the poor condition of the main canal and storage, which is now bypassed, and the irregular river channel fragments before the command area into a rivuletted command area. These rivulets have developed naturally as the unregulated runoff abraids and meanders across the natural fan area. Cultivation is now practiced in small pockets with furrow and/or surface flood irrigation. This replaces an original design that had 6 center pivot circles (total 278 ha) including some additional spray irrigation for trees to be planted in the void areas between the circles, set up 2 by 3 as shown in Figure 63. It is not clear if the old center pivot system was developed, but apart from the storage tank and sections of main canal upstream of it, there is no remnant of the scheme

129 remaining in the command area. The planned upgrade/modernization will be a whole new development based on the backbone of the old scheme.

Figure 63: Original Design Plan for Khoid Gol Irrigation Scheme

Source: Institute of Geography and Geo-ecology

b. Area and Crop Maps

354. The project area, at 1,392 to 1,760 masl, sits within valley of Jargalant mountain (3462 m) to the north, by Baatar Khairkhan Mountain (4013 m) on the south of the mountain ranges of the Mongolian Altai Mountains, which range from 2100 to 4013 m around soum area. The project area irrigation scheme bounded on south by the Khusheet river. The project area valley is formed from stream alluvial, proluvial and alluvial-proluvial accumulative fans (Figure 64).

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Figure 64: Location of Khoid Gol Irrigation Scheme

Legend: headworks, main canal, fields Source: TA Consultants based on Google Map

355. The original scheme layout was for an area of 280 ha, which would be covered by 6 center pivots (220 ha) with the balance in corners irrigated using local pipes and positioned rain guns. The plans appear to show these areas would grow trees, whilst the larger circles would grow fodder. The new requirement is for a command area of 400 to 420 ha, which allows for access between the installed equipment, development of the spaces between circles at the corners, and for some strategic windbreaks. However, for any development to be sustainable, the flow in the Khusheet River, coming quickly down the steep floodplain and abrading, will need to be controlled to minimize risk to the reconstructed and upgraded infrastructure. It is proposed this would be achieved by installing several protection banks built using the material removed to form purpose directive drains to take flow around the command area and away from all installed infrastructure. This will then provide the protected cultivable area for safe operation of 4 new Center Pivot irrigators.

356. As can be seen from Figure 65, a new reformed main canal is needed which would require an upgraded and durable intake headworks to capture and convey water safely to the irrigation scheme command area, through the reactivated balancing storage. All works except the balancing storage require reconfiguration and design, to be constructed and protected for long term sustainable operation. The new system will bring water from a controlled intake to the balancing storage by open canal, and from the storage to the command area through a pressure pipe. These main works will need to be protected from the aggressive overland flow that emanates from the Khusheet mountain outfall and from other subsidiary surface runoff streams. New control structures with the integrated use of natural hydraulic head from the balancing storage will provide pressure for the mechanical sprinkler irrigation systems without pumping. A provisional layout arrangement for the upgraded irrigation scheme is shown in Figure 66. The main canal is nominally protected by a flood bank against the risk of upland runoff, but this will require further work to include adequate bypass drainage around or over the canal, and similarly for any pipes to the command area. The command area is close to the main highway, so access to the site in general is easy both for operations and for harvesting and transportation of produce.

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Figure 65: Current Condition of Khoid Gol Irrigation Scheme

Upper Left: Balancing Water Tank; Upper Right: Main Canal - unlined Lower Left: Irrigation Field; Lower Right: Surface Irrigation Source: TA Consultants field survey –

Figure 66: Proposed Upgraded Irrigation Scheme for Khoid Gol

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Source: TA Consultants based on Google Map

357. Currently, all water used in the scheme comes from the Khusheet river, either from what remains of the existing main canal, or mostly by redirecting river flow directly from the multiple river fan channels towards the command area, for current irrigation of about 111 ha (97.2 fodder and rye, 16 ha of vegetable). Only about 40% of the original command area (Figure 63) is presently cultivated and irrigated using water obtained from the unregulated river flows. Diversion to the command area where needed is affected by the annual reconstruction by the farmers of sufficient small-scale low banks that aggregate flow from the rivulets and bring it to the head of the command area. It is not known how much damage, if any is done to the command area when the river streams are in spate flood and potentially break through into the used land. There is a main river channel that approaches the command area and has been diverted westwards around the command area, but this is not totally secure. A much stronger diversion barrier and drainage channel is needed for durability (Figure 67). The command area plan is shown in Figure 68.

Figure 67: Preliminary Revised Layout for Khusheet River Diversion Intake for Khoid Gol

Source: TA Consultants based on Google Map

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Figure 68: Proposed Khoid Gol Irrigation Command Area Layout

Source: TA Consultnat based on Google Map

c. Climate

358. Meteorological observations started at Darvi soum in 1985 where the Khoid Gol irrigation scheme was developed. There is 33 years of time series data (1985 to 2018) for monthly mean air temperature, wind speed and monthly precipitation. The Darvi soum meteorological station does not do observation for agro-climate parameters, such as the date when air temperature crosses 10oC in the spring and autumn, or the date when frost occurs. This data type has been sourced from the Khovd aimag center meteorological station for the time period 1999 to 2018.

359. In the Khoid Gol irrigation subproject area, the daytime temperature in mid-summer can reach up to 38.3oC (maximum daily) in June. Annual rainfall is approximately 88.5 mm, with about 80% of this rainfall occurring in the three months from June to August. Very little rain falls in the vegetative season, meaning there is a very heavy reliance on irrigation water. Average wind speed is moderate throughout the year. Mean monthly climate data of the project area is given in Table 55.

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Table 55: Mean Monthly Climate Data around Khoid Gol Irrigation Subproject Month Average Maximum Minimum Humidity Wind Precipitation Temperature Temperature Temperature (%) speed (mm) (oC) (oC) (oC) (m/s) January -22.9 6.6 -43.4 80.2 2.33 1.1 February -17.9 12.4 -42.3 74.8 2.58 1.8 March -6.9 18.6 -36.7 57.1 3.22 4.4 April 5.0 30.8 -23.0 44.1 3.90 4.6 May 12.7 36.3 -9.0 42.0 3.85 12 June 18.5 39.7 -2.7 47.0 3.27 25.7 July 20.4 39.1 0.0 52.5 3.19 21.4 August 18.2 38.6 0.0 52.6 3.00 28.3 September 11.9 32.1 -9.6 51.0 3.18 7.4 October 3.0 26.1 -27.5 54.1 3.09 5.6 November -8.9 16.9 -36.0 66.4 3.00 3.7 December -18.5 10.4 -39.9 77.9 2.43 1.9 Average 1.2 39.7 -43.4 58.3 3.1 118 Source: National Agency for Meteorology and Environment Monitoring

360. Air temperature. Figure 69 shows the trend in monthly mean air temperature from April to September. The April mean temperature is 5.0oC, below the 10oC growth temperature. The minimum temperature can fall to -23oC (Table 55) which means there is insufficient heat to support crop growth, and the occurrence of severe frost is highly likely. Therefore, no irrigation is required in April, and all crop growth is completed from May through August into early September (harvest).

361. Trend in air temperature. The growing season monthly temperatures have increased over the past 30 years: in April by 4.8oC, in June by 1.6oC, in July by 2.8oC, and in August by 1.2oC. However, there is no change in the May mean temperature.

Figure 69: Trend in Monthly Air Temperature at Khoid Gol Irrigation Scheme

Source: National Agency for Meteorology and Environment Monitoring

362. Duration of hot days. The number of days when daily average air temperature is above 25oC has increased by 41 days, whilst days with air temperature greater than 30oC has increased by 9 days over the last 30 years (Figure 70).

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Figure 70: Trend in Hot Days at Khoid Gol Greater than 25 oC and 30oC

Source: National Agency for Meteorology and Environment Monitoring

363. Precipitation. Precipitation in May and July has decreased by 8 mm and 16 mm respectively, there is no change in June precipitation, and August precipitation has increased by 6 mm (Figure 71).

Figure 71. Trends in Monthly Precipitation around the Khoid Gol Irrigation Scheme

Source: National Agency for Meteorology and Environment Monitoring

364. The overall tendency for decreased precipitation has led to an increase in the number of days with no precipitation by about 4 to 6 days in the months from May to July, but there is no clear trend for any change in August (Figure 72).

Figure 72: Trend in Number of Days with no Precipitation at Khoid Gol Irrigation Scheme

Source: National Agency for Meteorology and Environment Monitoring

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365. Wind. The monthly mean wind speed in the growing season ranges from 3.0 to 3.9 m/s as shown in Table 55, while the maximum may reach 30 m/s on average twice a year. Days with wind speed greater than 10 m/s have increased sharply to 76 days over the last 30 years (Figure 73). About 36% of the wind comes from the northwest and north, with about 15% of the wind coming from the southwest and south. This suggests windbreaks to protect the cultivated area should be located between the command area on the northwest round to southwest side, set between the command area and protection bank.

Figure 73: Trend for High Winds and Wind Direction at Khoid Gol Irrigation Scheme

Source: National Agency for Meteorology and Environment Monitoring

366. Agro-climate. There is a clear trend for in spring for the start of warm days to come earlier by about 1 week, and conversely for the decline in warm days to come later in the autumn by about 4 days. Thus, the overall growing season is tending to be longer and warmer (Figure 74, upper). There is no clear trend for change in the accumulated temperature to support crop growth and the frost-free days is increased by 20 days. (Figure 74, lower).

Figure 74: Agro-climate Characteristics Around the Khoid Gol Irrigation Scheme

Source: National Agency for Meteorology and Environment Monitoring

367. The current trends for an increase in temperature in combination with a decrease in precipitation clearly demonstrates there is a need for improved irrigation to optimize crop production.

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368. Climate Projections. The summer temperature is projected to increase by another 1oC, 2.0oC by 2035 and 2065 respectively (Figure 4), while it is projected there could be about a 10% decrease in precipitation by 2035 and 2065 respectively (Figure 5). A further increase in temperature and a decrease in precipitation are the most likely projections which will lead to increased irrigation water demand in the future.

d. Soils

369. The soil map of Khoid gol Irrigation subproject area (Figure 75) shows that the soil types of the command area are meadow and aluvial meadowish. By World Reference Base soil classification, command area soil is grouped in Calcic Kastanozems, that type soils having a mollic horizon (deep, dark colored surface horizon with a significant accumulation of organic matter and high base saturation) and accumulation of secondary calcium carbonate within 100 cm from the soil surface. Shallow typical mountain dark chestnut with typical mountain chestnut soils

Figure 75: Soil Map of the Khoid Gol Irrigation Subproject Area

Source: Institute of Geography and Geo-ecology

370. Soils have low organic matter (<1%) and water erosion affected soil and clay particles in the upper horizon. Dark brown color soils appear to 80 cm depth. Each horizon was highly reactive with 10% hydrochloric acid, meaning weak alkaline soil (Table 56). Carbonate contents are around 0.5%. Soil pH is 8.5 and EC= 232 μS, meaning there is a low salinization effect on crops. Irrigation channel water was flowing with lots of clay particles from the field, which will affect soil compaction. The soil density is 1.08g/cm3, because fields were tilled.

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Table 56: Soil Profile of Khoid Gol Irrigation Subproject Area Soil Depth, Characteristic horizon m 1 Tilled to 0.3 m 2 A 0.1-0.6 Loam 3 E 0.6-0.9 Silty loam 4 B >0.9 Sandy clay loams

Source: Integrated agricultural laboratory

e. Water Sources

371. Khusheet River is the main water source for the Khoid Gol irrigation subproject, which is located on the right bank of the mainstream and, in flood, there are many branches of the river (Figure 76). There is no gauging station at Khoid Gol or elsewhere on the Khusheet River, so a sample flow measurement was conducted during the field visit on 19 June 2019, where it was found the discharge was about 0.44 m3/sec(Figure 77 and Table 57).

372. Khusheet River originates on the north-west slopes of the Sutai mountain, and the river basin is part of the Great Lakes depression. The catchment area has been measured to the water intake site for Khoid Gol irrigation scheme as 265.1 km2, with a river length of about 44.8 km (Figure 76).

Figure 76: Khoid Gol Irrigation Scheme and Hydrological Gauging Station in the Khuisiin Gobi - Tsetseg Lake River Basin

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Source: TA Consultants based on National Atlas

Figure 77: Khoid Gol River Flow Measurement

Source: TA Consultants–field survey

Table 57: Discharge Measurement Results, Khusheet River, Darvi Soum, 2019-6-19 River at Coordinates Alt F B V H Q Remarks Khoid Gol masl m2 m m/s m m3/s Headworks Khusheet 46o 52‘ 39.6” 1739 0.54 3.50 0.81 0.15 0.44 Water is clear, no smell, no 93o 17’ 34.7” odor, pH=7.2 EC-147 μS/m Source: TA Consultants–field survey

373. A discharge measurement was made on the Khusheet River in May 2016 when it was found to be 0.58 m3/s [done as part of preparation of the Integrated Water Resources Management Plan (IWRM) plan for the Khuisinn Gobi-Tsetseg Lake River Basin study].

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374. To estimate the relationship between the Khusheet river basin mean elevation and its specific run-off (M = f(H)), equations for the Khovd river basin and rivers draining from the Altai Mountain range25 have been used. Annual runoff distribution is estimated using the Altai Mountain regional reference ratio for monthly percentage mean annual runoff. This shows that the mean annual runoff for the Khusheet river is about 1.98 l/s/km2 which calculates to about 0.52 m3/sec.

375. Table 58 provides the estimated monthly mean flow data, developed from the flow measurement data, which ranges from 0.74 m3/s to 1.22 m3/s during the growing season. Net water availability is positive from May to September. The environmental flow is 0.48 as 90 percent of the annual mean flow 0.52 m3/s (Error! Reference source not found.).

Table 58: Water Resources of the Khusheet River at Khoid Gol Subproject Area Environmental Mean Discharge % of Annual Net Water available Month flow (m3/s) Discharge (m3/month (m3/s) (m3/s) April 0.43 0.48 6.84 - - May 0.74 0.48 12.1 0.27 728,525 June 1.07 0.48 16.9 0.60 1,560,384 July 1.22 0.48 19.9 0.75 2,014,157 August 1.12 0.48 18.3 0.65 1,746,317 September 0.71 0.48 11.2 0.24 627,264 October 0.40 0.48 6.50 - - November 0.18 0.48 2.98 - - December 0.06 0.48 0.97 - - January 0.02 0.48 0.31 - - February 0.03 0.48 0.41 - - March 0.22 0.48 3.54 - - Source: TA Consultants

376. Water quality. As there is no hydrological gauging station on the Khusheet River, water quality has not been monitored. During the field visit, water turbidity was visually seen to be good, and the e pH was measured at 7.1, both of which confirm the water is within acceptable standard26. The electrical conductivity was later checked and found to be 147 μS/m.

377. Impact on groundwater quality. During the field survey, 80 percent of responders advised that the water level in developed groundwater wells was at least 20 meters deep. On this basis, it is estimated that irrigation in the area will have no negative impact on the ground water.

f. Existing Irrigation System and Design Maps

378. Khoid Gol was originally designed in the mid-1980s as a sprinkler irrigation system (6 no. Center Pivots) on an area that sits astride the divide between two catchments, adjacent to the main Highway at Darvi between Govi-Altai and Khovd aimags. It sits directly in the path of the Khusheet river flowing directly north from the Sutai Mountain, and by review of Google maps, it is possible to see that whilst the main Kusheet river then flows wet as it approaches the highway, some of the water paths to the east of the natural flow path fan turn eastwards. However, in order to protect the command area, which sits in the rich fertile river fan adjacent to the highway, it is important to intercept and divert the river flows around the command area, to the west.

25 MET, 2015, Surface water regime and water resource of Mongolia, [Editor G.Davaa]. Ulaanbaatar. P. 26 MNS-irrigation schemeO-16075: Project development for irrigation.

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379. The original scheme was to intercept flow from the river on its left bank, about 16 km to the south of the command area, but any remnant of the original diversion headworks, if it was constructed, is no longer present. The water was then conveyed by a constructed main canal, predominantly straight, which flowed about 10 km, down the slope, to a constructed storage tank (balancing pond or storage). From this storage, controlled flow could be released through a pipe system, dropping about 110 m, to provide flow and pressure to operate the Center Pivots. Today, there is nothing left of the pipes or center pivots, if they were ever installed.

380. The overall concept is sound, but the project has been susceptible to the erosive force of the poorly managed natural river flows, which have ravaged the original works, and left it now with barely 100 ha that can be irrigated by surface water control to small blocks of land. Overall, this system has been almost totally destroyed, with just parts of the main canal and the balancing storage remaining. Whilst the canal and storage can be upgraded, the rest of the system will be full construction for a modern well protected center pivot sprinkler system.

2. Irrigation Water Requirement

381. The designed command area is 420 ha out of which 75 ha for potatoes, 75 ha for vegetables, 75 ha for cereals, 190 ha for fodder and 5 ha for fruits (Table 59). There is 3.85 ha for a tree windbreak around the northwestern, west and southwestern sides of the command area. It is proposed to plant two rows of deciduous trees and one row of bushes to arrest the strong winds from the north and west, in a 7 m wide strip, and irrigated width for even tree root growth of about 10 m.

Table 59: Current and Planned Command Area Crop type Current Allocation Irrigation method Planned Allocation Irrigation method of command area, of command area ha Potatoes, ha 5 Furrow 75 drip Vegetables, ha 6.6 75 drip Cereals, ha 83.5 75 sprinkler Fodder, ha 14 190 sprinkler Fruit trees and drip 8.85 wind break, ha Source: TA Consultants

382. Overall efficiency (Table 60) will be raised up to 75% using lined canal systems, piped field system, modern sprinkler irrigation machines for at least 64% of the area and low pressure drip systems for rest of the area and windbreak (Table 61).

Table 60: Scheme Irrigation Efficiency Characteristics Field irrigation Percentage of Conveyance Field Scheme application total command efficiency application irrigation area (%) efficiency efficiency (%) (%) Current for total Surface irrigation 100.0 60 60 36 command area (border, furrow, basin) Designed fodder and Sprinkler 64.0 95 75 71 cereal area, 265 ha, Designed potatoes and Drip 36.0 95 90 86 vegetable, 158 ha Average for designed Combined sprinkler 100.0 95 80 76 command area and drip

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Source: TA Consultants–field survey

383. If the full project were developed and operational, up to 2,853,674 m3 (0.21 m3/s) with project and 2,918,060 (0.22 m3/s) with climate change based on the irrigation water utilization norm (Table 6) with the planned crops of potatoes, vegetables, cereals and fodder (Table 61). This irrigation water accounts for 35.9 percent of total available water in the growing season or about 10.3-34.8 percent of the river flow of the given month (Table 41), after meeting the environmental flow of 0.47 m3/s thus there water is available to meet the irrigation needs.

Table 61: Irrigation Water Requirements for KhoidgoI Irrigation period Item Total May June July August September Allocation of command area (ha) Potatoes 75 75 75 75 75 Vegetables 75 75 75 75 75 Cereals 75 75 75 75 75 Fodder 190 190 190 190 190 Fruit trees and wind break 5 5 5 5 5 420 Water requirement with project Gross irrigation norm (m3/month) 526,401 604,696 511,058 382,391 144,245 Irrigation efficiency (%) 0.76 0.76 0.76 0.76 0.76 Total irrigation water requirement (m3) 692,633 795,653 672,445 503,147 189,796 2,853,674 Water requirement with project with climate change Increase in ET, (m3) 228 994 458 1363 61 94 Projected irrigation water requirement (m3/month) 544,639 611,900 518,720 390,958 151,509 Irrigation efficiency (%) 0.76 0.76 0.76 0.76 0.76 Projected total water requirement (m3) 716,630 805,132 682,526 514,418 199,355 2,918,060 Source: TA Consultants–field survey

Table 62: Water Availability for Irrigation Percentage Projected total of irrigation Monthly Environ- irrigation water water use Irrigation River ment Net available flow in the requirement from net period Discharge, Flow, river with project river flow m3/s m3/s m3/s m3/month m3/s m3/month % May 0.74 0.47 0.27 728,525 0.26 716,630 94.7 June 1.07 0.47 0.60 1,612,397 0.30 805,132 49.1 July 1.22 0.47 0.75 2,014,157 0.25 682,526 33.2 August 1.12 0.47 0.65 1,746,317 0.19 514,418 28.7 September 0.71 0.47 0.24 648,173 0.07 199,355 9.94 Total 6,749,568 2,918,060 42.9 Source: TA Consultants

3. System and Layout

a. Area Topography

384. Whilst the water intake is at a very high elevation (1,760 to 1,765 masl depending on where the eventual new intake is located), the irrigation command area is much lower (the high point (southeast) is about 1,419 masl; the low point (northwest) is about 1,399 masl). Thus, there

143 is a total fall from water intake to command area high point of about 345 m over about 16 km (I=0.02138), whilst the fall across the command area is diagonally to the northwest another 22 m over a distance of about 590 m (i=0.03729). The natural fall from headworks to command area is broken by the use of a balancing storage, which is then used to provide up to 115 m static head, and a minimum of 30 m dynamic head.

385. The huge elevation difference in the main water supply canal and pipeline means there is more than enough pressure head available to operate low to medium pressure Center Pivot Irrigation systems. Much of the static head from the water source is dissipated by having an open channel supply to the balancing storage (Figure 78). For the lower part of the system, any excess pressure head can be dissipated by including smaller diameter conveyance and distributary pipes with higher friction loss for the peak flow rate required of 0.20 m3/s (to be verified and possibly adjusted to irrigation equipment operating schedules and flow rates).

386. The irrigation scheme has been selected to restore irrigated agricultural to support the soum vegetable, fodder and agricultural needs that provide support to the local herders. The development will secure the water supply through a complex river flow diversion, canal, balancing storage and pressure pipeline to support the use of four Center Pivot irrigation machines over 400 ha. Of the land not covered by the pivot circles, it is estimated that at least another 85 ha could be irrigated where circle corners meet, excluding the four outermost corners of the overall command area. With the available pressure in the pipeline, small micro spray and/or drip systems could be set up to use some or all of these unused areas for vegetables (with/without greenhouse), fruit trees or similar crops operated by the interested farmers. A drip system will also be supplied from the pressure pipelines to nurture the proposed windbreaks on the south, southwest, west and northwest sides of the command area.

Figure 78: Khoid Gol Balancing Storage

Source: TA Consultants based on Google Map

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b. System Components

387. The existing and planned irrigation scheme, upgraded and modernized to improve water use efficiency, will have the following key components which make effective use of the topography and opportunity to tap pressure in the pipelines from the significant change in elevation from water source intake to irrigated command area. Figure 79 shows the overall layout of the upgraded Khoid Gol irrigation scheme.

Figure 79: Planned Irrigation Water Supply for Khoid gol Irrigation Scheme

Source: TA Consultants–field survey

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388. Water Intake and Barrier Wall. The existing water intake is now nothing more than a regularly reconstructed low bank in the river channel, which readily washes away in floods and disrupts water diversion. A more durable and effective solution is needed, so it is proposed to construct a low rockfill wall, up to 80 m long, with a central weir, up to 15 m long (all subject to actual location adopted) to form a permanent shallow pool (2 to 3 m deep) which will then feed a new permanent intake structure. The barrier wall will have an impermeable core and incorporate a central weir (concrete faced with armored spillway (gabion baskets), with sill level 1 m lower that the top height of the barrier wall. The weir should be able to pass at least a 1 in 50-year flow before any water would need to pass over the main rock wall. The rockfill wall, if constructed with appropriate rock size and layout, should also withstand any short-term shallow overtopping if the flood flow is greater than 12.0 m3/s. The barrier wall will need to be uniform in height to ensure a reasonably even shallow discharge across the width of the wall on those rare occasions when this may happen. The bank height in proximity to the left bank intake structure (a new standardized design solution with coarse to medium sediment exclusion facility) would be set 1 m higher than the barrier wall across the river, in order to protect it from wash out.

389. The intake structure will be new, in accordance with a standardized approach proposed for all schemes where such type of structure is required and feasible. There is ample river channel grade to make it possible to utilize hydraulic head (the pool behind the barrier wall) to flush sediment in the trap/exclusion chamber of the structure via an outlet sluice back to the river section. Hydraulic head will force the cleaner water over an internal weir wall set 0.5 mower than the regular river pool water level (maintained by the wall and weir), after which it can enter the open channel (or pipe) as appropriate. The internal weir wall could be constructed with movable stop logs should it be necessary to get low flow from the river because the pool level is low.

390. Main Canal. The existing main canal is a relatively rough and small open earth U section, with no obvious lining. By being rough, it can offset the tendency for high speed flow down the canal due to the grade, especially with small flows. The canal runs almost directly down the slope over 10.1 km to discharge into a constructed tank (balancing storage) about 115 m above the command area. The main canal is in poor condition, though much of the length is still obvious and functional. However, it appears the flow no longer enters the balancing storage and has been purposely diverted around to rejoin the open canal alignment on the downstream side of the storage.

391. The most damaged section of the main canal is the initial 2.6 km, which runs close to the Kusheet river and been variously washed away over the years. Site survey will be needed to ascertain what is needed to rebuild the canal and ensure it is secure from erosion over the long term. The canal may also need to be protected against washout from upland flows coming from the west, with inclusion of some suitably sized buried pipe sections providing adequate clear space for surface runoff to pass. It has not been possible to quantify what is required at this stage.

392. The gradient for the main canal is about 1 in 50, which means any large flow would travel at high velocity and could do significant damage to a fragile unlined canal. Roughness and very shallow flow in the section means that flow velocity can be kept in check, but it may still be difficult without some check/drop structures to moderate the peak flows. Preliminary analysis shows that something like a 250 to 300 mm diameter pipe would be needed to carry a steady flow of about 170 l/s, As this discharges into the balancing storage, then it should be possible to set up a modernized canal or pipe with steady flow from the newly created river pool to the established balancing storage. The required flow does not need to peak to match the irrigation demand in May/June, as the existing balancing storage has sufficient capacity (about 100,000 m3) to meet any peak requirements on the supply side via the planned pressure pipeline. The layout of these primary infrastructure components is shown in Figure 67 and Figure 78.

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393. Balancing Storage. This does not require any major work but needs to be checked and possibly repaired for being returned to full use. It will however need three new structures constructed in the banks: (i) Inlet structure – to control, check and safely discharge inflow from the main canal into the storage; (ii) Outlet structure – to screen the water and allow flow to enter the pressure pipe to the command area. This outlet will need to be set at the dead storage level of the pond, have an inlet penstock gate or valve, and be controllable from the top of the storage bank; and (iii) An overflow spillway, near the southeast corner of the storage, so that if open canal inflow is too great, any excess can be spilled back to the river. To facilitate this, an escape drainage channel should run from the escape structure (a simple armored weir and spillway box) to the east for discharge into the Khusheet river channel (approximately 250 to 450 m).

394. The inlet structure, escape structure and escape channel should be protected by a flood protection bank, running along the high side from the main canal to the outfall of the escape channel. This should help to mitigate the risk for the uncontrolled Khusheet river flow in flood from overtopping and damaging any of the critical infrastructure.

395. Pipeline Intake. The pipeline intake to the pressure pipeline must be controllable with a sealable gate (penstock type) or valve so that in winter, water will be retained in the storage, and the pipe can be emptied through a scour valve at its end. Released water, if not directed for any irrigation, would go northwards through a constructed ditch to join the eastern drain as it runs across the northern side of the command area. The intake to the pipe should have a concrete intake wall and wings, with the inclusion of rakeable coarse and medium trash gratings, to prevent the ingress into the pipe of any windblown and floating trash from the storage. The inlet need not be wide, but it will be deep so that the storage could, if necessary, be almost fully drained in the event of a long drought period. The structure should provide enough space for workers to enter to change the valve or penstock, should this be necessary, so it is suggested a minimum open chamber 1.5 m by 1.5 m would be appropriate. It is not known how deep the storage is, but it is assumed to be between 2 and 3 m when full of water. There appears to be a 4 m ground level difference across the width of the balancing storage. There is no information available as to whether there was any original structure in the storage embankment (pipe with valve) where the original pipe would have been. It is possible it is buried under sediment, or else it may have been removed. This will have to be investigated prior to detail design to determine where and how deep the pressure pipeline intake should be set.

396. A pressure pipeline will be required to take water from the storage to the command area, and maintain the hydraulic head needed to operate the sprinkler and drip systems. The pipe is 6.65 km long, and with HDPE (PN 2 increasing to PN 12.5, subject to safe operating pressure requirements), and a capacity 1,750 m3/hr. (490 l/s), a minimum 450 mm internal diameter (500 mm OD, 450 ID) will be required. The maximum static head on the pressure pipe will be about 115 m at Distributary 1 and the outlet end with Scour valve. The static head at distributary 2 is about 107 m. Due to friction loss in the pipe, of about 80 to 85 m, the dynamic head at these three locations is reduced, but still exceeds the 20 to 25 m required to operate the Center Pivot and spray/drip systems. In order to ensure there is no excessive pressure in the sprinkler and drip systems, pressure regulating valves will be required to check the actual pressure being applied to sprinkler and drip system outlets, with a target maximum of 25 m and 20 m respectively. A check should also be made to evaluate whether it will be necessary to include a pressure surge chamber, probably in

147 conjunction with a backwash filter arrangement immediately before the first drip system offtake for the windbreak. Initial guideline pipe and pressure information is given in Table 63.

Table 63: Flow and Pressure Details for Pressure Pipes Pipeline Length Static Internal Dynamic Discharge Material Pressure (m) Head (m) Diameter a Head Loss (m3/hr.) Rating b (mm) (m) (x10 m) Main 6,650 up to 115 450 80 to 85 1,750 HDPE PN6 to m PN12.5 Distributary 4 x 600 25 m 280 Up to 5 m 360 HDPE PN 6 Spray/Drip 800 Up to 20 170 Up to 8 m 75 HDPE PN 6 Main m a Internal diameters are nominal and relate to the hydraulic requirements/actual outer diameter (OD), used for defining particular pipes, will be larger based on the pressure rating and particular PE mix used. b PN X means 10 times X m maximum head. In most cases the estimated dynamic head loss is compensated for through the physical drop in level along pipe. In the case of distributary and drip main, the start pressure in the pipe off the main will need control valve set to the required operating pressure for the sprinkler or drip system. Source: TA Consultants

397. There will be two spray/drip systems with initial flow filtration banks and a suitable aligned network of pressure pipes – primary main flow; secondary header pipe; and multiple lateral pipes from each header running downslope to maximize head. The lateral pipes will have inline pressure compensating drippers, so can operate at constant flow under significant pressure variance in the pipes. Manufacturers/suppliers will be able to provide test data to confirm the performance of their products to meet the required performance specification. The first drip system will service the multiple small areas around the Center pivots for up to 85 ha of potato and vegetables, which would also have sufficient capacity to include 1 or more greenhouses if they are to be developed. The second system will feed off the incoming main pressure pipeline, with suitable head control valve, to irrigate the windbreak area. Starting with regulation down to 20 m head, a drip system filter bank will then supply water through a 4,180 m long main, 90 mm internal diameter, to water two main tree lines and one line of nut/fruit bushes, for a total 3.9 ha of windbreak (3,900 m long), consisting of blocks of up to 300 m long sections each with 3 lateral lines. Specific details for the final layout and pipe sizing can be obtained from the contracted supplier.

398. Sprinkler Irrigation. The original irrigation system involved 6 Center Pivots for a net 240 ha in a 290-ha block. It is not clear how these were to be supplied, but most likely using a similar system of pressure pipes from the balancing storage. The new proposal is to revise the arrangement and use 4 No. larger Center Pivots with more advance technological control systems. These will use four buried distributary pressure lines (each up to 600 m long, 280 mm ID) in the command area running east-west, fed from the main pressure supply pipe. Subject to the eventual choice of Center Pivot, its operating parameters and included fittings, it may be necessary to include a pressure regulation valve at the start of the buried field supply pipes so that pressure at the connection hydrant for the Center Pivot matches the manufacturers specification. The pressure distributary pipeline is aligned across the slope, so the dynamic head loss has to be allowed for when setting the regulating pressure limits. The objective is to ensure the optimal operating pressure is available at the head of the Center Pivot.

399. Center Pivots can operate effectively over a range of water pressure, with some in-built control features to regulate flow in relation to travel speed, and thus get uniformity of cover greater than 90%, and ideally closer to 95%. It will be necessary to discuss with suppliers about the features of their equipment and examine how positive operational features and performance parameters can be managed with any particular pressure variance, to thereby ensure the pressure pipeline design

148 is appropriate to maximize the value of the system. In particular, the need to understand how best to operate when water application requirements are a proportion of peak – to irrigate at peak rate for shorter hours (or faster cycle), or some other logical management approach. In the process, to understand what tools are in-built with the control logic for the machine, and how to make best use of such controls to enhance crop production. These particular details can only be discussed and assessed for the benefit of the irrigation scheme and Soum farmers once detailed discussions can commence with the suppliers.

c. Irrigation Scheme Layout

400. Sprinkler Systems. The Khoid Gol irrigation scheme will be a pressure piped combined sprinkler and drip system. The main command area block of 400 ha with 4 center pivots will be primarily for fodder and wheat. It is assumed that the center pivots could be operated continuously to provide the necessary irrigation water at a near constant rate, but there will be times when the machines are not required (post rain) or because the root zone is full to saturated. The start of each cycle will depend on the necessity for the next water application to replenish the crop root zone, and the typical rate for replenishment could be 20 to 25 mm per cycle (or pass). For Khoid Gol, the center pivots will be supplied from permanently full (in the growing season) buried pressure pipeline through a direct mechanical connection on the end of each of four distributary pressure pipes. This connection point for the center pivot will be permanent and so can be set with a constant pressure for uniform operation at all times. The only variance will be within the center pivot itself based on where it is in the cycle and whether water in the machine is flowing downhill – thus higher pressures at the outer end of the frame – or flowing uphill – thus slightly lower pressures at the outer end. Generally, the machine can maintain a high degree of uniformity under varied pressure through the design of the sprinkler heads, so provide the landform is not too severe, then uniformity should be good. The fall across the command area is s – 0.0089 or 1 in 112. The difference in level across the circle can be in the order of 10 m, or +/- 5m of pressure at the outer end of the center pivot. Manufacturers can confirm if this degree of level variance across a circle is manageable for crop water distribution uniformity.

401. To illustrate likely peak irrigation application rate/day for predominantly high permeability sandy soils to sandy/silt loams: (i) Irrigation application rate: a. Rootzone – say rootzone b. Assumed water holding capacity (WHC) – say 8% c. Depth to be applied (100%) = 32 mm d. Assume 75% spread between permanent wilting point (PWP) and field capacity (FC) – depth needed = 24 mm e. Adopt an application depth per pass of say 20 mm; (ii) Assume irrigation cycle for 100 ha (per machine) takes 8 days = 12.5 ha/day; 27 (iii) Volume required per day (net) = 12.5 ha x 10,000 m2 x 0.020 m = 2,500 m3; (iv) Allow for operational efficiency – spills, flushing, backwashing, over irrigation, then overall system losses in order of 5 to 8%, take system efficiency to be 92.5%; (v) Overall system water requirement/ irrigation machine = 2,500/0,925 = 2,700 m3; (vi) Assume 12.5 ha irrigation completed in a 20-hour day, then the flow rate required is 2,700 / (20 * 60 x 60) = 37.5 l/s or 135 m3/hr.

27 It is assumed 2 irrigators will be used making a circular cycle around each of two buried field pipes with 8 hydrants on each, 400 m apart. Actual details will need to be checked and adjusted at detail design stage.

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It is assumed that the center pivot can if necessary draw water at the rate of 100 l/s, so there are alternate options for completing an irrigation cycle, such as putting the water on at a faster rate and run for a shorter time or modify the application rate of the water whilst travelling at the same speed.

402. The controlling factor, besides water holding capacity within the root zone, is the effective infiltration rate that can sustained without causing runoff. These factors have to be assessed at detailed design before finalizing the selection of a machine. Thus, for the main fodder/wheat irrigated area, possibly interspersed with some potatoes (not recommended as difficult then to balance the different crop IWR (Norm) if crops are intermixed), a flow of 135 m3/hr. per machine is required, when working to a 20-hour daily schedule. Alternatively, to apply a fixed amount every pass with the machine outputting 100 l/s (360 m3/hr.), it could complete a circle (100 ha) in approximately 56 hrs. to deliver a depth of 20 mm per ha. This then suggests one machine, allowing for certain inefficiencies, moving, recoupling could do two circles or 200 ha every 6 days. If the area needs 3,000 m3/ha per season, then this is equal to 9 to 10 applications per season, from early May to late August. Thus, one machine could do two circles, but would need to be towable between the designated circles for this mode of operation. Again, the details need to be discussed with potential suppliers as to how the center pivots can be operated most effectively to minimize how many units are required for the irrigation scheme.

403. Besides the use of center pivots for the main irrigation command area, there are areas around the circles that will not get watered from the center pivots, and there is also the windbreak that is to be set up outside the actual command area boundary, predominantly on the western side. Due to the center pivot circles, within the overall command area, there is one central area of about 58 ha, and four boundary areas, each between two circles, of 29 ha each – a total of about 170 ha. These areas can be left fallow, unused, or they could be separately cultivated and irrigated from the pressure main using a mix of sprinkler, spray or drip systems (movable/rollout). Hydrants would need to be placed for connections in each area, connected with small distributary pipes (up to 170 mm internal diameter) and a central filtration unit. Pressure comes from the main pressure pipe.

404. For these separate sprinkler/spray/drip systems, around the circles, they could be readily developed for mixed vegetable and potato production, or for fruit trees and/or greenhouse operations. It is proposed that, subject to further interest, designs should provide for roll out drip irrigation systems, taking water through branch pipes from the main pressure supply pipe to suitably positioned hydrants, with local pressure regulating valves and separate small scale drip filtration systems for small diameter drip systems with inline emitter pipe. There could if required be a supply from these local area systems to any greenhouses that are developed. For each 30-ha block, a combined flow rate of up to 100 l/s (i.e. 3.3 l/s/ha) should be sufficient to satisfactorily irrigate these crops over 100 days. That is: 100 days x avg. 15 hrs. per day x 60 mins x 60 secs at 95% efficiency = 18,750 m3. The peak flow rate for the whole vegetable and potato block (30 ha) will be about 80 m3/hr., with flow rotated between sub-blocks on a 5- to 6-day cycle. Irrigation water can be provided on a needs basis over the growing season, taken to be 100 days, and it has been assumed that the systems would operate for at least 18 hours per day up to 24 hours for peak demand. The remaining block header and lateral in-line dripper sizing and flow rates will need to be determined with the potential equipment supplier.

405. Drip Systems. Drip system 1 will be set up specifically for vegetables and potatoes in the corner areas around the center pivot circles in the command area, covering about 170 ha outside of the coverage under the sprinkler system. Again, the detail for how this would operate will need to be determined with the equipment supplier, but water demand is established based on uniform irrigation over the additional area for at least a 15-hour operational day. Pressure will always be

150 available in the main water supply pipe. The position of offtakes from the main pressure supply pipe should be downstream of the supply pipe backwashable fine sediment filter, which when operating discharges to the eastern drain. Each of the drip systems will also have their own filtration elements to trap any finer sediments that could otherwise over time clog the in-line emitters suggested for this drip system. In-line emitter pipe is much easier to roll out and rollup once the crop is established or once irrigation stops for the season. Downstream of the filtration set, there will be a main low pressure (up to 2 MPa) header pipe, up to 150 mm internal diameter of varying length, which then supplies subsystems of lateral pipes sized to suit length and area covered (typically 19 to 32 mm external diameter, aligned down the slope (to offset pressure head loss when flowing). Drip emitters can be chosen for the appropriate flow rate, though reference to manufacturer design guidelines. Typically, these can work at rates from 0.5 to 3 l/hr., and actual application rates can be matched by adopting appropriate spacing. Higher flow rates will saturate soil over a larger area but may be less efficient due to percolation loss. Closer in-line spacing can be adopted to suit the plant spacing and minimize wetting areas away from the effective plant roots.

406. Drip system 2 will be for the 3,900 m long (total length along the south, west and north of the command area) by up to 10 m wide windbreak (3.9 ha) depending on how the two tree rows and single bush row are spaced. The arrangement will determine how the drip main line, spur lines and laterals can be laid out, and the supplier will need to determine the appropriate layout to optimize pipe sizing, maintenance of effective operating pressures, taking water from the tail of the main pressure supply pipe. Suitable pressure regulating and filtering is needed to be drawn from the main pressure pipe before it enters the command area, so as to ensure long life for the dripper lines. As inline emitters could be damaged by frost, the lined will have to be rolled up each autumn and reinstalled each spring. Pipes would be fitted with end stops so they can be effectively drained before roll-up. The windbreak layout might also include land forming to capture rainfall runoff (a drain) and consideration could be given to including small checks in the adjacent drains to retain water for nurturing the trees and bushes.

407. Figure 80 provides an overview of the proposed irrigation command area, which is protected by formed banks on the downstream side of drains cut to run the Khusheet river and other runoff around and/or away from the command area. If at the detail design it is assessed there is some advantage to incorporate the windbreak design with one or more of the drains, thereby entrapping runoff to sustain the trees, this will need to be fully assessed and detailed prior to construction.

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Figure 80: Overview of Upgraded Khoid Gol Command Area

Source:TA Consultants–field survey

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408. Drainage. Drainage will be needed to protect the area against the risks of large overland flows, coming from the south and east as shown in Drawing Y. The drains will need to carefully manage and divert the Khusheet river and other local surface runoff around and away from the command area. The indicative drainage layout, with and eastern and western demarcated drain will be formed as relatively wide natural earth channels, with material pushed up on the low side as a protection bank to prevent any risk for water spilling across the drain and into the command area. The material needed for the protection bank will generally be won from the formation of the drain, that will follow the natural fall around the command area until it can be freely released to the natural drainage systems at no risk to the command area or any other system infrastructure. For the main Khusheet river flow, some rock armoring may be required to ensure safe redirection of the flow westwards.

409. It may also be necessary to protect any exposed infrastructure – pipes, canals, cropped area, windbreaks, roads and associated structures from the uncontrolled risk for erosion from overland flow or any infrastructure failure. The main form of protection would be pushed up earth banks suitably position and shaped to deflect any runoff around the key infrastructure and cropped area. The only structures specifically foreseen to protect infrastructure from runoff risks are: (i) Rock armored protection in the bed and sides of the drain in proximity to crossing the installed pressure pipeline where it crosses the western drain; (ii) Protection of the balancing storage inflow section of main canal, inflow structure and the escape structure and channel by having a suitably aligned bank to catch and deflect any overland runoff back towards the main river channel; and (iii) Possible installation of a short piped sections in the upper main canal (from ch 0+000 to 2+900 m) to facilitate, with flow management banks, the safe passage of runoff flows from the foothills over the line of the main canal, and thereby mitigate the risk for disruption of diverted water from the Khusheet river.

4. Design Discharge

410. The river intake structure maximum capacity is 0.40 m3/sec, and the water flow in the main canal (10,100 m long) is nominally up to 0.30 m3/s. The main canal discharges into the balancing storage through a gated inlet structure with energy dissipation features. There is an escape outlet from the pond, about 10 to 15 m east of the inlet structure that will safeguard the storage from overfilling and washout, designed for up 0.50 m3/s discharge. This weir will spill into a formed and initially armored drainage canal that will carry excess inflow coming from the canal back to the river section coming down the slope to the east. An outlet structure from the storage will regulate inflow into the main pressure pipe (6,480 m long) to carry water to the command area. Within the command area, there will be four 560 to 600 m long pressure distributary pipes to each carry up to 0.10 m3/s to each center pivot irrigator for 100 ha each, total 400 ha.

411. The monthly average water available from the river for irrigation ranges from 0.27 m3/s to 0.75 m3/s. However, whilst this is the possible flow that can be extracted, peak flows can be moderated by establishing a headworks pool on the river. To do this, a low rock filled barrier wall with central spillway needs to be constructed to retain a headwater pool from which water can be drawn at a steady rate through the main canal intake. The with-project average water demand varies from 0.20 to 0.24 m3/s, so once the river intake pool is full, any excess flow would pass over the central armored (concrete) spillway to safely pass down the river.

412. This intake structure (to a standard design layout) will have a maximum flow capacity of 0.40 m3/s, but will include a flow regulation gate to stabilize the main canal flow at about 0.30

153 m3/s. This steady flow will start early spring to top off the balancing storage, from where water would be released to supply irrigation water to center pivots at a maximum flow rate of 0.40 m3/s (4 pivots at 0.10 m3/s each). Use of the existing balancing storage (approx. 100,000 m3, with a surface area of about 4 ha) means that a steady main canal water inflow can be managed within the storage, irrespective of the water drawn for irrigation. Safeguards will include the provision of an overflow weir/spillway from the storage that would return any excess flow to the river. Should irrigation demand exceed the available water held in storage with inflows, then the intake outlet from the river pool can be opened further to provide additional short-term flow.

In the without project, these irrigation water demand ranges from 0.33 to 0.50 m3/s, which is 50.3 to 83.7% of the net river flow during June to August (Table 64). Insufficient water would be available in May in a without-project situation due to higher inherent water use efficiency with a poorly and difficult to control surface water irrigation system. In the with-project scenario, through better control and management of the diverted water, the total volume needed for successful operation of the irrigation scheme will be half that require din the ‘without project’ case.

Table 64: Design Discharge from the Khusheet River Irrigation Net Average Water extracted from Irrigation Scheme Design Capacity period Available Water river for irrigation with m3/s after environmental project flow allowance Main 4 Field m3/s Main Pressure Distributary m3/s % Canal Pipeline Pipelines May 0.27 0.26 94.7 <0.30 <0.40 <0.10 June 0.60 0.31 49.1 0.30 0.40 0.10 July 0.75 0.25 33.2 0.30 0.40 0.10 August 0.65 0.19 28.7 0.30 0.40 0.10 September 0.71 0.07 9.9 0.30 0.40 0.10 Source: TA Consultants–field survey

5. Civil Works

413. The main civil works for the diversion headworks from Khusheet River and conveyance of water to the irrigation sprinkler/drip systems in the command area will include: (i) construction of a rockfill barrier wall (with impermeable core) up to 3.5 m high (1,765 masl nominal), u/s slope 2:1, d/s slope 3:1, top about 130 m across the Khusheet River channel between natural abutments (east and west), at a location to be confirmed downstream of the existing but broken intake channel; (ii) incorporation of a reduced level (- 1 m, 1764 masl nominal) reinforced concrete spillway section, up to 15 m wide, to control pool water level upstream, and pass moderate excess flows back to main river, over an armored spillway on the rockface of the barrier wall; (iii) construction of a new intake structure in the barrier wall at the head of the existing intake channel, with vertical screw lift sluice gate (0.5 m x 0.3 m), with free release of the small flow (up to 0.3 m3/s) into the main canal; (iv) construction of a sediment sluicing channel in the box section of the new intake structure, with a sluice gate (0.4 x 0.3 m) from the head of the main canal to discharge on the left bank of the river in a channel, on the downstream side of the new barrier wall, for periodic sediment sluicing; the base of sediment collection chamber to be formed for effective guidance of sediment under flow toward sluice outlet;

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(v) construction as necessary (cutting, forming, shaping and protection) of a channel to carry sediment back toward the river on the downstream side of the barrier wall, away from the toe of the wall; (vi) to the west of the main canal and intake structure, formation of any revised Soum road alignment that may be required, that goes up and over the left abutment of the barrier wall and around the edge of the water pool formed by the barrier wall; (vii) reformation and re-lining/repair of the main canal to balancing storage (about 10,100 m, subject to actual start and finish location); flow of up to 0.5 m3/s, max velocity not to exceed 1.5 m/s in a lined section, or 0.9 m/s in an unlined section, the need for any flow control structures to be assessed and incorporated as necessary. (viii) on main canal, at high risk zones, suggested possible inclusion of a 100 to 200 m buried pipe section with inlet and outlet transition structures, as needed to pass any overland flow to the Khusheet River, with this or multiple sections (to be confirmed) to allow for the passage of high risk overland flow that would if not controlled damage the main canal. These provisions should be inclusive of all necessary water guidance and protection earth embankment and appropriate inflow/outflow structures on the pipe ends, sufficient to prevent normal canal flow exiting around the structure; (ix) a main canal discharge structure to guide flow into the balancing storage (southern side) to calm inflow velocity from the main canal, and to minimize scour when the balancing storage is low. To protect the storage bank from scour, the outlet from this structure into the storage should be set at dead storage level, with suitable energy dissipation from the inlet side to outlet lip incorporated in the structure base; (x) intake structure to the main pressure pipeline (6.48 km, pipe size to be determined, but about 450 mm diameter) out of the storage tank through a gated control (secure penstock gate or closure valve) to enable pipe to be sealed at intake and drained at the command area scour valve with outfall to drain (for winter). The intake should be fitted with rakeable pre-intake coarse and medium screens (trashracks) for control and removal of windblown and washed in trash and sediment, pre-entry to pipe, or else some other durable form of filtration to mitigate entry of trash and debris; ensure design includes access to the structure, which must be positioned to enable water withdrawal down to the dead storage level of the storage (perhaps 2 to 3 m below storage high water level (HWL); (xi) implement any necessary earthworks on the storage walls to restore design thickness and uniform height with freeboard 1 meter above the HWL (1,528 masl – to be confirmed) (xii) main pressure pipeline from header canal (6,480 m long, 450 mm diameter, pressure rated PN 2 to PN12.5 as static and dynamic head combined) to feed the 2 main distributary pipes for the four center pivot systems; (xiii) main pressure line backwash filtration unit with associated flow control valves and pressure surge vessel to ensure clean water operations for irrigation systems, all suitable for PN 12.5 static head; (xiv) 4 distributary pressure pipelines (560 m long, 250 mm diam., PN 12.5 (static)) to be installed with end connection fittings, for each center pivot connection, each also to include a blanking cap and butterfly valve; (xv) reforming or building new U-shaped earth drains (up to 11.5 km) to protect the canals and command area, and enable clear drainage of rainfall runoff and any canal overspills; (xvi) construction of protective embankments against main canal, on the southern side and around the command area, up to 12 km;

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(xvii) construction of earth channel main canal escape drain (bw=0.5 m, SS 3:1, depth up to 1 m, with protective bank 2 m top width, ss=2:1, 2 m high with armored southern bank face, all for about 250 m minimum; (xviii) installation of various flow control, pressure regulation and outlet structures in the main pressure and distributary pipes (est. 5 x 350 mm; 4 x 275 mm, and 16 x 200 mm); (xix) development of the windbreaks (4.2 km) on the north and west sides of the command area.

414. At this stage, the design and related details are preliminary, and as detail design and operational requirements are clarified, some additional works may be identified (e.g. additional protection measures for pipes, construction of field covered and protected valve boxes, minor earth checks in drains to support windbreaks).

6. Equipment

415. Within the civil works, required equipment will be limited to gates, pressure pipes (HDPE) and associated fittings to the sprinkler system buried pipelines (T-joints, control and scour valves) to each center pivot (4 No.) with pipe end connection hydrants. The following specific equipment, some of which was mentioned for installation with civil works are: (i) The Water Intake – one vertical lift sluice gate with preliminary 0.5 m wide and 0.3 m lift; (ii) Intake Sediment Sluice – vertical lift sluice gate, provisionally 0.4 m wide with 0.30 m opening, sufficient to flush rapidly at up to 2 m3/s, details to be finalized around operational and physical levels at site; (iii) A pressure pipe (450 mm diameter) intake control valve or penstock gate, with long spindle for the release of water from the balancing storage into the main pressure pipe; (iv) Provision and installation of various valves and fittings (No. and open diameter (mm)) as shown in (Table 65); Two100 ha self-propelled center pivot sprinkler sets, 560 m diameter, each with fixed connection to anchor point with hydrant (250 mm diam) at end of 560 m long distributary pressure pipe, all inclusive of fixture/anchor parts, power supply, flow controls, and associated spare parts, spray nozzles and drop pipes suitable for particular crops, all details to be discussed with potential suppliers before confirming detailed specifications (specifics of lateral drive to be discussed and agreed based on local electricity power available, and the operational convenience of available options; (v) Provision of relevant power supply infrastructure, whether connection to main national or local electricity grid, inclusion of diesel power and generator sets, or provision of diesel power to drive irrigation systems (pumps, self-propulsion, etc.) [there is an expectation that adopted sprinkler equipment would include suitable on- board power controls and drive mechanisms if electric power supply and cabling is not viable].

Table 65: Proposed Valves and Fittings Pipe Intake Valve Outlet Valve Scour Valve Filter Set a Main 1 x 450 1 x 450 1 x inline Distributary 1 2 x 250 2 x 250 2 x 250 Distributary 2 2 x 250 2 x 250 2 x 250

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a Inline filter set to process all flow and include provisions with their installation for local flow management (valves) to use the line pressure for backwashing the filters, Specific details and arrangements to be discussed with suppliers. Source: TA Consultants–field survey

7. Bill of Quantities

416. The cost estimation for KhoidgoI irrigation scheme construction and equipment is given in Table 66. The table summarizes the cost for key components required for the upgrading and modernization of the Khoid gol gravity supply and operated irrigation scheme.

417. The preliminary estimated cost for KhoidgoI irrigation scheme is MNT8,668.85 million, equivalent to MNT21.72 million/ha

Table 66: Bill of Quantities for Khoid gol Irrigation Scheme Modernization Budget No Item Unit Quantity (MNT million) Unit cost Total Civil Works 1 Headworks Sluicing structure with intake sluice piece 1 72.68 72.68 channel and outlet flushing channel 2 Rockfill Barrier and Water level Control Weir, Wall m 80 11.34 907.11 L=80m, h=5 m, Weir L= 13 m, h=1.0 m 3 Headworks protection embankment m 500 0.04 18.48 4 Main Canal m 10,100 0.13 1,271.42 5 Main pipe laying m 6,480 0.08 541.60 6 Distribution pipe laying m 3,360 0.07 234.93 7 Drain m 5,000 0.004 22.06 8 Bridge piece 3 4.06 12.18 9 Roads – forming and grading m 8,100 0.00 26.49 10 Windbreaks – prepare land and install ha 3.85 44.41 170.97 11 Drain and protection bank m 9,100 0.03 289.94 12 Balancing storage m2 14,000 0.03 446.79 13 Control well piece 6 2.33 13.95 14 Fence km 5.4 7.00 37.80 15 Pump House no 1 100 100.00 Subtotal 4,166.39 Equipment 13 Head work Control Sluice Gate, Width 1.0 m x piece 2 1.68 3.36 Height 0.6 m, vertical screw 14 PE400, SDR17, 1,0mpa, DN400mm, PN10 m 6,480 0.18 1,186.54 15 PE400, SDR17, 1,0mpa, DN250mm, PN6 m 3,360 0.08 268.08 16 Culvert for bridge (0.75x0.75 m) piece 3 1.48 4.43 17 Central pivot sprinkler, 100 ha set 2 303.88 607.77 18 5ha Water Efficient Drip Watering Advanced set 30 43.47 1,304.24 System 19 3ha Water Efficient Drip Watering Advanced set System 20 Trees, number piece 11400 0.004 45.60 21 Pump (diesel) piece 2 15.00 30.00 22 Excavator for O&M piece 1 168.60 168.60 Subtotal 3,618.62 23 VAT, 10% % 47.25 778.50 24 Environmental baseline assessment number 1 42.67 42.67 25 Environmental impact assessment number 1 42.67 42.67 26 Design cost ha 400 0.10 40.00 Subtotal 903.84 Grand total 8,688.85

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Source: Consultants’ estimates

G. Subproject 6 – Tsul-Ulaan Irrigation and Drainage System Design

1. Site Description

a. Scheme Background

418. Bayannnur Soum owns the Tsul-Ulaan irrigation scheme. The original irrigation scheme was developed in 1984, with an open main canal from the Khovd River, that then discharged into a series of contour-aligned field canals, set at 120 m spacing. Self-propelled sprinkler units (Russian manufactured DDA-100MA crawler mounted sprinkler boom) sucked water from the contour aligned straight field canals to water strips of land in the command area in accordance with a sequential plan. The irrigation scheme had a main canal 5.75 km long, 2.5 km of distributary canals, and 14 km of field canals.

419. The existing scheme is in a serious state of disrepair (Figure 81). Significant investment is needed to upgrade and modernize the irrigation water supply and irrigation operations. The main irrigable command area is 161 ha within a total area of 184.6 ha, giving an effective land use coefficient of 0.87. At the present time, the scheme is non-operable. No water is passed through the existing main canal, as there is limited means to control the flow down the slope from the river intake headwork to the start of the command area, and therefore there is no on-going cultivation in the command area.

Figure 81: Current Situation for Tsul-Ulaan irrigation scheme

Upper left: intake from river; Upper right; head work structure and outlet channel; Lower left: main canal and control structure; Lower right: main canal with protection bank Source: TA Consultants–field survey

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b. Area and Crop Maps

420. Geomorphology. The project area sits at 1,300 to 1,350 masl, within the mountain ranges of the Mongolian Altai Mountains, which range from 2,000 to 3,000 m. The project area is bounded on the south west by Tsetseg Uul mountain (2,094 m), on the east and south east by the Tsagaan Uush mountain (2,745 m), and on the north-east and north by the Khovd river. The project area valley is formed from eroded gravels, in alluvial and alluvial-proluvial eroded and accumulative fans. There are old river streams, with oxbow-lakes across the river flood-plain, which is now the western edge of the modern Khovd River.

421. The Tsul-Ulaan irrigation scheme is located in Bayannuur Soum, Khovd Aimag, and lies adjacent to the anabranch of the Khovd River (Figure 82). The intake is 5.75 km upstream from the start of the command area, and this main canal then continues as a distributary canal for further 2.55 km along the southwestern side of the area. From the distributary canal, water is diverted into field canals which run southwest to northeast in the direction of the river, at parallel intervals of 120 m. The field canals in the original scheme generally follow the contours of the area, and therefore act as retention ponds from which water is drawn by the moving sprinkler irrigation machines. These boom spray irrigators, mounted on crawler tractors, had a reach of approximately 60 m each side. The water storage arrangement in the field canals, with relatively flat grade and deep section, provided a sump where the travelling irrigation machine placed a floating intake. The water level in the field canal was controlled by a set overspill outlet at the downstream end into a drainage ditch.

Figure 82: Location of Tsul-Ulaan Irrigation Scheme

Source: TA Consultants based on Google Map

c. Climate

422. Meteorological observations at Bayannuur soum began in 1996, after Tsul-Ulaan irrigation scheme was developed in 1984. There are now 22 years (1996-2018) of monthly mean air temperature, wind speed and monthly precipitation data which has been analyzed. The climate of the Altai mountain region is sharply continental. It is characterized by dry air, with relatively low rainfall throughout the year, and has significant weather variability for both individual seasons and between years.

423. In the Tsul-Ulaan subproject area, the daily temperatures throughout the growing season can exceed 30oC (maximum daily) between May and August, and humidity is about 50%. Precipitation, when water is required for crop production, varies from an average of 7.6 mm (May)

159 to 27.4 mm (July), with an overall average for the year of 95 mm, where 50% of that falls in July and August, and 80% falls in May to August. The average wind speed for the year is 1.7 m/s, with peak wind speeds experienced through the warmer crop growing months. Mean monthly climate data for the project area is given in Table 67.

Table 67: Mean Monthly Climate Data in the Tsul-Ulaan Subproject Area Average Absolute Absolute Humidity Wind Precipitation, Temperature, Maximum Minimum (%) speed, (mm) (oC) Temperature, Temperature, (m/s) (oC) (oC) January -23.7 3.2 -45.1 73.9 0.5 1 February -17.6 12.9 -44.5 67.6 0.8 0.8 March -5.4 19.4 -37.0 54.2 1.8 1.8 April 5.9 29.6 -19 42.5 2.7 5 May 13.2 32.0 -9.5 41.9 2.9 7.6 June 18.8 34.8 -0.5 46.2 2.4 21 July 20.5 36.9 3.2 50.7 2.1 27.4 August 18.0 34.3 -2.4 52.3 1.7 20.6 September 11.3 32.0 -8.2 50.1 1.7 3.9 October 2.2 24.0 -27.8 51.5 1.4 2.8 November -9.1 15.6 -35.5 63.7 1.1 1.7 December -18.9 9.2 -44.6 72.7 0.7 1.5 Average 1.3 36.9 -45.1 55.4 1.7 95.0 Source: National Agency for Meteorology and Environment Monitoring

424. Air temperature. Figure 83 illustrates the trend for change in monthly mean air temperature from April through to September. As the April mean temperature is 5.9oC, and below 10oC, there is insufficient natural warmth in the air to support crop growth for most of that month.

425. Air temperature trends. Monthly mean air temperature from April to September has not been changing consistently (Figure 83). Whilst May and September show a declining trend, April and June to August show an increasing trend. April mean temperature has increased by 0.9oC, June by 2.1oC, July by 0.3oC and August by 0.3oC, while May mean temperature has decreased by 2.0oC. On balance, there has been minimal significant shift in the mean annual growing season temperature, though there are some shifts that could impact crop production. With increased temperatures in June, it is likely some increased irrigation will be required.

Figure 83. Trends of Monthly Air Temperature at Tsul-Ulaan Subproject Area

Source: National Agency for Meteorology and Environment Monitoring

426. Duration of hot days One important climate factor that influences irrigated crop production is hot days. Figure 84 shows the number of days each year with a daily average air temperature above 25oC has increased by 15 days over the last 20 years. Despite this, the number of average days where air temperature exceeds 30oC have not increased, though it can reach this temperature for about 10 days during the growing season.

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Figure 84: Trends in Hot Days with Daily Mean Temperature more than 25 oC and 30oC

Source: National Agency for Meteorology and Environment Monitoring

427. Precipitation. Monthly precipitation is decreasing during the growing season except for June (Figure 85). For April, May, July and August, precipitation has decreased by 5 mm, 8 mm, 15 mm and 11 mm, respectively, while June precipitation has increased by 10 mm.

Figure 85: Trends of Monthly Precipitation at Tsul-Ulaan Irrigation Scheme

Source: National Agency for Meteorology and Environment Monitoring

428. Despite the decrease in precipitation for most months of the growing season, the number of days with no precipitation in May and August has decreased slightly, while it has increased slightly in June with no notable change for July (Figure 86).

Figure 86: Trends in Days with no Precipitation

Source: National Agency for Meteorology and Environment Monitoring

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429. Wind. The monthly mean wind speed in the growing season tends to be higher than for other months (Table 67). Even though the mean wind speed for the months of April (2.7 m/s), May (2.9 m/s), June (2.4 m/s), July (2.1 m/s) and August (1.7 m/s) are low, the maximum wind speed can reach 30 m/s once a year. The number of days when wind speed has exceeded 10 m/s has increased by 30 days (one month) over the last 25 years (Figure 87). Thirty five percent of the wind comes from the northwest.

Figure 87: Trends in High Winds and Wind Direction

Source: National Agency for Meteorology and Environment Monitoring

430. Agro-climate. Significant climatic changes occurred in the subproject region between 1996 to 2018 and this impacted the agro-climatic characteristics. Over this period, the growing season length has increased by about 10 days because of a shift in when the air temperature transitions above 10oC (earlier dates in spring) and falls to 10oC (later dates in autumn). The accumulated temperature that supports longer crop growth with frost free days has increased, thereby favoring greater crop growth (Figure 88).

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Figure 88: Agro-climate Characteristics

Source: National Agency for Meteorology and Environment Monitoring

431. Temperature Projections. The summer temperature is projected to increase by 1oC, 2.0oC and 4.2oC (Figure 4) and precipitation decrease by 10% by 2035, 2065 (Figure 5) in the Tsul-Ulaan subproject area. A continued increase in temperature respectively and a slight increase in precipitation are the most likely combined future impacts necessitating more intense irrigation.

d. Soils

432. The Tsul-Ulaan Irrigation subproject command area soils map is shown in Figure 89. The predominant crop root zone soil types in the command area are mountain light kastanozem (silt loam) and light kastanozem (sandy-silt loam). These soils do not have high water-holding capacity, typically in the range of 100 to 150 mm/meter depth.

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Figure 89: Soil Map for Tsul-Ulaan Irrigation Scheme

Source: Institute of Geography and Geo-ecology

433. Kastanozems are humus-rich soils previously covered with early-maturing native grassland vegetation, that produces the characteristic brown surface layer. Each horizon reacts strongly with 10% hydrochloric acid, meaning weak alkaline, calcic soil. Soil pH = 8.5 and EC = 135 μS, meaning the soils have low salinity. Kastanozems have relatively high levels of available calcium ions bound to the soil particles. These and other nutrient ions percolate downwards with water to form layers of accumulated calcium carbonate or gypsum. Kastanozems are the principal soils that are most suited to irrigated agriculture and grazing.

434. Seven soil samples were taken in the command area during field surveys. Analysis shows that there are two different soil textures. In the western area, the soil is more silt clay, whereas in the east it is more sandy clay, as a clear effect of wind erosion over the last 2 decades. Volumetric water content was found to be 12 to 14%. Stone and gravel greater than 2 mm are about 20%. The soil analysis is given in Table 68.

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Table 68: Soil Profile and Analysis Soil Depth, m Characteristic horiz on 1 O 0 to 0.1 Grass Root zone with slightly decomposed organic matter. Silty clay soil and surface littered with stones. Surface highly susceptible to wind erosion 2 A 0.1 to 0.35 Grey brown soil, with less stone and gravel. High calcic soil. Silty clay 3 E 0.35 to 0.5 Ferrous red soils have accumulated have in this layer, where 5 to 10 cm diameter gravel is found, and because of water erosion, clay particle sediment lies in this layer between sand and gravel. 4 B 0.5 to 0.7 Sand and gravel. 5 C > 0.7 Fully saturated sandy clay soil with gravel

Source: Integrated agricultural laboratory

e. Water Sources

435. The main water source for irrigation is the Khovd River. The Tsul-Ulaan irrigation scheme is situated in the middle basin of The Khar Lake – Khovd River basin (Figure 90), which is one of the largest river basins of Mongolia. The basin, located in the western region, has a drainage area of 88,821 km². Khar Lake - Khovd River basin includes 96% of the glaciers of Mongolia, meaning that the major source of river water resources is glaciers. To assess the water resources for Tsul- Ulaan irrigation scheme, 30 years of time series data (1982 to 2018) from Bayannuur gauging station have been analysed.

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Figure 90: Khovd River Basin – Location of Hydrological Gauging Stations and Tsul- Ulaan Irrigation Scheme

Source: TA Consultant based on National Atlas

436. Table 69 shows monthly mean flow data at Bayannuur gauging station, which ranges from 65.5 m3/s to 183.1 m3/s during the growing season. The environmental flow requirement is 56.8 m3/s as 90 percent of long-term average flow of 63.1m3/s (Error! Reference source not found.) o f the Khovd river at Bayannuur gauging station. Therefore, at Bayannuur station, just upstream of the Tsul-Ulaan irrigation scheme, there is an average monthly mean flow of at least 8.69 m3/s available to meet non-environmental flow demands in May, and more in the other months through to September. Even then, the monthly high flow can range from 109.3 m3/s in May up to 358.3 m3/s in July, whilst low discharge can fall below the environmental flow requirement in all months except July. In general, there is more than enough water for reliable irrigation at Tsul-Ulaan during the growing season, though some prudent storage management in May and June would be beneficial for potential dry years.

Table 69: Water Resources of the Khovd River at Tsul-Ulaan Subproject Area

Mean Mean Mean Water available for use Mean % of Maximum Minimum Environ’t Month Discharge flow Annual Discharge Discharge m3/s m3/s Discharge 3 3 m3/s m3/s m /s M /month April 50.1 14.7 28.6 56.8 3.78 - - May 109.3 30.4 65.5 56.8 8.65 8.69 23,273,712 June 272.2 53.9 146.2 56.8 19.3 89.4 231,808,103 July 358.3 63.4 183.1 56.8 24.2 126.3 338,323,378 August 237.5 51.1 131.5 56.8 17.37 74.7 200,150,202 September 117.0 31.2 71.2 56.8 9.41 14.4 37,447,294 October 66.3 26.4 45.0 56.8 5.94 - - November 38.7 17.5 27.9 56.8 3.68 - - December 26.9 7.0 18.7 56.8 2.47 - -

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January 22.8 4.2 14.1 56.8 1.86 - - February 30.1 3.7 12.1 56.8 1.60 - - March 32.1 3.3 13.1 56.8 1.72 - - Source: National Agency for Meteorology and Environment Monitoring

437. Khovd River flow during the irrigation period of May to August at Bayannuur has been decreasing since 1982 (Figure 179).

Figure 91: Khovd River Flow at Bayannuur Gauging station (1982-2017)

May June July August Linear (May) Linear (June ) 400.0 350.0 300.0 250.0 200.0 150.0 100.0 50.0 0.0 1980 1985 1990 1995 2000 2005 2010 2015

Source: National Agency for Meteorology and Environment Monitoring

438. The Khovd River flow sensitivity to climate change is shown in Table 70. If precipitation remains unchanged and average temperature increases by 1°C, 2°C, 3°C or 5°C, then it is projected that the river flow could decrease by 3.4% (+1oC) to 15.3 % (+5oC). The impact of precipitation declining by up to 20% is substantially more marked than if precipitation increases by 20%, but an increase of 5oC would almost eliminate any gains expected from additional precipitation. If precipitation has declined by 20%, then the reduction in river flow from increased temperature is relatively small. Overall, river flow is highly sensitive to reduced precipitation, but with unchanged or increased precipitation, the impact of increased temperature is more significant in moderating river flow.

Table 70: Khovd River Flow Sensitivity to Climate Change a Temperature Increase Probability (°C) -20% -10% 0% +10% +20% 0 -62.9 -38.2 25.8 33.9 1 -64.4 -40.4 -3.4 20.8 26.7 2 -65.6 -42.4 -6.6 15.7 19.2 3 -66.8 -44.5 -10.0 10.6 11.7 5 -68.2 -47.4 -15.3 2.1 8.7 a Percent change of average river flow. Source: TA consultant

439. Water quality. Water chemistry analysis for Khovd river from 2013 to 2018 is shown in Figure 92. The overall assessment is that the chemical composition of water in Khovd river is 2+ 2+ - good, where the concentration of Ca , Mg , SO4 and Cl do not exceed the irrigation water

167 standards thresholds. The sodium adsorption ratio (SAR) that is a critical factor for sustainable irrigation is also found to be within acceptable limits, so it is concluded that water from the Khovd River is well suited for irrigation use.

Figure 92: Water Chemistry of the Khovd River

Source: Central Laboratory for Environment and Metrology

440. Suspended solids in the Khovd River water range from 4.6 to 106 mg/l (or 0.004 to 0.1 kg/m3), but do not exceed 25 mg/l (0.02 kg/m3) most of the time (Figure 93). There is no clear seasonality to suspended solid concentrations, but there are periodic and short duration increases as a result of peak snow melt flows and summer flood flows when intense rainfall can lead to excessive runoff and peak river flows and water levels. There is therefore a need for careful management of water diversions from the river to contain suspended sediment discharge into the intake and canal/irrigation system, which may require additional sediment management measures at intake or through settlement and flushing basins aligned with the main canal.

Figure 93: Suspended Solids in the Khovd River Water

Source: Central Laboratory for Environment and Metrology

441. Water quality in the Khar Lake – Khovd river basin system are also monitored for nutrient concentrations, covering the presence of nitrite, nitrate, ammonium, and phosphorus. Recent monitoring has shown that all of these pollution parameters are generally within acceptable concentration limits for irrigation water use.

442. Ammonium is one of the nutrients that is abundant in Mongolia’s river water, as compared to other nitrogen linked chemicals. The concentration of ammonium can vary from 0.1 to 1.0 mg/l, but rarely exceeds 1.0 mg/l. The Maximum Allowable Concentration (MAC) for ammonium in river

168 water is 0.5 mg/l. Higher concentrations (approaching 1.0 mg/l) are typically observed during spring flood events arising from snowmelt which is most likely influenced by the wash-off of livestock waste (i.e. a surface runoff derived nutrient).

443. Water quality in the rivers of the Khar Lake - Khovd River basin is classified “very clean”, with index of 0.28 based on water quality analysis and assessment against the Water Quality Index (WQI).28

f. Existing Irrigation System and Design Maps

444. The Tsul-Ulaan Irrigation Scheme supplies water for a command area of 161 ha. Water is diverted from an anabranch of the Khovd River, from which a lined, but poor condition, intake canal takes water to a gated headworks. Excess flow spills back to the river through a continuation of the intake canal. A 5.75 km long main canal, lined with stone masonry (now in very poor condition), conveys water from the gated intake to the command area, with a fall of about 10 m (1 in 500 to 1 in 550). The nominal canal bed width is 0.6 m with a trapezoidal section, and side slopes of 1.5:1. However, deterioration and erosion now mean the section is irregular. For a lined canal, the flow velocity for 0.5 m3/s would be about 0.6 to 0.7 m/s, but in the current rough unlined canal it will be lower, as the X-section is generally wider but shallower with sediment deposition.

445. The main canal feeds a 2.55 km distributary canal that runs along the southwest side of the command area, with a general slopes to the east/northeast and eventually back to the Khovd river, The command area shows the remaining form for 14 km of field canals, and about 6.5 km of drains. The headwork design discharge capacity is 0.50 m3/sec. It is sited on a constructed diversion channel about 200 m from the riverbank and is fed by a diversionary intake canal that overflows back to the river. The Khovd river runs along the north side of Bayannuur soum which has been an important region for irrigated agriculture in Bayan-Ulgii aimag for several decades. The river is abraded with many channels over a wide flood plain, and although farmers are cultivating land within the plain, using simple water diversion for surface flood irrigation, their land holdings are vulnerable should river channels realign post flood events. The upgrade and modernization of the disused Tsul Ulaan irrigation scheme area (161 ha) will provide more assured and durable alternative irrigated crop production opportunities for local farmers, in conjunction with the ongoing irrigation activities maintained within the river channels across the flood plain of Khovd River near the soum.

446. The main crops produced by Bayannuur soum are potatoes, vegetables, fodder, and apples, though currently there is no production from the designated Tsul Ulaan irrigation scheme area. Bayannnur soum is the only region where apples have been grown since the mid-1980s. In 2018, the soum produced about 107 tons of fodder from 66.7 ha, 304 tons of potatoes from 38 ha, and 6 tons of apples from 6 ha of land, all lying outside of the irrigation scheme command area. Bayannuur soum meets all the local market demand for potatoes and vegetables, which provides 60% of Khovd aimags needs for potatoes and 17% of its vegetables.

447. The existing Tsul-Ulaan irrigation scheme needs to be upgraded and modernized so the command area of 161 ha can be returned to full production (Figure 94). The irrigation scheme will be irrigated with water diverted through an improved intake structure and reformed and lined canal system, taking water from the Khovd River. Currently the command area receives no water and there is no irrigated crop production. Following discussions with local government, it is understood that the modernized irrigation scheme command area will be allocated to grow 20 ha of potatoes, 31 ha of vegetables, 126 ha of fodder, and up to 5 ha of fruit trees. There will also be, as part of

28 Ministry of Nature and Environment, 1998. Water quality monitoring guidelines.

169 the overall modernization, the installation of approximately 3 ha of windbreak, which will be nurtured with an associated drip system, supplied from the end of the main canal. This will then enable the soum to provide 80% of the Bayan-Ulgii aimags potato requirements, and 40% of its vegetable needs.

Figure 94: Tsul-Ulaan Command Area Map

Source: TA Consultants

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2. Irrigation Water Requirement

448. The designed command area is 161 ha out of which 15 ha for potatoes, 15 ha - vegetables, 126 ha – fodder and 5 ha-fruits. There is also 3 ha for tree wind break. It is proposed to plant leafy trees at two rows and one row bushes to the west and west-northern boundary of the command area according to the wind direction data (Table 71).

Table 71: Current and Planned Command Area Crop type Current Allocation Irrigation method Planned Allocation Irrigation method of command area of command area Potatoes, ha Currently no crop is Used Furrow 15 drip Vegetables, ha cultivated as there 15 drip Cereals, ha is no is coming to sprinkler Fodder, ha the command area 126 sprinkler Fruit trees and drip 8 wind break, ha Source Consultant’s estimates

449. Overall efficiency will be increased to 74% using lined canal systems, modern controllable linear move sprinkler irrigation machines for 126 ha for fodder, and low pressure drip systems for 30 ha for potatoes and vegetables and 3 ha windbreak (Table 72). Other key measures proposed for the new irrigation works to improve overall operational performance and water management efficiency will include lining the main and distributary header canals and improving overall flow control within the system to direct water to the main modern sprinkler systems for irrigation of fodder and cereals.

Table 72: Scheme Irrigation Efficiency Characteristics Field irrigation Percentage Conveyance Field Scheme application of total efficiency application irrigation command (%) efficiency efficiency area (%) (%) Current for total command Surface irrigation 100.0 60 60 36 area (border, furrow, basin) Designed fodder area, 126 ha Sprinkler 78.2 95 75 71 Designed potatoes and Drip 21.8 95 86 vegetable, 30 ha 90 Average for designed Combined sprinkler 100.0 95 78 74 command area and drip Source: TA Consultants

450. This irrigation season water requirement has been calculated based on the irrigation water utilization norm (Table 6) applicable for the region and planned crops. Following analysis for the future upgraded and modernized irrigation system development, the estimated total water use for the irrigation season, based on irrigation water utilization norm (Table 6) with the planned crops of potatoes, vegetables, cereals and fodder is 1,120,632 m3 (0.084 m3/s) with project and 1,121,161 (0.085 m3/s) with climate change (Table 39). This irrigation water accounts for 0.13 percent of total net available water in the growing season or about 0.6-2.0 percent of the river flow of the given month (Table 74), after meeting the environmental flow of 56.8 m3/s thus there water is available to meet the irrigation needs.

Table 73: Crop Water Requirements Irrigation period Item Total May June July August September Allocation of command area

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Potatoes, ha 15 15 15 15 15 Vegetables, ha 15 15 15 15 15 Cereals, ha 0 0 0 0 0 Fodder, ha 126 126 126 126 126 Fruit trees and wind break, ha 5.0 5.0 5.0 5.0 5.0 161 Water requirement with project Gross irrigation norm, m3/month 204,792 228,369 198,929 133,697 63,481 Irrigation efficiency (%) 0.74 0.74 0.74 0.74 0.74 Total irrigation water requirement (m3) 276,746 308,606 268,824 180,671 85,785 1,120,632 Water requirement with project with climate change Increase in ET (m3) 23 109 110 140 120 50 Projected irrigation Water requirement, m3/month 204,815 228,369 199,039 133,837 63,600 Irrigation efficiency (%) 0.74 0.74 0.74 0.74 0.74 Projected total irrigation water requirement (m3) 276,776 308,606 268,972 180,860 85,946 1,121,161 Source: TA Consultants

Table 74: Water Availability for Irrigation Net Projected total Percentage of Monthly Environ- available irrigation water irrigation water Irrigation River ment flow in requirement with use from net period Discharge, Flow, the river project river flow m3/s m3/s m3/s m3/month m3/s m3/month % May 65.5 56.8 8.69 23,273,712 0.10 276,776 0.16 June 146.2 56.8 89.4 239,535,040 0.12 308,606 0.08 July 183.1 56.8 126.3 338,323,378 0.10 268,972 0.05 August 131.5 56.8 74.7 200,150,202 0.07 180,860 0.05 September 71.2 56.8 14.4 38,695,537 0.03 85,946 0.05

Total 839,977,869 1,121,161 0.13

451. The maximum discharge capacity required at the headworks (intake from Khovd river) is 0.50 m3/s. The planned irrigation demand (161 ha, mixed cropping) requires a peak flow of 0.17 m3/s (at 74% overall efficiency), which means that if conveyance and application losses can be further reduced through modernization, then it may still be possible to eventually expand the overall command area. However, the current assumption is for a fixed command area of 161 ha, with up to an additional 6 to 8 ha for the fruit trees, windbreak and possible greenhouses (in entrapped area to southwest of the command area, fed directly from the distributary canal).

3. System and Layout

a. Scheme Area Topography

452. The existing headworks are located at elevation 1,340 masl, at 48.97.05.57N and 91.10.79.85E. The new irrigation scheme headworks will be located on the riverbank to the northwest, at the start of the existing intake canal. The water source is approximately 10 m above the command area, 5.75 km to the northwest. The main canal is aligned on a regular slope with a gradient of 1 in 500. This is sufficient for the main canal to be constructed without intermediate check structures. As a way to reduce maintenance costs, the possibility of using a pipe (i.e. HDPE or PE, 1.0 MPa) was considered as an alternative, but the costs for pipes when compared against concrete lining slabs was deemed to be too high. However, a second more detailed comparative

172 analysis should be completed at the detail design stage, especially in terms of the most suitable costs effective pipes now available. The natural gradient also allows for effective and complete drainage of a pipe, thereby eliminating any potential for frost damage each winter.

453. The boundary of the command area starts at elevation 1,330 masl, at 48.93.48.85N and 91.16.65.36E. The main canal discharges into the distributary canal (total 2.55 km) along the boundary of the command area, with its end at elevation 1,326 m, at 48.92.29.07N and 91.19.55.10E (Figure 95).

Figure 95: Map of Tsul-Ulaan Irrigation Scheme

Source: TA Consultants

454. The main canal will start from a new headwork structure located close to the current intake channel start point on the riverbank. The old headworks will be abandoned, and the upgraded main canal will continue through the existing intake channel and into and along the existing alignment of the main canal to the command area. The main canal is sized to accommodate the peak flow required to support the main irrigation activities at peak demand.

455. For the command area, there are currently planned two types of canal to get water to the fields – a line distributary canal and field canals. The distributary canal runs alongside the southwestern side of the area for about 2.55 km. This would be a similar form and size to the main canal, with a similar gradient, but in two parts, 1.25 km carrying the full 1,2 m3/s adjusted, if necessary, at detail design, and the second part for the remaining 1.25 km, to carry 50% of that flow. It is assumed that the distributary canal sections will be supporting 2 (upper) and one (lower)

173 irrigation sprinkler systems, that will draw water from the field canals that are fed off the distributary canal. These sprinkler systems would each service 50 % (80 ha) of the total command area.

456. Within the command area, it is currently assumed there will be 19 field canals, running southwest to northeast. These distributary canals, fed from the header channel, will be on a relatively flat gradient (1 in 2,000 to 1 in 1,500) as they will act as water sump from which the irrigation units can draw water (unless at detail design, and alternative layout is deemed more cost effective and practical). These distributaries will have a relatively narrow and deep section and be unlined. They will vary in length from 550 to 925 m long, so careful planning and operational control will be required for effective flow management and in-field operations. Final adjustments of design at detail design could be beneficial to balance things out.

457. The connection between header canal and distributary will also need careful consideration to ensure movement and position of irrigation machines on each distributary is not compromise. The connection needs to be a buried pipe with an inlet control gate.

b. Irrigation System

458. The planned irrigation system will include a gravity water source to field channel, and sprinklers, and possibly some small drip systems for windbreaks and greenhouses. The original system had open main and header canals, to feed water to open unlined field distributary canals. This is retained as the basis for the modernized irrigation scheme design, though a secondary option, using a low-pressure PE pipe in lieu of the open main and header canals was considered. Preliminary costs comparisons soon showed that with PE pipe, a pipe option was too costly.

459. Headworks. To ensure permanent and secure water availability for the irrigation system intake, it is proposed that a low-level barrage be constructed on an approximate north-south axis across the existing river anabranch, just downstream of where the current intake starts. The schematic drawing of head work is shown in Annex 1. This barrage will be approximately 60 m long and include a reduced level central section to facilitate excess river flow overspill while ensuring the safety and permanence of the barrage. At this stage, it is assumed the central spill section will be up to 10 m wide, with an overspill sill level at the required pool height in the river needed to securely feed the main canal intake structure. Further details on this barrage are included under civil works.

460. The river section upstream of and leading to the intake structure and barrage will require some dredging to secure inflow. A pool will then form behind the barrage which will provide operational head, a stilling pool to help sediment reduction, and a water reserve to help cover times when natural river flow is low (particularly in May). To ensure overall water retention in the pool, and to accommodate any large flood events, it will be necessary to build, subject to prevalent levels and topography, a low level earth embankment to the operational water level with sufficient additional height to ensure any high level flood water would pass over the purpose built barrage. As most major river flow would still be using the established main river channels to the north, this additional height over and above the barrage spillway sill level is not expected to exceed 0.5 m above the top embankment height of the barrage. Under extreme conditions, the barrage (a rock fill structure) will be able to pass additional shallow flow over its full width for short durations. Specific information on levels for embankments, the width for the spillway section, and the overall barrage wall level will have to be firmed at detailed design stage.

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461. The water is diverted from the right anabranch of the Khovd River. The width of this branch varies up to 92 m. The diversion headworks will involve a barrier wall (with central weir section) built across the right branch of Khovd river at a section about 60 m wide. This barrier will increase and normalize water level in a pool (which will encourage sediment settlement) for reliable diversion through the canal intake structure. This permanent wall/weir will replace the current temporary bunds that typically have to be reconstructed every year following the winter and/or summer floods if irrigation supply is to be assured in the following summer. The barrier wall will be a rockfill structure (Annex 1). It will include a central clay or impermeable core arrangement from below existing ground/riverbed level (depth to be determined but assume 1 to 2 m), to mitigate risk for underflow and/or percolative flow through the wall.

462. The wall will include a central 10-m wide concrete armored weir section for regular spill flows, with a sill 0.5 m lower than the designed pool height. This then allows for head losses in the structure and controlled flow and discharge between the pool and the main canal. The sluice gate can be adjusted to better regulate flow entering the canal. The weir, side walls, sill and sloping face to riverbed level will be reinforced concrete over the rock wall, minimum 200 mm thick, keyed to the central impermeable core wall (with a downturn leading edge toe, 0.5 m below the top of the impermeable core. The overflow weir will need to be verified for width, to safely pass summer rainfall flood discharge and melting spring water discharge. In extreme circumstance, some shallow overflow of the rock barrier wall for short periods would be possible without causing undue damage. The estimated discharge that can be passed over a 10 m wide weir structure, with a flow depth of 0.3 m is 1.46 m3/s. Actual discharge requirements will need to be verified, but this anabranch pool is not the main channel for Khovd river flow, so it does not have to pass the full river flood discharge. The main objective will be to ensure all bank heights, weir widths and other structure levels are appropriate for safe manage of partial flood flows, without over spilling the intake structure and any associated river flow containment banks. Annex 1 provides an indication of spillway width and head over weir required for a safe discharge up to 6.26 m3/s. General topography in proximity to the intake structure and barrier wall will likely preclude a head over the spillway weir in excess of 0.5 m.

463. Intake Structure. At the right side of the barrier wall, it is proposed that a gated sluicing structure be installed as a ready means to remove sediment entrained in the water. This sediment separation and sluicing arrangement should maximize the available head between the intake gate invert level and the sluicing gate invert level. The sediment sluice gate will need to be of a size to facilitate high velocity sluicing when there is adequate river pool head - the central weir may be spilling or close to spill – so that fast flow will removed any sediment in the settling chamber and discharge it via an open channel back to the river. The settlement chamber should have a shaped floor that will aid in directing mobile sediment towards the sluicing gate. The sluicing channel will discharge downstream of the head water pool barrier. The objective is to minimize the potential for river flow entrained sediment to enter the canal system.

464. The canal intake structure, with a standardized format for all similar requirements in modernizing the irrigation scheme, will be controlled by a simple vertical lift sluice gate, of sufficient size to pass up to 0.5 m3/s. Within the intake structure, water initially enters an elongated sediment settlement chamber with an elongated and sloping floor towards the flushing sluice. As the water rises, it will then, with much reduced sediment, flow over a long side spill weir, and discharge into the outlet chamber of the structure and then into the main canal. Collected sediment can then be periodically flushed from the structure through a gated outlet structure at times that does not impact on irrigation operations. As part of making this arrangement work, some careful consideration of water and bank/structure levels will be needed at the detail design stage to ensure the sediment exclusion functionality. Subject to water depth and other operating

175 requirements, it should be possible each season to implement some specific sediment removal operations around the structure inlet, thereby ensuring pool water storage volume is retained for successive seasons.

465. Canals: Details on each of the canals are given in Table 75. In combination, both the main and distributary canals can operate freely under gravity, so no pumping is necessary until water is drawn from the field canals by the sprinkler equipment, and through a separate drip system installed at the outfall of the main canal for the windbreak area.

Table 75: Preliminary Canal Design Details Canal Water Canal Side New Design Discharge Gradient Mannings Bedwidth Gradient Velocity Freeboard Lining Depth Depth Slope Q (m3/s) (1 in x) n m m S m/s m m Main Canal (5.7 km) 0.50 Concrete 500 0.015 0.6 0.220 0.0020 2.448 0.52 0.3 1.5 Distributary Canal (upper 50%, 1,25 km) 0.50 Concrete 550 0.015 0.6 0.227 0.0018 2.354 0.53 0.3 1.5 Distributary Canal (lower 50%, 1,25 km) 0.25 Concrete 550 0.015 0.35 0.214 0.0018 1.756 0.51 0.3 1.5 Field Canals (length varies, see Figure 15) 0.25 Earth 5000 0.025 0.4 0.433 0.0002 0.551 0.73 0.3 1.5 Bank side slope = 1:1.5 Freeboard = 0.3 Source: TA Consultants

466. The planned cross-section of the lined main canal is trapezoidal; with bed width 0.6 m, top width of 2.1 m, side slope of 1.5:1, and canal depth of 0.55 m (Figure 95). The distributary canal will also be lined, trapezoidal and initially (1.25 km) will have the same size as the main canal. The lower half of the distributary canal is sized to accommodate only 50% of the flow of the upper part. Gated offtakes from the distributary canal will enable diversion of water into the field canals on a rotational basis. All of these field canals will be unlined with trapezoidal X-section, and a gradient so they can act as water sumps for the sprinkler suction intakes as they move along the canals. The longest distributary, when there is no flow, will have 200 mm difference in water depth from start to finish, whilst when in operation, the dynamic condition will mean this water depth should be as per design to allow the suction of the irrigation machine to work. Each field canal will have a small concrete overspill structure at its downstream end to discharge any excess flow to the command area drain.

467. A schedule of irrigation scheme components for modernizing with open channels is given in Table 76.

Table 76: Irrigation Design (Open Canals) № Irrigation Scheme Details and Value and Units Components 1 Gross irrigation scheme Area 186.4 ha 2 irrigation scheme Command Area 161.0 ha 3 Land Use Coefficient (1/2) 0.87 4 Main Canal Discharge and Dimensions Q = 500 l/s, L = 5,775 m, a = 2.1 m, b = 0.6 m, h = 0.6 m, m = 1.5 5 Distributary Canal Discharge and Q = 500 l/s, L = 2,554 m, a = 2.1 m, Dimensions b = 0.6 m, h = 0.6 m, m = 1.5 6 Field Canal Dimensions L = 14,047 m, m = 1.5, n = 0.025 7 Drainage Canal within Command Area L = 2,936 m, b = 1.0 m, m = 1.5 8 Concrete water intake structure with steel Q = 0.2 to 0.25 l/s, b = 0.4 m, m = 1.5, gate n = 0.015 (concrete/masonry) 9 Concrete sediment sluicing channel/apron Q = up to 0.5 m3/s b = 1.0 m, m = 1.5 and steel gated outlet N = 0.025 (earth/rock) 10 L = 60 m, H = varies. TL = xx.x masl 11 Overflow Weir at river Q = xxxxx l/s, L = 10 m, Sill L = yy.y masl 12 River channel reforming to weir L = xxxxx m, W = varies, D = varies

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13 South Riverbank Berm L = xxxxx m, TW = 3 m, H = varies, SS = 2:1 14 Road 17,224 m, area = 7.75 ha 15 Windbreak / Forest Strip L = 2,630 m, b = 6 m, area = 2.10 ha 16 Sprinkler Equipment 2 sprinkler units - to work in parallel 17 Fence Length 6,785 m Source: TA Consultants

468. The original main and distributary canal were lined with thin concrete panels, but this has been removed. The upgraded canals should be lined with concrete slabs (cast in-situ or pre-cast based on relative cost associated with speed and quality of construction). These concrete slabs will overlay natural ground, formed to canal trapezoidal section, and be vulnerable over the long term to the effects of groundwater and frost heave. Consideration should be given to mitigating frost movement risk by laying the lightly reinforced (4 mm steel round bar mesh, 100 mm centers) concrete panels over a thin impermeable plastic sheet, covering the canal cross-section with ends buried each side in the finalized canal embankments. On the left bank of the header canal, a road should be constructed to facilitate access to the command area, with 2 culvert bridges over the header canal. There are up to 19 small gated outlet structures from the header canal to the field distributary canals. The specific details required for these connections should be determined at detail design, when it is determined exactly which irrigation sprinkler equipment is selected, and what if any particular requirements are applicable for moving them between distributary field canals.

c. Irrigation Scheme Layout

469. Field Canals. There are 19 planned field canals spaced 120 m apart to cover the planned command area (161 ha). These canals vary in length from 550 to 925 m, will be unlined and relatively flat (gradient in range 1 in 4,000 to 1 in 5,000), and have a uniform section (bed width 0.6 m, depth 0.9 m and side slope of 1.5 to 1. These field canals will include an inlet control sluice gate off the distributary canal, which may be on the upstream side of a connecting buried pipe to enable unrestricted movement around the end of the field canal where it offtakes from the distributary canal. An end of field canal to drain overflow spillway (small weir structure) should be provided in the event excess water is allowed to enter the field canal. The need for any other control structures and outlets in the field canal will need to be determined at detail design stage, together with an assessment of what other protective measures will be required (e.g. field canal bank stabilization).

470. Drains. Drains are needed to safely and regularly remove excess runoff water and any unused overspill or drainage water from the field canal. The estimated length for drains required within and from the command area (end of field canal) is 2,936 m. This will have a bed width of 1.0 m, and a side slope of 1.5 to 1. This earth channel will be open to livestock, traffic and general runoff, and will therefore require periodic inspection and maintenance to ensure adequacy for purpose. The field canal will, under overflow conditions, spill through suitable end of canal weirs into the drain.

471. Another protective drain will be required running along the southwest side of the command area to catch overland flow from upland areas, and also to catch and discharge any spillway flows coming from the escape structures on main canal (end) and distributary canal (mid-point and end – 2 No.). The drain will sit on the upland side of a protection bank, which will sit on the upland side of the windbreak. This drain will be of a similar size to the command area drain, and the protection bank will be nominally 1 m above ground level, and higher through depressions,

177 sufficient to contain and direct the runoff flow. The drain will turn northeast and run broadly parallel to the southeastern boundary of the command area, all as shown in Figure 95.

472. Command Area Fence. A fence to a standard 4 wire strand design will be installed around the command area to protect the cropped area, equipment, windbreak areas and seedlings from disturbance by livestock and other outside interference. The 6,785 m fence around the command area will include 4 lines of galvanized steel wire between wooden posts 5m apart.

473. Access Road. Earth roads, up to a width of 4.5 m, and total length 17, 23 m, will be installed alongside the distributary canal and field canals. These roads will be formed as earth roads, suitably elevated in known water lying areas, in conjunction with construction of the canal works.

474. Windbreak/Forest Strip. Windbreaks are used as a means of checking aggressive winds locally to protect dry soils from erosion. These windbreaks are located in suitable alignments adjacent to the command area or canals, on the windward (approach) side. For Tsul Ulaan, the dominant wind direction is from the north and northwest. It is proposed that wind breaks be installed on the north side of the command area (up to 600 m) close to field canal 1 and the northwestern side (up to 2,550 m), adjacent to the distributary canal and road, but including any greenhouse and/or additional vegetable growing area. The windbreak will consist of two rows of trees and 1 row of shrubs/bushes. The distance between each tree will be 4 m, and between each bush 2 m. The distance between the tree lines and shrub line will be 3 m, with shrubs on the upwind side of the trees. At the initial development stage of these windbreaks, it is proposed that they be supplied with water via permanently installed inline emitter driplines, with the intake pump station located off the main canal, just upstream of the main canal discharge into the distributary canal. The specific design of drip systems – pump, filters, control valves, main supply lines, and dripper pipes to tree and/or bush base should be completed at detail design stage. It is assumed that up to 3,000 m of main supply pipe, and at least 6,000 m of outlet small diameter drip pipe will be required to reach each tree from the central main supply pipe. Alignment of the main pipes will be downslope with partial pressure recovery. However, pumping will be needed to provide sufficient operating head to ensure minimum outflow pressure at the furthest outlet.

475. There is an area adjacent to the distributary canal which could potentially be developed with small-scale greenhouses to produce additional vegetable varieties (e.g. tomato, cucumber). The need and opportunity for this needs further investigation, but with water available in the distributary canal to feed the field canal, a local micro-spray or drip supply system could readily be supplied to support greenhouse development.

476. Irrigation Method – Sprinkler. As the original design layout for the command area has been retained, at least 2 travelling sprinkler machines will have to be procured and installed at this site. The initial assumption is that these two machines. Based on the supply canal layout, lateral move travelling sprinklers, drawing water via own pump from the field canal, are the most appropriate option. The 2 units would work in parallel, each irrigation by rotation around an 80-ha block. If the maximum application rate is taken to be 8 mm/day (normal for large sprinkler machines), then the required flow per machine, allowing for 85% application efficiency (FAO – sprinklers), and covering 8 ha/day is 753 m3/day, or about 31.4 m3/hr. (8.72 l/s) for a 24 hour day and 10 day irrigation cycle per block. If the irrigation schedule were cut to 12 hours per day, then all flow rates would double, but for 2 units operating in tandem, the canals would have capacity to supply the required water.

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4. Design Discharge

477. The maximum discharge capacity possible from the headworks will be 0.40 m3/sec, which at 74% overall conveyance and application efficiency, equates to a net average water supply rate to the field of 296 l/s, or 1.75 l/s/ha. The peak water flow in the main canal can be up to 0.30 m3/s; though it can be moderated through partial opening of the intake structure gate. Similarly, even after allowing for any conveyance losses in the system, including allowances for windbreak and greenhouse irrigation, there will still be a need to include adjustable sluice gates to control water entering the distributary canal sections, and entering each of the field canals. Whilst field canals can be switched out of the system at any time, if water continues to flow in the main canal, then the distributary canal must have equal capacity to receive and convey water to spill should irrigation be abruptly halted at any time (lack of power, heavy rainfall etc.) Thus, the distributary canal should be able to safely convey the equivalent flow released at the intake structure. Without specific details available from sprinkler equipment suppliers, the allowable safe discharge through the irrigation sprinkler equipment sets cannot be confirmed. But if it is assumed that one sprinkler unit can operate at 0.0815 m3/s (1.02 l/s/ha average over 80 ha), then the required peak discharge capacity for two irrigation units is 0.163 m3/s. This is well below the net peak deliverable flow in the canal of 0.30 m3/s with a 95% (FAO) open lined canal conveyance efficiency. Any excess that cannot be drawn by the sprinkler units would pass through the end of field canals and into drains. Where flow exceeds usable volume, then some adjustment should be made at the intake structure to moderate the flow release. All irrigation flow requirements, up to peak of 0.30 m3/s are below the available flow available from the Khovd river as shown in Table 77.

Table 77: Mean Monthly Irrigation Design Discharge Irrigation Net Average Water extracted Capacity of irrigation scheme Design period Available Water from river canal Discharge a without project (m3/s) (m3/s) (m3) m3/s % Main Distributary Field May 8.69 0.10 0.16 0.50 0.50 0.20 0.40 June 89.4 0.12 0.08 July 126.3 0.10 0.05 August 74.7 0.07 0.05 September 71.2 0.03 0.05 a Data from Table 69 Source: TA Consultants

5. Civil Works

478. The main civil works include for the diversion headworks from Khovd River anabranch, and conveyance of water to irrigation sprinkler/drip systems will include: (i) dredging of river section from main Khovd river channel to existing intake channel on right bank (assume a provisional quantity of 400 m x 1 m x 5 m -2,000 m3); (ii) construction of a rockfill barrier wall (with impermeable core) across Khovd River anabranch channel, immediately downstream of the existing intake channel; (iii) incorporation of a reduced level reinforced concrete spillway section (up to 10 m wide), to control pool water level upstream, and pass moderate excess flows back to main river; (iv) construction of a new intake structure at the head of the existing intake channel, with an inlet sluice gate, a formed sediment settlement chamber with outlet sluice gate, an overflow weir section 5 to 6 m long, 0.5 m below river pool level, and an outlet section into the main canal;

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(v) construction of a sediment sluicing channel from the sluice gate outlet back to the river; (vi) construction of a safety protection embankment from right end of the barrier wall, incorporating the intake and sediment sluicing structure, following the anabranch right riverbank upstream until ground level (west end) equals bank height level (1 m above river pool level); (vii) reformation and lining of the main canal (5.75 m), header canal (2.55 m), and 19 distributary canals (14.05 m); (viii) reforming of drains (about 2.5 km) or building new drains (approx. 3 km) to protect the canals and command area, and enable clear drainage of rainfall runoff and any canal overspills; (ix) construction of various flow control (2 No.), and escape structures (3 No.), including road bridges (2 No.), and overspill outlets (19 No.) from end of field canals; and at ends of main and header canals, discharging to drain alongside or at end of those canals; (x) construction of appropriate outlets/connections for discharge from distributary (xi) construction of a fence around the command area; and (xii) development of the windbreaks on northwest and southwest sides of the command area.

479. At this stage, the design and related details are preliminary, and as detail design and operational requirements are clarified, some additional works may be required (e.g. crossing points on the main canal at headworks, or at start of the command area). If conversely a pipe is substituted for the main canal, then this is not a necessary consideration, though the pipe might need to be deeper and/or protected in concrete at some designated crossing point(s).

6. Equipment

480. Within the civil works, required equipment will be limited to gates to be installed for: (i) The Water Intake – vertical lift sluice gate with preliminary 1.2 m wide and a 0.6 m lift; (ii) Intake Sediment Sluice – vertical lift sluice gate sufficient to flush rapidly at up to 1 m3/s, details to be finalized around operational and physical levels at site; (iii) A control sluice gate with adjacent spill section between the main canal and distributary canal, size similar to intake structure gate, for flow control; (iv) A control sluice gate with adjacent spill section between the upstream distributary canal and downstream distributary canal, size 0.8 m wide, lift 0.4 m, for flow control; (v) Provision of 19 sluice gates and pipe sets (detail to be determined) for release of water from header canal into field canals; (vi) Two self-propelled lateral move sprinkler sets, 120-m spray width, for parallel tracking alongside field canals, inclusive of power supply, controls, pump and associated spare parts, spray nozzles and drop pipes suitable for particular crops, all details to be discussed with potential suppliers before confirming detailed specifications; (vii) One low pressure drip filtration, pump and control station, with sufficient associated main and connecting drip pipes, for up to 3 ha of windbreak; (viii) One low pressure spray or drip filtration, pump and control station, with sufficient associated main and connecting drip pipes, for up to 5 ha of fruit trees; (ix) Provisionally, one or more sets of low-pressure micro spray and/or drip systems for installation in greenhouses (size and number to be determined), should the option to develop such facilities at the eastern end of the header canal be required;

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(x) Provision of relevant power supply infrastructure, whether connection to main national or local electricity grid, inclusion of diesel power and generator sets, or provision of diesel power to drive irrigation systems (pumps, self-propulsion, etc.) [there is an expectation that adopted sprinkler equipment would include suitable on- board power controls and drive mechanisms if electric power supply and cabling is not viable].

7. Bill of Quantities

481. The cost estimation of the construction and equipment of Tsul-Ulaan irrigation scheme is given in Table 78. The following summarizes the costs for the key component parts of the Tsul Ulaan irrigation scheme upgrade and modernization program. The overall project cost is MNT3,238.34 million, equal to MNT20.11 million/ha

Table 78: Bill of Quantities for Tsul-Ulaan Irrigation Scheme Modernization Budget

No Item Quantity (MNT million) Unit Unit cost Total Civil Works Headworks Sluicing structure with intake sluice channel and 1 piece 1 72.68 72.68 outlet flushing channel Rockfill Barrier and Water level Control Weir, Wall L = 60 m, 2 m 60 3.44 206.16 h = 1.5 m, Weir L = 10 m, h = 1.0 m 3 Headworks protection embankment m 500 0.04 18.48 4 Main Canal – reforming and lining m 5700 0.13 761.04 5 Header Canal – reforming and lining m 2,554 0.14 358.72 6 Field Canals – reforming and shaping m 14,047 0.01 127.40 7 Drains – reforming and grading m 2,936 0.004 12.95 8 Bridge piece 5 4.06 20.30 9 Roads – forming and grading m 6,600 0.003 21.58 10 Windbreaks – prepare land and install ha 3.1 44.41 137.67 11 Drain and protection bank m 2,900 0.03 92.40 12 Fence km 6.6 7.00 46.20 Subtotal 1,875.58 Equipment Head work Control Sluice Gate, Width 1.0 m x Height 0.6 m, 13 piece 2 1.68 3.36 vertical screw Header Field Canal Flow Control Gate, Width 0.4 m, height 14 – piece 38 1.05 39.76 0.3 m 15 Culvert for bridge (0.75 x0.75 m) piece 5 1.48 7.38 Lateral Move Sprinkler sets install, commission, train, with x 16 – set 2 210.55 421.09 years parts 17 Water Efficient Drip Watering Advanced System (5 ha) set 6 42.38 254.30 18 Water Efficient Drip Watering Advanced System (3 ha) set 1 28.36 28.36 19 Trees, number piece 9300 0.004 37.20 20 Pump, VTP-300/0.5-0.12 piece 21 Universal Excavator for O&M piece 1 168.60 168.60 Subtotal 960.04 22 VAT % 0.00 283.56 23 Environmental baseline assessment number 1 42.67 42.67 24 Environmental impact assessment number 1 42.67 42.67 25 Design cost ha 161 0.21 33.81 Subtotal 402.72 Grand total 3,238.34 Source: TA Consultants’ estimate

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H. Subproject 7 – Ulaandel Irrigation and Drainage System Design

1. Site Description

a. Scheme Background

482. Ulaandel irrigation scheme is owned by Sagsai Soum. The original irrigation scheme was developed in 1980 with an open main canal from the Sagsai River that discharged into a series of contour-aligned field canals, set at 110-m spacing. Self-propelled sprinkler units (Russian manufactured DDA-100MA crawler-mounted sprinkler boom) sucked water from these contour- aligned straight canals to water strips of the command area in accordance with a sequential plan. The irrigation scheme had two header canals with a total length of 8.89 km, one to the left of the command area and the other through middle.

483. The existing scheme is in a serious state of disrepair (Figure 96). Significant investment is needed to upgrade and modernize the irrigation water supply and irrigation operations. The overall irrigated area is 400 ha. Currently, the scheme is non-operable. Water passes through the existing main canal as there is no means to control the flow down the slope from the river intake headworks to the start of the command area.

Figure 96: Current Situation for Ulaandel Irrigation Scheme

Upper left: intake from river; Upper right: head work structure and outlet channel; Lower: main and distributary canals Source: TA Consultants-field survey

b. Area and Crop Maps

484. Geomorphology: The project area, at 1,775 masl to 1,812 masl, sits within mountain ranges of the Mongolian Altai Mountains, which range from 2,171 m to 2,715 m around the soum

182 area. The project area is bounded on the north by Khardel mountain (1,869 m), to the east and south east by Tsagaan-Umne mountain (2,325 m), and to the west by the Sagsai River. The project area valley is formed from stream alluvial and alluvial-proluvial eroded and accumulative fans.

485. The Ulaandel irrigation scheme is located 20 km south-west from the Sagsai Soum center, Bayn-Ulgii Aimag, and lies adjacent to the right bank of the Sagsai River (Figure 97). The intake is about 2.5 km upstream from the command area. The capacity of the main canal is 2.2 m3/s and continues for another 4.44 km through two distributary canals to the command area. From the latter part of the main canal, water is diverted into field canals which run east to west along the river, at parallel intervals of 110 m. Ostensibly following the alignment of field canals in the original scheme, they follow the contour, and act as retention ponds out of which water was drawn for sprinkler irrigation. To achieve this storage effect, the distributaries need to be formed to a level grade, with a controlled overspill outlet to drainage to manage the water level.

Figure 97: Location of Ulaandel Irrigation Scheme

Source: TA Consultants based on Google Map

c. Climate

486. Meteorological observations at Sagsai soum began in 1985, after Ulaandel irrigation scheme was developed in 1980. There are now 34 years (1985-2018) of monthly mean air temperature, wind speed and monthly precipitation data which have been analyzed. The climate of the Altai mountain region is sharply continental. It is characterized by dry air, with relatively low rainfall throughout the year, and has significant weather variability for both individual seasons and between years.

487. In the Ulaandel irrigation subproject area, the daily temperatures throughout the growing season can exceed 30oC (maximum daily) between May and August, and humidity is about 40%. Precipitation, when water is required for crop production, varies from an average of 9.9 mm in May to 20.4 mm in June, 26.1 mm in July) and 21.2 mm in August, with an overall yearly average of 94.7 mm, where 50% of that falls in June and July, and 80% in May to August. The average wind speed

183 for the year is 3.3 m/s, with peak wind speeds experienced through the warmer crop growing months. Mean monthly climate data for the project area is given in Table 79.

Table 79: Mean Monthly Climate Data in the Ulaandel Irrigation Subproject Area Month Average Absolute Absolute Humidity Wind Precipitation Temperature Maximum Minimum (%) speed (mm) (oC) Temperature Temperature (m/s) (oC) (oC) January -21.9 3.2 -46.1 55.0 2.5 0.6 February -16.5 5.1 -42.7 49.2 2.7 0.5 March -7.7 17.1 -34.3 40.4 3.7 1.4 April 1.9 24.1 -21.0 36.5 4.2 4.1 May 9.1 28.9 -10.9 36.5 4.2 9.9 June 14.8 31.3 -2.3 41.1 3.4 20.4 July 16.7 34.6 0.0 43.8 3.2 26.1 August 14.5 30.6 -2.4 45.2 2.9 21.2 September 8.0 32.8 -11.1 43.4 2.9 5.7 October -0.4 20.1 -22.8 45.3 3.3 2.6 November -10.9 12.5 -33.0 49.7 3.3 1.3 December -18.2 7.0 -39.7 53.6 2.8 1.0 Average -0.9 34.6 -46.1 45.0 3.3 94.7 Source: National Agency for Meteorology and Environment Monitoring

488. Air temperature. Figure 98 shows the trend for change in monthly mean air temperature from April through to September. As the April mean temperature is 1.9oC, and below 10oC, there is insufficient natural warmth in the air to support crop growth for most of that month.

489. Air temperature trends. Air temperature trends (Figure 98) indicate that monthly mean air temperature changes for the months of April to September have been occurring consistently. April mean temperature has increased by 6.8oC, May by 3.0oC, June by 2.2oC, July by 0.6oC and August by 0.6oC, while September mean temperature has decreased by 0.4oC. On balance, it is reasonable to assume there has been minimal significant shift in the mean annual growing season temperature, though there are some shifts that could impact crop production. With increased temperatures in growing months, it is likely some increased irrigation would be required.

Figure 98: Trends of Monthly Air Temperature at Ulaandel Irrigation Scheme

Source: National Agency for Meteorology and Environment Monitoring

490. Duration of hot days. One important climate factor that influences irrigated crop production is the number of hot days. Figure 99 shows that the number of days each year with a daily average air temperature above 25oC has increased by 26 over the last 34 years. Despite this, the number of average days where air temperature exceeds 30oC has only increased by 3 days.

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Figure 99: Trend in Hot Days with Mean Temperature more than 25oC and 30oC

Source: National Agency for Meteorology and Environment Monitoring

491. Precipitation. Annual average precipitation is 94.1 mm, which shows that the region is in the agriculture arid zone.29 Figure 100 shows that monthly precipitation changes for the months from April to September have not been occurring consistently. For May and August, precipitation has decreased by 3 mm and 1 mm, while April, June and August precipitation increased by 1 mm, 2mm and by 3 mm, respectively.

Figure 100: Trends of Monthly Precipitation at Ulaandel Irrigation Scheme

Source: National Agency for Meteorology and Environment Monitoring

492. Though there has been an increase in precipitation for most months of the growing season, the number of days with no precipitation has decreased in May by 2 days, and in June and July by 6 days , while there has been no change for August (Figure 101).

29 MNS-ISO-16075-1:2018 Guidelines for treated wastewater use for irrigation projects: The basis of a project for irrigation

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Figure 101: Trends in Days with no Precipitation

Source: National Agency for Meteorology and Environment Monitoring

493. Wind. The monthly mean wind speed in the growing season tends to be higher than for other months (Table 79). Even though the mean wind speed for the months of April (4.2 m/s), May (4.2 m/s), June (3.4 m/s), July (3.2 m/s) and August (2.9 m/s) are low, the maximum wind speed can reach 30 m/s once a year. The number of days when wind speed has exceeded 10 m/s has increased by 19 days over the last 34 years (Figure 102). Forty percent of the wind comes from the west and 30 percent from the south-west. Therefore, the wind break should be developed to west and south-west (Figure 102).

Figure 102: Trends in High Winds and Wind Direction

Source: National Agency for Meteorology and Environment Monitoring

494. Agro-climate. Over the period from 1985 to 2018, the growing season length has increased by about 20 days due to a shift in when the temperature transitions above 10oC (earlier dates in spring) and below 10oC (later dates in autumn). With a higher accumulated temperature for the growing season, with a longer crop growth period free of frost, overall crop growing conditions have increased and that favors greater crop production (Figure 103).

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Figure 103: Agro-climate Characteristics

Source: National Agency for Meteorology and Environment Monitoring

495. Projections: The summer temperature is projected to increase by another 1oC, and 2.0oC (Figure 4) and 10 % increase in precipitation (Figure 5) by 2035, 2065 in the Ulaandel subproject area. A continued increase in temperature respectively and a slight increase in precipitation are the most likely combined future impacts necessitating more intense irrigation.

d. Soils

496. The Ulaandel subproject area soils map (Figure 104) shows that the predominant soil type in the command area is light kastanozem (silt loam). The command area is located in the riverside riparian area. Soil is white brown color and classified as Leptic Kastanozem calcic. Kastanozems have relatively high levels of available calcium ions bound to soil particles. These and other nutrient ions leach downward with percolating water to form layers of accumulated calcium carbonate or gypsum. Kastanozems are principally used for irrigated agriculture and grazing.

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Figure 104: Soil Map of Ulaandel Irrigation Scheme

Source: Institute of Geography and Geo-ecology

497. Leptic Kastanozems are chemically rich soils with cation exchange capacity of 21- 25meq/100g dry soil. Soil organic matter is about 0.95%, which is at the lower level of organic matter concentration. Available soil nutrients are low with soluble nitrogen about 12 mg/kg, plant- available phosphorus about 12-14 mg/kg, and potassium about 45-50 mg/kg. Some soil-sample locations differed in nutrient levels because fields were affected by wind and water erosion.

498. For the soil profile, each horizon was highly reactive with 10% hydrochloric acid, meaning weak alkaline, secondary carbonate accumulated in soil upper horizon (Table 80). The soil pH is about 8.6 and EC= 85-95 μS, meaning soils are weakly saline. Soil is sandy loam to sandy particle by depth. Volumetric water content was the 12-14%. Stone and gravel of more than 2 mm was around 30%. Detailed soil analysis is presented in Annex 2 and Annex 3.

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Table 80: Soil Profile of Ulaandel Irrigation Scheme Soil Depth, Characteristic horizon m 1 A 0.0- Grey brown soil. > 0.25 2mm Stone and gravel around 30 % of soil. High calcic soil. Sandy loam 2 E 0.25- 5-10 cm diameter 0.5 gravel occurs and by the water erosion affected to clay particle sediment to down layer between sand and gravel. 3 B 0.5-0.7 Sand and gravel.

Source: Integrated agricultural laboratory

e. Water Sources

499. The main water source for irrigation is the Sagsai River, which is a right-hand tributary of the upper basin of the Khar Lake – Khovd River basin (Figure 105). The hydrological station is located in Buyant soum which is upstream of the subproject area. For the water resources assessment for the Ulaandel irrigation scheme, 62 years of time series data (1965-2017) from Bayannuur gauging station has been used.

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Figure 105: Khar-Us Lake-Khovd River Basin Showing Ulaandel Irrigation Scheme, Hydrological Gauging Stations and Meteorological Observation Stations

Source: TA Consultants based on National Atlas

500. Table 81 shows monthly mean flow data at Sagsai-Buyant river gauging station, which ranges from 6.87 m3/s to 41.5 m3/s during the growing season. The environmental flow requirement is 13.6 m3/s. Thus, in Sagsai river just upstream of Ulaandel, there is an average monthly mean flow of at least 10.9 m3/s available to meet non-environmental flow demands in May, and more in other months through to August. Even then, the monthly high flow can be 33.7 m3/s (September) up to 112.0 m3/s (June), whilst low discharge can fall below the environmental flow requirement in all months except July. In general, there is more than enough water for reliable irrigation at Ulaandel during the growing season, though some prudent storage management in May and June would be beneficial for potential dry years.

Table 81: Water Resources of the Sagsai River at Ulaandel Subproject Area

Maximum Minimum Mean Environ- Mean Water available % of Annual Month Discharge Discharge Discharge mental flow for use 3 3 3 3 Discharge (m /s) (m /s) (m /s) (m /s) (m3/s) m3 April 20.0 0.06 6.87 13.6 3.79 - - May 59.8 8.11 24.5 13.6 13.5 10.9 29,353,042 June 112.0 11.40 39.7 13.6 21.9 26.1 69,989,393 July 94.6 16.54 41.5 13.6 22.9 27.9 74,668,760 August 71.1 9.74 27.9 13.6 15.4 14.3 38,367,885 September 33.7 3.59 16.0 13.6 8.81 2.40 6,361,553 October 24.7 0.02 9.44 13.6 5.21 - - November 13.5 0.02 5.30 13.6 2.92 - - December 9.3 0.04 3.23 13.6 1.78 - - January 7.2 0.01 2.33 13.6 1.28 - - February 6.5 0.01 1.84 13.6 1.02 - - March 7.5 0.08 2.61 13.6 1.44 - - Source: National Agency for Meteorology and Environment Monitoring

501. Sagsai River flow during the irrigation period of May to August at Sagsai-Buaynt has been increasing slightly since 1965 except May, and more clearly since the mid-2000s (Figure 106).

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Figure 106: Sagsai River Flow at Sagsai-Buyant Gauging Station (1965-2017)

Source: National Agency for Meteorology and Environment Monitoring

502. Sagsai River flow sensitivity to climate change is shown in Table 82. If precipitation remains unchanged and average temperature increases by 1°C, 2°C, 3°C or 5°C, then it is projected that the river flow could decrease by 1.4% (+1oC) to 7.3 % (+5oC). The impact of precipitation declining by up to 20% is substantially more marked than if precipitation increases by 20%, but an increase of 5oC would almost eliminate any gains expected from additional precipitation. If precipitation has declined by 20%, then the reduction in river flow from increased temperature is relatively small. Overall, river flow is highly sensitive to reduced precipitation, but with unchanged or increased precipitation, the impact of increased temperature is more significant in moderating river flow.

Table 82: Khovd River Flow Sensitivity to Climate Change Temperature Projected Percentage Change in Precipitation Increase (oC) -20% -10% 0% +10% +20% 0 -36.9 -18.2 25.8 33.9 1 -34.4 -20.4 -1.4 20.8 26.7 2 -35.6 -22.4 -3.6 15.7 19.2 3 -36.8 -24.5 -5.0 10.6 11.7 5 -38.2 -27.4 -7.3 2.1 8.7 Source: TA consultant estimates

503. Water quality. Water chemistry analysis for Sagsai river from 2013 to 2018 is shown in Figure 107. The overall assessment is that the chemical composition of water in Sagsai river is 2+ 2+ - good, where the concentration of Ca , Mg , SO4 and Cl do not exceed the irrigation water standards thresholds. The sodium adsorption ratio (SAR) that is a critical factor for sustainable irrigation is also found to be within acceptable limits.30 Therefore, water from the Sagsai River is concluded to be well-suited for irrigation use.

30 MNS-ISO-16075-1:2018 Guidelines for treated wastewater use for irrigation projects: The basis of a project for irrigation

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Figure 107: Water Chemistry of the Sagsai River

Source: Central Laboratory for Environment and Metrology

504. Suspended solids in the Sagsai River water range from 1.2 to 19.8 mg/l (or 0.001 to 0.02 kg/m3), but do not exceed 20 mg/l (0.02 kg/m3) most of the time (Figure 108). Even though there is a need for careful management of water diversions from the river to contain suspended sediment discharge into the intake and canal/irrigation system, which may require additional sediment management measures at intake or through settlement and flushing basins aligned with the main canal.

Figure 108: Suspended Solids in the Sagsai River Water

Source: Central Laboratory for Environment and Metrology

505. Water quality in the rivers of the Sagsai River is classified “very clean”, based on water quality analysis and assessment against the Water Quality Index (WQI).

f. Existing Irrigation System and Design Maps

506. The Ulaandel Irrigation Scheme supplies water for a command area of 400 ha. Water is diverted from the Sagsai River from which a lined, but poor condition, intake canal takes water to a gated headworks. Excess flow spills back to the river through a continuation of the intake canal. A 3.14-km long main canal, lined with B10 cement underlined by waterproof coating (now no lining)

192 conveys water from the gated intake to the command area, with a fall of about 14 m. The nominal canal bed width is 1.0 m, with a trapezoidal section, and side slopes of 1.5:1. For a lined canal, the flow velocity for 2.8 m3/s would be about 1.38 m/s but, in a rough unlined canal, it will be lower, though the X-section is generally wider but shallower with sediment deposition.

507. The main canal feeds an 8.8-km two-header canal. One header canal runs to the north and other through the command area, generally slopes down to the south. There are the remains of 40 km of distributary canals within the command area, and 4.4 km of drains. The headwork design discharge capacity is 2.8 m3/sec. It is sited on a constructed diversion channel about 650 m from the riverbank. The Sagsai river runs along the north side of Bayannuur. The upgrade and modernization of the Ulaandel irrigation scheme area (400 ha) will provide more assured and durable alternative irrigated crop production opportunities for local farmers, in conjunction with any continued irrigation activities maintained within the river channels across the flood plain of Sagsai River.

508. The main crops produced by Sagsai soum are potatoes, vegetables, and fodder, though currently there was no production from the Ulaandel irrigation scheme in 2018. In 2017 a Chinese company rented 100 ha to produce raps, but nothing remains.

509. The existing Ulaandel irrigation scheme needs to be upgraded and modernized so that the command area of 400 ha can be returned to full production. The scheme will be irrigated with water diverted through an improved intake and canal system from the Sagsai River. Currently this command area receives no water and there is no irrigated crop production. Following discussions with local government, it is understood that the modernized irrigation scheme command area is expected to grow 25 ha of potatoes, 25 ha of vegetables, 100 ha of fodder, and 250 ha of grains. This will then enable the soum to provide fodder to livestock which is the main economic sector of the soum.

2. Irrigation Water Requirement

510. The current and designed allocation of the command area is shown in Table 83. There is 7 ha for tree wind breaks to the west, and south-west. If conveyance and application losses can be further reduced through modernization, then it may still be possible to eventually expand the overall command area.

Table 83: Current and Designed Command Area and Irrigation Method Crop type Current allocation Irrigation Planned Irrigation of command area method allocation of method command area Potatoes, ha Currently no crop is Used 25 drip Vegetables, ha cultivated as there Furrow 25 drip Cereals, ha is no water coming 250 sprinkler Fodder, ha to the command 100 sprinkler Fruit trees and wind break, ha area 7 drip Source: Consultant’s estimates

511. Overall efficiency (Table 84) will be raised up to 73% using piped systems, modern pivot sprinkler irrigation machines for 350 ha for fodder and cereals, and low pressure drip systems for 50 ha for potatoes and vegetables and windbreak (Table 85).

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Table 84: Scheme Irrigation Efficiency Characteristics Field irrigation Percentage Conveyance Field Scheme application of total efficiency application irrigation command (%) efficiency efficiency area (%) (%) Current for total Surface irrigation 100.0 60 60 36 command area (border, furrow, basin) Designed fodder Sprinkler and cereals area, 87.7 95 75 71 350 ha Designed potatoes Drip and vegetable, 50 12.3 95 90 86 ha Average for Combined sprinkler designed and drip 100.0 95 77 73 command area Source: TA Consultant

512. The total irrigation water requirement of 2,894,465 m3 (0.22 m3/s) with project and 2,978,834 m3 (0.23m3/s) with climate change over 4 months for the full Ulaandel command area and irrigation season has been calculated based on the irrigation water utilization norm (Table 6) applicable for the region and planned crops. This projected total irrigation water requirement is just 1.28% of the net available in the growing season. Based on the analysis (Table 85), the irrigation scheme total water requirement—after allowing for deep percolation, evaporation, system efficiency and project impacts of climate change—even after fulfilling environmental flow obligations, there remains ample water at source to support the irrigation scheme (Table 86).

Table 85. Crop Water Requirements for Ulaandel Irrigation period Item Total May June July August September Allocation of command area Potatoes (ha) 25 25 25 25 25 Vegetables (ha) 25 25 25 25 25 Cereals (ha) 250 250 250 250 250 Fodder ha 100 100 100 100 100 Fruit trees and wind break (ha) 7 7 7 7 7 407 Water requirement with project Gross irrigation norm (m3/month) 517,233 545,060 492,694 346,681 211,291 Irrigation efficiency (%) 0.73 0.73 0.73 0.73 0.73 Total irrigation water requirement (m3) 708,539 746,658 674,924 474,906 289,439 2,894,465 Water requirement with project with climate change Increase in ET, (m3) 4236 2668 2802 2599 6577 4747 Projected Irrigation Water Use (m3/month) 538,921 552,041 502,477 356,261 224,849 Irrigation efficiency (%) 0.73 0.73 0.73 0.73 0.73 Projected total water requirement (m3) 759,869 688,319 488,025 308,010 2,982,464 759,869 ET = evapotranspiration Source: TA Consultant

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Table 86: Water Availability for Irrigation Projected total Percentage of Monthly Environ- irrigation water irrigation Irrigation River ment Net available flow in requirement with water use from period Discharge Flow, the river project net river flow (m3/s) (m3/s) (m3/s) (m3/month) (m3/s) (m3/month) (%) May 24.5 13.6 11.0 29,353,042 0.26 738,248 2.41 June 39.7 13.6 26.1 69,989,393 0.29 756,220 1.11 July 41.5 13.6 27.9 74,668,760 0.25 688,324 0.91 August 27.9 13.6 14.3 38,367,885 0.18 488,029 1.24 September 16.0 13.6 2.4 6,361,553 0.11 308,012 0.70

Total 218,740,634 2,978,834 1.28 Source: Consultant’s estimates

3. System and Layout

a. Area Topography

513. The existing intake from the Sagsai River at elevation 1,799 masl (riverbank level), at 48.50.21.28 N and 89.32.4.89 E upstream of the existing bridge location. There is no possibility for change of river course (thalweg line) due to the existing bridge. Water requirement for this project is less compared with the minimum flow during September low flow season. Hence, no barrier across the river has been proposed. There will be side intake with head regulator at the left bank of the river. There will be no balancing reservoir due to inflow during low flow should be adequate to feed the canal (Figure 109). The proposed irrigation design option is shown in Table 87.

514. The boundary of the main fodder/cereal/potato command area, starting 2.015 km downstream from the headworks, sits at elevation of 1,797 masl and the command area starts at 1,796 masl to 1,771 masl.

b. Irrigation System

515. Headworks Weir. The upgraded scheme will include a new weir across the river. The headworks location has been selected at the existing headworks of the canal. The existing water intake relies on being able to draw water from the river flow on the outside of a bend, with no pool formation in the river. The river is meandering within the shallow valley so does not have a particularly stable channel and can change direction/path under large flows. There is no river barrier (permanent or temporary) that helps form a stable pool in the river, so the reliability of inflow during very low flow periods will be uncertain. It is therefore proposed that a permanent barrier wall (up to 200 m long with maximum height of 3.5 m) be built, sufficient to keep a 1m head in the pool over the intake and 2 m plus depth relative to the riverbed. The main section of the barrier across the river, with a central spill weir, would be set at 2 to 2.5 m above the riverbed level, subject to what is possible in the location and constraints of the environment (detail survey is needed of possible sites). The barrier wall would incorporate the main canal intake on the right bank of the river, and provide an in-built sluicing facility for sediment exclusion, with sediment flow returned to the river downstream of the barrier. Embankments may be needed alongside the river to protect the head regulator of the system.

516. Headworks intake. A new-gated side intake and sediment sluicing arrangement (similar as shown in Annex 1) will be installed at the right bank, with two sluice gates, suitably sized to pass

195 the design peak flow for the canal (2.8 m3/s). The design discharge is kept same to the existing canal capacity. This intake structure will be rectangular in general form and include: (i) The intake location is suggested at the location where sluiceway is provided in the existing system. However, it will be re-assessed during the detail design. (ii) An intake sluice gate of appropriate size for flow with minimal head loss when fully opened; (iii) A sediment trap chamber with a suitable alignment and formed floor to guide flow and encourage sediment removal when the flushing sluice gate is opened; (iv) An outlet sluice of sufficient size to engender high velocity discharge and flushing to an external channel that runs back to the river downstream of the river barrier/weir; (v) An internal obliquely aligned side spill weir wall (to get length) where clean water (without the settled sediment) can flow over into the outlet chamber, be steadied in a pool area and released steadily into the canal (or pipe) (indications are an internal weir wall length of 4 to 6 m is required to pass the design flow at 0.4 m to 0.5 m depth over the weir wall); (vi) An outlet basin to steady the flow prior to it exiting into the pump; and The outlet canal to be set at a level (making use of level differential) to facilitate installation and functionality of the sediment excluding intake structure.

517. The original intake had no sediment exclusion feature, so sediment entered the open main canal and this sediment either settled in the canal, reducing section and capacity (going hard over time) or else was discharged either into any balancing storage (gradually reducing capacity) or passed through to settle in distributaries and/or field canals. Where pipes, pumps and mechanical sprinkler and drip systems are used, sediment is the enemy, and everything should be done to exclude sediment from the water before it enters into any closed pipe system.

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Figure 109: Ulaandel Irrigation System Layout

Source: TA Consultant

Table 87: Irrigation Design Option No. Irrigation Scheme Details and Value and Units Components 1 Gross irrigation scheme area 420 ha 2 irrigation scheme command area 400.0 ha 3 Land Use Coefficient (1/2) 0.95 4. Main canal intake structure and Q = 2,800 l/s, see Annex 2 sediment sluice 5 Main canal (lined) capacity Q = 2,800 l/s, L = 2,015 m, 6 Settling basin V = 2,100 m3, L = 30 m, W = 20 m, d = 3.5 m, 7 Pumping station intake pipework and see Annex 2 filtration units 8 Drains around command area up to L = 6, 000 m, b = 1.0 + m, m = 1.5 9 Drip irrigation system for windbreaks Q=25 l/s, L=7,000m , A= up to 7 ha and orchard/vegetable area 10 Pipes (HDPE or equivalent) to center L = 500 m, Diam (ID) = 500 mm, pivot irrigators (4) L = 1033 m, Diam (ID) = 400 mm, L = 1033 m, Diam (ID) = 315 mm, L = 1033 m, Diam (ID) = 100 mm, etc. Diameter will be to standard available, OD or ID, best next size 11 Center pivot machines (1) Details to be developed 12 Road L = 12,000 m 13 Windbreak/forest strip 7,000 m (7.0 ha)

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14 Small sprinkler equipment sets A = 84 ha, Radius = 518 m, App Rate = 8 mm/day 15 Pump station, 2 pumps (one standby), Details to be developed power supply and control panels Source: Consultant’s estimates

518. Settling Basin. Settling basin has been proposed of size 30 m x 20 m x 3.5 m near the command area. The basin will provide the clean water to the pump and sprinkler system. The settling basin will receive regulated flow from the river, at a required rate, whilst extraction will be in accordance with the needs of the irrigation system. The sluiceway will be provided from settling basin to the natural drainage/river.

519. Pumping Station. Due to the local topography, there is no natural hydraulic head available from the river for the operation of piped sprinkler and drip irrigation systems. It is therefore essential, if adopting these types of systems, to include sufficient pumping capacity to deliver water to the irrigation machines/systems at the required operating pressure. Water can be pumped using centrifugal or combined axial/centrifugal pumps. Selection should depend on operational efficiency for the particular flow and capacity, and cost. It is expected that, for complete operational independence, there will be one center pivot system, which supplies water to a movable center pivot with four operating positions (circles). The required flow rate is estimated at 8 mm/day equivalent across the 100-ha center pivot circle. Each pump would also be supplying water at the same rate to an additional 25% of the area, this being the infill areas between/around the circles, which will use smaller specific types of irrigation equipment. Thus, each pump is supplying sufficient water to irrigate 125 ha at 8 mm/day. It is also proposed that all four pumps be connected at the pump station with common inflow and/or outflow manifolds, which would then also provide flow for the windbreak and orchard irrigation systems and, by virtue of connection, can equalize pressure and flow to all parts of the command area. The specifics for linking or not linking the separate irrigation systems from a common pumping arrangement, with valves and manifolds, will need to be discussed and finalized at detailed design. By linking the pumps and comparing combinations to meet expected output and pressure requirements, there may be possibilities to moderate overall equipment, energy and operating costs. For this analysis, it is assumed there will be four separate center pivot pump systems with outflow capacity of 125 to 130 l/s against an overall operating head up to 50 m (conservative as may need only about 40 m depending on pipe length, size and hydraulic friction loss).

520. A provisional estimate has been made for pumping costs, based on the arrangement outlined above (Table 88). Operating cost has been analyzed based on the FAO manual.31 On this basis, to operate one pump to service the four center pivot units and other ancillary irrigation systems, the electricity costs (subject to actual applicable tariff) are in the order of MNT141,600 /ha/season.

521. The pump station should also include a water filtration system, to remove any suspended sediment that could otherwise be harmful to and might collect in the pipes, valves, sprinklers and drip emitters. Whilst some coarse screening to trap vegetative matter and other large items can be included as a strainer on the intake side of the pumps, the fine sediment filtration should be located on the pressure side of the pumps. Then, by suitable pipe and valving arrangements, the pump pressure can be used to backwash filters periodically (programmed or when the operate observes significant pressure differential across the filters) and thereby protect the irrigation equipment from any sediment induced problems. The layout for the pumps, pipes and filtration are shown in Annex 1.

31 FAO. 2001. Irrigation Pumping Plants, Irrigation Manual Module 5

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Table 88: Provisional Estimate for Annual Pumping Costs No Item Unit Ulaandel 1 Command area ha 400 2 Total Dynamic Head m 30 3 Total volume of water required m3/year 2,625,685 (Water pumped during May-Sep) 4 Total Water Requirement in June m3/month 668,960 5 Peak Pumping hours hrs. 20 6 Quantity of water required m3/hr 1114 7 Pump operation hours in a year hrs. 2,355 8 Power requirement Kw 162 9 Motor efficiency % 0.88 10 Energy requirement for total command are Kw 432,425 11 Energy per ha Kwh/ha 108,1 12 Rate per Kwh MNT 130 13 Operation cost/ha MNT 141,600

Source: Consultant’s estimates

c. Irrigation Scheme Layout

522. Distributary/field canals. A total of 4 circles are provided. The general land form is well suited to the use of center pivots, and as the soils are highly permeable with a sandy silt topsoil, low in organic matter, overlying a more permeable sand transitioning to gravelly sand at depth, it is best to use an irrigation system that more uniformly distributes and limits the depth of water application per path. This is not possible with surface irrigation, where much of the water would be lost to deep percolation. By using center pivots, water can be spread more evenly, and can be applied at rates within the general water holding capacity of the topsoil, and thereby constrain overall loss of scarce water through deep percolation. Therefore, the prime means of distributing water over the land for the crops will be center pivot sprinklers. This will be enhanced, within the substantive blocks between the pivot circles that cannot be readily irrigated, by deploying some smaller localized sprinkler/spray/drip systems supplied from the center pivot buried supply pipes, to suit particular cropping requirements in those smaller areas. In this way, 400 ha is covered directly by one 84 ha center pivot.

523. Additionally, it is proposed that 1- 3 drip systems to be supplied directly from the pumping station to irrigate up to 7 ha of windbreak.

524. Drains. Ulaandel command area lies on the alluvial flood plain slopes formed over many years. These slopes carry runoff water from rain and snowmelt, and the route of this runoff can be seen in Google Earth across the command area. Once the irrigation systems are in place, it will be preferable to ensure there is no overland flow crossing the cultivated areas and causing aggressive erosion as such washouts are disruptive to both cultivation and the passage of the irrigation equipment. To avoid such risks, a combination of surface drains and raised banks is proposed to be installed along the high side boundaries of the command area.

525. Drains and banks are needed to intercept and reliably direct excess runoff water, and filter backwash water, safely around and away from the command area. The drains will discharge to the Sagsai River. The estimated length for drains required within and around the command area is about 6,000 m. They will have a minimum width of 1.0 m, and a side slope of 1.5 to 1. They will be earth channels open to livestock, traffic and general runoff, and will therefore require periodic inspection and maintenance to ensure adequacy for purpose.

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526. Constructing and forming drains will provide material that can be used to form the protective banks needed on the lower side of the drain. These banks will be nominally 2-m wide at the top, follow the grade line of the drain and be up to 2-m high across any localized depressions. Their purpose is to prevent runoff from crossing over the drain line and help redirect any major runoff along the line of the drain. The banks could, if required, duplicate as part of the access road network. Specific arrangements may have to be made to safeguard access to the command area with appropriate locations to cross the drains and the banks without disrupting flow in the drain or weakening the effectiveness of the banks. Where the drains are to cross the main pumping main from the pump station, special attention will need to be given to set the pipe well below the drain bed level and provide added rockfill or concrete protection for the pipe and the drain banks.

527. Command Area Fence. A fence will be designed and installed around the command area to protect the cropped area, forest strips and seedlings from livestock and other outside interference. The fence will be up to 10,000 m long. It will include 4 lines of galvanized steel wire between wooden posts 5 m apart.

528. Access Road. Roads, with a minimum width of 3.0 m, and total length of up to 4 km, will need to be formed and within the irrigation command area. These will run alongside or on the protection banks and between the center pivot connection hydrants. They will be formed as earth roads, suitably elevated where necessary, in conjunction with the pipe, canal, drain, protection bank and windbreak network.

529. Windbreak/forest strip. Windbreaks are used as a means of checking aggressive winds locally to protect dry soils from erosion. These windbreaks are located in suitable alignments adjacent to the command area or canals, on the windward (approach) side. About 7,000 m of windbreaks are proposed to be developed.

530. The windbreak will consist of two rows of trees and 1 row of shrubs/bushes (for fruit and/or nuts). The distance between each tree will be 4 m, and between each bush 1 m. The distance between the tree lines will be 4 m and the shrub line will lie a further 3 m away from the second tree line. The general arrangement for setting out the windbreak lines is shown in Annex 1. At the initial development stage, these windbreaks are proposed to be supplied with water via permanently installed dripper lines, with the intake located at and using filtered water from the main pump station. Specific design of drip systems – pump, filters, control valves, main supply lines, and dripper pipes to tree and/or bush base should be completed at detail design stage. Up to 7,500 m of main supply pipe, and at least 24,000 m of small diameter in-line emitter drip pipe will be required to reach all trees and bushes. For water demand estimation purposes, the effective wetted area is assumed to be the length of the treelined times an effective 10 m overall width. Alignment of the main pipes will, wherever possible, be downslope to provide some partial pressure recovery over distance. However, where lines run uphill, sufficient initial pressure can be provided from the pumping station to ensure operating lateral lines (there will be some rotation between blocks) will have sufficient pressure to ensure minimum outflow pressure at the furthest outlet.

531. Irrigation Method – Sprinkler. The modernized design retains the use of center pivot irrigation machines. With 4 circles for 336 ha, the area can be covered with one 84-ha unit (518 m radius) working on a 72-hour irrigation period per circle, On the assumption that each machine can deliver an equivalent of 8 mm per day over the circle and take three days to complete the circle, the irrigation depth would be 24 mm per cycle. Given that the root zone soil depth is about 400 mm, and the water holding capacity (replenishment) is a minimum of 5%, then 24 mm represents 6% of the water holding capacity of the soil. This application rate reduces the risk for

200 any excessive deep percolation, with a 12- to 15-day period between irrigations. Taking this approach, within the 12- to 15-day period the center pivot can be used sequentially on up to four circles, with relevant disconnection, moving and reconnection of the machine for each successive circle estimated to take from 3 to 4 hours. It would complete between 8 and 10 cycles each per season.

532. Additionally, the corner areas in the square for each circle in the main command area could also be irrigated with small subsystem sprinkler or drip as suited, either covering the main crop, or for smaller parcels of potatoes, vegetables or fruit trees. The water would be sourced through connections from the main central pivot pressure lines with strategically placed hydrants and movable irrigation infrastructure – pipelines and risers, rain guns or drip roll out. A single corner block between four central pivots is effectively 84 ha of potentially unused land so there is merit in considering how to utilize this as a small subunit or as a supplementary area attached to the central pivot circles. In total, this could be 6 subunits totaling 48 ha. Similarly, there are 4 corner blocks at about 4 ha each, which would provide another 16 ha or irrigated land. Thus, whilst the central pivots are the main irrigation machines, it would still be feasible to arrange infill irrigation for up to another 64 ha.

533. Besides the main central pivot sprinkler systems, and any additional sprinkler or drip systems tapped to the central pivot pressure supply pipes, there is also need for drip systems for up to 7 ha of windbreak on the command area. The drip systems will include a filtration unit on the main feedline, which will backwash through control valves and discharge to the escape drain from the balancing storage. Sprinkler systems would operate on a rotational basis under lower pressure, with pressure compensating in-line emitters or otherwise higher head movable sprinkler/riser lines.

4. Design Discharge

534. The estimated maximum discharge capacity from the river intake headworks is taken to be 0.29 m3/sec, which at 73% overall conveyance and application efficiency, equates to a net average water application rate of 0.232 m3/s or 0.58 l/s/ha for 400 ha. The peak water flow in the main canal can be designed to be up to 0.58 m3/s. Without use of the balancing storage, the peak flow rate is more critical.

535. Under the without-project situation, the water extraction from the river for irrigation ranges from 0.20 m3/s in September to 0.46 m3/s in June, with an operational efficiency of 45%. These flow requirements are well below the mean monthly flow available (net of environmental flow) in the river at just 1.3% to 3.9%, respectively. In the with-project situation, and with a projected improved irrigation water use efficiency of 86%, the water to be extracted from the river is about 50% of the without-project requirement, 0.09 m3/s in September and 0.20 m3/s in June (Table 89).

Table 89: Design Discharge from Sagsai River Month Net Average Water extracted from Water extracted from Irrigation Scheme Canal Available river for irrigation with river for irrigation and Pipe Capacities Water project without project (m3/s) (m3) Distributary m3/s % m3/s % Main Pipe Pipes May 10.96 0.19 0.8 0.43 3.9 0.58 0.25 June 26.13 0.20 0.5 0.46 1.7 0.58 0.25 July 27.88 0.18 0.4 0.41 1.5 0.58 0.23 August 14.32 0.13 0.5 0.30 2.1 0.58 0.16 September 15.97 0.09 0.6 0.20 1.3 0.58 0.10

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Source: Consultant’s estimates

5. Civil Works

536. The main civil works for the diversion headworks on Sagsai River include: (i) construction of a new intake structure at the head of the existing intake channel, with inlet sluice gate, internal flow control weir for discharge to the main canal, and a shaped sediment collection basin, with outlet sluice gate for flushing sediment back, via a formed channel, to the river below the river barrier. This internal weir acts like a side spill weir and has to be a minimum 5 m long to ensure depth of water over the weir does not exceed 0.4 m; assume with 0.1 m headloss through sluice gate and sediment settlement chamber, the weir sill level will be set at least 0.5 m below the set river pool water level; (ii) provision of a pump house, to house up to 2 pumps, inclusive of suitable water filtration unit(s), pipe connections, valves and monitoring/control systems, and power connections, to supply the central pivot and associated small irrigation systems for the windbreaks and infill areas; (iii) installation of main and subsidiary pressure pipes to deliver water from the pump house to all irrigation systems (central pivot, sprinkler/spray, drip) for the complete 400-ha command area, inclusive of pressure monitoring and warning systems for fault management; (iv) reforming and/or new drains (about 1.0 km) to protect the canals, associated infrastructure, windbreaks and command area, with clear effective drainage of rainfall runoff and any canal overspills to Khovd river; (v) formation of relevant protection banks around the command area and other infrastructure, in conjunction with the development of drains and windbreaks; (vi) construction/formation of up to 1.2 km of access road; (vii) construction of up to 2 km of fence for stock proofing the command area.

537. At this stage, the design and related details are preliminary and, as detailed design and operational requirements are clarified, some additional works may be required (e.g. crossing points on the main canal at headworks, or at the start of the command area). Details of whether the balancing storage could be constructed at the same level as the river pool need early checking and confirmation, or there will need to be more detailed consideration for regulating flow in the main canal to the storage and management of the storage water level.

6. Equipment

538. Within the civil works, required equipment will be limited to gates to be installed for: (i) Water intake – vertical lift sluice gate with preliminary 1.2 m wide and a 0.6 m lift; (ii) Intake sediment sluice – vertical lift sluice gate sufficient to flush rapidly at up to 1 m3/s, details to be finalized around operational and physical levels at site; (iii) Provision of up to 2 pumps (1 standby) and associated pipes, with up to 40 m operating head and output of at least 80 l/s, to supply all planned irrigation systems (CP, sprinkler/spray, drip) to cover the full 400 ha in a maximum 15-day cycle; (iv) Provision of pipework – HDPE or other as suitable – to distribute pumped water around the command area to the designated central pivot anchor stations and other offtakes for minor systems; (v) Provision of one 84-ha center pivot sprinkler set with 518-m boom, inclusive of propulsion power supply, operating control, and associated spare parts, spray nozzles and drop pipes suitable for particular crops;

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(vi) Provision of two drip system controlling stations and associated low-pressure drip pipework with associated connections and control valves for up to 7.0 ha of windbreak; (vii) Provision of relevant power supply infrastructure, whether connection to main national or local electricity grid, inclusion of diesel power and generator sets, or provision of diesel power to drive irrigation systems (pumps, self-propulsion, etc.). The sprinkler equipment would include suitable on-board power controls and drive mechanisms if electric power supply and cabling is not viable.

7. Bill of Quantities

539. The cost estimation for Ulaandel irrigation scheme construction and equipment (Table 90) summarizes the cost for key components required for upgrading and modernization of the scheme. The estimated cost for Ulaandel irrigation scheme is MNT4,693.98 million, equivalent to MNT11.73 million/ha.

Table 90: Bill of Quantities for Ulaandel Irrigation Scheme Modernization Budget

No Item Quantity (MNT million) Unit Unit cost Total Civil Works 1 Headworks Sluicing structure with intake sluice piece 1 76.55 76.55 channel and outlet flushing channel 2 Rockfill Barrier and Water level Control Weir, m 200 2.87 574.00 Wall L=200m, h=2 m, Weir L= 13 m, h=1.0 m 3 Headworks protection embankment m 500 0.04 18.48 4 Main canal reforming and lining m 2,015 0.14 282.10 5 Main pipe laying m 500 0.07 35.00 6 Distribution pipe laying m2 3,781 0.04 151.24 7 Settling Basin m 3,000 0.03 90.00 8 Settling Basin sluiceway no 1 38.27 38.27 9 Drain m 10 3.02 30.20 10 Bridge piece 3 4.06 12.18 11 Roads – forming and grading m 12,000 0.003 39.24 12 Windbreaks – prepare land and install ha 7.0 44.41 310.86 13 Drain and protection bank m 6,000 0.03 191.17 14 Pump station piece 1 100.00 100.00 15 Fence km 12.0 7.00 84.00 Subtotal 2,033.30 Equipment 16 Head work Control Sluice Gate, Width 1.0 m x piece 2 1.68 3.36 Height 0.6 m, vertical screw 17 Sluiceway gate for settling basin Piece 2 1.68 3.36 18 Main PE: PE100, SDR17, 1,0mpa, DN500mm, m 1 1.68 1.68 PN10 19 Distributary PE: PE100, SDR11, 1,0mpa, m 500 0.40 200.00 DN450mm, PN10 20 Distributary PE: PE100, SDR11, 1,0mpa, m 1,033 0.34 347.60 DN400mm, PN10 21 Distributary PE: PE100, SDR11, 1,0mpa, m 1,033 0.27 274.26 DN315mm, PN10 22 Distributary PE: PE100, SDR11, 1,0mpa, m 1,033 0.16 170.24 DN100mm, PN10 23 Culvert for bridge (0.75x0.75 m) piece 628 0.02 12.69 24 Central pivot sprinkler 84 ha set 3 1.48 4.43 25 10ha Water Efficient Drip Watering Advanced set 1 303.88 303.88 System

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26 3ha Water Efficient Drip Watering Advanced set 6 79.00 474.00 System 27 Trees, number piece 1 28.36 28.36 28 Pump (diesel) piece 22,500 0.004 90.00 29 Excavator for O&M piece 2 15.00 30.00 Subtotal 2,109.10 30 VAT, 10% % 50.17 414.24 31 Environmental baseline assessment number 1 42.67 42.67 32 Environmental impact assessment number 1 42.67 42.67 33 Design cost ha 400 0.13 52.00 Subtotal 551.58 Grand total 4,693.98 Source: Consultant’s estimates

I. Subproject 9 – Khuren Tal Irrigation and Drainage System Design

1. Site Description

a. Scheme Background

540. Telmen Soum owns the Khuren Tal irrigation scheme, which is located to the north of soum at about 10 km from the soum center (Figure 110). The system was commissioned in 1976. There is no lining of the main canal (4.4 km) or distributer canal (2.3 km). The original system used DDA-100M sprinklers with an initial capacity of 200 ha, which is now increased to 300 ha. The area could potentially be increased to 3,000-6,000 ha subject to availability of irrigation water.

Figure 110: Location of Khuren Tal Irrigation Scheme

Source: TA Consultant based on Google Map

b. Area and Crop Maps

541. Geomorphology: The project area, at 1,738 masl to 1,756 masl, sits in the valley of the Ider River surrounded by the Khangai Mountains, which range from 1959 m to 3040 m around the soum area, which is bounded in the north by the Khavchuu Mountain (2,306 m), in the east by the Tarvagtain Mountain (3,040 m) and the Ider River, and in the south by Serten Khar Mountain (1,959 m).

542. Whilst active farmers are managing to produce vegetables and other crops in this difficult situation, it is seen as an ideal area in which to develop a long-term durable irrigation scheme at an affordable cost. This is a major crop area where the local brand of garlic, named as “red skin garlic,” is planted.

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543. As can be seen from Figure 111 the intake structure and canal to bring water to the scheme needs to be reconstructed following loss of lining and lack of land management.

Figure 111: Current Situation for Khuren Tal Irrigation Scheme

Upper: head work/intake; lower: main canal and cropland Source: TA Consultant field survey

c. Climate

544. The 34 years (1985-2018) time series of monthly mean air temperature, wind speed and monthly precipitation data observed at Uliastai meteorological station has been analyzed. The climate of the Khangai mountain region is sharply continental as any other region of Mongolia.

545. In the Khuren Tal subproject area, the daily temperatures throughout the growing season may exceed 30oC (maximum daily) between May and August, and humidity is about 47-55%. Precipitation, when water is required for crop production, varies from an average of 17.3 mm in May, 34.8 mm in June, 59.9 mm in July, and 49.0 mm in August, with an annual average of 219.8 mm, with 42% of that falling in June and July, and 83% in May through August. The average annual wind speed is 1.6 m/s, with peak wind speeds experienced through the warmer crop growing months. Mean monthly climate data for the project area is given in Table 91.

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Table 91: Mean Monthly Climate Data in the Khuren Tal Subproject Area Month Average Absolute Absolute Humidity Wind Precipitation Temperature Maximum Minimum (%) speed (mm) (oC) Temperature Temperature (m/s) (oC) (oC) January -22.4 -0.2 -42.1 70.4 0.9 3.0 February -18.6 8.0 -42.3 66.7 1.0 2.6 March -10.1 15.3 -37.2 58.7 1.5 4.3 April 1.5 23.9 -24.4 47.1 2.1 7.9 May 9.0 29.2 -12.4 43.3 2.4 17.3 June 14.4 32.7 -3.8 47.6 2.2 34.8 July 16.5 35.8 0.1 52.0 2.0 58.9 August 14.0 32.0 -3.2 55.3 1.8 49.0 September 7.8 27.2 -13.5 52.4 1.8 24.0 October -0.7 21 -29.5 55.2 1.5 8.9 November -12.4 10.5 -36.7 65.2 1.2 5.3 December -19.7 4 -39.8 69.8 1.0 3.9 Average -1.7 35.8 -42.3 57.0 1.6 219.8 Source: National Agency for Meteorology and Environment Monitoring

546. Air temperature. Figure 112 illustrates the trend for change in monthly mean air temperature from April through to September. As the April mean temperature is 1.5oC (but may fall to -23.3 oC), and below 10oC, there is insufficient natural warmth in the air to support crop growth for most of that month.

547. Air temperature trends. Air temperature trends are shown in Figure 112 and illustrate that monthly mean air temperature for the months from April to September have been occurring consistently increasing. April mean temperature has increased by 1.9oC, June by 2.7oC, July by 3.2oC and August by 2.1oC, September by 2.9oC while no change in May. On balance, it is perhaps reasonable to assume there has been minimal significant shift in the mean annual growing season temperature, though there are some shifts that could impact crop production. With increased temperatures in the growing season, some increased irrigation will likely be required.

Figure 112: Trends of Monthly Air Temperature at Khuren Tal Subproject Area

Source: National Agency for Meteorology and Environment Monitoring

548. Duration of hot days. One important climate factor that influences irrigated crop production is that of hot days. Figure 113 shows the number of days each year with a daily average air temperature above 25oC can reach about 4 days while air temperature never exceeds 30oC.

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Figure 113: Trends in Hot Days with Daily Mean Temperature more than 25oC and 30oC

Source: National Agency for Meteorology and Environment Monitoring

549. Precipitation. Annual average precipitation is 219.8 mm, which shows the region is in the agriculture arid zone.32 Figure 114 shows that monthly precipitation change for the months from April to September has not been occurring consistently in growing season. Precipitation has decreased by 2 mm in May and June, by 22 mm in July, and by 20 mm August and September.

Figure 114: Trends of Monthly Precipitation at Khuren Tal Irrigation Scheme

Source: National Agency for Meteorology and Environment Monitoring

550. Though there has been a decrease in precipitation in the months of the growing season, the number of days with no precipitation has increased by 4 days in June and 5 days July, which may indicate that intensity of rainfall is increasing (Figure 115).

Figure 115: Trends in Days Without Precipitation

Source: National Agency for Meteorology and Environment Monitoring

32 MNS-ISO-16075-1:2018 Guidelines for treated wastewater use for irrigation projects: The basis of a project for irrigation

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551. Wind. The monthly mean wind speed in the growing season tends to be higher than in other months (Table 91). Even though the mean wind speed for the months of April (2.1 m/s), May (2.4 m/s), June (2.2 m/s), July (2.0 m/s) and August (1.8 m/s) are low, the wind speed can reach 20 m/s and this can happen on average 6 days per year. The number of days when wind speed exceeds 10 m/s has increased by 80 and the number when wind speed exceeds 15 m/s by more than 30 over the last 34 years (Figure 116). Figure 116 shows that 20% of the wind comes from the south, and 15% from the west and south-east, indicating irregular wind direction. Therefore, the wind break should be designed in close discussion with farmers.

Figure 116: Trends in High Winds and Wind Direction

Source: National Agency for Meteorology and Environment Monitoring

552. Agro-climate. Over the period from 1985 to 2018, the growing season length has increased by about 15 days because of a shift in when the air temperature transitions above 10oC (earlier dates in spring) and falls to 10oC (later dates in autumn). The accumulated temperature that supports longer crop growth with frost free days has also increased, thereby favoring greater crop growth (Figure 117) and may also require longer irrigation.

Figure 117: Agro-climate Characteristics

Source: National Agency for Meteorology and Environment Monitoring

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553. Projections. Summer temperature in the Khuren Tal subproject area is projected to increase by 2oC, and 2.25oC by 2035 and 2065, respectively (Figure 4) and precipitation decrease by 10% (Figure 5). A continued increase in temperature and a slight decrease in precipitation are the most likely combined future impacts necessitating increased irrigation.

d. Soils

554. The Khuren Tal irrigation scheme command area soils map is shown in Figure 118. The predominant crop root zone soil types in the command area are dark kastanozem (silt loam) and alluvial meadowish (clayey loamy). Kastanozems are principally used for irrigated agriculture and grazing.

Figure 118: Soil Map of Khuren Tal Subproject Area

Source: Institute of Geography and Geo-ecology

555. Ten samples were collected from nine points in the command area. The soil of the command area is dark brown color and classified to Dark Kastanozem soil. The subproject is located in the riverside riparian area with groundwater at about 1.5 m. Kastanozems have relatively high levels of available calcium ions bound to soil particles. These and other nutrient ions move downwards with percolating water to form layers of accumulated calcium carbonate or gypsum.

556. Kastanozems are chemically rich soils with good soil reaction for cation exchange capacity of 12-15 meq/100g. Soil organic matter is around 1.5% which is a low level of soil organic carbon. Soluble nitrogen contents are around 42 mg/kg which means high nitrogen supply, plant available phosphorus contents of around 15-16 mg/kg which means acceptable level of phosphorus supply, and potassium contents of around 65-70 mg/kg which is sufficient level supply in soil.

557. For the soil profile, soil pH is 7.9 and each horizon reacted weak with 10% hydrochloric acid, meaning neutral or weak alkaline. Secondary carbonate accumulated in the soil’s deeper horizons with an EC of 160 μS, meaning soils are of low salinity. The dominant soil texture is sandy loam with stone and gravel of greater than 2 mm around 20% of the soil (Table 92).

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Table 92: Soil Profile Soil Depth, Characteristic horizon m 1 A 0-0.3 Grass Root zone with slightly decomposed organic matter. Sandy loam soil and surface filled with small gravel. 2 E 0.3-0.4 Grey brown soil. Less stone and gravel. Low calcic soil. Sandy loam 3 B 0.4-0.6 Sandy loam, low calcic layer. 4 C >0.6 Fully saturated sandy clay soil with gravel

Source: Institute of Geography and Geo-ecology

e. Water Sources

558. The main water source for irrigation is the Ider River (Figure 119). The hydrological station is located in Ider Soum and is located above the subproject area. For water resources assessment for the Khuren Tal irrigation scheme, the 38 years (1979-2017) of time series data from Ider-Ider gauging station has been used.

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Figure 119. Ider River Basin – Location of Khurental irrigation scheme, Hydrological Gauging Stations and Meteorological observation stations

Source: TA Consultant based on National Map

559. Table 93 provides monthly mean flow data at Ider-Ider gauging station, which ranges from 9.00 m3/s to 13.63 m3/s during the growing season. The environmental flow requirement is 4.8 m3/s as 95 percent of the long-term average flow of 5.05 m3/s at the Ider gauging station that is located in the upper basin of the Ider River. Thus, in the Ider River, just upstream of Khuren Tal, there is an average monthly mean flow of at least 4.12 m3/s available to meet non-environmental flow demands in September, and more in other months. Even then, the monthly high flow can be 21.0 m3/s in September and up to 66.6 m3/s in June, while low discharge can fall below the environmental flow requirement in all months. In general, there is more than enough water for reliable irrigation at Khuren Tal during the growing season, though some prudent storage management in May and June would be beneficial for potential dry years.

Table 93: Water Resources of the Ider River at Khuren Tal Subproject Area

Maximum Minimum Mean Environ’t % of Mean Water available for use Month Discharge Discharge Discharge flow Annual 3 3 3 3 (m /s) (m /s) (m /s) (m /s) Discharge m3/s m3 April 8.8 0.00 2.24 4.80 3.70 - - May 24.3 1.01 9.57 4.80 15.8 4.77 12,789,512 June 32.1 0.60 9.79 4.80 16.1 4.99 12,937,551 July 36.2 0.15 11.24 4.80 18.5 6.44 17,247,680 August 48.9 1.22 13.63 4.80 22.5 8.83 23,659,508 September 21.0 1.25 9.00 4.80 14.8 4.20 10,893,435 October 18.4 0.64 3.95 4.80 6.52 - - November 2.2 0.00 0.59 4.80 0.98 - - December 1.7 0.00 0.19 4.80 0.31 - - January 1.2 0.00 0.11 4.80 0.19 - - February 1.3 0.00 0.11 4.80 0.19 - - March 1.9 0.00 0.18 4.80 0.30 - - Source: National Agency for Meteorology and Environment Monitoring

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560. According to observed data (Figure 120), the Ider river flow during the irrigation period of May to August at Ider-Ider has been decreasing sharply since 1979: by 4 m3/s in May, by 2.5 m3/s in June, by 9.5 m3/s in July, by 10 m3/s in August and by 5.0 m3/s in September. However, the Ider river flow has increased slightly in June and July since the mid-2000s.

Figure 120: Ider River Flow at Ider Gauging Station (1965-2017)

Source: National Agency for Meteorology and Environment Monitoring

561. The Ider River flow sensitivity to climate change is shown in Table 94. If precipitation remains unchanged and average temperature increases by 1°C, 2°C, 3°C or 5°C, then it is projected that the river flow could decrease by 17.1% (+1oC) to 34.9 % (+5oC). The impact of precipitation declining by up to 20% is substantially more marked than if precipitation increases by 20%, but an increase of 5oC would almost eliminate any gains expected from additional precipitation. If precipitation has declined by 20%, then the reduction in river flow from increased temperature is relatively small. Overall, river flow is highly sensitive to reduced precipitation, but with unchanged or increased precipitation, the impact of increased temperature is more significant in moderating river flow.

Table 94: Khovd River Flow Sensitivity to Climate Change a Temperature Change in Precipitation (%) Increase (oC) -20% -10% 0% +10% +20% 0 -37.3 -19.8 22.2 46.6 1 -48.1 -33.6 -17.1 1.5 22.1 2 -51.4 -37.9 -22.3 -4.8 14.8 3 -54.3 -41.5 -26.8 -10.2 8.3 5 -59.4 -47.7 -34.9 -19.9 -3.2 a Percentage change of average river flow Source: TA consultant

562. Water quality: Water chemistry analysis for Ider River from 2013 to 2018 is shown in Figure 121. The overall assessment is that the chemical composition of water in Sagsai River is 2+ 2+ - good, where the concentration of Ca , Mg , SO4 and Cl do not exceed the irrigation water standards thresholds. The sodium adsorption ratio (SAR) that is a critical factor for sustainable irrigation is also found to be within acceptable limits33. Therefore, it is concluded that water from the Ider River is well suited for irrigation use.

33 MNS-ISO-16075-1:2018 Guidelines for treated wastewater use for irrigation projects: The basis of a project for irrigation

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Figure 121: Water chemistry of the Ider River

Source: Central Laboratory for Environment and Metrology

563. Suspended solids in the Ider River water range from 0.2 to 24.6 mg/l (or 0.002 to 0.02 kg/m3), but do not exceed 20 mg/l (0.02 kg/m3) in most of the time (Figure 122). Even though the concentration is low there is a need for careful management of water diversions from the river to contain suspended sediment discharge into the intake and canal/irrigation system, which may require additional sediment management measures at intake or through settlement and flushing basins aligned with the main canal in case drip irrigation.

Figure 122: Suspended Solids in the Ider River Water

Source: Central Laboratory for Environment and Metrology

564. Water quality in the rivers of the Ider River is classified “very clean”, with index 0.2 based on water quality analysis and assessment against the Water Quality Index (WQI).

f. Existing Irrigation System and Design Maps

565. This irrigation system was commissioned in 1974 and 195 ha of it were cultivated by 2019. On the basis of discussions with local government and farmers, the current command area will

213 be irrigated by open canal and an additional area of 200 ha will be irrigated by piping water to central pivot sprinklers (Figure 123).

Figure 123: Khuren Tal Irrigation Scheme Command Area

Source: Google earth Map

2. Irrigation Water Requirement

566. The designed command area is 500 ha out of which 25 ha is for potatoes, 25 ha for vegetables, 445 ha for fodder and 5 ha for fruits. There is 3 ha for tree wind break outside of the command area (Table 95). Two rows of leafy trees are proposed to be planted and one row of bushes to the west and north western boundary of the command area according to wind direction data (Table 97).

Table 95: Current and Planned Command Area Crop type Current allocation of Irrigation Planned allocation of Irrigation command area method command area method Potatoes, ha 7.7 Furrow 25 drip Vegetables, ha 5.42 25 drip Cereals, ha Fodder, ha 105.2 445 sprinkler Fruit trees and 4.5 drip 8 wind break, ha

567. Overall efficiency (Table 7) will be raised up to 73% using lined canal systems, modern controllable central pivot sprinkler irrigation machines for at least 90 percent area and low pressure drip systems for rest of the area and windbreak (Table 96).

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Table 96: Scheme Irrigation Efficiency Characteristics Field irrigation Percentage Conveyance Field Scheme application of total efficiency application irrigation command (%) efficiency efficiency area (%) (%) Current for total Surface irrigation 100.0 60 60 36 command area (border, furrow, basin) Designed fodder area, Sprinkler 90.0 95 445 ha 75 71 Designed potatoes and Drip 10.0 95 90 86 vegetable, 45 ha Average for designed Combined sprinkler 100.0 95 76 73 command area and drip Source: TA Consultant

568. Seasonal irrigation water requirement has been calculated based on the irrigation water utilization norm (Table 6) applicable for the region and planned crops. Following analysis for the future upgraded and modernized irrigation system development, the estimated total water use for the irrigation season is 3,010,715 m3 (0.23 m3/s) with project and 3,129,889 (0.24 m3/s) with climate change (Table 97). This irrigation water accounts for 3.90% of total net available water in the growing season or about 2.45-6.75% of the river flow of the given month (Table 98) after meeting the environmental flow of 55.7 m3/s. Thus there is sufficient water available to meet the irrigation needs.

Table 97: Crop Water Requirements for Khuren Tal Irrigation period Item Total May June July August September Allocation of command area Potatoes, ha 25 25 25 25 25 Vegetables, ha 25 25 25 25 25 Cereals, ha 0 0 0 0 0 Fodder, ha 445 445 445 445 445 Fruit trees and wind break, ha 8 8 8 8 8 503 Water requirement with project Gross irrigation norm (m3/month) 227,954 634,454 647,542 464,107 223,765 Irrigation efficiency, % 0.73 0.73 0.73 0.73 0.73 Total irrigation water requirement,m3 312,265 869,115 887,043 635,763 306,528 3,010,715 Water requirement with project with climate change Increase in ET,( m3) 1,300 4,622 14,219 11,656 3,744 Projected irrigation Water requirement, m3/month 250,823 643,081 670,388 484,390 236,137 Irrigation efficiency, % 0.73 0.73 0.73 0.73 0.73 Projected total water requirement,m3 343,593 880,933 918,340 663,548 323,475 3,129,889 Source: TA Consultant

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Table 98. Water availability for irrigation Percentage of Projected total irrigation water Monthly Environ- irrigation water use from net Irrigation River ment Net available flow in the requirement with river flow period Discharge, Flow, river project (m3/s) (m3/s) (m3/s) (m3/month) (m3/s) (m3/month) (%) May 9.57 4.80 4.78 12,789,512 0.12 343,593 2.45 June 9.79 4.80 4.99 12,937,551 0.34 880,933 6.75 July 11.24 4.80 6.44 17,247,680 0.33 918,340 5.17 August 13.63 4.80 8.83 23,659,508 0.24 663,548 2.70 September 9.00 4.80 4.20 10,893,435 0.12 323,475 2.83 Total 77,527,687 3,129,889 3.90 Source: Central Laboratory for Environment and Metrology

3. System and Layout

a. Area Topography

569. The existing intake from the Ider River pool is located at an elevation of 1,783 masl (river bank level), at 48.39.55 N and 97.40.08 E, and the nominal river pool level is 1,783 masl (these positions and levels to be confirmed at detailed design). This intake will have a closure sluice gate, but if feasible it would be optimal to have the TWL in the new balancing storage equal to the storage level in the river pool. The existing storage is relatively small and on the west side of the main canal, and partly filled with sediment. This has a relatively low level but can currently gravitate to the existing vegetable area.

570. The boundary of the extended command area, starting 5 km downstream from the headworks sits at an elevation of 1,777 masl, at 48.42.17 N and 97.41.27 E (north corner of the center pivot area). To the north/northwest of this point is the existing cereal and vegetable surface irrigation (224 ha) – sloping to the north and the Ider River.

571. The existing main canal was originally trapezoidal; the dimension was 4m wide and 3.5 m deep on average. This canal to an existing small off stream storage with gated outlet is about 4.46 km long, with a grade of about 1 to 1,000.

b. System

572. Headworks Weir. The planned new irrigation system will include a revised gravity water supply system from the Ider River to the start of the existing command area boundary, approximately 4.9 km from the river. This gravity part of the system will include an upgraded and strengthened barrier across the river with a weir length equal to the width of the river plus the addition of abutments to both banks at a minimum level of 1,782 masl. The abutments will blend into any additional embankments that may be needed alongside the river to at least contain a peak river pool water level up to 1,783 masl without overtopping. It is estimated that under normal flood flows, the water level with flow passing over the weir (at river width) will rarely, if ever, exceed the indicated top of bank height, but this should be checked at detailed design and the abutment and bank height should be raised if necessary.

573. Headworks Intake. With the weir upgraded and strengthened so water pool level can be maintained, a new gated intake and sediment sluicing arrangement should be installed at the right abutment, with two sluice gates, suitably sized to pass the design peak flow for the canal (1.4 m3/s).

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This intake structure would be rectangular in general form and embedded as an integral part of the embankment in the right abutment. It would include: (i) An intake sluice gate of appropriate size for flow with minimal head loss when fully opened; (ii) A sediment trap chamber with a suitable alignment and formed floor to guide flow and encourage sediment removal when the flushing sluice gate is opened; (iii) An outlet sluice of sufficient size to engender high velocity discharge and flushing to an external channel that runs back to the river downstream of the river barrier/weir; (iv) An internal obliquely aligned side spill weir wall (to get length) where clean water (without the settled sediment) can flow over into the outlet chamber, be steadied in a pool area and released steadily into the canal (or pipe) [the indications are an internal weir wall length of 4 to 5 m is required to pass the design flow at 0.4 m to 0.5 m depth over the weir wall]; (v) An outlet basin to steady the flow prior to it exiting into the lined canal; (vi) The outlet canal to be set at a level (making use of level differential) to facilitate installation and functionality of the sediment excluding intake structure.

574. The original intake had no sediment exclusion feature, so sediment entered the open main canal and this sediment either settled in the canal, reducing section and capacity (going hard over time) or else was discharged either into any balancing storage (gradually reducing capacity) or passed through to settle in distributaries and/or field canals. Where pipes, pumps and mechanical sprinkler and drip systems are used, sediment is the enemy, and everything should be done to exclude sediment from the water before it enters into any closed pipe system.

575. The designed pipe system hydraulic parameters of the Khuren Tal irrigation scheme is shown in Table 99. The scheme layout is Figure 124 in and Irrigation Design Option is in Table 100.

Table 99: Hydraulics Calculations Elevation Loss Plot Discharge, Diameter, Velocity, length 1000i Along № number l/sec mm m/s Beginning End Hydraulic irrigation Hydrant total length 0-6 total loss 1 0-1 224.17 330.00 450.00 1.793 5.96 1777.40 1776.83 -0.57 1.97 0.22 16.12 17.73 2 1-2 224.17 538.00 450.00 1.793 5.96 1776.83 1775.10 -1.73 3.21 0.35 1.83 3 2-3 181.67 835.00 400.00 1.837 7.21 1775.10 1773.55 -1.55 6.02 0.66 5.13 4 3-4 90.83 1133.00 315.00 1.487 6.59 1773.55 1773.65 0.10 7.46 0.82 8.39 33.08 Source: Mungun Minj Co.Ltd

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Figure 124: Khurental Irrigation Scheme Layout

Source: Mungun Minj Design Institute

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Table 100: Irrigation Design Option № irrigation scheme Details and Value and Units Components 1 Gross irrigation scheme area 618 hectares 2 Irrigation scheme command area 500 hectares 3 Land use coefficient (1/2) 0.81 4 Main canal (lined) capacity and Q = 1,400 l/s, L = 1,350 m, d = 0.6 m, dimensions Depth = 0.6 m, h = 0.8 m, m=1.5 5 Main canal intake structure and Q = 1,400 l/s, sediment sluice 6 Balancing storage (water surface V = 100,000 m3, L = 250 m, W = 150 m, dimensions) d = 3.0 m, Top Bank = 1,214 masl, m = 1.5 7 Storage inlet structure and escape outlet see Annex 2 8 Drains around command area up to L = 10,000 m, b = 1.0 + m, m = 1.5 9 Protection barriers around command Up to L = 10,000 m, b = 2.0 m top, m = 1.5, h = up to 2 m area 10 Pumping station intake pipework and filtration units 11 Pump Station, 5 pumps (one standby), Details to be developed power supply and control panels 12 Drip irrigation system for windbreaks and Q = 25 l/s, L = 7,000 m, A = up to 80 ha orchard/vegetable area 13 Pipes (HDPE or equivalent) to center L = 24480 m, Diam (ID) = 500 mm, pivot irrigators L = 4600 m, Diam (ID) = 450 mm, L = 5690 m, Diam (ID) = 355 mm, etc. Diameter will be to standard available, OD or ID, best next size 14 Center pivot machines A = 100 ha, Radius = 565 m, App Rate = 8 mm/day 15 Road 10000 m, with surface area of 3 ha 16 Windbreak/forest strip L = 8,000 m, b= 10 m, with area of 8.00 ha 17 Small sprinkler equipment sets Up to X sprinkler units - to be used in multiple areas 18 Fence length Up to 20.000 m Source: Mungun Minj Design Institute

c. Irrigation Scheme Layout

576. Distributary/field canals. The original irrigation system design was based on the use of center pivots ranging from 21 to 100 ha each. A total of 4 circles were defined. The general land form is well suited to the use of center pivots, and as the soils are highly permeable with a sandy- silt top soil, low in organic matter, overlying a more permeable sand transitioning to gravelly sand at depth, it is best to use an irrigation system that more uniformly distributes and limits the depth of water application per path. This is not possible with surface irrigation, where much of the water would be lost to deep percolation close to the canal, limiting effective overland flow runs. By using center pivots, water can be spread more evenly, and can be applied at rates within the general water holding capacity of the topsoil, and thereby constrain overall loss of scarce water through deep percolation. Therefore, the prime means of distributing water over the land for the crops will be center pivot sprinklers, and this will be enhanced within the substantive blocks between the pivot circles that cannot be readily irrigated, by also deploying some smaller localized sprinkler/spray/drip solutions, supplied from the center pivot buried supply pipes, to suit particular cropping requirements in those smaller areas. In this way, whilst 200 ha is covered directly by the

219 required 2 100-ha center pivots, up to another 50 ha will be covered by smaller center pivot systems.

577. Drains. Khuren Tal command area is large and lies on the alluvial flood plain slopes formed over many years. These slopes still carry runoff water from rain and snowmelt, and the route of this runoff can be seen in Google Earth across the command area. Once the irrigation systems are in place, it will be preferable to ensure there is no overland flow crossing the cultivated areas and causing aggressive erosion, as such washouts are disruptive to both cultivation and the passage of the irrigation equipment. To avoid such risks, it is proposed that a combination of surface drains and raised banks are installed around the southeastern, southwestern and northwestern boundaries of the center pivot command area.

578. The drains and banks are needed to intercept and reliably direct excess runoff water and any overspill from the balancing storage, and filter backwash water, safely around and away from the command area. The drains will discharge to the Ider river. The estimated length for drains required within and around the command area is about 3,200 m. They will have a minimum width of 1.0 m, and a side slope of 1.5 to 1. They will be earth channels open to livestock, traffic and general runoff, and will therefore require periodic inspection and maintenance to ensure adequacy for purpose.

579. In constructing and forming the drains, this will provide material that can be used to form the protective banks that are needed on the lower side of the drain. These banks would be nominally 2 m wide at the top, follow the grade line of the drain and be up to 2 m high across any localized depressions. Their purpose is to prevent runoff from crossing over the drain line and help redirect any major runoff along the line of the drain. These banks could if required duplicate as part of the access road network. Some specific arrangements may have to be made to safeguard access to the command area, with appropriate locations to cross the drains and the banks without disrupting flow in the drain or weakening the effectiveness of the banks. Where the drains are to cross the main pumping main from the pump station, special attention will need to be given to set the pipe well below the drain bed level and provide added rockfill or concrete protection for the pipe and the drain banks.

580. Command area fence. A fence will be designed and installed around the command area to protect the cropped area, forest strips and seedlings from livestock and other outside interference. The fence will be up to 9,900 m long and will include 4 lines of galvanized steel wire between wooden posts 5 m apart.

581. Access road. Roads, with a minimum width of 3.0 m and total length of up to 10 km, will be formed and protected to the site and headworks, and within the irrigation command area. These will run alongside or on the protection banks, alongside the main canal and storage, and between the center pivot connection hydrants. They will be formed as earth roads, suitably elevated where necessary, in conjunction with the pipe, canal, drain, protection bank and windbreak network.

582. Windbreak/forest strip. Windbreaks are used as a means of checking aggressive winds locally to protect dry soils from erosion. These windbreaks are located in a suitable alignment adjacent to the command area or canals, on the windward (approach) side. For Khuren Tal, the dominant wind direction is from the northwest and southwest. Wind breaks are proposed to be installed on the northwest side of the command area, to the west of the existing orchard (2,300 m) and also along the southwestern side (up to 2,146 m) adjacent to the main pipeline, road, protection bank and command area.

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583. The windbreak will consist of two rows of trees and 1 row of shrubs/bushes (for fruit and/or nuts). The distance between each tree will be 4 m, and between each bush 1 m. The distance between the tree lines will be 4 m and the shrub line will lie a further 3 m away from the second tree line. At the initial development stage of these windbreaks, it is proposed that they be supplied with water via permanently installed drip lines, with the intake located at and using filtered water from the main pump station. Specific design of drip systems – pump, filters, control valves, main supply lines, and drip pipes to tree and/or bush base should be completed at detailed design. Where lines run uphill, sufficient initial pressure can be provided from the pumping station to ensure operating lateral lines (there will be some rotation between blocks) have sufficient pressure to ensure minimum outflow pressure at the furthest outlet.

584. Irrigation method – sprinkler. For Khuren Tal, the modernized design retains the use of center pivot irrigation machines. With 4 circles for 250 ha, the area can be covered with 2 100-ha units (565 m radius) working on a 72 hour irrigation period per circle, On the assumption that each machine can deliver an equivalent of 8 mm per day over the circle, but take three days to complete the circle, the irrigation depth would be 24 mm per cycle. Given that the root zone soil depth is about 400 mm, and the water holding capacity (replenishment) is a minimum of 5%, then 24 mm represents 6% of the water holding capacity of the soil. This application rate reduces the risk for any excessive deep percolation, with a 12- to 15-day period between irrigations.

585. Besides the main center pivot sprinkler systems, and any additional sprinkler or drip systems tapped to the center pivot pressure supply pipes, there is also need for drip systems for up to 4.4 ha of windbreak on the southwest (long side) and northwest (short side) of the command area. There would also be benefits to upgrading the existing vegetable area (up to 50 ha) with a purpose arranged drip or fixed sprinkler system to be fed directly from the main pump station. The drip systems would also include a filtration unit on the main feedline, which would backwash through control valves and discharge to the escape drain from the balancing storage. These systems would operate on a rotational basis under lower pressure, with pressure compensating in-line emitters or otherwise higher head movable sprinkler/riser lines.

4. Design Discharge

586. The estimated maximum discharge capacity from the river intake headworks is taken to be 30 m3/sec, which at 86% overall conveyance and application efficiency equates to a net applied average water application rate of 0.43 m3/s or 430 l/s/ha for 500 ha. The peak water flow in the main canal can be designed to be up to 30 m3/s, though with the effective use of the balancing storage, the peak flow rate is less critical.

587. Under the ‘without project’ situation, the water extraction from the river for irrigation ranges from 0.24 m3/s in September to 0.68 m3/s in June, with an operational efficiency of 36%. These flow requirements are well below the mean monthly flow available (net of environmental flow) in the river at about 5.4% to 13.6% respectively (Table 101). In the ‘with project’ situation, and with a projected overall improved irrigation water use efficiency of 73%, the water to be extracted from the river is about 50% of the ‘without project’ requirement, at 0.12 m3/s in September up to 0.34 m3/s in June.

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Table 101: Design Discharge from the Ider River Month Net Average Water extracted from river Canal and Pipe Capacities Available for irrigation with project m3/s Water a Main Main Pipe Distributary m3/s m3/s % Canal Distributary Pipes Pipes May 4.78 0.12 2.45 0.43 0.2 0.23 June 4.99 0.34 6.75 0.43 0.2 0.23 July 6.44 0.33 5.17 0.43 0.2 0.23 August 8.83 0.24 2.70 0.43 0.2 0.23 September 4.20 0.12 2.83 0.43 0.2 0.23 a See Table 2 Source: Consultant’s estimates

5. Civil Works

588. The Khuren Tal irrigation scheme in Telmen soum of Zavkhan aimag is 140 km from Uliastai and is located 10 km from the soum east of the Ider river. The most important indicator is the reliability of the irrigation system. The main source of Khurental irrigation system is a key Ider. At any time during the maximum flow of the river it is necessary to obtain reliable water. The 3 maximum discharge of the Ider river is estimated at Q1% = 310 m / s. For this purpose, the water level of the water level shall be as follows: These include:

1. Water level port, dam – 519 m, 2. Head building - 1 unit 3. Main channel – 4,966 m, 4. Main channel PS-1, - 4,466 m 5. Distribution Channel – 2,030 m 6. Channel to break – 85 m 7. Tube HDPE Dy = 450 mm – 868 m 8. Tube HDPE Dy = 400 mm – 835 m 9. Tube HDPE Dy = 315 mm – 1,133 m 10. Tube HDPE Dy = 100 mm – 570 m 11. Waste well Dy = 1000 mm – 1 h Rock filled barrier across the river ➢ The chin length is 519 m, ➢ Height 1.2-3.8 m, ➢ Spacious section 80 m wide ➢ The length of the section is 7.53 m ➢ The height of the wean was 1,785.48 m, ➢ The height of the overflow zone is 1,785.48 m ➢ The maximum water level is 1,785.22 m, ➢ At the entrance of the leachate level 1,784.50 m and 1,784.16 m in the exit area ➢ Upper slopes of 1.5, ➢ Slope of lower section 3.0 ➢ Thickness of the fastening device is 0.3-0.4 m ➢ The length of the water well is 3.0 m ➢ Deep wells are 0.5 m deep ➢ Dental depth is 0.5 m.

589. The main civil works for the Diversion Headworks on Ider River left anabranch will include survey, detailed design and strengthening/raising the cross river barrier to maintain a river pool

222 level at minimum 1784.50 masl, for the diversion and conveyance of water to a balancing storage, pump station and irrigation sprinkler/drip systems. The works can be summarized as: (i) improvement, raising and strengthening of the existing rockfill barrier wall (with impermeable core) across Ider River anabranch channel, immediately downstream of the existing intake channel, to raise the pool water level to a reliable 1784.50 masl; (ii) The dump trucks will be pumped into the dumps of pits. Upon reaching the required level of sand preparation, cover the synthetic film. The outside is fastened to a concrete mortar with cement mortar. Water wells are also counted. It is advisable to continue to marmalade with a 1m wide double-sided fixture. It is advisable to compensate for the dimensions of the fabric in the lower water. When the battery through the frozen water into the dangerous entrance of the structure damaged. (iii) formation of relevant protection banks around the command area and other infrastructure, in conjunction with the development of drains and windbreaks; (iv) development of the windbreaks on northwest and southwest sides of the command area; (v) construction/formation of up to 10 km of access road; (vi) construction of up to 9.7 km of fence for stock proofing the command area. (vii) Main channel. The cross-sectional area of the main channel b = 1.50m, i = 0.0002- 0.0008, m = 2.0, n = 0.025, and 4966m channel lined. It is necessary to clear the lung of the channel. (viii) Distribution channel size b = 0.8 m, i = 0.0015, m = 1.5, n = 0.025, and lined size 2030m. (ix) Take the channel from the main channel PK49 + 20. At the beginning of the shut- off stage, the RO will set up a 50x50 adjusting bracket. The dimensions of this channel are b = 0.5 m, i = 0.0015, m = 1.5, n = 0.025 sized 80 m channel. (x) Adjustable reservoir. The size of the reservoir will be 75 m3 of reservoir with h = 1.56 m depth m = 1.5 with base bottom 10x10m. Provide a seepage protection seal of the water pool. Make 2x2m concrete design in the water suction area. (xi) The pump station is designed to have 2 pumps. The pumps will be installed in a 3m x 3 m building. The sprinklers will be operated with one pump and the other will be standby in case of breakdown. Once irrigation has been completed for the season, water will be drained, and the pumps lubricated and sealed with plastic bags. The pumping bases shall be in accordance with the drawings and shall be fitted with drainage tanks to ensure that the water does not stay in the building. Pumps should be firmly grounded and prevented from packing and shaking. (xii) Electricity. 35 / 04-600 transformers from the 35kW line to power and 3400m power lines and pumping stations. (xiii) A mesh fence is required for a length of 9,745m

6. Equipment

590. Within the civil works, required equipment will be limited to gates to be installed for: (i) The Water Intake – vertical lift sluice gate with preliminary 1,5 m wide and a 1.0m lift; (ii) Replace the rotary pulley bracket (iii) Stop ladder 0,4х0,2х2,0 (width x height x length) (iv) Intake Sediment Sluice – vertical lift sluice gate sufficient to flush rapidly at up to 1 m3/s, details to be finalized around operational and physical levels at site; (v) Provision of up to 2 no pumps and associated pipes, with up to 35 m operating head and output of at least 230 l/s, to supply all planned irrigation systems (CP, sprinkler/spray, drip) to cover the full 250 ha in a maximum 15 day cycle;

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(vi) Provision of all required pipework – HDPE or other as suitable – to distribute all pumped water around the command area to the designated CP anchor stations and other required offtakes for minor system; (vii) Provision of 2 No. 101.2 ha (2 No. 22.5ha) Center Pivot sprinkler sets, with 565 m (268 m) boom, inclusive of propulsion power supply, operating control, and associated spare parts, spray nozzles and drop pipes suitable for particular crops, all details to be discussed with potential suppliers before confirming detailed specifications; (viii) Provision of three drip system controlling stations and all associated low-pressure drip pipework, with sufficient associated connections and control valves for up to 8.0 ha of windbreak and up to 80 ha of upgraded and revitalized orchard; (ix) Provisionally, one or more sets of low pressure microspray and/or drip systems for installation in greenhouses (size and number to be determined), should the option to develop such facilities be adopted;

591. Provision of relevant power supply infrastructure, whether connection to main national or local electricity grid, inclusion of diesel power and generator sets, or provision of diesel power to drive irrigation systems (pumps, self-propulsion, etc.). Adopted sprinkler equipment is expected to include suitable on-board power controls and drive mechanisms if electric power supply and cabling is not viable

7. Bill of Quantities

592. The cost estimation for Khurental irrigation scheme construction and equipment (Table 102) summarizes the cost for key components required for the upgrading and modernization of the irrigation scheme. The estimated cost for Khurental irrigation scheme is MNT4,163.42 million equivalent to MNT8.33 million ha.

Table 102. Bill of Quantities for Khurental Irrigation Scheme Modernization Budget (MNT million) No Item Unit Quantity Unit cost Total Civil Works 1 Headworks Sluicing structure with intake sluice piece 1 70.96 70.96 channel and outlet flushing channel 2 Rockfill Barrier and Water level Control Weir, Wall m 480 1.81 867.47 L=480m, h=2 m, Weir L= 13 m, h=1.0 m 3 Headworks protection embankment m 500 0.04 18.48 4 Main Canal, reforming m 4,400 0.03 116.29 5 Distributary pipe m 3,406 0.03 108.45 6 Distribution canal, reforming m 1,520 0.03 40.16 7 Drain well piece 2 2.88 5.75 9 Roads – forming and grading m 10,000 0.003 32.70 10 Windbreaks – prepare land and install ha 4.9 45.41 220.23 11 Drain and protection bank m 3,600 0.03 114.70 12 Electricity sub-station set 1 11.20 11.20 14 Pump station number 1 100.00 100.00 15 Fence km 10.0 7.00 70.00 Subtotal 1,776.41 Equipment 12 Head work Control Sluice Gate, Width 1.0 m x piece 2 1.68 3.36 Height 0.6 m, vertical screw 13 Distributary PE: PE100, SDR11, 1,0mpa, m 868 0.34 292.08 DN450mm, PN10 14 Distributary PE: PE100, SDR11, 1,0mpa, m 835 0.27 221.69 DN400mm, PN10

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16 Distributary PE: PE100, SDR11, 1,0mpa, m 1,133 0.16 186.72 DN315mm, PN10 17 Distributary PE: PE100, SDR11, 1,0mpa, m 570 0.02 11.51 DN100mm, PN10 18 Central pivot sprinkler, for 100 ha set 1 303.88 303.88 19 Central pivot sprinkler, 22 ha set 1 133.00 133.00 20 Self-propelled lateral move sprinkler 25 ha set 4 77.16 308.66 21 10 ha Water Efficient Drip Watering Advanced set 2 79.00 158.00 System 22 5 ha Water Efficient Drip Watering Advanced set 1 28.36 28.36 System for wind break 23 Trees, number piece 14700 0.004 58.80 24 Electricity sub-station set 1 17.00 17.00 25 Pump piece 2 16.30 32.60 26 Excavator for O&M piece 1 168.60 168.60 Subtotal 1,924.27 21 VAT, 10% % 53.75 370.07 22 Environmental baseline assessment number 1 0.00 23 Environmental impact assessment number 1 42.67 42.67 24 Design cost ha 500 0.10 50.00 Subtotal 462.74 Grand total 4,163.42 Source: Mungun Minj Design Institute

J. Subproject 10 – Nogoon Khashaa Irrigation and Drainage System Design

1. Site Description

a. Scheme Background

593. Uliastai Soum owns the Nogoon Khashaa irrigation scheme, which is located in the center of Uliastai City. Uliastai City is the capital of Zavkhan Province in the Western Region of Mongolia (Figure 125). The irrigation scheme was commissioned in 1974. The command area of the scheme is 93 ha, with a 2.1-km concrete-lined main canal gravity flow and distribution system. A MA200 sprinkler was used to irrigate the crops.

594. Whilst the scheme is a primary source of vegetables for the Uliastai City and there is sufficient water at the source, there are constraints to its operation as the main canal goes through a built-up area close to the city, and is also constrained by the recently installed wastewater drainage and treatment system to the west.

Figure 125: Location of Nogoon Khashaa Irrigation Scheme

Source: Based on Google Maps.

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b. Area and Crop Maps

595. Geomorphology: The subproject area, at 1,738 masl to 1,756 masl, sits in a valley where the Chigestei and Bogd rivers meet and is surrounded by the Khangai Mountains, which range from 2,444 to 3,290 masl The soum is bounded to the north by the Asgat Khairkhan (2,981 masl), to the east by the Ayaga Shangan mountain (3,290 masl), and to the south by Khargani Nuruu (2,444 masl).

596. Whilst active farmers are managing to produce vegetables and other crops in this difficult situation, it is an ideal area in which to develop a long-term durable irrigation scheme at an affordable cost. This is a major area where the local variety of garlic named as “red-skin garlic” is planted.

597. The system water intake structure and conveyance canal that bring water to the scheme area need to be reconstructed, to replace water distribution control and canal lining, and the WUAs need to be assisted to improve overall land management (Figure 126).

Figure 126: Current Situation for Nogoon Khashaa Irrigation Scheme

Upper: left head work/intake; Upper Right intake structure; Lower Left: main canal; Lower Right: cropland Source: TA Consultants’ field trip

c. Climate

598. The 34-year time series (1985-2018) of monthly mean air temperature, wind speed and precipitation observed at Uliastai meteorological station has been analyzed (Table 103). The climate of the Khangai mountain region is sharply continental as are other regions of Mongolia.

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599. In the Nogoon Khashaa irrigation subproject area, daily temperature during the growing season can exceed 30oC (maximum daily) between May and August, and humidity is about 47- 55%. Precipitation, when water is required for crop production, varies from an average of 17.3 mm in May, 34.8 mm in June, 59.9 mm in July and 49.0 mm in August, with an overall for the year of 219.8 mm, where 42% of that falls during June and July, and 83% falls in May to August. The average wind speed for the year is 1.6 m/s, with peak wind speeds experienced throughout the warmer crop growing months.

Table 103: Mean Monthly Climate Data in the Nogoon Khashaa Irrigation Subproject Area Month Average Absolute Absolute Humidity Wind Precipitation, Temperature Maximum Minimum (%) speed, (mm) (oC) Temperature Temperature (m/s) (oC) (oC) January -22.4 -0.2 -42.1 70.4 0.9 3.0 February -18.6 8.0 -42.3 66.7 1.0 2.6 March -10.1 15.3 -37.2 58.7 1.5 4.3 April 1.5 23.9 -24.4 47.1 2.1 7.9 May 9.0 29.2 -12.4 43.3 2.4 17.3 June 14.4 32.7 -3.8 47.6 2.2 34.8 July 16.5 35.8 0.1 52.0 2.0 58.9 August 14.0 32.0 -3.2 55.3 1.8 49.0 September 7.8 27.2 -13.5 52.4 1.8 24.0 October -0.7 21 -29.5 55.2 1.5 8.9 November -12.4 10.5 -36.7 65.2 1.2 5.3 December -19.7 4 -39.8 69.8 1.0 3.9 Average -1.7 35.8 -42.3 57.0 1.6 219.8 Source: National Agency for Meteorology and Environment Monitoring

600. Air temperature. Figure 127 shows the trend for change in monthly mean air temperature from April through to September. As the April mean temperature is 1.5oC, and can be as low as - 23.3 oC, there is insufficient natural warmth in the air to support crop growth for most of that month.

601. Air temperature trends. Air temperature trends (Figure 127) show that monthly mean air temperature for the months from April to September have been increasing consistently. April mean temperature has increased by 1.9oC, June by 2.7oC, July by 3.2oC, August by 2.1oC and September by 2.9oC, while there has been no change in May. On balance, there has been small shift in the mean annual growing season temperature, which could impact crop production. With increased temperatures in growing months, it is likely increased irrigation will be required.

Figure 127: Trends of Monthly Air Temperature at Nogoon Khashaa Irrigation Scheme

Source: National Agency for Meteorology and Environment Monitoring

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602. Duration of hot days. One important climate factor that influences irrigated crop production is the frequency of hot days. Figure 128 shows that the number of days each year with a daily average air temperature above 25oC can reach 4 while air temperature never exceeds 30oC.

Figure 128: Trend in Hot Days with Daily Mean Temperature more than 25oC and 30oC

Source: National Agency for Meteorology and Environment Monitoring

603. Precipitation. Average annual precipitation is 219.8 mm, which shows the region is in the agriculture arid zone.34 Figure 129 shows that monthly precipitation changes for the months from April to September have not been occurring consistently during the growing season. Precipitation has decreased by 2 mm/month in May and June, by 22 mm in July, and by 20 mm in August and September.

Figure 129: Trends of Monthly Precipitation at Nogoon Khashaa Irrigation Scheme

Source: National Agency for Meteorology and Environment Monitoring

604. As monthly precipitation has decreased during the growing season, the number of days without precipitation has increased by 4 days in June, and 5 days July which indicates a small increase in the intensity of rainfall (Figure 130).

34 MNS-ISO-16075-1:2018 Guidelines for treated wastewater use for irrigation projects: The basis of a project for irrigation

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Figure 130: Trends in Days Without Precipitation

Source: National Agency for Meteorology and Environment Monitoring

605. Wind. The monthly mean wind speed in the growing season tends to be higher than in other months (Table 103). Even though the mean wind speed for the months of April (2.1 m/s), May (2.4 m/s), June (2.2 m/s), July (2.0 m/s) and August (1.8 m/s) are low, the wind speed can reach 20 m/s and this can happen, on average, 6 days/year. The number of days when wind speed has exceeded 10 m/s has increased by 80 and the number of days when it has exceeded 15 m/s by more than 30 over the last 34 years (Figure 131). Twenty percent of the wind comes from the south, and 15% from the west and south-east showing irregular wind direction (Figure 131). Therefore, any windbreak should be designed to contain adverse impacts from these directions, in agreement with the concerns of affected farmers.

Figure 131: Trends in High Winds and Wind Direction

Source: National Agency for Meteorology and Environment Monitoring

606. Agro-climate Over the period from 1985 to 2018, the growing season length has increased by about 15 days due to of a shift in when the air temperature transitions above 10oC (earlier dates in spring) and falls below 10oC (later dates in autumn). The accumulated temperature that supports longer crop growth with frost free days has also increased by 15 days, thereby favoring greater and more diverse crop production (Figure 132), which may also require longer irrigation.

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Figure 132: Agro-climate Characteristics

Source: National Agency for Meteorology and Environment Monitoring

607. Projections. Summer temperature in the Nogoon Khashaa subproject area is projected to increase by 2oC, and 2.25oC (Figure 4) and precipitation to decrease by 10% (Figure 5) by 2035 and 2065, respectively. A continued increase in temperature and a slight decrease in precipitation are the most likely combined future impacts necessitating more intense irrigation.

d. Soils

608. The Nogoon Khashaa subproject area soils map (Figure 133) shows that the predominant soil types in the command area are mountain light kastanozem (silt loam) and alluvial meadowish (clayey loamy). Soil is riparian area alluvial meadow and meadow yellow brown soils dominated. By World Reference Base soil classification, the command area soil is Light leptic Kastanozems. Kastanozems are potentially rich soil which can produce high yields under controlled irrigation.

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Figure 133. Soil Map of Nogoon Khashaa Subproject Area

Source: Institute of Geography and Geo-ecology

609. Soils are weak developed, low organic matter (1.5%) and meadow yellow brown soil. Soils have sufficient nutrients, but the soil profile is not so deep because, from 40 cm depth, riverbed stone gravels appear. Each horizon was highly reactive with 10% hydrochloric acid and, meaning they are weak alkaline or near to neutral. Carbonate contents are around 1%, secondary carbonate sediment collected to soils. Soils have a pH of 8.6 and EC of 180-200 μS, which means there is a low salinization effect to the crops (Annex 2).

610. Soil texture is sandy clay loam with 50-70% sand. The ‘B’ horizon has greater porosity because texture is sandy loam and lots of gravel. Stone and gravel greater than 2 mm fraction accounted for less than 20% of the soil in the ‘A’ horizon (Table 104). Soluble nitrogen contents are lower, around 8-9 mg/kg, plant available phosphorus levels are lower, around 8-10 mg/kg, and exchangeable potassium levels are 75-85 mg/kg, which means a sufficient level of nutrients.

611. Soil cation exchange capacity is high at around 33-35 meq/100g, with strong cation binding to clay particles indicating soils that will provide nutrients to plants. Calcium content is higher between other cations (Annex 3).

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Table 104: Soil Profile of Nogoon Khashaa Subproject Area Soil Depth, Characteristic horizon m 1 A 0.0-0.3 Silty clay loam, High organic matter, dark brown color. High carbonate content 2 E 0.3-0.6 Light color soil. loamy clay. High carbonate content, less organic matter than upper layer. 3 B >0.6 Silty clay. High carbonate content 4 C >0.9 Gravel and sandy loam.

Source: Integrated agricultural laboratory

e. Water Sources

612. The main water source for irrigation is the Chigestei River which is the right-hand tributary in the upper basin of the Khyargas Lake-Zavkhan River Basin (Figure 134). The hydrological station is located in Uliastai Soum and is upstream of the subproject area. For water resources assessment for the Nogoon Khashaa irrigation scheme, the 68-year of time series data (1959- 2017) from the Chigestei-Uliastai gauging station has been used for the analysis.

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Figure 134: Khyargas Lake-Zavkhan River Basin

Source: TA consultant based on National atlas

613. Monthly mean flow at Chigestei-Uliastai gauging station ranges from 5.35 m3/s to 9.17 m3/s during the growing season (Table 105). The environmental flow requirement is 3.7 m3/s, 95% of the long-term average flow of the Chigestei River. Thus, in the Chigestei River, just upstream of Nogoon Khashaa, there is an average monthly mean flow of at least 1.66 m3/s available to meet non-environmental water requirements in September, and more in other months. Even then, the monthly high flow can be 19.2 m3/s (September) up to 45.4 m3/s (August), whilst low flow can fall below the environmental flow requirement in all months. In general, there is more than enough water for reliable irrigation at Nogoon khashaa during the growing season, though some prudent storage management in May and June would be beneficial for potentially dry years.

Table 105: Water Resources of the Sagsai River at Nogoon Khashaa Subproject Area Environ- Maximum Minimum Mean Water available for use mental % of Annual 3 Month Discharge Discharge Discharge (m /s) flow Discharge 3 (m3/s) (m3/s) (m3/s) 3 (m /month) (m3/s) (m /s) April 23.1 0.17 4.87 3.7 10.44 1.68 4,499,712 May 26.7 0.95 9.17 3.7 19.7 4.14 14,635,971 June 20.8 0.60 6.41 3.7 13.7 2.26 7,249,020 July 24.0 0.64 7.08 3.7 15.2 3.27 9,048,264 August 45.4 0.28 7.53 3.7 16.2 2.72 10,257,109 September 19.2 0.25 5.35 3.7 11.5 2.28 4,415,152 October 12.7 0.39 2.90 3.7 6.21 - - November 4.56 0.26 1.23 3.7 2.64 - - December 1.66 0.04 0.57 3.7 1.23 - - January 1.64 0.00 0.42 3.7 0.90 - - February 1.77 0.00 0.42 3.7 0.89 - - March 2.05 0.01 0.68 3.7 1.46 - - Source: National Agency for Meteorology and Environment Monitoring

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614. According to data (Figure 135), the Chigestei river flow during the irrigation period of May to August at Chigestei-Uliastai has been decreasing sharply since 1959: in April by 5 m3/s, May by 10 m3/s, June by 5 m3/s, July by 9 m3/s and August by 10 m3/s. However, the Chigestei river flow has increased slightly in June to September since the mid-2000s.

Figure 135: Chigestei River Flow at Uliastai Gauging Station (1965-2017)

Source: National Agency for Meteorology and Environment Monitoring

615. There is excess net flow in Chigestei and the net flow in May is higher than in other months. This is clearly the result of snow melt creating a spring surge in runoff. This should be studied in greater depth during subproject detailed design to ensure there is low risk for water supply to all dependent users and the environment.

616. The sensitivity of flow to climate change in the Chigestei River is shown in (Table 106). If precipitation remains unchanged and average temperature increases by 1°C, 2°C, 3°C or 5°C, the river flow is projected to decrease by 8.3% (+1oC) to 36.0 % (+5oC). The impact of a reduction in precipitation of up to 20% is substantially more marked than if precipitation increases by 20%, but an increase of 5oC would almost eliminate any gains expected from additional precipitation. If precipitation has declined by 20%, then the reduction in river flow from increased temperature is relatively small. Overall, river flow is highly sensitive to reduced precipitation, but with unchanged or increased precipitation, the impact of increased temperature is more significant in moderating river flow.

Table 106. Khovd River Flow Sensitivity to Climate Change a Temperature Projected Percentage Change in Precipitation Increase (oC) -20% -10% 0% +10% +20% 0 -40.4 -22.1 26.0 56.0 1 -45.4 -28.6 -8.3 15.6 43.5 2 -50.3 -35.1 -16.7 5.1 30.6 3 -54.8 -41.0 -24.3 -4.4 18.9 5 -61.7 -50.1 -36.0 -19.2 0.7 a Percentage change of average river flow. Source: TA consultant

617. Water quality. An assessment of water chemistry for the Chigestei River from 2013 to 2018 (Figure 136) shows that the chemical composition of the river water is good, with the 2+ 2+ - concentration of Ca , Mg , SO4 and Cl not exceeding the irrigation water standards thresholds. The sodium adsorption ratio (SAR) that is a critical factor for sustainable irrigation is also found to be within acceptable limits.35 Therefore, water from the Chigestei River is considered to be

35 MNS-ISO-16075-1:2018 Guidelines for treated wastewater use for irrigation projects: The basis of a project for irrigation

234 suitable for irrigation use.

Figure 136: Water Chemistry of the Chigestei River

Source: Central Laboratory of Environment and Metrology

618. Suspended solids in the Chigestei River water range from 0.2 to 35.6 mg/l (or 0.002 to 0.04 kg/m3), but do not exceed 20 mg/l (0.02 kg/m3) in most of the time (Figure 137). Even though the concentration is low there is a need for careful management of water diversions from the river to contain suspended sediment discharge into the intake and canal/irrigation system, which may require additional sediment management measures at intake or through settlement and flushing basins aligned with the main canal in case drip irrigation.

Figure 137: Suspended Solids in Chigestei River Water

Source: Central Laboratory of Environment and Metrology

619. Water quality in Chigestei River is classified as very clean based on water quality analysis and assessment against the Water Quality Index (WQI).

f. Existing Irrigation System and Design Maps

620. The Nogoon Khashaa irrigation scheme supplies water for a command area of 93 ha but only 64 ha is currently used. Water is diverted from the Chigestei River, through a lined canal that is in poor condition, from a gated intake located on the right bank of the river. Excess flow spills

235 back to the river through a continuation of the intake canal. A 603-m long main canal, lined with B10 cement and underlined by a waterproof coating, conveys water from the gated intake to the command area with a fall of about 7 m. The nominal canal bed width is 0.6 m, with a trapezoidal section, and side slopes of 1.5:1. For a lined canal, the flow velocity would be about 2.0 m/s, but in a rough unlined canal it will be lower, though the cross-section is generally wider but shallower with sediment deposition.

621. Nogoon Khashaa irrigation scheme needs to be upgraded and modernized so that the command area of 64 ha can produce more red skin garlic (Figure 138). During the field survey it was found that as the canal now goes through private properties, which pollute the irrigation water. One option to avoid pollution is to use a pipe system from headworks to command area.

Figure 138: Nogoon Khashaa Command Area Layout

Source: TA Consultant

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2. Irrigation Water Requirement

622. The designed command area is 64 ha out of which 15 ha is for potatoes, 39 ha for vegetables36 and 10 ha for fruits. There is 3.1 ha for tree wind breaks. The planned irrigation demand requires a peak flow of 0.05 m3/s (74% overall efficiency), which means that if conveyance and application losses can be further reduced through modernization, there may be a possibility of further expanding the area of red-skin garlic (Table 107).

Table 107: Current and Planned Command Area Crop type Current Allocation Irrigation Planned Allocation Irrigation method of command area method of command area (ha) (ha) Potatoes 33 Used Furrow 15 Drip & sprinkler Vegetables 28.9 39 drip & sprinkler Cereals Fodder 0.5 Fruit trees and 1.5 drip 13.1 wind break Source: TA Consultant

623. Overall scheme irrigation efficiency will be raised up to 74% using piped systems, modern self-propelled lateral move sprinkler irrigation machines for 54 ha and low-pressure drip systems for 10 ha (Table 108).

Table 108: Scheme Irrigation Efficiency Characteristics Field irrigation Percentage of Conveyance Field Scheme application total command efficiency application irrigation area (%) efficiency efficiency (%) (%) Current for total Surface irrigation 100.0 60 60 36 command area (border, furrow, basin) Designed for Sprinkler 80.5 95 75 71 sprinkler, 54 ha Designed for drip, 10 Drip 19.5 95 90 86 ha Average for designed Combined sprinkler 100.0 95 75 74 command area and drip Source: Source: Consultant’s estimates.

624. The total irrigation water requirement of 526,776 m3 (0.040 m3/s) with project and 542,458 m3 (0.041 m3/s) over 4 months for the full Nogoon Khashaa command area and irrigation season has been calculated based on the irrigation water utilization norm (Table 6) applicable for the region and planned crops (Table 109). This projected total irrigation water requirement is 1.15 percent of the net available water in the river in the growing season or is 0.32 -1.94 percent of the given monthly flow in the Chigestei river (Table 110). Even after fulfilling environmental flow obligations, there remains ample water at source to support this irrigation scheme.

Table 109: Irrigation Water Requirements for Nogoon Khashaa Irrigation period Item Total May June July August September Allocation of command area

36 Including red-skin garlic.

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Potatoes (ha) 15 15 15 15 15 Vegetables (ha) 39 39 39 39 39 Cereals (ha) 0 0 0 0 0 Fodder (ha) 0 0 0 0 0 Fruit trees and wind break (ha) 13.1 13.1 13.1 13.1 13.1 67.1 Water requirement with project Gross irrigation norm (m3/month) 86,840 100,714 99,780 69,951 32,530 Irrigation efficiency (%) 0.74 0.74 0.74 0.74 0.74 Total irrigation water requirement (m3) 117,351 136,100 134,838 94,528 43,959 526,776 Water requirement with project with climate change Increase in ET (m3) 174 617 1897 1555 499 Projected irrigation water Use (m3/month) 89,891 101,865 102,828 72,656 34,180 Irrigation efficiency (%) 0.74 0.74 0.74 0.74 0.74 Projected total water requirement (m3) 121,474 137,655 138,956 98,184 46,189 542,458 Source: Consultant’s estimates.

Table 110: Water Availability for Irrigation Percentage of Projected total irrigation Monthly Environ- irrigation water water use Irrigation River ment Net available flow in requirement with from net river period Discharge, Flow, the river project flow (m3/s) (m3/s) (m3/s) (m3/month) (m3/s) (m3/month) (%) May 9.17 3.71 5.46 14,635,971 0.04 121,474 0.80 June 6.41 3.71 2.71 7,249,020 0.05 137,655 1.94 July 7.08 3.71 3.38 9,048,264 0.05 138,956 1.49 August 7.53 3.71 3.83 10,257,109 0.04 98,184 0.92 September 5.35 3.71 1.65 4,415,152 0.02 46,189 0.32 Total 45,605,515 542,458 1.15 Source: Consultant’s estimates.

3. System and Layout

a. Area Topography

625. The proposed irrigation scheme layout is in Figure 139. The existing headworks are located at an elevation of 1,756 masl, at 47.44.21.01 N and 96.50.56.78 E. The upgraded scheme headworks will be at the same location. The water source is about 7 m above the command area. The main canal is aligned on a regular slope with a gradient of 1 in 500. Three intermediate check structures are required at suitable locations along the distributary canals.

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Figure 139: Proposed Nogoon Khashaa Irrigation Scheme Layout

Source: TA consultants

626. The main canal will be lined, trapezoidal and 603 m long. Gated offtakes from the main canal will enable diversion of water into distributary canals on a rotational basis. All of these distributaries will have a lined trapezoidal shape, and flat gradient so they can act as water sumps for the sprinkler suction intakes as they move along the line of the distributary.

627. The main canal will start from a new headwork structure located close to the current intake channel. The old headworks will be abandoned, and the upgraded main canal will continue through the existing intake channel into the existing alignment of the main canal to the command area.

628. To ensure permanent and secure water availability for the irrigation system intake, a low- level weir is proposed to be constructed across the river just downstream of the existing intake. This weir will be about 60 m long and include a reduced level central section to facilitate excess river flow overspill while ensuring the safety and permanence of the weir. At this stage, the central spill section is assumed to be up to 10 m wide, with an overspill sill level at the required pool height in the river needed to securely feed the main canal intake structure. Further details on this weir are included under civil works.

629. A pool will form behind the weir, which will provide operational head, a stilling pool to help sediment reduction, and a water reserve to help cover times when natural river flow is low (particularly in May). To ensure overall water retention in the pool, and to accommodate any large

239 flood events, it will be necessary to build, subject to prevalent levels and topography, a low-level earth embankment to the operational water level with sufficient additional height to ensure any flood water will pass over the weir. As most major river flow will still be using the established main river channels to the north, the additional height over and above the weir spillway sill level is not expected to exceed 0.5 m above the top embankment height of the barrage. Under extreme conditions, the weir (a rock-fill structure) will be able to pass additional shallow flow over its full width for short durations. Specific information on levels for embankments, the width for the spillway section, and the overall barrage wall level will have to be confirmed at detailed design stage.

630. The canal intake structure will be a simple gated structure of sufficient size to pass up to 1.0 m3/s. As part of this intake, located adjacent to the proposed weir wall, a designed sediment entrapment and flushing outlet will be included, set at a level such that with sufficiently frequent operation (when water is plentiful), the approach to the intake gate can be kept free of sediment. The flushed sediment will pass through a gated outlet structure, to return back to the main river section, downstream of the weir. Careful consideration of water and bank/structure levels will be needed at the detailed design stage to ensure this arrangement can be fully effective from normal intake pool operating height. Subject to water depth and other operating requirements, it should be possible each season to implement sediment removal operations, thereby ensuring pool water storage volume is retained for successive seasons.

631. For the command area, there are currently planned two types of canal to get water to the fields – a header canal and the field distributary canals. The header canal runs 603 m. This will be a similar in form, and size, to the main canal with a similar gradient carrying the full 1.0 m3/s, adjusted, if necessary, at detailed design. The header canal sections are expected to support 13 irrigation plots with mini portable vegetable sprinkling equipment that will draw water from the distributary canals fed off the header canal.

632. The distributary canals will be on a relatively flat gradient (1 in 2,000 to 1 in 1,500) and will act as water sump from which the irrigation units can draw water, unless at detail design an alternative layout is deemed more cost effective and practical. These distributaries will have a relatively narrow and deep section and be unlined. Careful planning and operational control will be required for effective flow management and in-field operations.

633. The connection between header and distributary canals will need careful design to ensure movement and position of irrigation machines on each distributary is not compromised. The connection needs to be a buried pipe with an inlet control gate.

b. Irrigation System

634. The planned irrigation system will include gravity water source to field channel, and sprinklers, and possibly some small drip systems for windbreaks and greenhouses. The original system had open main and header canals, to feed water to open unlined field distributary canals. A schedule of irrigation scheme components for modernizing with open channels is given in Table 111.

Table 111: Irrigation Design Using Open Canals No Irrigation Scheme Details and Components Value and Units 1 Gross irrigation scheme area 93 ha 2 Irrigation scheme command area 64 ha 3 Land use coefficient (1/2) 0.96 4 Main canal discharge Q = 1000 l/s, L = 603 m

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5 Distributary canal discharge Q = 140 l/s, L = 4,352 m 6 Field channel L = 6,550 7 Concrete water intake structure with steel gate Q = 0.3 to 1.0 m3/s 8 Concrete sediment sluicing channel/apron and steel Q = up to 1 m3/s b = 2.0 m gated outlet 9 Settling Basin 30 m x 20 m x 3.5 m 10 River rockfill/clay core barrage L = 60 m, H = varies. 11 Overflow weir at river Q = 50,000 l/s, L = 10 m, 12 Riverbank berm L = 50 m, TW = 3 m, H = varies, SS = 2:1 13 Road 6,940 m, 14 Windbreak/forest strip L = 3,100 m, b = 6 m, area = 3.10 ha 15 Sprinkler equipment 4 lateral move sprinkler units Source: Consultant’ estimates

635. Diversion Headworks. The irrigation water is diverted from the right bank of the Chigestei River. The width of this river varies up to 60 m. The diversion headworks will involve a barrier wall (with central weir section) built across the right bank of Chigestei River at a section about 60 m wide. This barrier will increase and normalize the water level in a pool, which will encourage sediment settlement, for reliable diversion through the canal intake structure. The barrier wall will be a rockfill structure (Annex 1). It will include a central clay or impermeable core arrangement from below existing ground/riverbed level (depth to be determined but assumed 1-2 m) to mitigate risk for underflow and/or percolative flow through the wall.

636. The wall will include a central 10-m wide concrete armored weir section for regular spill flows, with a sill lower than the designed top of wall height. This will equal the required steady pool level at the intake structure. The weir side walls, sill and slope face to riverbed level will be reinforced concrete over the rock wall, minimum 150 mm thick, keyed to the central impermeable core wall (with a downturn leading edge toe, 0.5 m below the top of the impermeable core. The overflow weir will need to be verified for width to safely pass summer rainfall flood discharge and melting spring water discharge. In extreme circumstance, some shallow overflow of the rock barrier wall for short periods will be possible without causing undue damage. The estimated discharge that can be passed over a 10-m wide weir structure, with a flow depth of 0.3 m is 1.46 m3/s. Actual discharge requirements will need to be verified to pass the full river flood discharge. The main objective will be to ensure all bank heights, weir widths and other structure levels are appropriate for safe manage of partial flood flows, without over-spilling the intake structure and any associated river flow containment banks. Table 111 provides an indication of spillway width and head over weir required for a safe discharge up to 6.26 m3/s. General topography in proximity to the intake structure and barrier wall will likely preclude a head over the spillway weir in excess of 0.5 m.

637. At the right side of the barrier wall, a gated sluicing structure is proposed to be installed as a ready means to remove sediment deposited immediately in front of the intake structure. This sediment trap and sluice should be set at a level up to 1 m below the intake gate invert level. The gate will need to be large enough to enable high velocity sluicing so flowing water (when plentiful – central weir may be spilling or close to spill) can, from a suitably formed (concrete) bed chute to the gate, collect and carry sediment through to the discharge channel that flows back to the anabranch channel, downstream of the barrier wall. The objective for this structure and head pool to the intake structure is to minimize the potential intake of sediment into the canal (or pipe) system.

638. Main canal intake headwork structure. The intake structure is designed to pass from 0.3 m. This structure will be fitted with a rectangular gate submerged under normal pool height. Ideally the pool depth is 2-3 times the normal operational opening of the gate. Outflow from the gate

241 should be unimpeded (no backwater) so the main canal invert level will be lower than gate sill level by as much as the depth of flow in the main canal. The intake structure is designed to pass from 0.3 to 1.0 m3/sec, between minimum and maximum opening limits. The intake structure is proposed to be located at the start of the current intake channel, adjacent to the right abutment of the planned new river barrier wall. The intake structure will have one gate, nominally 1 m wide, with an opening up to 0.5 m. (specific sizing can be reconsidered when detail designs confirms final pool water level, main canal invert level and other key dimensions). The intake structure will be abutted by a protective earth embankment with a top height at least 1 m above the pool water level. The side walls and base of the intake structure will include key walls to embankment and base, as a means to stabilize and mitigate seepage risks around the structure. The main walls and base of the structure will be reinforced concrete, whilst additional protective anti-scour walls can either be concrete lining and or stone masonry/stone from 0.2 to 0.30 m in diameter.

639. Settling Basin. The settling basin of size 30 m x 20 m x 3.5 m downstream of the head regulator will be constructed for the settling of sediment. The settled sediment will be hydraulically flushed to the river. This is very useful after modernization of the system when it will use sprinkler and drip irrigation.

640. Main canal and distributary canal. The existing canal is gravity fed open channel flow, which has been in operation for a long time. The canals will be lined with concrete slabs (cast in- situ or pre-cast based on relative cost associated with speed and quality of construction). The pipe will not be used for the main or distributary canal. This will facilitate the farmers to irrigate from the system when the sprinklers are not be operational. The concrete slabs will overlay natural ground, formed to canal trapezoidal section, and be vulnerable over the long term to the effects of groundwater and frost heave. Consideration should be given to mitigating frost movement risk by laying lightly reinforced (4 mm steel round bar mesh, 100 mm centers) concrete panels over a thin impermeable plastic sheet, covering the canal cross-section with ends buried each side in the finalized canal embankments. On the left bank of the header canal a road should be constructed to facilitate access to the command area. There are up to 12 small gated outlet structures from the distributary canal to the field canals. Specific details for these connections should be determined at detailed design, when it is determined exactly which irrigation sprinkler equipment is selected, and particular requirements for moving them between field canals.

c. Irrigation Scheme Layout

641. Distributary/field canals. Twelve field canals are proposed to cover the command area (64 ha). The field canals will include an inlet control sluice gate. The need for any other control structures and outlets in the field canals will need to be determined at detailed design, together with an assessment of what other protective measures will be required (bank stabilization, end overspill to drain, etc.).

642. Access road. Roads, with a width of 4.5 m, and total length of 6.94 km, will be formed alongside the header canal and field canals. This will be earth roads, suitably elevated, in conjunction with the canal construction work.

643. Windbreak/forest strip. Windbreaks are used as a means of checking aggressive winds locally to protect dry soils from erosion. These windbreaks are located in suitable alignments adjacent to command area or canals, on the windward (approach) side. A windbreak with a length of 3.1 km is proposed for this subproject. The windbreak will consist of two rows of trees and 1 row of shrubs/bushes. The distance between each tree will be 4 m, and between each bush 1 m. The distance between the tree lines will be 4 m and the shrub line will be 3 m behind the tree line.

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Provisionally, the trees and shrubs/bushes are proposed to be supplied with water via permanently installed dripper lines, with the intake pump station located on the upstream side of where the main canal discharges into the header canal. Specific design of drip systems – pump, filters, control valves, main supply lines, and dripper pipes to tree and/or bush base should be completed at detailed design. Up to 3,200 m of main supply pipe, and at least 6,500 m of outlet small diameter drip pipe will be required to reach each tree from the central main supply pipe. Alignment of the main pipes will be downslope with partial pressure recovery. However, pumping will need to provide sufficient pressure to ensure minimum outflow pressure at the furthest outlet.

644. There is an area adjacent to the header canal which could potentially be developed with small-scale greenhouses to produce additional vegetables (e.g. tomato, cucumber). The potential for this needs further investigation, but with water available in the header canal, a local micro-spray or drip supply system could readily be supplied to support greenhouse development.

645. Irrigation method. It is proposed that at 4 units of self-propelled lateral move sprinklers be procured and installed at this site. Based on the supply canal layout, lateral move sprinklers are proposed, drawing water by their own pumps from the field canal. For this area, 4 units will be required, working in parallel, to work on rotation around on average 16 ha each. As these sprinklers will be moved between field canals, irrigation cannot be implemented continuously, 24 hours per day. The supply canal system will need to be carefully managed to match actual water release in accordance with sprinkler operating times and water application rates. Such details will be provided by equipment suppliers when submitting bids, and operation procedures and schedules can be developed when relevant details are available.

4. Design Discharge

646. The planned irrigation system will include a gravity water source to field channel, and sprinklers, and some small drip systems for windbreaks and greenhouses. The original system had open main and header canals, to feed water to open unlined field distributary canals. This is retained as the basis for the modernized irrigation scheme design, though a secondary option, using a low-pressure PE pipe in lieu of the open main and header canals was considered. Preliminary costs comparisons soon showed that with PE pipe, a pipe option was too costly.

647. The available discharge in the canal system will be adequate with the improved system. The discharge required to irrigate at the intake at 5 l/s/ha (conservative estimate) and requires 0.43 m3/s at the head regulator (Table 112).

Table 112: Design Discharge from the Chigestei River Irrigation period Net Average Water extracted from Capacity of irrigation scheme Available Water, river for irrigation with canals, m3/s m3/s project m3/s % Main Distributary Field May 4.14 0.43 10.39 0.43 0.14 0.025 June 2.26 0.43 19.03 0.43 0.14 0.025 July 3.27 0.43 13.15 0.43 0.14 August 2.72 0.43 15.81 0.43 0.14 0.025 September 2.28 0.43 18.86 0.43 0.14 0.025 a See Table 105 Source: TA Consultant

648. One sprinkler unit is assumed to operate at 0.025 m3/s. Excess that cannot be drawn by the sprinkler units would pass through the end of field canals and into drains. Where flow exceeds

243 usable volume, then some adjustment should be made at the intake structure to moderate the flow release.

5. Civil Works

649. The main civil works include for the diversion headworks from Chigestei River, and conveyance of water to irrigation sprinkler/drip systems will include: (i) construction of a rockfill barrier wall (with impermeable core) across Chigestei River channel, immediately downstream of the existing intake channel; (ii) incorporation of a reduced level reinforced concrete spillway section, to control pool water level upstream, and pass moderate excess flows back to main river; (iii) construction of a new intake structure at the head of the existing intake channel, with sluice gate, and flow control for steady release into the main canal; (iv) construction of a sediment sluicing channel across the front of the new intake structure, leading to a gated outlet through the right bank side of the new barrier wall, for periodic sediment sluicing; (v) construction of a safety protection embankment from the barrier wall, incorporating the intake structure and along the anabranch right riverbank until it meets ground level; (vi) reformation and lining of the main canal (603 m), distributary canal (4,352 m), and 12 field canals (6,550 m); (vii) construction of various flow control and outlet structures in and between canals, and overspill outlets from end of field canals and at ends of main and header canals, discharging to drain alongside those canals; (viii) construction of appropriate connections for discharge from header canal to field canals that suit the key irrigation equipment movement and alignment for each field canal; and (ix) development of the windbreaks of the command area.

650. At this stage, the design and related details are preliminary, and as detailed design and operational requirements are clarified, some additional works may be required (e.g. crossing points on the main canal at headworks, or at start of the command area). If conversely a pipe is substituted for the main canal, then this is not a necessary consideration, though the pipe might need to be deeper and/or protected in concrete at some designated crossing point(s).

6. Equipment

651. The main equipment required for upgrading of the irrigation system includes: (i) Water intake – vertical lift sluice gate for the water intake with preliminary dimensions of 1.2 m wide and a 0.6 m lift; (ii) Intake sediment sluice – vertical lift sluice gate sufficient to flush rapidly at up to 5 m3/s, details to be finalized around operational and physical levels at site; (iii) A control sluice gate with adjacent spill section between the main canal and header canal, size similar to intake structure gate; (iv) Provision on 12 sluice gates and pipe sets (detail to be determined) for release of water from header canal into field canals; (v) Four self-propelled lateral move sprinkler sets, 120 m spray width, for parallel tracking alongside field canals, inclusive of power supply, controls, pump and associated spare parts, spray nozzles and drop pipes suitable for particular crops, all details to be discussed with potential suppliers before confirming detailed specifications;

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(vi) One low pressure drip filtration, pump and control station, with sufficient associated main and connecting drip pipes, for up to 3.1 ha of wind breaks; (vii) Provisionally, one or more sets of low pressure micro spray and/or drip systems for installation in greenhouses (size and number to be determined), should the option to develop such facilities at the eastern end of the header canal be approved; (viii) Provision of relevant power supply infrastructure, whether connection to main national or local electricity grid, inclusion of diesel power and generator sets, or provision of diesel power to drive irrigation systems (pumps, self-propulsion, etc.). There is an expectation that adopted sprinkler equipment would include suitable on- board power controls and drive mechanisms if electric power supply and cabling is not viable.

7. Bill of Quantities

652. The cost estimation for Nogoon Khashaa irrigation scheme construction and equipment (Table 113) indicates the estimated cost is MNT2,610.94 million, equivalent to MNT40.80 million/ha

Table 113: Bill of Quantities for Nogoon Khashaa Irrigation Scheme Modernization Budget No Item Unit Quantity (MNT million) Unit cost Total Civil Works Headworks Sluicing structure with intake sluice channel piece 1 72.68 72.68 1 and outlet flushing channel Rockfill Barrier and Water level Control Weir, Wall L=60 m 60 2.87 172.50 2 m, h=3.75 m, Weir L= 13 m, h=1.0 m 3 Headworks protection embankment m 500 0.04 18.84 4 Header Canal – reforming and lining m 607 0.13 81.77 5 Excavation for settling basin and sluiceway m3 3000 0.03 90.00 6 Sluice way for outlet flushing channel piece 1 36.34 36.34 7 Distributary pipe (concrete) m 354 0.27 96.36 8 Distributary canal reforming and lining m 6,550 0.11 724.53 9 Bridge piece 4 4.060 16.24 10 Roads – forming and grading m 6,940 0.00 22.69 11 Windbreaks – prepare land and install ha 3.1 46.27 143.44 12 Fence km 8.4 7.00 58.80 Subtotal 1,533.82 Equipment 13 Head work Control Sluice Gate, Width 1.0 m x Height 0.6 piece 2 1.68 3.36 m, vertical screw 14 Sluiceway gate in settling basin piece 1 0.84 0.84 15 Distributary pipe (concrete Ф1000mm) m 353 0.27 95.99 16 Header Field Canal Flow Control Gate, Width 0.4 m, – piece 13 1.05 13.60 height 0.3 m 17 Self-propelled lateral move sprinkler set 4 77.16 308.66 18 5ha Water Efficient Drip Watering Advanced System set 2 43.47 86.95 19 3ha Water Efficient Drip Watering Advanced System set 1 28.36 28.36 20 Trees number 9300 0.004 37.20 20 Excavator for O&M piece 1 168.60 168.60 Subtotal 743.56 20 VAT % 25.76 227.74 21 Environmental baseline assessment number 1 42.67 42.67 22 Environmental impact assessment number 1 42.67 42.67 23 Design cost ha 64 0.32 20.48 Sub-Total 333.56 Grand total 2,610.94 Source: Consultant’s estimates

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K. Subproject 12 – Iven Gol Irrigation and Drainage System Design

1. Site Description

a. Area and Crop Maps

653. Iven Gol irrigation scheme is located 5.0 km west of Sant soum center. The project area is situated at 730 to 772 masl, and within the valley of the Iven Gol River surrounded by Shandiin Gosgor Mountains (971 masl) to the south, Budlan Mountain (1576 masl) to the north and the Iven Gol river to the east. The target command area is currently about 250 ha, straddling the Iven Gol river. The main supply canal follows the contour on high ground to the north of the river and around the northern boundary of Sant Soum, eventually petering out to the northeast on the boundary of an allocated, but now rainfed commercial land holding. The current development situation for irrigation around Sant Soum is as shown in Figure 140.

Figure 140: Iven Gol Canal Intake and Convoluted Path of Main Canal to Command Areas

Source: TA Consultant based on Google Map

654. Iven Gol irrigation scheme originally had a dam constructed at an approximate top height of about 780 masl with a dam wall length of about 400 m long, on an 865.6 km2 catchment (no design drawings have been sighted). However, it appears that if this was the original height, a large part of the current dam wall has settled substantially and now sits at about 777 to 778 masl. This failed dam is located about 1.75 km from the start of the irrigation scheme command area (2.1 km by river alignment) and as near as can be determined, the fall from river level at dam to river level at canal intake is in the order of 7 to 10 m over 2 km. Detailed survey will be needed to clarify the before considering whether to redevelop the dam for the irrigation scheme. Currently, the dam holds no water, with a washed-out and collapsed spillway, including much of the south west end of the dam. Dam failure occurred due to a spring snow melt flood, when the spillway/dam

246 attendant was unavailable to operate spillway gates. Without the dam, there is no available balancing storage facility currently available to help moderate flows between high flood and low drought.37 Flows in the river during drought periods (June/July) can be seriously depleted, approaching zero temporarily. Therefore, any upgraded and modernized irrigation scheme will need improved flow regulation of the river, or a supplementary balancing storage, to safeguard water supplies for the occasional drought periods. An overview of the current irrigation scheme and broader land use around Sant Soum is in Figure 141.

Figure 141: Location of Iven Gol Irrigation Scheme on the North Side of Iven River Valley

Source: TA Consultant based on Google Map

655. All river discharge is now unchecked by the dam and passes immediately downstream through the deeply incised river channel, past the original canal intake and flow control structures, and through the lower part of the command area. Both constructed outflow structures for two main canals are badly damaged, but the reservoir area does not appear to be heavily silted. The area is now populated by substantial regrowth of trees and bushes. The restoration of this dam to full original design capacity would require substantial investment, following relevant due diligence, and this cannot be undertaken as part of the irrigation scheme modernization. For Iven Gol irrigation scheme to be fully upgraded and modernized, it will improve water regulation of flow in the river for reliable intake to the system, and additional flow management of the water supply within the irrigation scheme to overcome the irregular availability of the water in the river. If any rehabilitation of the dam is to be done (and some investigations for this have already been initiated), this may only be feasible if the majority of the irrigation areas (up to 9,000 ha) are integrated into a larger development. For the smaller Iven Gol irrigation scheme command area (now estimated at about 200 ha, a more appropriately scaled and reliable river flow capture and diversion is required.

656. The Iven Gol irrigation scheme was rehabilitated in 2007 at a cost of MNT200 million, but it is assessed that the work done at that time did not revise the original scheme design, and much of the rehabilitation work was done to a poor standard. Today, the varied irrigation that is being undertaken is generally flood irrigation for the irrigation scheme area, with water diverted through several main canals (earth, irregular) and offtakes to access and use water in an irregular pattern. The larger area is in commercial hands, and a high proportion of the irrigation is undertaken with center pivots using water pumped from the Orkhon river as shown in Figure 141.

37 A design institute was commissioned in recent years to look at and scope the work/costs for reinstating this dam, but it has not been possible to access the report, if it is in fact completed. The spillway collapse is reported to have occurred in the early 1990’s with failure incurred due to delayed or non-operation of spillway gates during a major river flow event.

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657. The small Iven Gol irrigation scheme system under consideration, to support approximately 100 farmers families, currently lacks good water management control in the canals, and has poor allocation and distribution of the water between the farmers. This is evident from Google imagery where the upstream land (in the west) appears to be more actively used than is the case for land closer to the Soum center in the east. It is clear that with suitable upgrading, to capture and deliver water to the famers, and with improved means to apply the water over the land, there is potential to improve overall land and crop productivity for the dependent small farmers. It is understood the small farmers are not comfortable to have their water supply linked with the water supply (pumped from Orkhon river) developed by and for the large commercial farmers (3 companies).

b. Climate

658. Iven Gol has had an operational meteorological station for 34 years (1985 to 2018), so analysis has been undertaken for monthly mean air temperature, wind speed and monthly precipitation data. There is no meteorological station at Sant soum itself, which lies to the north northeast of the command area, but the Iven Gol station is located just on the other side of the Iven Gol river about 5 km from Sant soum.

659. At Iven Gol irrigation sub-project, the daily temperature in mid-summer can reach up to 40oC in June to August. The annual rainfall is approximately 285 mm, with about 80% of this rainfall occurring in the three months from June to August, and the average wind speed is moderate (average 1.7 m/s) throughout the year. The mean monthly climate data for the project area are in Table 114.

Table 114: Mean Monthly Climate Data at Iven Gol Irrigation Subproject Month Average Absolute Absolute Humidity Wind Precipitation Temperature Maximum Minimum (%) speed (m) (oC) Temperature Temperature (m/s) (oC) (oC) January -25.0 1.5 -48.5 76.0 0.6 2.7 February -19.7 8.1 -42.5 75.6 0.8 2.4 March -7.7 22.9 -36.0 66.9 1.9 2.8 April 3.8 30.0 -23.3 48.9 2.9 6.4 May 11.6 35.6 -12.2 48.2 2.8 20.4 June 17.3 39.8 -5.0 54.7 2.4 55.4 July 19.7 43.0 -1.1 62.8 1.9 72.0 August 17.1 39.1 -0.3 67.2 1.7 72.7 September 10.1 33.0 -9.4 63.3 1.9 32.3 October 1.3 28.3 -25.1 64.9 1.6 8.7 November -11.0 19.1 -36.5 73.8 1.0 5.2 December -20.7 10.4 -44.0 77.1 0.6 4.0 Average -0.3 43.0 -48.5 64.9 1.7 284.9 Source: National Agency for Meteorology and Environment Monitoring

660. Air temperature. Figure 142 shows the trend for change in monthly mean air temperature from April to September. As the April mean temperature is 3.8ºC, lower than the 10oC crop growth threshold, and the minimum temperature could fall to -23.3oC (Table 114), there is insufficient warmth in the air to support crop growth for most of that month, so no irrigation is undertaken in April. However, snow and ice melt will occur, and this can be captured to fill any intermediate balancing storage. This spring flow (sometimes flood) is reported to be the major peak flow available

248 from the Iven Gol river during the year and was the cause of the original dam failure in the early- 1990s.

661. Air temperature trends. Figure 142 shows that monthly mean air temperature has changed over recent years for April through to September. All months demonstrate an increasing temperature trend, though in May, August and September the trend is less marked. The April mean temperature has increased by 2.0oC, May by 0.4oC. June by 2.5oC, July by 2.3oC and August by 1.3oC. On balance, there has been a significant lift in the mean annual growing season temperature for June and July, which could favorably impact crop production if there is sufficient irrigation water supply. With these increased temperatures in June and July, there will be need for increased irrigation, even if there is some marginal increase in rainfall during those months.

Figure 142: Trends of Monthly Air Temperature at Iven Gol Irrigation Scheme

Source: National Agency for Meteorology and Environment Monitoring

662. Duration of hot days One important climate factor that influences irrigated crop production is that of hot days. Figure 143 shows the number of days each year with daily average air temperature above 25oC has increased by 28 days over the last 34 years. The number of days where air temperature has exceeded 30oC has increased by 19 days over the last 34 years. This has a clear implication that additional water will be needed, with some increased irrigation application necessary for sustained crop production (as crop evapotranspiration need and evaporative loss from the reservoir will both be higher).

Figure 143: Trends in Hot Days with Daily Mean Temperature more than 25oC and 30oC

Source: National Agency for Meteorology and Environment Monitoring

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663. Precipitation. Figure 144 shows that monthly precipitation has increased in April by 6 mm, in May by 24 mm, and in August by 3mm, but there is a decrease in June by 0.4 mm, in July by 20 mm and in September by 18 mm. Thus, more precipitation is coming earlier in the year with less in the critical hot months leading to the wet season.

Figure 144: Trends of Monthly Precipitation at Iven Gol Irrigation Scheme

Source: National Agency for Meteorology and Environment Monitoring

664. The decrease in precipitation in June and July may be explained by the decrease in the number of days when there was no precipitation by 3 to 10 days in both of these months, whereas the number of days with no precipitation in May is unchanged (Figure 145).

Figure 145: Trends in Days with no Precipitation

Source: National Agency for Meteorology and Environment Monitoring

665. Wind. The monthly mean wind speed in the growing season varies from 0.6 to 2.9 m/s (Table 114) while the maximum speed can exceed 20 m/s on average twice a year. There are more than 100 days per year when wind speed exceeds 10 m/s, and this has increased by 70 days over the last 30 years (Figure 146). The number of days when the wind speed exceeds 20 m/s has increased by 3 days over the last 30 years. Figure 146 shows that 20% of the wind comes from the north and northeast, and 15% from the southeast. This indicates that any windbreak is needed along the north and northeast sides of the command area, though with modest peak windspeeds for few days per year, the extent of any protection against wind and wind erosion needs to be reviewed and confirmed in relation to topography around the area.

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Figure 146: Trends in High Winds and Wind Direction

Source: National Agency for Meteorology and Environment Monitoring

666. Agro-climate. Due to changes in when the air temperature transitions above/below 10oC (9 days earlier in spring, 5 days later in autumn), the growing season has become longer, with increased overall temperatures for longer duration, which provides extended opportunity for crop growth. The number of frost-free days has increased by about 5 days over the past 30 years, which favors increased crop growth and yield (Figure 147).

Figure 147: Agro-climate Characteristics

Source: National Agency for Meteorology and Environment Monitoring

667. Climate Projections: The summer temperature is projected to increase by another 1oC, to 2oC (Figure 4) with a probable 10 % decrease in precipitation (Figure 5) from 2035 to 2065 at Iven Gol subproject area. A continued increase in temperature and a slight decrease in overall precipitation are the most likely combined future impacts that will intensify the need for irrigation.

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c. Soils

668. The soil map for Iven Gol irrigation scheme (Figure 148) shows that the dominant type of topsoils in the command area are kastanozem and riparian area’s alluvial meadow soil. By World Reference Base soil classification is Fluvisol and Meadow swamp alluvial with meadow saline soil. Fluvisol soil is a very young soil with weak horizon differentiation. Brown dark is grey brown to brown.

Figure 148: Soil Map of Iven Gol Irrigation Scheme

Source: Institute of Geography and Geo-ecology

669. Soils are high organic matter 3.2 % dark brown soil and water erosion affected soil. Soil nutrients medium level. Clay particles accumulated by river flow in A horizon. River water EC= 375 μS Also long time used for irrigated agriculture that’s why clay particle moved to depth. Each horizon was high reacting with 10% hydrochloric acid and it means weak alkaline or near to neutral. Carbonate contents around 0.5%, secondary carbonate sediment collected to soils. Soil pH=8.3 and EC= 180-190 μS. Which means there is middle salinization effect to the crops.

670. For the soil particles texture is silty clay loam and 50-70 percent of soil is silt fraction. B horizon is more compacted, no root in this zone and more silty soils. Stone and gravel more than 2 mm fraction is about 1-2 % of the soil (Table 115). Soil chemical properties will indicate soil nutrients level. Acceptable levels of nutrients are about 31 mg/kg for soluble nitrogen, 8-11 mg/kg for plant available phosphorus, and 50-55 mg/kg for exchangeable potassium, which means that these soils do not have sufficient levels of nutrients.

671. Soil cation exchange capacity is high around 40-45 meq/100g which meaning cation are binding with clay particles and indicating soil will good enough to deliver nutrients to plant root.

Table 115: Soil profile Soil Depth, m Characteristic horizon

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1 A 0.0-0.3 Silty clay loam, High organic matter, dark brown color. High carbonate content 2 E 0.3-0.6 Light color soil. loamy clay. High carbonate content, less organic matter than upper layer. 3 B >0.6 Silty clay. High carbonate content 4 C >0.9 Gravel and sandy loam.

Source: Integrated agricultural laboratory

d. Water Sources

672. The main water source for irrigation of the designated command area for up to 100 farmers producing mostly potatoes and vegetables from small plots in the Iven Gol irrigation scheme is the Iven Gol River as highlighted in Figure 140. The overall Orkhon River Basin is shown in Figure 149, which highlights the location of the Iven Gol river, a tributary to the Orkhon river, the location of the Iven Gol irrigation scheme within the Orkhon river basin, and the location of the meteorological station on the Orkhon river right bank. The Orkhon river eventually discharges into the Selenge River, and the Orkhon is the primary source of water for the large commercial irrigation schemes in the area around Sant Soum.

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Figure 149: Iven Gol River Basin with Location of Irrigation Scheme, Gauging Station and Meteorological Station

Source: TA consultants based on National Atlas

673. There is no gauging station on the Iven Gol River. During the field visit in June 2019, measurement of the Iven Gol river discharge was undertaken (Figure 150, Table 116), and it was found to be 0.44 m3/sec. The measurement site was located in Sant soum, just upstream of the Iven Gol irrigation scheme dam (now failed). The small river Iven locates in the Orkhon river basin and originates from Dalkh south-east slope of Dalkh mountain at elevation of 1550 m. Catchment area at measurement site is 865.6 km2 with river length of 57.1 km.

Figure 150: Iven Gol River Flow Control Measurement

Source: TA consultants’ field survey

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Table 116: Control Discharge Measurement, Iven Gol River (2019.06.11) River Coordinates H F B V h Q Remarks Location m m2 m m/sec m m3/sec Iven Gol 49o 16’ 15.7” Water is clear, no smell, no Sant 105o 16’ 789 1.48 5.20 0.15 0.28 0.23 odor, Soum 49.3” pH=8.8 EC-124 μS/m Source: TA consultants

674. To estimate the relationship between basin mean elevation and specific run-off (M=f(H)), reference is made to the equations derived for the Orkhon river basin.38 The annual runoff distribution has been estimated in accordance with the Orkhon river basin reference ratios for monthly percentage of the annual runoff. The estimation shows that the mean annual spatially related runoff for the Iven Gol river is about 0.62 l/sec km2, or when expressed in terms of discharge, 0.54 m3/sec.

Table 117 provides data on the estimated monthly mean flow on the basis of reference data for the Orkhon River, and results in runoff values from 0.74 m3/s to 1.18 m3/s during the growing season.

Table 117: Water Resources in Iven Gol River for Iven Gol Subproject Area Environmental Net Water Mean Discharge % of Annual Month flow available (m3/s) Discharge (m3/s) (m3/s) April 0.60 0.49 8.27 0.11 May 0.90 0.49 8.88 0.41 June 0.92 0.49 11.60 0.43 July 1.11 0.49 17.80 0.62 August 1.18 0.49 19.71 0.69 September 0.98 0.49 17.23 0.49 October 0.55 0.49 11.52 - November 0.17 0.49 2.65 - December 0.02 0.49 0.37 - January 0.02 0.49 0.33 - February 0.02 0.49 0.25 - March 0.09 0.49 1.46 - a Derived with reference to the available data for flow estimation in the overall inclusive Orkhon River Basin Source: TA consultants

675. Water quality. As there is no hydrological gauging station, water quality of flow in Iven Gol river is unmonitored. During the field visit, the Iven Gol river water was visually inspected, and measurements confirmed the pH was 7.1, which is within acceptable standard,39 and the electrical conductivity was measured as 124 μS/m, which again falls with acceptable limits for irrigation water.

676. Impact on ground water quality. During the field visit, a survey of the local community members showed that the water level in 60% of local boreholes is 40 m below ground level. On this basis, there is unlikely to be any negative impact on ground water from crop/land irrigation.

38 MET, 2015, Surface water regime and water resource of Mongolia, [Editor G.Davaa]. Ulaanbaatar. P. 39 MNS-irrigation schemeO-16075: Project development for irrigation.

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e. Existing Irrigation System and Design Maps

677. The original Iven Gol irrigation scheme was a natural gravity supplied surface irrigation system, for mixed cropping (mostly potatoes, vegetables and some small fruit areas). Subsequent to the development of Iven Gol in the 1970’s, there was a failure of the main storage dam (early 1990’s), and an amended solution was developed that fed the main northern canal from a location off the river, about 1.75 km from the dam (direct) or about 2.1 km by the river path. The current intake for the northern canal relies on run of river, with no means to control water level at the intake. Additionally, there is a large neighboring command area, mostly on the south side of the river, which includes a major pumping station from the Orkhon river to support multiple irrigation machines (center pivots, lateral moves). It is not clear exactly how much area is under command at present, but whilst earlier designs suggest it should include the 6 pivot area to the east of sant soum, this area has not benefited from pumped water, nor does it receive water from the Iven Gol left bank (northside) canal. Due to flow limits from the Iven Gol catchment, there is barely enough water in summer months to support the roughly 200 plus hectares being cultivated by about 100 farmers from the west towards Sant soum center, on the north side of the Iven Gol river. If effective reliable irrigation is to be supplied to the farmers in Iven Gol (with up to 250 ha), then more reliable water supply is required in summer months.

678. The main canal used to be supplied directly from the failed dam. There is more than enough hydraulic head to push water under gravity to the far eastern part of the northern canal, that follows the contours of the foothills, passes to the north of Sant Soum, and ceases to flow much further with current water available, and the low surface irrigation water use efficiencies. The existing main/ distributary canal alignment is relatively straight and could be realigned in several sections to reduce the overall length. The canal, when full, feeds various open canals/field ditches to help get water down the sloped from the canal to the various cultivated blocks. The main canal, developed to follow the contour, starts at approx. 765 masl (canal diversion of river) and ends about 5.6 km later at level 753 masl. The canal needs to be lined to improve hydraulic efficiency and minimize water loss. It could and should potentially be realigned with fewer sharp bends, even if that requires some additional cut and fill sections (balanced). Currently, the main canal that becomes a distributary along the north side of the command area, is an unregulated rough earthen channel, which gradually disappears east of Sant Soum. Farmers access water from this channel by cutting unregulated outlets to run water in local field ditches to their plots. Whilst it is clear many plots are cultivated, by up to 100 farmers, the exact area reliably covered each year, and thus productive is not known.

679. The command area extends down the slope from the main/distributary canal in a north to south direction ending close to the meandering Iven Gol river through the valley (Figure 151). Plots closer to the river appear to be more regularly cultivated, and this is because when necessary, farmers can probably access limited water with small pumps to water their crops. This could be necessary as there is also some other land, close to the river further upstream, that is reliant on water withdrawn from the main canal. It is likely this may continue in the future, so the upgraded main canal is sized to allow for this ‘risk’. It will be up to the Soum managers of the irrigation scheme to implement appropriate measures to either manage or curtail this practice.

680. Within the irrigation scheme command area, despite any earlier plans, it appears there is currently no mechanized irrigation (sprinkler or drip) being used to make water use more efficient. The area, and the farmers collectively, will benefit from using more precise irrigation methods, rather than surface irrigation, to making better use of their land with scarce and uncertain water supply.

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Figure 151: Concept Plan to Upgrade Iven Gol Irrigation Scheme at Sant Soum

Source: TA consultants based on Google Map

2. Irrigation Water Requirement

681. The designed command area (Table 118) is up to 240 ha with the planned windbreak, with 126 ha for potatoes, 114 ha for vegetables, and around 5.9 ha for tree windbreaks to the north and east. The windbreak will include the planting of leafy trees (two rows) and bushes (fruits and nuts mixed in one row) along the northern and eastern boundaries of the command area in accordance with the dominant wind direction data.

Table 118: Current and Planned Command Area Crop type Current Allocation of Irrigation Planned Allocation Irrigation command area method of command area method Potatoes, ha 60 Furrow 126 Drip & sprinkler Vegetables, ha 59.6 114 drip & sprinkler Cereals, ha Fodder, ha Fruit trees and wind drip 5.9 break, ha Source: TA Consultant and field survey

682. Overall efficiency (Table 119) will be improved up to 78%, by lining canals, managing the water supply with balancing storage, and adopting modern irrigation equipment (sprinkler systems, drip systems, spray/drip for any new greenhouses) to grow a mix of potatoes and vegetables, plus sustain the development of a windbreak, for a total of 246 ha, as outlined in Table 119.

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Table 119: Irrigation Efficiency Characteristics Field Application Percent of Conveyance Field Scheme Command Efficiency Application Irrigation Area (%) Efficiency Efficiency (%) (%) Existing Surface Surface irrigation 100.0 60 60 36 Irrigation (border, furrow, basin) Planned Potatoes and Vegetables, 120 Sprinkler 51.0 95 75 71 ha Planned Potatoes, Vegetables and Drip 49.0 95 90 86 Windbreak, 126 ha Average for Combined sprinkler 100.0 95 83 78 Command Area and drip Source: TA consultants

683. If the full project was working, then the total water requirement for the planned cropping would be 1,796,286 m3 (0.136 m3/s) with project and 1,824,770 m3 (0.138 m3/s) with climate overall water use efficiency of 78 percent by using modern controllable linear move or towable sprinkler irrigation machines, and multiple low-pressure drip systems, dispersed throughout the command area to best meet the farmer and crop requirements. This total irrigation water requirement is 25.3 percent of the net available water in the river in the growing season or is 6.32 -41.7 percent of the given monthly flow in the Iven Gol river.

684. Initially, the Iven Gol irrigation scheme was designed with a large dam and water reservoir to regulate river flows and allow releases to meet irrigation water requirements, but no data is available to confirm the original storage volume for this reservoir. However, the study results show that even without the reservoir, there is sufficient water available from the Iven River to irrigate 245 ha, if an overall system water use efficiency of 78% can be secured in the with-project scenario (Table 121).

Table 120: Irrigation Water Requirements for Iven Gol Irrigation Period Item Total May June July August September Command Area Cropping Plan Potatoes (ha) 126 126 126 126 126 Vegetables (ha) 114 114 114 114 114 Cereals (ha) 0 0 0 0 0 Fodder (ha) 0 0 0 0 0 Fruit Trees and Windbreak (ha) 5.9 5.9 5.9 5.9 5.9 246 Water Requirement With-project Gross irrigation norm (m3) 288,673 362,966 353,840 269,344 126,279 Irrigation Efficiency (%) 0.78 0.78 0.78 0.78 0.78 Total Water Requirement (m3) 370,093 465,341 453,641 345,313 161,896 1,796,286 Water Requirement With-project and Climate Change Increase in ET (m3) 706 5,391 8,101 10,440 2,971 Projected irrigation water (m3) 289,379 362,966 361,941 279,785 129,250 Irrigation Efficiency (%) 0.78 0.78 0.78 0.78 0.78 Projected total Water Requirement (m3) 370,999 465,341 464,027 358,698 165,705 1,824,770 Source: TA consultants

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Table 121: Water Availability for Irrigation Percentage of Projected total irrigation Monthly Environ- irrigation water water use Irrigation River ment Net available flow in requirement with from net river period Discharge, Flow, the river project flow m3/s m3/s m3/s m3/month m3/s m3/month % May 0.90 0.49 0.41 1,093,821 0.14 370,999 33.7 June 0.92 0.49 0.43 1,147,962 0.18 465,341 41.7 July 1.11 0.49 0.62 1,669,562 0.17 464,027 27.0 August 1.18 0.49 0.69 1,848,292 0.13 358,698 18.6 September 0.98 0.49 0.49 1,317,140 0.06 165,705 6.32 Total 7,076,778 1,824,770 25.3 Source: Consultant’s estimates

3. System and Layout

a. Area Topography

685. The Iven Gol command area is a long narrow area on an east-west alignment. The Iven Gol catchment (865.6 km2) lies to the west northwest, and the main canal runs from west to east, falling from about 765 m to 752 masl. Actual numbers will need to be checked and verified with detail site survey prior to detail design, but there appears to be sufficient land fall and land level variance to support incorporating a gravity flow interception, diversion and storage arrangement at the head of the main canal, prior to feeding the distributary system from the northern elevated side of the Iven Gol valley, as shown in Figure 152.

Figure 152: Proposed Iven Gol Command Area (240 ha) and Upgrading Infrastructure

Source: TA consultants based on Google Map

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b. Overall System

686. The existing and planned upgrade and modernization of the Iven Gol irrigation scheme has the following key components which make effective use of the topography and opportunity to deliver and manage water under gravity to feed the in-field sprinkler and drip irrigation systems. Figure 153 shows the general arrangement for the key headworks to balancing storage.

Figure 153: General Headworks Arrangement for Iven Gol Irrigation Scheme

Source: TA consultants based on Google Map

687. Water Intake and Barrier Wall. The existing water intake relies on being able to draw water from the river flow on the outside of a bend, with no pool formation in the river. The river is meandering within the shallow valley so does not have a particularly stable channel and can change direction/path under large flows. There is no river barrier (permanent or temporary) that helps form a stable pool in the river, so the reliability of inflow during very low flow periods will be uncertain. It is therefore proposed that a permanent barrier wall (up to 300 m long with maximum height of 3.5 m) be built, sufficient to keep a 1m head in the pool over the intake and 2 m plus depth relative to the riverbed. The main section of the barrier across the river, with a central spill weir, would be set at 2 to 2.5 m above the riverbed level, subject to what is possible in the location and constraints of the environment (detail survey is needed of possible sites). The barrier wall would incorporate the main canal intake on the left bank of the river, and provide an in-built sluicing facility for sediment exclusion, with sediment flow returned to the river downstream of the barrier.

688. Main Canal. The existing main canal is an earth channel, following closely to the riverbank for about 400 m before turning northeast to run along the top side of the command area. There is no official command area in the first 0.5 km, though there are small cultivated areas between the canal and the river. It is not clear if they access water from the canal or otherwise pump water from the river – possibly both as necessary. The main command area starts west of Sant Soum and is almost wholly within the area between the existing main canal alignment and the Iven Gol river leading to the Soum center. The formed strip of land varies in width from about 200 m up to as much as 915 m, over a distance of 4.23 km, for a net command area of about 240 ha. This land slopes generally from north to south, starting from the main/distributary canal to end at the Iven Gol river.

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689. The initial section of the upgraded main canal would be new, lined and evenly graded (1 in 600) with a flow capacity up to 0.80 m3/s to take water from the river when in high flow to a planned new balancing storage (est. 100,000 m3) installed on the existing canal alignment just upstream of the command area. This flow rate is about 30% higher than the peak command area requirement, but will then enable capture of substantive water volume, net of environmental flow allocation, when the Iven Gol river has periodic peak (flood) flows. As flow in the Iven Gol river can be highly variable, and low flows are insufficient to meet irrigation water demand during summer months, a balancing storage is needed to hold captured water for later steady release for irrigation. With careful detailed planning, this should enable more reliable water supply to efficient sprinkler and drip irrigation systems installed throughout the command area.

690. Balancing Storage. Balancing storage is proposed to be located about 0.52 km downstream of the new Iven Gol river intake. The storage will be built along part of the existing main canal alignment, cut into the hillside (north) with full supply water level of up to 766 masl (equal to river pool HWL), and a bank height 0.75 to 1 m higher at up to 767 masl. Detailed survey is needed of the proposed site to assess what would be viable with a cut/fill balance for the storage formation. The storage invert level will be about 763 masl, and the start of the distributary canal invert level will be about 764 masl, giving about 2 m of active storage. A storage that is 250 m long by 200m wide by 2 m deep (to dead water level) gives an effective capacity of 100,000 m3. This storage will be safeguarded by having either a bellmouth intake spillway or an overspill weir, whichever is most cost effective, and will discharge from the southwest corner through a short secure drain back to the river. Under normal operations, this spillway should hardly ever be activated, but as the storage will have a high embankment on the southern side (up to 5 m high), adequate protection must be provided to safely manage any excess inflow. The storage embankment slopes should be 2:1 on the inside of the storage and 2.5:1 on the external face. The northern bank will be, after being cut back into the hillside, natural ground. Care will be needed to make sure there is minimal if any risk for a seepage (piping) failure through the constructed bank. If necessary, appropriate soil treatment should be used to ensure reduced permeability and scour resistance.

691. Irrigation Area Offtakes from Canals. the natural terrain of the command area has an average grade of from 1 in 100 in the west to 1 in 50 in the east. The grade is steeper closer to the main/distributary canal and becomes flatter closer to the river. This makes the release of water from the canal into field channels difficult, with the risk for high flow velocity and scour. The canal will, when upgraded, include defined offtake points (up to 15 or one about every 300 m), consisting of permanent gated structures. It is proposed that these will release water into pipes to take water to each of the planned sub-area irrigation systems (sprinkler lateral move or pivot or roll up drip systems. These systems will be strategically located in agreement with the farmer groups (or WUAs) to best service individual blocks of land (from 5 to 20 ha for drip; up to 40 ha for sprinkler). The specific details of how this is to be arranged, and confirming whether these systems, complete with water filtration, can operate under available gravity head from the canal, has to be assessed at detail design. In some cases, pumping will be required, in which case power supply to the system control head/pumps and filters will need to be arranged. At this stage, it is assumed that the sprinkler irrigation system (3 units) will require pumping – whether by suction from a contour based open canal – or with roll out hose from strategically positioned hydrants. The drip systems will utilize gravity head if sufficient and this will negate pumping but where pumping is needed, then a power supply will need to be installed (assume initially for 50% of the estimated 11 sub schemes with 1 of 20 ha, 3 of 15 ha, 3 of 10 ha and 4 of 5 ha, totaling 114 ha). The flow details for canals and pipes, to the extent these can currently be provided, are shown in Table 122.

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Table 122: Flow and Details for Gravity Lined Canals Canals Length Static Bedwidth Depth of Discharge Lining Gradient (m) Head (m) (m) Flow m3/s 1 in (m) Main 520 up to 3 0.8 0.331 0.80 Concrete 600 Distributary 4,880 up to 13 0.5 0.327 0.60 Concrete 1,000 Pressure tbd. max up to Diam Pipes to 11 PN4 a 12 m tbd sub-schemes a PN X means 10 times X m maximum head. In most cases the estimated dynamic head loss is compensated for through the physical drop in level along the pipe. In the case of drip and sprinkler pressure pipe supply off the main/distributary, control valve may be required to set the safe operating pressure for the irrigation system, though this valve would be most likely at the control station inlet, together with a drain/scour valve for clearing any settled sediment and draining the pipes. Source: TA consultants

692. Pressure Pipes. Pressure pipes will be needed to take water from defined offtakes on the main/distributary canal to each of the sprinkler/drip system control stations. All other required pipes will be part of the sprinkler and/or drip equipment packages, provided and managed by the soum, in conjunction with the farmer groups/WUAs. In the existing irrigation system, there are 20 plus indicated offtake points from the main canal. For the indicated breakdown of irrigation subsystems, the maximum required would be 15, suitably located (about 300 m spacing) of the upgraded main and distributary canal to supply by the most direct route to each of the proposed irrigation subsystems (3 sprinkler, 10 to 12 drip systems). This number of offtakes might also be consolidated further if an offtake could serve 2 or more of the smaller subsystems through connecting pipes, thereby enabling larger pipes to be adopted with less overall head loss within the pipes. The specifics of how best to arrange this should be resolved at detail design.

693. Drip Systems. The scheme will have several small area drip systems (up to 12), to service potatoes (up to 20 ha per system), vegetable (up to 10 ha per system) and windbreaks (a total of about 5 ha along the northern side of the main/distributary). Some of the vegetable drip systems may also provide supply to any included greenhouse sub-areas, whether as drip, spray or other forms of high intensity vegetable cropping (e.g. hydroponics for lettuce, strawberries or other specialist crops, subject to farmer interest).

694. Sprinkler Irrigation. Three lateral move systems are proposed to irrigate up to 126 ha of mostly potatoes and some vegetables, most likely at the western end of the command area but not necessarily in contiguous blocks. The areas will run up and down the slope between the distributary canal and the river. The choice for irrigation lies between lateral move irrigators, operating on a shuttle path (back and forth), with either strategic hydrant connections for roll up hose, or else with reel hose type winched machines. In all cases, the machines will need to be equipped with power source and pumps, to both drive the machine and pressure the system for uniform distribution. For 40 ha blocks, it should be feasible to operate with one unit, but this should be resolved at detailed design. If the blocks are about 700 m long then the 40 ha would involve a strip about 570 m wide, which could be irrigated over 10 days (25 mm depth) at 60 m strips, one per day. The actual performance characteristics and operating schedules would be confirmed by the equipment suppliers, and irrigable areas can then be selected that work best within those criteria and limitations.

695. Lateral move irrigators require of the order of 20-30 m head at the command area, with a preference towards the lower pressure. Some of that pressure will be available at the supply hydrants, which will then reduce power supply requirements. Whilst it is possible to use electrical power with moving irrigators, this is not so easy or reliable with lateral move or winch tow hose reel

262 irrigators, as the cabling has also to be dragged and rewound by the machine from the hydrant and power point. It is therefore likely these 3 units may need to be equipped with their own small engine and generator set, to drive pumps and reel winch.

c. Irrigation Scheme Layout

696. Sprinkler Systems. The Iven Gol irrigation scheme will have a low pressure piped supply from the main canal to up to 3 sprinkler lateral move or towed systems, each for a command area block of 40 ha. Within the confines of the Iven Gol boundaries, this can be achieved within each block by three strips 700 m long by 200 m wide, or with two strips 700 m long by 300 m wide. The actual configuration to be adopted will need to be confirmed before finalizing the field pipeline alignment and hydrants position (for hose connection). The alternative to the lateral move could be one or more towable boom spray/raingun machines, which may be more flexible for the slopes and irregular areas. The exact position, alignment and control of water to the machines, and their general operational cycles will need to be defined before the required flow and application rates for the unit(s) can be confirmed. Whilst a lateral move machine can cover a wider pass per cycle, it is best suited to longer runs using a level open canal (sump) for water access, or else a sequence of spaced hydrants with a reel hose. By definition, the requirements for this canal mean that the lateral move irrigator would have to travel across rather than up and down the slope. With hydrants and reel hose it could go either way. If smaller towable boom spray and raingun machines are used, then the hydrants can be set centrally to the area and the machines can run out either side of the central water supply pipe and hydrants. In this case, the optimal travel direction is up and down the slope, with winch pull for multiple positions across the slope. Ownership and operation of the lateral move (or equivalent) sprinkler irrigator will have to be agreed between Soum government and farmer groups/WUAs.

697. Drip Systems. It is not possible to be specific about how the drip systems will be laid out. Discussions will need to be held with farmers to first define farmer group or WUA blocks for irrigation, and whether they are generally intending to grow potatoes or vegetables, on a regular basis. This may then define row crop spacing and alignment with specific guidance on where to place the drip system filter/pump/control unit and system main header pipe. Lateral pipes would be connected to the header pipe and rolled out along the rows once the crops are planted. These schemes may also include, if required, one or more greenhouses for some farmers to grow more specialist vegetables and/or fruit. Any such requirement needs to be discussed with farmer groups, and if there is interest, relevant system inclusions can be made to enable water supply to greenhouses, and the internal water distribution/application method.

698. A key aspect for selecting hydrant and/or system control station location will be the access to power (assumed to be electricity). Whilst each farmer group/WUA, once established, will operate over a contiguous block, the actual size of the blocks will vary. Therefore, until the block size and layout are known, the particular details of a drip system area and layout cannot be fixed. It is however presumed that once the position for the filter/pump/control unit is agreed, then the appropriately sized pipelines can be installed from the main/distributary canal, with maximal use of the natural head difference from canal to system control station location. Whilst the soum will supply the equipment, it is expected that once installed, the farmers would operate and support the costs for their own drip system.

699. The other remaining drip system will be a small unit to support windbreak development from seedlings to maturity. This will need to be located at the upstream end of the windbreak (near the balancing storage), supported if needed by a pump and power to ensure the full windbreak line can

263 be watered effectively on rotation. The detailed layout can be prepared at detailed design, but it is assumed that installing fruit and/or nut bearing bushes will provide some return for this investment.

700. Figure 154 shows the overall layout of the upgraded Iven Gol irrigation scheme. The command area is protected by formed banks located on the downstream side of drains, which run on the high side of the command area to intercept overland runoff and carry this water around and/or away from the command area. If at the detail design it is assessed that there is some advantage to incorporate the windbreak with the drain, thereby entrapping runoff to sustain the trees, then this will need to be more fully assessed and detailed prior to construction. An outline for the installation of windbreak, drains and protection banks is given in Annex 1.

Figure 154: Plan of Proposed Upgraded Iven Gol Irrigation Scheme

Source: TA consultants based on Google Map

701. Drainage. Drainage will be needed to protect the area against the risks of large overland flows, coming from the north and west. The main and distributary canal presents a barrier to the free passage of overland flow, and a safe way to convey any runoff around or under/over the main/distributary canal is required, linked together with a protection bank and the windbreak. If water is to pass through the command area, then a suitable drain alignment should be identified, with drains formed to safely pass the runoff between the irrigated land. Such drains should not interrupt the movement of the lateral move or towed irrigation machines in the specified command area blocks.

702. It may also be necessary to protect any exposed infrastructure – pipes, canals, cropped area, windbreaks, roads and associated structures – from the uncontrolled risk for erosion from overland flow or any infrastructure failure. The main form of protection would be pushed up earth banks suitably position and shaped to deflect any runoff around the key infrastructure and cropped area. The only structures specifically foreseen to protect infrastructure from runoff risks are: (i) Rock protection in the bed and sides of drains in proximity to crossing installed canals or pipelines where the drain flows south to the river; and (ii) Possible installation of short piped sections in the upper reaches of the main canal (various locations and lengths) to facilitate, with flow management banks, the safe passage of runoff flows from the upland areas across the line of the main canal, and thereby mitigate the risk for disruption of diverted water from the Iven Gol river.

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4. Design Discharge

703. The average potential discharge flow in the river can vary through the growing months from 0.41 to 0.98 m3/s, but these are average and do not allow for periods of low flow, which have been observed as close to zero. The average flows range from 17.2 to 19.7% of the net river flow (Table 123) in the without-project situation, but if irrigation water use efficiency is improved to 77%, then water extracted from the river will range from 8.1 to 24.7% of the available average flow. This then gives much improved flexibility, through use of a balancing storage, to manage the variable river flows whilst still providing the steadier flow required for irrigation.

Table 123: Available Water Discharge from the Iven Gol River Irrigation Net Off-river Irrigation Water from Design Discharge for Main Water period Average Balancing river Supply Infrastructure a Available Storage With Project’ m3/s Water in (provisional) Main Distributary Distributary River (m3) Min Canal Canal Pressure Pipes (m3/s) (m3/s) % (m3/s) (m3/s) (m3/s) May 0.41 100,000 0.18 19.5 0.80 0.60 up to 0.10 June 0.43 100,000 0.23 24.7 0.80 0.60 up to 0.10 July 0.62 100,000 0.21 19.3 0.80 0.60 up to 0.10 August 0.69 100,000 0.16 13.8 0.80 0.60 up to 0.10 September 0.98 100,000 0.08 8.1 0.80 0.60 up to 0.10 a Design discharge capacity does not mean that this flow is taken all the time or at the maximum rate. Source: TA consultants

704. The average available water flow in the river can vary through the growing months from 0.41 to 0.98 m3/s, but in dry periods, the average low water flow can be close to zero.40 On average, with an improved irrigation system, total water extracted from the river will be about 50% less than what is currently needed for the ‘without project’ situation. The peak flow required for crops during the growing season is assessed at 0.60 m3/s with an overall water use efficiency of 77%. The peak flow in the main canal, feeding the balancing storage would be 30% higher at 0.80 m3/s.

705. Because the low flow condition is substantially below the average gross flow required in the canal, then to minimize risk to crops during such periods, a balancing storage is proposed to manage and balance flows within the irrigation system. It is proposed that a small buffer storage will be created at the main canal intake by construction of a cross river barrier wall. This will always ensure the capacity to divert water, as the pool level in the river will remain steady, provided there is some flow in the river with overspill for the environment. Within the canal system, between the main canal and the distributary canal, it is proposed to install a larger (up to 100,000 m3) balancing storage, that will provide the substantive buffer for water supply to the crops, even when river flows are low for extended periods. Whilst the mean average flow values indicate the water taken for irrigation will range from 8.10 to 24.7 percent of the net river flow (Table 140) through the crop growth period, there will be times when natural river flow is below the actual required irrigation water demand. With the improved project and improved water use efficiency of 77%, it will still be necessary to have reserve water in storage to enable irrigation to continue uninterrupted during dry periods/years. With the storage, water can be diverted from the river when it is plentiful, to be held in storage for gradual release to the crops when the available main canal inflow is too low to meet full irrigation water demand.

40 Anecdotal information from field investigations.

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706. To enable the full water requirement to be supplied, the main canal will need additional capacity to transfer water from the river when it is available, over and above matching the irrigation water demand at that time. It is therefore proposed, that with the balancing storage in place, the main canal conveyance capacity be 30% larger than the peak irrigation demand flow requirement, so that additional flow can be used to fill and/or replenish the storage. Therefore, design should allow for the main canal conveyance to be up to 0.80 m3/s. In the distributary canal, the peak capacity is set at 0.60 m3/s, for up to 245 ha. On that basis, the pipe and/or canal needed to supply the sprinkler system (126 ha) would have a flow capacity of 0.31 m3/s. However, it is expected that the sprinkler irrigated areas would be about 40 ha, and a peak flow requirement of 0.10 m3/s would be required in each individual sprinkler irrigated area. Pipelines to supply the drip areas would need up to a peak of 0.05 m3/s. These provisional estimates should be checked and revised at detailed design, in accordance with how the final design is organized and operated, to best provide supply for the differing crops and systems operating in parallel.

5. Civil Works

707. The main civil works for the diversion headworks from the Iven Gol River, and conveyance of water to irrigation sprinkler/drip systems in the command area will include: (i) construction of a (up to 3.5 m high, u/s slope 2:1; d/s slope 2.5:1, top level at 767 masl and top width 2 m) rockfill barrier wall (with impermeable core) up to 300 m across the Iven Gol River channel, incorporating the intake structure, between natural abutments (north and south), at or close to the location of the existing intake, actual length, height and alignment to be confirmed at detailed design stage; (ii) incorporation of a reduced level (- 1.0 m) reinforced concrete spillway section, up to 10 m wide, to control pool water level upstream, and pass moderate excess flows back to the main river, over a concrete armored spillway, before any possibility for flow over the rockface of the barrier wall, final details to be assessed and confirmed at detail design; (iii) construction of a new intake structure (to indicative design) in the barrier wall at the location of the existing intake and main canal, including a vertical screw lift sluice gate, with free release of the flow (up to 0.80 m3/s) into the new, graded (1 in 600) lined main canal; (iv) construction of a sediment sluicing channel in the box section of the new intake structure, with a sluice gate (0.75 x 0.40 m) to the right side of the intake structure, for periodic sediment sluicing; base of sediment collection chamber to be formed for effective guidance of sediment under flow toward sluice outlet; (v) construction as necessary (cutting, forming, shaping and protection) of a channel to carry sediment back toward the river on the downstream side of the barrier wall, away from the toe of the embankment; (vi) cutting and formation of an extended Soum road up to the barrier wall left abutment and main canal intake structure; (vii) as the barrier wall will form a shallow pool (up to 2.5 m deep), the ponded area will need to be cleared of vegetation and possible low saddles around the pool may need to be raised to mitigate any risk for overspill around the barrier wall; (viii) construction and lining of a new trapezoidal section main canal to balancing storage (about 520 m, subject to actual start and finish location); it is suggested piped sections may need to be included for runoff overspill, including inlet and outlet transition structures, where there is risk for concentrated runoff to and across the canal line; inclusive of any necessary water guidance and protection earth embankment; canal depth 0.65 m, bed width 0.8 m, sideslope 1.5:1 and water depth 0.33 m;

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(ix) construction of a controlled main canal discharge structure (capacity 0.80 m3/s, canal invert level 764 masl) into the balancing storage (western end) to steady inflow velocity from the main canal, and to minimize scour around the toe of this structure within the balancing storage when water level in the storage is low; the main canal inflow bed level should be set close to the full storage level in the storage to minimize backup of flow in the main canal [though it can be partially submerged without issue provided there is no risk for overtopping the canal banks (freeboard minimum 0.3 m at full discharge)]; (x) construction of an outlet from the balancing storage to the distributary canal including a gated outlet to the distributary canal (Q = 0.60 m3/s) to be designed at detailed design stage; (xi) up to 15 field distributary pressure pipelines (various lengths and diameters to be determined at detailed design, up to PN 4) to be installed, to supply either open canal (sump) for sprinkler systems or to the distributed drip irrigation control stations (intake, filter, pressure and control stations (up to 12 No.)); (xii) reforming or building new U-shaped earth drains (up to 8 km, 1 m bed width, 3:1 side slope) to protect the canals and command area, and enable clear drainage of rainfall runoff and any canal overspills; (xiii) installation of various flow control and outlet structures in the main and distributary canals, with outlet to pipes (up to 15 No., maximum capacity 0.10 m3/s); (xiv) development of the windbreaks (up to 5 km) on the north side of the command area; and (xv) installation of a protective fence around the command area (about 15 km) with posts at 5 m and four strands of wire

708. At this stage, design and related details are preliminary, and as detail design and operational requirements are clarified, some additional works may be identified (e.g. additional protection measures for pipes, construction of field covered and protected valve boxes, minor earth checks in drains to support windbreaks).

6. Equipment

709. Within the civil works, required equipment will be limited to gates, pressure pipes (HDPE) and associated fittings to the sprinkler system connection hydrants. The following specific equipment, some of which was mentioned for installation with civil works are: (i) Water intake – one vertical lift sluice gate with preliminary 1.5 m wide and a 0.75 m lift, with capacity up to 1 m3/s; (ii) Intake sediment sluice – vertical lift sluice gate, provisionally 0.75 m wide with 0.4 m opening, sufficient to flush rapidly at up to 1 m3/s, details to be finalized around operational and physical levels at site; (iii) Provision for overland flow crossing points in the main canal, using either low pressure pipe sections (up to 3 no., up to 5 m long) and/or box culvert section (one) giving at least a 0.75 m2 free flow section (depth of flow 0.35 m), each up to 6 m long, at required locations to pass the canal under formed drainage overpass, sizes to be confirmed at detail design; (iv) Provision and installation, as may be required, of various gates, valves and fittings to regulate flow from canal to irrigation subsystem (Table 124); (v) Three self-propelled lateral move sprinkler sets or equivalent winch tow hose reel spray boom units, up to 200 m spray width, double sided with flexible hose reel connection to installed field hydrants (200 mm diam, up to 300 m centers) to track up and down the line of the buried field distributary pipe(s), all inclusive of power

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supply, flow controls, and associated spare parts, spray nozzles and drop pipes suitable for particular crops, all details to be discussed with potential suppliers before confirming detailed specifications (specifics of lateral drive to be discussed and agreed based on local electricity power available, and the operational convenience of available options; (vi) Up to 12 low pressure drip filtration, pump and control stations, with sufficient associated main and connecting drip pipes, for up to 120 ha (vegetable areas, greenhouses and windbreak); (vii) Provisionally, one or more sets of low-pressure micro-spray and/or drip systems for installation in greenhouses (size and number to be determined), should the option to develop such facilities at the eastern end of the header canal be approved; (viii) Relevant power supply infrastructure, whether connection to main national or local electricity grid, inclusion of diesel power and generator sets, or provision of diesel power to drive irrigation systems (pumps, self-propulsion, etc.) [there is an expectation that adopted sprinkler equipment would include suitable on-board power controls and drive mechanisms if electric power supply and cabling is not viable].

Table 124: List of Various Gates, Valves and Fittings Pipe Intake Gate Outlet Sediment Sluice Gate Filter Set a Emitters b or Valve Valve or Scour Valve Main 2 3 1 with drip Distributary 15 15 15 with drip Drip Systems (x 12) 1 x 50mm in the pipe end 1 x inline inline Sprinkler System 3 3 3 3 online a Inline filter sets process all flow, and include provisions with their installation for local flow management (valves) to use the line pressure for backwashing the filters, Specific details and arrangements to be discussed with suppliers. b These are pressure compensating steady flow rate emitters installed in the rollout drip lines during manufacture at specified intervals as required. Source: TA consultants based on Google Map

7. Bill of Quantities

710. The cost estimation for Iven Gol irrigation scheme construction and equipment (Table 125) summarizes the cost for key components required for the upgrading and modernization. The estimated cost is MNT4,815.82 million, equivalent to MNT20.07 million/ha.

Table 125: Bill of Quantities for Iven Gol Irrigation Scheme Modernization Budget No Item Unit Quantity (MNT million) Unit cost Total Civil Works Headworks Sluicing structure with intake sluice 1 piece 1 72.68 72.68 channel and outlet flushing channel Rockfill Barrier and Water level Control Weir, Wall 2 m 40 2.87 115.00 L=40 m, h=2.75 m, Weir L= 13 m, h=1.0 m 3 Headworks protection embankment m 500 0.04 18.48 4 Main Canal m 520.0 0.13 69.24 5 Main pressure pipe m 4,310.0 0.07 301.70 6 Distribution pressure pipe m 4,740 0.13 616.20 7 Drain well m 1,000 0.004 4.41 8 Balancing storage m2 50,000 0.02 1,000.00 9 Roads – forming and grading m 12,700 0.003 41.53 10 Windbreaks – prepare land and install ha 5.9 42.27 249.39 11 Drain and protection bank m 5,900 0.03 187.99 12 Fence km 6.9 7.00 48.58

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Budget No Item Unit Quantity (MNT million) Unit cost Total Subtotal 2,725.19 Equipment Head work Control Sluice Gate, Width 1.0 m x Height 13 piece 2 1.68 3.36 0.6 m, vertical screw 14 PE400, SDR17, 1,0mpa, DN400mm, PN10 piece 60 1.05 62.77 15 PE400, SDR17, 1,0mpa, DN250mm, PN11 m 4,310 0.08 343.87 16 Self-propelled lateral move sprinkler set 3 77.16 231.49 17 5ha Water Efficient Drip Watering Advanced System set 8 43.47 347.80 10ha Water Efficient Drip Watering Advanced 18 set 4 79.00 316.00 System 19 Trees number 17700 0.00 70.80 20 Excavator for O&M piece 1 168.60 168.60 Subtotal 1,544.70 21 VAT % 30.91 426.99 22 Environmental baseline assessment number 1 42.67 42.67 23 Environmental impact assessment number 1 42.67 42.67 24 Design cost ha 240 0.14 33.60 Sub-Total 545.93 Grand total 4,815.82 Source: Consultant’s estimates

L. Subproject 13 – Okhindiin Tal Irrigation and Drainage System Design

1. Site Description

a. Scheme Background

711. The Zuunburen Soum owns the Okhindiin Tal irrigation scheme, which is located to the north-east of soum capital at about 10-13 km. (Figure 155). The subproject area is a virgin land area and herder’s summer camp area with the potential for growing vegetables for small-scale farm households.

712. The district has a total area of 15,000 ha to 20,000 ha and has selected 3,000 ha for undertaking a feasibility studies for irrigated crop production. The area was selected following consultation with MOFALI and local authorities.

Figure 155: Location of Okhindiin Tal Irrigation Scheme

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b. Area and Crop Maps

713. Geomorphology: Okhindiin Tal subproject area is located on the west bank of the Selenge river and 8-10 km from the south west side of the Sukhbaamar city in Ohindoi valley (east bank side of the Orkhon river). The elevation is 610-620 masl.

714. Currently a small area of 1-2 hectares of land is planted by households for the production of potatoes, vegetables and watermelon.

715. Figure 156 illustrates that the area for implementation of the field survey work is mainly used for pasture

Figure 156. Field Survey Work for Okhindiin Tal Subproject Area

Source: Survey team’s fieldwork

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c. Climate

716. The 53 years (1966-2018) time series of monthly mean air temperature, wind speed and monthly precipitation data observed at Sukhbaatar meteorological station has been analyzed. The climate of this area is characterized by influences between Khentii branch mountains of Buren and Buteel mountains along the valley of the Orkhon and Selenge rivers, as a continental as any other region of Mongolia.

717. In the Okhindiin tal subproject area, the daily temperatures throughout the growing season may exceed 20oC (daily maximum) between May and August, and humidity is about 48-68%. Precipitation, when water is required for crop production, averages 22 mm in May, 49.6 mm in June, 71.39 mm in July and 73.3 mm in August. Overall annual precipitation is 291.2 mm, with 80% in crop growing season period (June-September) and 63% in July and August. The average annual wind speed is 2.1 m/s and the maximum of wind speed is 24 m/s, with peak wind speeds experienced through the spring months. Mean monthly climate data for the project area is given in Table 126.

Table 126: Mean Monthly Climate Data in the Okhindiin Tal Irrigation Subproject Area Average Absolute Absolute Humidity,% Wind Precipitation, Temperature, Maximum Minimum speed, mm oC Temperature, Temperature, m/s oC oC January -22.9 -18.3 -27.8 74.2 1.4 3.1 February -18.2 -11.4 -24 71.6 1.5 2.4 March -6.6 1.2 -12.8 61.9 2.2 3.1 April 3.9 12.8 -2.2 48 2.9 9.7 May 11.5 20.2 4.4 48.4 3.1 22 June 17.7 26.8 11.6 56.3 2.6 49.6 July 19.9 28.2 14.7 64.1 2.1 71.3 August 17.4 25.3 12 68.6 2.1 73.3 September 10.3 10.3 4.8 65.3 2.1 36 October 1.5 1.5 -3.7 65.1 1.9 11 November -9.9 -9.9 -14.8 71.7 1.7 5.8 December -19.3 -19.3 -24.1 74.6 1.5 3.9 Average 0.4 7.7 -5.2 64.1 2.1 291.2

718. Air temperature. Figure 157shows the trend for change in monthly mean air temperature from April to September. In April, the mean temperature is 3.9oC (lower than 10oC), whilst the minimum can be as low as -2.2oC (Error! Reference source not found.). This means there is i nsufficient warmth to support crop growth, and there is a serious risk for damaging frost to occur. Therefore, no irrigation is undertaken in April.

719. Trends in air temperature: April mean temperature has increased by 3.19oC, May by 1.66oC, June by 2.17oC, July by 2.7oC, August by 2.13oC and September by 1.88oC (Figure 157). On balance, it is reasonable to conclude there has been minimal significant shift in the mean annual growing season temperature, although there are some shifts that could impact crop production. With increased temperatures in months of growing period, some increased irrigation will likely be required.

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Figure 157: Trends of Monthly Air Temperature at Okhindiin Tal Subproject Area

Source: National Agency for Meteorology and Environment Monitoring

720. Duration of hot days. One important climate factor that influences irrigated crop production is that of hot days. Figure 158 shows the number of days per year with a daily average air temperature above 25oC was a maximum of 17 in the extreme drought year of 2002 and was about 6 days on average while air temperature exceeds 30oC only in 3 years.

Figure 158: Trends in Hot Days with Daily Mean Temperature more than 25oC and 30oC

721. Precipitation: Precipitation is most important factor which influences a crop plantation and it can limit an agricultural business in Mongolia. Annual mean precipitation is 291.2 mm and the snow accounts for 15%. About 63% of precipitation falls only in July and August (144.7mm). According to 53 years precipitation record the annual mean precipitation has decreased by 14mm (Figure 159).

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Figure 159: Trend in Annual Mean Precipitation, 1966-2018

722. Although, the decrease in annual mean precipitation the number of days without precipitation in months in June and July is decreasing. (Figure 160).

Figure 160: Trends in Days Without Precipitation

Source: National Agency for Meteorology and Environment Monitoring

723. Wind. The monthly mean wind speed in the growing season is higher than in other months (Table 126). Even though the mean wind speeds for the months of April (2.9 m/s), May (3.1 m/s), June (2.6 m/s), July (2.1 m/s) and August (2.1 m/s) are low, the wind speed can reach 30 m/s. The number of days when wind speed has exceeded 15 m/s has increased by 120 over the last 25 years (Figure 161). Figure 161 also shows that 25% of the wind comes from the north and 19% from the north-west. The wind break should be designed in close discussion with farmers to ensure it is effective.

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Figure 161: Trends in High Winds and Wind Direction

724. Agro-climate. Over the period from 1985 to 2018, the growing season length has increased by about 15 days because of a shift in when the air temperature transitions above 10oC (earlier dates in spring) and falls below 10oC (later dates in autumn). The accumulated temperature that supports longer crop growth with frost free days has also increased, thereby favoring greater crop growth (Figure 162). This may also require increased irrigation.

Figure 162: Agro-climate Characteristics

725. Projections. The summer temperature in the Okhindiin Tal subproject area is projected to increase by 2oC, and 2.25oC by 2035 and 2065, respectively and precipitation is projected to decrease by 10% during the same time period. A continued increase in temperature and a slight decrease in precipitation are considered the most likely combined future impacts, necessitating increased irrigation.

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d. Soils

726. The soil map for Okhindiin tal Irrigation subproject (Figure 163) shows the command area consists of predominantly light Kastanozem with some small areas of Aluvial meadowish soil, suitable for cultivable crops and vegetables/potatoes. Soil was riparian area’s alluvial meadow soil and meadow yellow brown soils dominated. By World Reference Base soil classification is Fluvisol and Meadow swamp alluvial with meadow saline soil. Fluvisol soil is a very young soil with weak horizon differentiation. Brown dark is grey brown to brown.

Figure 163. Okhindiin tal Irrigation Subproject Soil Map

Source: Institute of Geography and Geo-ecology

727. Soils are predominantly dark brown with a high level of organic matter (3.3%). Clay particles have accumulated by river flow in the A horizon. River water has an EC of 131 μS. Each horizon is highly reactive with 10% hydrochloric acid, indicating weak alkaline or near to neutral. Carbonate contents are about 0.3% with secondary carbonate sediment collected to soils. Soil pH=8.4 and EC= 21-199 μS, which means there is low salinity effect on crops

728. Soil texture is sandy loam and silty clay loam with 31.2% of the soil in the silt fraction. B horizon is more compacted with an absence of roots in the zone and higher incidence of silty soils. Stone and gravel greater than 2 mm account for less than 1% of the soil (Table 127). Soil chemical properties indicate acceptable levels of nutrients: about 30 mg/kg for soluble nitrogen, 1-9 mg/kg for plant available phosphorus, and about 30 mg/kg for exchangeable potassium.

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Table 127: Soil Profile Soil Depth, Characteristic horizon m 1 O 0.0-0.3 Sandy and silt loam, High organic matter, dark brown color. High carbonate content 2 A 0.3-0.6 Dark color soil. loamy clay. High carbonate content, less organic matter than upper layer. 3 E >0.6 Silty loam. High carbonate content

Source: Integrated agricultural laboratory

e. Water Sources

729. The main water source for irrigation is the Selenge River. The subproject site is located at the confluence of the two biggest rivers of Selenge and Orkhon (Figure 164). The hydrological station is located upstream of the proposed irrigation scheme near to the Zuunburen Soum. There is a total of 28 years (1989 to 2017) of time series data from the Zuunburen gauging station that has been used for the analysis.

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Figure 164: Confluence of the Selenge and Orkhon Rivers

Source: Gidrocom Co.Ltd

730. Table 134 provides monthly mean flow data from the Zuunburen gauging station, which ranges from 331.8 m3/s to 544.9 m3/s during the months of the growing season. The environmental flow requirement is 218.1 m3/s (90% of the long-term average flow) at the Zuunburen gauging station, which is located in the lower basin of the Selenge River. Thus, there is an average monthly mean flow of at least 113.7 m3/s available in the river to meet irrigation demand in June, and more in the other months. Even then, the monthly high flow can range from 728.0 m3/s in May up to 2465.0 m3/s in August, while the low discharge flow can be less than the declared environmental flow requirement in all months of the growing season.

Table 128: Selenge River Water Resources for Okhindiin Tal Subproject Area Mean Mean Environ- Percent of Mean Mean Water available for Maximum Minimum mental Annual Month Discharge use Discharge Discharge flow Discharge (m3/s) (m3/s) (m3/s) (m3/s) (%) (m3/s) (m3/month) April 379.0 50.7 191.8 218.1 6.60 - - May 728.0 176.0 346.1 218.1 11.90 128.0 342,783,066 June 737.9 125.0 331.8 218.1 11.41 113.7 294,735,226 July 1252.0 160.7 442.7 218.1 15.22 224.6 601,475,115 August 2465.0 135.0 544.9 218.1 18.73 326.7 875,064,532 September 1465.0 114.0 458.3 218.1 15.76 240.2 622,470,519 October 751.0 110.0 288.4 218.1 9.91 70.2 188,121,259 November 309.0 43.9 137.2 218.1 4.72 - - December 118.0 22.5 55.1 218.1 1.90 - - January 95.5 11.3 37.7 218.1 1.30 - - February 113.0 11.3 31.7 218.1 1.09 - -

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March 152.0 17.5 42.8 218.1 1.47 - - Source: National Agency for Meteorology and Environment Monitoring

731. According to observed data (Figure 165), the Selenge river flow during the irrigation period of May to August at Zuunburen has been decreasing sharply since 1975—in May by 300 m3/s, June by 200 m3/s, July by 200 m3/s, and August by 150 m3/s. However, river flow has increased slightly since the year 2000.

Figure 165: Selenge River Flow at Zuunburen Gauging station (1975 to 2017)

Source: National Agency for Meteorology and Environment Monitoring

732. There was no sufficient data available to conduct sensitivity analysis.

733. Water quality. Water chemistry analysis for Selenge river from 2013 to 2018 is shown in Figure 166. The overall assessment is that the chemical composition of the Selenge river water 2+ 2+ - is good, where the concentration of Ca , Mg , SO4 and Cl do not exceed the irrigation water standards thresholds. The sodium adsorption ratio (SAR) that is a critical factor for sustainable irrigation is also found to be within acceptable limits41. Therefore, it is concluded that water from the Selenge River is well suited for irrigation use.

Figure 166: Water Chemistry of the Selenge River

Source: Central Laboratory for Environment and Metrology

41 MNS-irrigation scheme O-16075-1:2018 Guidelines for treated wastewater use for irrigation projects: The basis of a project for irrigation.

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734. Suspended solids in the Selenge river water range from 0.4 to 234.4 mg/l (or 0.004 to 0.23 kg/m3), but do exceed 100 mg/l (0.1 kg/m3) most of the time (Figure 167). According to the MNS 4943: 2015,42 the concentration of suspended solids in Selenge river water often exceeds the threshold. Thus, there is a need for careful management of suspended solids in case of drip and sprinkler irrigation.

Figure 167: Suspended Solids in Selenge River Water

Source: Central Laboratory for Environment and Metrology

735. The quality of the water in the Selenge River is classified as “very clean” with an index value of 0.22, when water quality analysis and assessment results are assessed against the Water Quality Index (WQI).

736.

f. Existing Irrigation System and Design Maps

737. This is a new irrigation system.

2. Irrigation Water Requirement

738. Irrigation norms were used as specified in the Ministers’ Order (Table 129) of the Ministry of Nature and Environment Green Development in 2015.The total crop water requirement is 6,252,000 m3.

Table 129: Crop water requirements for Okhindiin tal. Irrigation Irrigation norm Moisture Irrigation Water Plants Area method for growing charge norm consumption (ha) (m3/ha) (m3/ha) (m3)

42 MNS 4943: 2015: Mongolian standard on effluent water quality in the environment

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period (m3/ha) Potatoes 120 sprinkler 3000 300 3300 990,000 Cereal 950 sprinkler 2400 300 2700 810,000 Vegetables 410 sprinkler 3200 300 3500 1,050,000 Fodder 1280 sprinkler 3300 600 3900 2,340,000 Fruit trees 20 sprinkler 3240 300 3540 1,062,000 Total 2780 6,252,000 Source: GidroCom Co.Ltd

3. System and Layout

a. Area Topography

739. The Okhindiin Tal subproject area is located between the coordinates 50.08.55 N to 50.12.25 N, and 106.03.06 E to 106.09.16 E.

740.

b. New Irrigation System

741. The design includes an open coast (without dam) water intake structure in the Selenge River. The water intake structure will be located at an elevation of 618 masl (riverbank level), at 50.09.30 N and 105.45.00 E. This intake will have no gate and open type of structure. It is necessary to dig from the right bank of Selenge River with 1.8 m depth and 600 m long, then connected with the right branch of the Selenge river. The open canal will be continued for 7-8 km to the beginning of the irrigation area.

722. Three crop rotation areas are proposed at the right branch at an altitude of 612.5 m. A water intake structure is proposed from which water will be pumped to the command area. The elevation of the command area is 611 m. The gradient of command area is 1m over 4,500 m from the southeast to the northwest making it impossible to use an open canal in the command area.

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Figure 168: Okhindiin Tal Irrigation Scheme Layout

Source: GidroCom Co.Ltd

Table 130: Irrigation Design Option № Proposed Irrigation Scheme Details Value and Units and Components 1 Gross area 3,200 ha 2 Command area 2,780 ha 3 Land use coefficient (1/2) 0.89 4 Pump station V = 12,000 m3, L = 80 m, W = 60 m, h = 2.5 m, m = 1.5 5 Protection barriers around command Up to L = 10,000 m, b = 3.0 m top, m = 1.5, h = up to 2 m area 6 Pumping station intake pipework and see Annex 1 filtration units 7 Pump station, 5 pumps (one standby), Details to be developed power supply and control panels 8 9 Pipes (HDPE or equivalent) to center L = 24,480 m, Diam (ID) = 500 mm, pivot irrigators (22) L = 4,600 m, Diam (ID) = 450 mm, L = 5,690 m, Diam (ID) = 355 mm, etc. Diameter will be to standard available, OD or ID, best next size 10 Center pivot machines (5 100-ha and 4 A = 100 ha, Radius = 565 m, App Rate = 8 mm/day 21-ha) A = 21 ha, Radius = 258 m, App Rate = 8 mm/day 11 Road 22000 m, with surface area of 3 ha 12 Fence Length Up to 20.000 m Source: GidroCom Co.Ltd

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742. Balancing Storage. Designed at the Selenge river branch 80 m long x 60m wide, up to 2.5 m high balancing storage, at about 100 m to the west of the command area. The balancing storage will have an approximate volume of 100,000 m3, and water withdrawal from the storage will be by suction of the main irrigation pumps, sited southeast of the storage. This storage will be the sump for the pumping station to supply all the planned irrigation systems. It will receive a regulated flow from the river, at a rate commensurate with water available from the river pool, whilst extraction will be in accordance with the needs of the irrigation systems.

743. To operate the storage, two possible options are considered: • The storage is constructed with a bank height equal to the enclosure bank at the river intake (612.5 masl – approx. 2.5 m above local ground level) and the balancing storage and river pool can equalize at full capacity; or • The storage is a cut and fill balance at the local site, and inflow is regulated with controlling sensors and solar powered operated automatic control of the intake sluice gate to reduce or cease flow when the balancing storage is full.

744. Pumping station. Due to the local topography, there is no natural hydraulic head available from the river for the operation of piped sprinkler systems. By linking the pumps and comparing combinations to meet expected output and pressure requirements, there may be possibilities to moderate overall equipment, energy and operating costs. For this analysis, it is assumed there will be four separate central pivot pump systems with outflow capacity of 125 to 130 l/s against an overall operating head up to 50 m (conservative as may need only about 40 m depending on pipe length, size and hydraulic friction loss).

745. A cost range has been developed utilizing a net norm on the assumption less water is needed when using sprinklers than if using surface irrigation, as is the general basis for derived norms. These also allow for the water losses that occur in the open canal systems, whereas with pumping, the costs are attributable to the net water actually pumped inclusive of direct on-field application losses, taken as 10%. On this basis, to operate four pumps to service the four central units and other ancillary irrigation systems, the annual electricity costs (subject to actual applicable tariff) are in the order of $6,000 to $6,750 per season.

746. The pump station should also include a water filtration system, to remove any suspended sediment that could otherwise be harmful to and might collect in the pipes, valves, sprinklers and drip emitters. While some coarse screening to trap vegetative matter and other large items can be included as a strainer on the intake side of the pumps, the fine sediment filtration should be located on the pressure side of the pumps. Then, by suitable pipe and valving arrangements, the pump pressure can be used to backwash filters periodically (programmed or when the operate observes significant pressure differential across the filters) and thereby protect the irrigation equipment from any sediment induced problems.

c. Irrigation System Layout

747. Distributary/field canals. The prime means of distributing water over the land for the crops will be center pivot sprinklers, and this will be enhanced within the substantive blocks between the pivot circles that cannot be readily irrigated, by also deploying some smaller localized sprinkler/spray/drip solutions, supplied from the center pivot buried supply pipes, to suit particular cropping requirements in those smaller areas. In this way, whilst 1,600 ha is covered directly by the required 5 100-ha center pivots, up to another 400 ha will be covered by smaller (21 ha) subsidiary systems.

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748. Windbreaks. Preliminary analysis suggests it is not necessary to use windbreaks in the command area since the area is protected from prevailing winds by Selenge bushes. However, this needs to be verified during detailed design.

749. Flooding: A flood protection dyke is needed to the northwest of the command area to protect it from flood risk from the Selenga River.

750. Command area fence. A fence will be designed and installed around the command area to protect the cropped area, forest strips and seedlings from livestock and other outside interference. The fence will be up to 23,100 meters long and will comprise 4 lines of galvanized steel wire between wooden posts 5m apart.

751. Access Road. Access earthen roads, with a minimum width of 3.0 m and total length of up to 35 km, will be formed and protected to the site and headworks, and within the irrigation command area.

752. Irrigation method - sprinkler: for Okhindiin Tal, the modernized design retains the use of center pivot irrigation machines. With 15 100-ha circles, the area can be covered with 5 100-ha units (560 m radius) working on a 72-hour irrigation period per circle, On the assumption that each machine can deliver an equivalent of 8 mm per day over the circle, but take three days to complete the circle, the irrigation depth would be 24 mm per cycle. Given that the root zone soil depth is about 400 mm, and the water holding capacity (replenishment) is a minimum of 5%, then 24 mm represents 6% of the water holding capacity of the soil. This application rate reduces the risk for any excessive deep percolation, with a 12- to 15-day period between irrigations. Taking this approach, then within the 12- to 15-day period, the center pivot can be used sequentially on up to four circles, with relevant disconnection, moving and reconnection of the machine for each successive circle estimated to take from 3 to 4 hours. On this basis, five 100-ha center pivots are required to service 3 circles each, 15 in total. They would complete between 8 and 10 cycles each per season. In a similar way the 21-ha units can be used to irrigate the smaller areas but, given the distribution of these areas, it is unlikely these center pivots can be used at the maximum efficiency.

753. Drip irrigation. Some of the area that cannot be covered by the center pivots can potentially be irrigated by a drip system, and this will provide opportunities for additional vegetable and greenhouse production, which will be financed under a proposed Japan Fund for Poverty Reduction grant. The specific options for this will be investigated during detailed design.

4. Design Discharge

754. No information has been provided on this issue.

5. Civil Works

755. The main civil works for the diversion headworks on Sеlеnge River right anabranch will include survey, detailed design and strengthening/raising the cross river barrier to maintain a river pool level at 613 masl for the diversion and conveyance of water to a balancing storage, pump station and irrigation sprinkler/drip systems. The works can be summarized as: (i) improvement, raising and strengthening of the existing rockfill barrier wall (with impermeable core) across Sеlеnge River anabranch channel, immediately downstream of the existing intake channel, to raise the pool water level to a reliable 613 masl;

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(ii) construction of a safety protection embankment from the barrier wall, incorporating the intake structure and along the anabranch right riverbank until it meets ground level (west end) at a top height of at least 613.5 masl [hydrology to be checked at detail design]; (iii) construction/formation of up to 35.0 km of access road; (iv) construction of up to 23.1 km of fence for stock proofing the command area.

756. At this stage, the design and related details are preliminary, and as detail design and operational requirements are clarified, some additional works may be required (e.g. crossing points on the main canal at headworks, or at start of the command area).

6. Equipment

757. Within the civil works, required equipment will be limited to gates to be installed for: (i) The water intake – vertical lift sluice gate with preliminary 1.2 m wide and a 0.6 m lift; (ii) Intake sediment sluice – vertical lift sluice gate sufficient to flush rapidly at up to 1 m3/s, details to be finalized around operational and physical levels at site; (iii) Provision of up to 5 pumps and associated pipes, with up to 40 m operating head and output of at least 125 l/s, to supply all planned irrigation systems (central pivots, sprinkler/spray, drip) to cover the full 2,000 ha in a maximum 15-day cycle; (iv) Provision of all required pipework – HDPE or other as suitable – to distribute all pumped water around the command area to the designated CP anchor stations and other required offtakes for minor system; (v) Provision of 5 100-ha center pivot sprinkler sets, with 560 m booms, and 4 21-ha center pivot sprinkler sets, with 258 m booms, inclusive of propulsion power supply, operating control, and associated spare parts, spray nozzles and drop pipes suitable for particular crops, all details to be discussed with potential suppliers before confirming detailed specifications; (vi) Provision of relevant power supply infrastructure, whether connection to main national or local electricity grid, inclusion of diesel power and generator sets, or provision of diesel power to drive irrigation systems (pumps, self-propulsion, etc.) There is an expectation that adopted sprinkler equipment would include suitable on- board power controls and drive mechanisms if electric power supply and cabling is not viable.

7. Bill of Quantities

758. The cost estimation for Okhindiin Tal irrigation scheme construction and equipment (Table 131) summarizes the cost for key components required for the upgrading and modernization of the irrigation scheme. The estimated cost is MNT13,475.34 million ,equivalent to MNT6.74 million/ha

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Table 131: Bill of Quantities for Okhindiin Tal Irrigation Scheme Modernization Budget No Item Unit Quantity (MNT million) Unit cost Total Civil Works 1 Headworks Sluicing structure with intake sluice piece 1 150.00 150.00 channel and outlet flushing channel 2 Rock dam for increase water level L=…m, h=. m, piece 6 51.00 306.00 3 Headworks protection embankment m 6,000 0.06 360.00 4 Main Canal, reforming and lining m 600 0.33 199.98 5 Settling Basin (Balancing Reservoir) m3 15,000 0.08 1,200.00 6 Main pipe m 5,891 0.03 176.73 7 Distribution pipe m 15,962 0.01 159.62 8 Drain well piece 16 3.02 48.32 9 Bridge 2 4.06 8.12 10 Roads – forming and grading m 35,000 0.01 175.00 11 Drain and protection bank m 6,000 0.05 300.00 12 Pump station number 6 100.00 200.00 Subtotal 3,283.77 Equipment Head work Control Sluice Gate, Width 1.0 m x 13 piece 4 1.68 6.72 Height 0.6 m, vertical screw Main PE: PE100, SDR11, 1,0mpa, DN500mm, 14 m 5,891 0.40 2,356.40 PN10 Distributary PE: PE100, SDR11, 1,0mpa, 15 m 4,036 0.40 1,614.40 DN500mm, PN10 Distributary PE: PE100, SDR11, 1,0mpa, 16 m 2,021 0.34 680.07 DN450mm, PN10 Distributary PE: PE100, SDR11, 1,0mpa, 17 m 5,408 0.27 1,435.82 DN355mm, PN10 Distributary PE: PE100, SDR11, 1,0mpa, 18 m 4,495 0.10 466.58 DN250mm, PN11 19 Central pivot sprinkler, 100 ha set 5 303.88 1,519.42 20 Central pivot sprinkler, 21ha set 4 133.00 532.00 21 Pump (diesel) piece 5 15.00 75.00 22 Excavator for O&M piece 1 168.60 168.60 Subtotal 8,855.02 21 VAT, 10% % 53.75 1,215.88 22 Environmental baseline assessment number 1 0.00 23 Environmental impact assessment number 1 42.67 42.67 24 Design cost ha 2000 0.04 80.00 Subtotal 1,336.55 Grand total 13,475.34 Source; consultant’s estimates

M. Subproject 14 – Sugnugur Irrigation and Drainage System Design

1. Site Description

a. Scheme Background

759. The Sugnugur irrigation scheme is located in Batsumber Soum of the Tuv Aimag. The original irrigation scheme was developed in 1976 to irrigate 2,684.5 ha but it was subsequently abandoned. Whilst Sugnugur is not a new scheme, there is a main canal with intake 5 km upstream of the command area, which is now to be returned the Soum local government for upgrading and modernizing. Under the modernization, more assured irrigation will be provided to up to 100 farmers working up to 140 ha – 40 ha fodder, 50 ha potatoes and 50 ha vegetables.

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760. The scheme source water from the Sugnugur river, about 3 km upstream of Sugnugur Bagh in a narrow valley and runs the water down a contour aligned canal to the command area. The existing canal is a narrow unlined channel, with many young trees adjacent to the canal in the first 0.75 km. As it approaches Sugnugur Soum, the canal enters open country, winds in and amongst some farm settlements, before crossing the Batsumber-Sugnugur road, and running along the hillside, to the south of the command area. Currently, farmers access water via temporary breaks in the canal bank to supply groups of farmers within blocks between roads, drains and gullies. The canal is also tapped by upstream farmers in a similar way for non- command area land. No specific area or data on crops and water withdrawals in this way is available. The canal headworks are in relatively good condition but there is no measured control on water intake, and any excess water drawn through the canal if not used for irrigation eventually flows back to the river (less any seepage and/or evaporative loss. The presence of overgrowth (trees and bushes) and the rocky terrain on the side of the hills makes reformation of the canal (straighter and lined) more difficult until reaching the open country. The overall canal length has the potential to be shortened and made more efficient by adopting (if possible) a less convoluted route around the contour (minimal earthworks) and with the inclusion of durable lining. If the canal could be straightened, then it could be reduced to about 3 km between the intake and the start of the command area. However, to do this, using modern machinery, would require more earthworks and provision for cross drainage.

b. Area and Crop Maps

761. Geomorphology. The project command area lies at 1,115 to 1,150 masl, in the Sugnugur River valley. It is surrounded by the Darkhint Mountains (2,172) to the south, and the Bugandai Mountains (2,104 m) to the north.

762. The Sugnugur irrigation scheme command area is located to the north east of Batsumber soum center, which by road is about 9.5 km to the start of the command area, but 14.0 km to the headworks and 11.5 km to the Sugnugur Bag center. The existing irrigation system is a simple gravity supplied system with a long single main canal (5 km) and distributary canal (4 km), initially with 40 hectares developed in 1977. In 2007, it was revitalized under state budget investment to cover 140 hectares. The overall irrigation system involves the continuous main/distributary canal (9 km) to support surface irrigation (border dike, basin check) implemented by the farmers/farmer groups, who take water from mainly ad hoc (i.e. no control) outlets with no formal structures/gates. Inflow to the main canal is controlled from a strategically placed inlet structure (Figure 169, left), with gate, on the left side of a bend in the Sugnugur river. There is no formal water pool maintained by a small barrier wall/weir, and thus inflow to the canal is at risk when the river flow is reduced (low river water level). The intake can be accessed by road from Sugnugur Bag, and in this wooded section, the canal is following the toe of the hills, and is quite rugged with rock outcrops and the alignment (banks) are disturbed by growing trees. The main canal continues to follow the toe of the bank, and as constructed has many sharp turns (Figure 169, right) as it approaches the command area. The canal then converts to a distributary along the south side of the command area, with limited fall to where it ends, with most water accessed through informal outlets to the command area (Figure 170).

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Figure 169: Sugnugur Canal Intake and Convoluted Path of Main Canal to Command Area

Source: TA consultants based on Google Map

Figure 170: Sugnugur Irrigation Scheme Plan and Overview

Source: TA consultants based on Google Map

c. Climate

763. There is 20 years (1999 to 2018) of time series data for monthly mean air temperature, wind speed and monthly precipitation data, as observed at Batsumber meteorological station. This data has been analyzed to assess the climate for the subproject. There is no meteorological station collected locally in immediate proximity to Sugnugur irrigation scheme.

764. Day time temperature in mid-summer at the Sugnugur irrigation subproject can reach up to about 30oC (maximum daily) in June to August. Annual rainfall is approximately 240.2 mm, with of this (about 80%) occurring during the growing season from May to August. The average wind speed is moderate (averaging about 3.2 m/s) throughout the year. A summary of mean monthly climate data for the project area is given in Table 132.

Table 132: Mean Monthly Climate Data for Sugnugur Irrigation Sub-Project Month Average Absolute Absolute Humidity Wind Precipitation Temperature Maximum Minimum (%) speed (mm) (oC) Temperature Temperature (m/s) (oC) (oC) January -26.0 -2.2 -46.5 70.2 2.1 2.4 February -21.3 5.9 -46.0 66.3 2.5 2.4 March -10.1 19.4 -36.9 61.0 3.3 2.8 April 1.5 27.9 -24.7 48.1 4.2 6.4 May 9.1 29.5 -18.9 47.4 4.3 21.6 June 15.2 27.9 -3.5 54.1 3.7 36.3 July 17.8 31.0 0.5 62.4 3.1 56.6 August 15.4 29.3 -1.5 64.3 3.1 70.8

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September 8.1 21.0 -14.0 59.0 3.4 25.3 October -0.6 23.2 -21.6 58.5 3.2 7.5 November -13.2 14.2 -35.0 65.9 2.7 4.0 December -22.0 3.0 -41.7 70.1 2.3 4.1 Average -2.2 23.1 -24.2 60.6 3.2 240.2 Source: National Agency for Meteorology and Environment Monitoring

765. Air temperature. Figure 171 shows the trend for change in monthly mean air temperature from April to September. As the April mean temperature is 1.5oC, lower than the 10oC crop growth threshold, and the minimum temperature could fall to -24.7oC (Table 132), there is insufficient warmth in the air to support crop growth, so no irrigation is implemented in April. However, snow and ice melt will occur, and the river starts to flow strongly from April onwards (Table 123). The mean temperature is also barely above 10oC in September, but as this is usually post or the harvest period, this does not affect irrigation or crop production.

766. Air temperature trend. Figure 171 shows that monthly mean air temperature has changed over time for the months from April to September. All months demonstrate a decreasing temperature trend, through May to September, with the May temperature down by 1.3oC, June by 1.6oC, July by 1.1oC and August by 0.6oC. The exception is April, where the mean temperature has increased by 2.0oC over the same period. On balance, it is perhaps reasonable to assume there has been minimal significant shift in the mean annual growing season temperature, though there are some shifts that could impact crop production. With decreased temperatures in June, it is likely some decreased irrigation would be required but this would also lead to some decrease in production.

Figure 171: Trends of Monthly Air Temperature at Sugnugur Irrigation Scheme

Source: National Agency for Meteorology and Environment Monitoring

767. Duration of hot days. One important climate factor that influences irrigated crop production is that of hot days. Figure 172shows that the number of days each year where the daily average air temperature is above 25oC has decreased by 1 day over the last 20 years. This suggests that temperature and hot days has been almost unchanged over the period, which means that crop production will remain unchanged provided enough water is available to meet crop water demand.

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Figure 172: Trends in Hot Days with Daily Mean Temperature more than 25 oC and 30oC

Source: National Agency for Meteorology and Environment Monitoring

768. Precipitation. Changes in precipitation during the growing season have not been consistent with increases in one month followed by decreases the next month (Figure 173). Based on the available data, precipitation has increased by 15 mm in July, but decreased in May by 31 mm, in August by 9 mm, with no change in June. There is no convincing trend to suggest more or less irrigation is required to secure crop production, but with so little precipitation there is still a need for supplementary irrigation, especially for vegetables and potatoes, when 300 to 400 mm of irrigation is needed per year (as indicated by crop ‘Norms’).

Figure 173: Trends of Monthly Precipitation at Sugnugur Irrigation Scheme

Source: National Agency for Meteorology and Environment Monitoring

769. There has been a sharp decrease of precipitation in May (by almost 25 mm), less so in June and August, but for the other months the precipitation has been steady or shown a slight increase over the 20 years of data. There has also been a mixed but slight increase in the number of days with no precipitation, which highlights that secure if not increased irrigation is required (Figure 174).

Figure 174: Trends in Days with no Precipitation

Source: National Agency for Meteorology and Environment Monitoring

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770. Wind. The monthly mean wind speed in the growing season varies from 3.1 to 4.3 m/s (Table 132) while the maximum speed can exceed 20 m/s on average twice a year. There are more than 70 days per year when wind speed exceeds 10 m/s, while the number of days when the wind speed exceeds 15 m/s has increased by 7 days over the last 20 years. Figure 175 shows that 30% of the wind comes from the north and southeast, and 15% from the southeast. This suggests that windbreaks could be beneficial to moderate wind erosion in the Sugnugur valley, and that windbreaks would be most effective if placed along the north (across the river and valley) and southeast (from the upper catchment) of the command area.

Figure 175: Trends in High Winds and Wind Direction

Source: National Agency for Meteorology and Environment Monitoring

771. Agro-climate: There is a clear trend that warm days start earlier in spring by about 10 days, whilst they remain longer in the autumn, by about one week. The trend is for the overall growing season to get longer (Figure 176, upper). However, with the trend for decreasing temperatures during the growing months, there is reduced accumulated temperature over the year to support crop growth, and there is little to no decrease in the number of frost-free days. (Figure 176, lower) to extend the effective growing season.

Figure 176: Agro-climate Characteristics

Source: National Agency for Meteorology and Environment Monitoring

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772. Climate Projections. Under the various scenarios, according to climate change studies, in the Sugnugur subproject area the summer temperature is projected to increase by between 1oC, and 2.5oC (Figure 4), with a 0% increase in precipitation, by 2035 through to 2065 (Figure 5). Whilst an increase in temperature and a slight increase in precipitation will be beneficial for crop production, these changes, if realized, will not negate the need for irrigation to sustain and enhance crop production.

d. Soils

773. The soil map for Sugnugur irrigation scheme (Figure 177) shows that the dominant topsoil type in the command area is mountain dark kastanozem, mountain taiga cryomorphic humic and riparian area’s alluvial meadow soil and mountain humic dark soil dominated. By World Reference Base soil classification, command area soil can be grouped in very young Fluvisol with weak horizon differentiation and Meadow swamp alluvial with mountain humic dark soils. Western part of field has meadow and valley soils.

Figure 177: Soil Map of the Sugnugur Subproject Area

Source: Institute of Geography and Geo-ecology

774. Soils are high organic matter 3.4% dark brown soil. Soil has high nutrients level. Clay particles accumulated by irrigation water flow in A horizon. River water EC= 60 μS, also long- used for irrigated agriculture, resulting in clay particles moving to depth. Each horizon was low reacting with 10% hydrochloric acid, meaning weak alkaline or near to neutral. Carbonate contents around 0.5%, secondary carbonate sediment collected to soils. Soil pH=7.6 and EC= 120-130 μS, which means there is low salinization effect to the crops.

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775. For the soil particles texture is silt loam and 35-60% of soil is silt fraction. B horizon is more compacted, no root in this zone and more loamy soils (Table 133). Stone and gravel more than 2 mm fraction is less than 1% of the soil. The soluble nitrogen contents are acceptable which around 33 mg/kg, plant available phosphorus levels are very high which around 85-90 mg/kg and exchange able potassium levels are 70-80 mg/kg which means enough sufficient level of nutrients.

Table 133: Soil profile Soil Depth, Characteristic horizon m 1 A 0.0-0.6 Silt loam, High organic matter, dark brown color. less carbonate content 2 E 0.6-0.8 Loamy soils. 3 B >0.8 Loamy. Medium react with carbonate content 4 C >1.2 Gravel and sandy loam.

Source: Integrated agricultural laboratory

776. Soil cation exchange capacity is very good condition level around 18-22 meq/100g which meaning cation are binding with clay particles and indicating soil will good enough to deliver nutrients to plant root

e. Water Sources

777. The main water source for irrigation is the Sugnugur river (Figure 178: Sugnugur River BasinFigure 178). The hydrological station is located on the river a short way upstream of the Sugnugur irrigation scheme canal intake. There is a total of 28 years (1989 to 2017) of time series data from the Sugnugur gauging station that has been used for analysis.

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Figure 178: Sugnugur River Basin with Sugnugur Irrigation Scheme and Gauging Station

Source: Consultant based on National atlas

778. Table 134 provides monthly mean flow data from the Sugnugur gauging station, which ranges from 2.72 m3/s to 4.97 m3/s during the four months growing season. As the environmental flow requirement is set at 1.64 m3/s, there is an average monthly mean flow of at least 1.08 m3/s available in the river above the intake to meet irrigation requirements in May, and more in the other four growing season months. Even then, the monthly high flow can be 16.8 m3/s (May) up to 615.0 m3/s (July), whilst the low discharge flow can be less than the declared environmental flow requirement in all growing season months. This would suggest there is a need, for dry years, to have some available balancing storage, whether on the river, or on the canal.

Table 134: Sugnugur River Water Resources for Sugnugur Subproject Area Mean Mean Environ- Percent of Mean Mean Water available for Maximum Minimum mental Annual Month Discharge use Discharge Discharge flow Discharge (m3/s) (m3/s) (m3/s) (m3/s) (%) (m3/s) (m3/month) April 4.06 0.06 0.80 1.56 3.87 - - May 8.45 0.37 2.72 1.56 13.15 1.16 3,114,979 June 8.07 0.34 2.76 1.56 13.3 1.20 3,222,115 July 11.9 0.54 3.67 1.56 17.7 2.11 5,659,459 August 16.8 0.56 4.97 1.56 24.0 3.41 9,141,379 September 9.13 0.38 3.29 1.56 16.0 1.73 4,641,667 October 6.64 0.32 1.79 1.56 8.62 1.16 3,114,979 November 0.90 0.04 0.40 1.56 1.93 - - December 0.62 0.01 0.25 1.56 1.19 - - January 0.08 0.00 0.01 1.56 0.04 - - February 0.05 0.00 0.01 1.56 0.04 - - March 0.34 0.00 0.06 1.56 0.30 - - Source: National Agency for Meteorology and Environment Monitoring

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779. According to observed data (Figure 179), the Sugnugur river flow during the irrigation period of May to August at Sugnugur has been decreasing sharply since 1998—April by 1.0 m3/s, May by 3.9 m3/s, June by 3.5 m3/s, July by 4.0 m3/s, and August by 6.4 m3/s.

Figure 179: Sugnugur River Flow at Sugnugur Gauging station (1989 to 2017)

Source: National Agency for Meteorology and Environment Monitoring

780. Since beginning of 2010, the average flow each month from May to September has been lower than the long-term average. Further study on this trend, and clarification on both mean and low flow data should be obtained prior to detailed design. The inclusion of any buffer storage – intake pool and onstream balancing storage – should help to cushion the worst effects of severe river flow fluctuations.

781. The Sugnugur River flow sensitivity to climate change is shown in Table 135. If precipitation remains unchanged and average temperature increases by 1°C, 2°C, 3°C or 5°C, then it is projected that the river flow could decrease by 10.2% (+1oC) to 32.6 % (+5oC). The impact of precipitation increasing by up to 20% is substantially more marked than if precipitation decreases by 20%, but an increase of 5oC would almost eliminate any gains expected from additional precipitation. If precipitation has declined by 20%, then the reduction in river flow from increased temperature is relatively small. Overall, river flow is highly sensitive to reduced precipitation, but with unchanged or increased precipitation, the impact of increased temperature is more significant in moderating river flow.

Table 135: Sugnugur River Flow Sensitivity to Climate Changea Temperature Probability Increase (oC) -20% -10% 0% +10% +20% 0 -42.1 -22.9 26.5 56.8 1 -48.3 -31.0 -10.2 14.0 41.7 2 -52.3 -36.2 -16.9 5.7 31.6 3 -55.6 -40.6 -22.6 -1.4 22.9 5 -61.5 -48.4 -32.6 -13.9 7.5 a Percentage change of average river flow. Source: TA consultant

782. Water quality. Water chemistry analysis for Sugnugur river from 2013 to 2018 is shown in Figure 180. The overall assessment is that the chemical composition of the Sugnugur river water 2+ 2+ - is good, where the concentration of Ca , Mg , SO4 and Cl do not exceed the irrigation water standards thresholds. The sodium adsorption ratio (SAR) that is a critical factor for sustainable irrigation is also found to be within acceptable limits43. Therefore, it is concluded that water from

43 MNS-irrigation scheme O-16075-1:2018 Guidelines for treated wastewater use for irrigation projects: The basis of a project for irrigation.

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Figure 180: Water Chemistry of the Sugnugur River

Source: Central Laboratory for Environment and Meteorology

783. Suspended solids in the Sugnugur River water range from 0.2 to 24.6 mg/l (or 0.004 to 0.02 kg/m3), but do not exceed 20 mg/l (0.02 kg/m3) most of the time (Figure 181). According to the MNS 4943: 2015,44 the concentration of suspended solids in the Sugnugur river water is suitable for irrigation.

Figure 181: Suspended Solids in the Sugnugur River Water

Source: Central Laboratory for Environment and Meteorology

784. The quality of the water in the Sugnugur River is classified as “very clean” with an index value of 0.2, when water quality analysis and assessment results are assessed against the Water Quality Index (WQI).

44 MNS 4943: 2015: Mongolian standard on effluent water quality in the environment

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f. Existing Irrigation System and Design Maps

785. The original Sugnugur irrigation scheme was a natural gravity supplied surface irrigation system, for mixed cropping (wheat, fodder, potatoes, vegetables and some small fruit areas). Though original plans were for about 2,800 ha, it is clear from the current availability of reliable water from Sugnugur river that it was unfeasible to support such an area. Even with the new revised 140 ha of modern sprinkler/drip irrigation, water availability under the current and trending climate is limiting.

786. The main canal follows the line of the river, moving downstream towards the west. The canal is aligned at the toe of the foothills on the southern side of the valley, which starts to widen out and become more uniformly graded once downstream of Sugnugur Bag, the local farmhouse and residential area. The main canal, developed to follow the contour, from approx. 1,160 masl (canal intake) to 1,152 masl (highest point of the south eastern corner of the elongated (east to west) command area), follows a winding path, which if upgrade and lined, could and should potentially be realigned with fewer sharp bends, even if that requires some additional cut and fill sections (balanced). Currently, the main canal that becomes a distributary on the south side of the command area, is an unregulated rough earthen channel, which gradually ceases after about 9 km. Farmers access water from this channel by cutting unregulated outlets to run water in local field ditches to their plots. Whilst it is clear many plots are cultivated, by up to 200 farmers, the exact area reliably covered each year, and thus productive is not known.

787. The command area extends down the slope from the main/distributary canal in a south to north direction ending close to the meandering river through the valley. Plots closer to the river appear to be more regularly cultivated, and this is because when necessary, farmers are using small pumps to access water directly from the river. This could be necessary as there is also some other land, further upstream, closer to the main canal intake and main canal reach, that are unofficially withdrawing water from the main canal. It is likely this may continue in the future, so the upgraded main canal is sized to allow for this ‘risk’. It will be up to the Soum managers of the irrigation scheme to implement appropriate measures to either manage or curtail this practice.

788. Within the command area, despite any earlier plans, it appears there is currently no mechanized irrigation (sprinkler or drip) though for more effective water management, the use of more precise irrigation methods, rather than surface irrigation, would be much more beneficial for making greater use of the scarce available and uncertain water supply.

2. Irrigation Water Requirement

789. The cropping pattern for the command area is not fully defined, but of the 140 ha, there will generally be 50 ha of potatoes, 50 ha of vegetables and 40 ha of fodder (Table 136). To protect the land from any aggressive wind erosion, it is planned to develop windbreaks on critical sides of the command area for a total of 4.9 ha. The windbreak will be made up of three rows which will require nurturing from seedlings to maturity. Leafy trees will be planted in two rows with one row of low fruit and/or nut bushes on the windward side. These windbreaks will be set along the north and northeastern boundary of the command area to contain the aggression of the prevalent strong winds, as determined in the wind direction data.

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Table 136: Current and Planned Command Area Crop type Current Irrigation method Planned Irrigation method Allocation of Allocation of command area command area Potatoes, ha 50 Furrow 50 Drip & sprinkler Vegetables, ha 49 50 drip & sprinkler Cereals, ha Fodder, ha 35 40 sprinkler Fruit trees and 5 drip 5 wind break, ha

790. Overall efficiency (Table 7) will be raised to 75% by using closed pipe systems from the balancing storage, modern controllable linear move sprinkler irrigation machines for 100 ha for fodder and vegetables, and low pressure drip systems for popatoes and windbreak.

Cropping Zone Field Irrigation Proportion of Conveyance Field Overall Scheme Application Total Efficiency Application Irrigation Method Command % Efficiency Efficiency Area % % % Existing Command Area Surface (border, 100.0 60 60 36 furrow, basin) Fodder and Vegetable Sprinkler 72.0 95 75 71 Area, 100 ha Potato Areas, 40 ha Drip 28.0 95 90 86 Average Upgrade Sprinkler plus 100.0 95 79 75 irrigation scheme Drip

791. The total water use for the planned cropping area and crop mix is estimated to be 1,044,715 m3 (0.079 m3/s) with project scenarios and 1,080,958 m3 (0.082 m3/s) with climate change scenarios overall water use efficiency of 75% using an upgraded lined canal for primary supply, and a mix of sprinklers for fodder and vegetables, drip systems for potatoes. Based on using lined canal systems, modern controllable sprinkler irrigation machines for 100 ha of fodder, and vegetables, several low pressure drip systems for a total of 45 ha of potatoes, and the windbreaks (Table 137). This irrigation water accounts for 4 percent of total available water in the growing season or about 1.0-7.4 percent of the river flow of the given month (Table 41), after meeting the environmental flow of 0.47 m3/s thus there water is available to meet the irrigation needs.

Table 137: Irrigation Water Requirements for Sugnugur Irrigation Period Item Total May June July August September Command Area Cropping Plan Potatoes (ha) 50 50 50 50 50 Vegetables (ha) 50 50 50 50 50 Cereals (ha) 0 0 0 0 0 Fodder (ha) 40 40 40 40 40 Fruit Trees and Windbreak (ha) 5 5 5 5 5 145 Water Requirement ‘With Project’ Gross irrigation norm (m3) 172,612 195,795 194,490 154,062 66,578 Irrigation Efficiency (%) 0.75 0.75 0.75 0.75 0.75 Total Irrigation Water Requirement (m3) 230,149 261,060 259,320 205,416 88,771 1,044,715 Water Requirement ‘With Project and Climate Change’

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Increase in Evapotranspiration, (m3) 666 1,313 6,598 1,156 129 Projected water requirement (m3) 179,281 198,196 200,044 163,062 70,135 Irrigation Efficiency (%) 0.75 0.75 0.75 0.75 0.75 Projected total irrigation water requirement (m3) 239,041 264,262 266,725 217,416 93,514 1,080,958 Source: TA Consultant

Table 138: Water availability for irrigation Percentage Projected total of irrigation Monthly Environ- irrigation water water use Irrigation River ment Net available flow in the requirement with from net river period Discharge, Flow, river project flow m3/s m3/s m3/s m3/month m3/s m3/month % May 2.72 1.56 1.16 3,114,979 0.09 239,041 7.36 June 2.76 1.56 1.20 3,222,115 0.10 264,262 8.34 July 3.67 1.56 2.11 5,659,459 0.10 266,725 4.56 August 4.97 1.56 3.41 9,141,379 0.08 217,416 2.24 September 3.29 1.56 1.73 4,641,667 0.03 93,514 1.04 Total 25,779,600 1,080,958 4.02 Source: TA Consultant

3. System and Layout

a. Irrigation Scheme Topography

792. The Sugnugur Command Area lies to the north of the Main and Distributary canals, on the left side of the Sugnugur valley. The canals are following the contour from the intake at 1,161 masl, and finish at the western end of the command area at about 1,151 masl – a fall of about 10 m over about 9 km. The land to the north of the canals falls away to the Sugnugur river, where the river has tender to meander over the years. The command area is narrow in the east with a fall of about 13 m to the river over 160 m, and wider in the west with a fall of about 35 m in 750 m. This leads to quite steep average slopes for effective surface irrigation, with potentially high flow velocities in canals. The use of pipes to bring water the sprinkler or drip systems from lined canals will provide improved water management capacity and minimize overspills and losses to drains. However, to formalize the in-field irrigation networks, further discussion is required with the participating farmers to confirm where pipes (or canals) can be placed, and to define the actual scale of each mechanical irrigation subsystem to be adopted across the varied slopes and length (east to west) of the command area.

793. The average slope is steeper near the head of the valley (the east) and moderates to the west, but that even then, the average grade – canal to limit of command area near the river – is from 1 in 15 in the east to 1 in 30 in the west. These are steep slopes, even for small open earth canals, and water management in such canals, without spillage, is difficult. As the modernization approach is to use a mix of lateral move irrigator (for fodder) and drip (for potato and vegetables), it is proposed that pipes be used, flowing under gravity, to take water from the main/distributary canal to the head of each irrigation subsystem. This will provide hydraulic head for filtration and operating the systems, though some additional pumping to ensure sufficient pressure in each system may be required. These details – in field layout for sub-systems in agreement with farmers, pipe alignments, and pressure requirements (gravity or additional pump) - will need to be resolved at the detail design

298 stage. For this pre-feasibility level assessment, an overall lump sum cost for infield works (pipes, filters, drip and sprinkler systems, drains etc.) has been adopted.

b. Overall System

794. The existing and planned upgrade and modernization of the Sugnugur irrigation scheme (Figure 182) has the following key components which make effective use of the topography and opportunity to deliver and manage water under gravity to feed the in-field sprinkler and drip irrigation systems.

795. Water Intake and Barrier Wall. The existing water intake relies on being able to draw water from the river flow on the outside of a bend. The river is meandering between the foothills so has a relatively stable channel though will move over the long term. There is no river barrier (permanent or temporary) that helps form a stable pool in the river, so the reliability of inflow during very low flow periods will be uncertain. It is therefore proposed that a permanent barrier wall be built, sufficient to keep a 1-m head in the pool over the intake. The main section of the barrier across the river, with a central spill weir, would be set at 1.5 to 2 m above the riverbed level, subject to what is possible in the location and constraints of the environment. The barrier wall would incorporate the main canal intake on the left bank of the river, and provide an in-built sluicing facility for sediment exclusion, with sediment flow returned to the river downstream of the barrier.

796. Main Canal. The existing main canal is an earth channel, heavily overgrown and disrupted in the first 750 m, before it becomes more regular, following the contour of the foothills, adjacent to irrigable land on the northern, downstream side. There is no official command area in the first 3 km, though there are some informal offtakes being utilized, supplementing other water pumped and/or diverted directly from the river by local landholders. The main command area starts west of Sugnugur Bag, with a narrow strip of about 150 m widening out eventually to about 800 m at the western end, a further 6 km downstream. An upgraded main canal lined and evenly graded (1 in 550 to 1 in 600) needs a capacity up to 0.75 m3/s to provide irrigation water, either directly to the upstream areas, or through a balancing storage for the larger downstream areas. As the flow in the Sugnugur river can be highly variable, and low flows insufficient to meet the irrigation water demand, a balancing storage is needed to capture water when river flows are plentiful, and then to be gradually used up to boost the irrigation supply when river flows are insufficient for the full command and irrigation water requirement.

797. Balancing Storage. It is proposed that the balancing storage will be located between km 4.5 and 5.0, and all flow will pass from the main canal through the storage before being control released into the distributary canal (4 km to 9 km). The storage will be built encompassing part of the existing main canal alignment, cut into the hillside with full supply water level of 1,154 masl, and a bank height 0.75 to 1 m higher. The storage invert level will be about 1,151.5 masl, and the start of the distributary canal invert level will be 1,151 m. The storage will be safeguarded by having either a bellmouth intake spillway or an overspill weir, whichever is most cost effective, and will discharge to a secure drain that passes safely between the irrigated blocks to empty into the river. Under normal operations, this spillway should hardly ever be activated, but with the storage located with a high embankment on the northern side, adequate protection must be provided to safely manage any excess inflow. The storage embankment slopes should be 2:1 on the inside of the storage and 2.5:1 on the external face. The southern bank will be, after being cut back into the hillside, natural ground. Care will be needed to make sure there is minimal if any risk for a seepage (piping) failure through the constructed bank. If necessary, appropriate soil treatment should be used to ensure reduced permeability and scour resistance.

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798. Irrigation Area Offtakes from Canals. the natural terrain of the command area has an average grade of from 1 in 15 to 1 in 30. The grade is steeper closer to the main/distributary canal and becomes flatter closer to the river. This makes the release of water from the canal into field channels difficult, with the risk for high flow velocity and scour. The canal will, when upgraded, include many formal offtake points, consisting of permanent gated structures. It is proposed that these will enable water to be released into a piped distribution network that takes water to each of the planned sub-area irrigation systems (sprinkler lateral move (fodder) or roll up drip (potato and vegetable) systems. These systems will be strategically located in agreement with the farmer groups (or WUAs) to best service individual blocks of land (from 5 to 20 ha for drip; up to 40 ha for fodder). The specific details of how this is to be arranged, and confirming whether these systems, complete with water filtration, can operate under available gravity head has to be assessed at detail design. In some cases, pumping may be required, in which case power supply to the system control head/pumps and filters will need to be arranged. At this stage, it is assumed that the sprinkler irrigation system will require pumping – whether by suction from a contour based open canal – or with roll out hose from strategically positioned hydrants. The drip systems will utilize gravity head if sufficient and this will negate pumping but where pumping is needed, then a power supply will need to be installed (assume initially for 50% of the estimated 10 sub-systems – with 1 x 20 ha, 2 x 15 ha, 3 x 10 ha and 4 x 5 ha = 100 ha). The flow details for canals and pipes, to the extent these can currently be provided, are shown in Table 139.

Table 139: Flow and Details for Gravity Lined Canals Canals Length Static Bed Depth of Discharge Lining Gradient (m) Head width Flow m3/s 1 in (m) (m) (m) Main 4,000 6 0.8 0.271 0.75 Concrete 600 Distributary 3,950 3 0.8 0.332 0.55 Concrete 3000 Pressure Pipes to 10 Tbd. Max up to Diam sub-schemes PN4 35 m tbd Diam = diameter, PN X = 10 times X m maximum head, Tbd = to be decided. Note: In most cases the estimated dynamic head loss is compensated for through the physical drop in level along pipe. In the case of drip and sprinkler pressure pipe supply off the main/distributary may require a control valve to set the required operating pressure for irrigation system, though most likely this will valve will be at the outlet to the control station, together with a drain/scour valve. Source: Ta Consultant

799. Pressure Pipes. As indicated above, pressure pipes will be needed to take water from formal offtakes on the canal to the sprinkler/drip system control stations. All other required pipes will be part of the sprinkler and/or drip equipment packages, provided and managed by the soum, in conjunction with the farmer groups/WUAs. In the existing irrigation system, there are 18 indicated offtake points from the main canal. For the indicated breakdown of irrigation subsystems, the maximum required would be 10, suitably located in the new main and distributary canal to supply by the most direct route to each of the proposed irrigation subsystems (1 sprinkler, 9 drip), the number of offtakes might also be consolidated further if an offtake could serve 2 or more of the smaller subsystems through connecting pipes, thereby enabling larger pipes to be adopted with less overall head loss within the pipes. The specifics of how best to arrange this should be resolved at detail design.

800. Drip Systems. The scheme will have several small area drip systems (up to 9), to service potato (50 ha), vegetable (50 ha) and windbreaks (5 ha).

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801. Sprinkler Irrigation. One lateral move system is proposed to be installed to irrigate the planned 40 ha of fodder, most probably at the western end of the command area, adjacent to the distributary canal. The choice for irrigation lies between a lateral move irrigator, operating on a shuttle path (back and forth), with either an open canal along the contour as the suction sump, or else with reel hose and suitably located hydrants. In the latter case, these might be winch/towed units running up and down the slope, whereas for the lateral move, it would travel across the slope with a spray boom length of up to 250 m. For 40 ha, it should be feasible to operate with one unit, but this should be resolved at detailed design.

802. Lateral move irrigators require in the order of 20 to 30 m head at the command area, with a preference towards the lower pressure. If using an open channel (sump) supply, then the irrigation unit will need its own pump and power supply. If it is feasible to operate effectively across the whole area with a pressure hydrant, then pumping can be minimized if not eliminated.

Figure 182: Planned Irrigation Water Supply for Sugnugur Irrigation Scheme

Source: TA Consultant

c. Irrigation Scheme Layout

803. Sprinkler Systems. The Sugnugur irrigation scheme will have a pressure piped sprinkler lateral move or tow system, for a command area block of 40 ha. Within the confines of the Sugnugur boundaries, this could be achieved either with two strips 1,000 m long by 200 m wide, or with three strips 220 m wide but 600 m long. The actual configuration to be adopted will need to be confirmed

301 before finalizing the field canal alignment (on contour) or hydrants position (for hose connected). The alternative to the lateral move could be 1 or more towable boom spray/rain gun machines, which may be more flexible for the slopes and difficult areas. The exact position, alignment and control of water to the machines, and their general operational cycles will need to be defined before the required flow and application rates for the unit(s) can be confirmed. Whilst the lateral move machine can cover a wider pass per cycle, it is best suited to longer runs using a level open canal (sump) for water access, or else a sequence of spaced hydrants with a reel hose. By definition of the requirements for the canal, it would have to travel across rather than up and down the slope. With hydrants and reel hose it could go either way. If smaller towable boom spray and rain gun machines are used, then the hydrants can be set centrally to the area and the machines can run out either side of the central water supply pipe and hydrants. In this case, the optimal travel direction is up and down the slope, with winch pull for multiple positions across the slope. Ownership and operation of the lateral move (or equivalent) sprinkler irrigator will have to be agreed between soum government and farmer groups/WUAs.

804. Drip Systems. It is not possible to be specific about how the drip systems will be laid out. Discussions will need to be held with farmers to first define farmer group or WUA blocks for irrigation, and whether they are generally intending to grow potatoes or vegetables, on a regular basis. This may then define row crop spacing and alignment and provide specific guidance on where to place the drip system filter/pump/control unit, from which pumps would be rolled out once the crops are planted. A key aspect for selecting location will be access to power supply. Whilst each farmer group/WUA, once established, will operate over a contiguous block, the actual size of the blocks will vary. Therefore, until the block size and layout are known, the details of a drip system area and layout cannot be fixed. It is however presumed that once the position for the filter/pump/control unit is agreed, then the appropriately sized pipeline can be installed from the main/distributary canal, with maximal use of the natural head difference from canal to system head location. Whilst soum will supply the equipment, it is expected that once installed, the farmers would operate their own drip system.

805. The other remaining drip system will be a small unit to support windbreak development from seedlings to maturity. This will need to be located at the upstream end of the windbreak, supported if necessary, with pump and power to ensure the full windbreak line can be watered effectively on rotation. The detailed layout can be prepared at detailed design.

806. Figure 182 shows the overall layout of the upgraded Sugnugur irrigation scheme, whilst Figure 183 provides an overview of the proposed irrigation command area. The command area is protected by formed banks located on the downstream side of drains, which run on the high side of the command area to intercept overland runoff and carry this water around and/or away from the command area. If at the detail design it is assessed that there is some advantage to incorporate the windbreak with the drain, thereby entrapping runoff to sustain the trees, then this will need to be more fully assessed and detailed prior to construction.

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Figure 183: Overview of Upgraded Sugnugur Command Area

Source: TA Consultant

807. Drainage. Drainage will be needed to protect the area against the risks of large overland flows, coming from the south and east. The main and distributary canal presents a barrier to the free passage of overland flow, and a safe way to convey any runoff around or under/over the main/distributary canal is required, linked together with a protection bank and the windbreak. If water is to pass through the command area, then suitable drain alignment should be identified, and drains formed to safely pass the runoff. Such drains should not interrupt the movement of the lateral move or towed irrigation machines for the fodder command area.

808. It may also be necessary to protect any exposed infrastructure – pipes, canals, cropped area, windbreaks, roads and associated structures from the uncontrolled risk for erosion from overland flow or any infrastructure failure. The main form of protection would be pushed up earth banks suitably position and shaped to deflect any runoff around the key infrastructure and cropped area. The only structures specifically foreseen to protect infrastructure from runoff risks are: (i) Rock armored protection in the bed and sides of drains in proximity to crossing the installed canals and pipelines where the drain flows north to the river; and (ii) Possible installation of short piped sections in the upper reaches of the main canal (various locations and lengths) to facilitate, with flow management banks, the safe passage of runoff flows from the foothills across the line of the main canal, and thereby mitigate the risk for disruption of diverted water from the Sugnugur river.

4. Design Discharge

809. The average available water flow in the river can vary through the growing months from 1.16 to 3,29 m3/s, but in dry periods, then the low average water flow can be as little as 0.34 m3/s (Table 140). On average, with the improved irrigation system, total water extracted from the river

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will be about 40% less than is currently needed for the ‘without project’ situation. The peak net flow required for crops during the growing season is assessed at 0.52 m3/s so with allowance for 88% water delivery efficiency, the minimum flow requirement in the canal would 0.58 m3/s.

810. Because the low flow condition is substantially below the average gross flow required in the canal, then to minimize risk to crops during such periods, a balancing storage is proposed to manage and balance flows within the irrigation system. It is proposed that a small buffer storage will be created at the main canal intake by construction of a cross river barrier wall. This will always ensure the capacity to divert water, as the pool level in the river will remain steady. Within the canal system, between the main canal and the distributary canal, it is proposed to install a larger (up to 100,000 m3) balancing storage, that will provide the substantive buffer for water supply to the crops, even when river flows are low for extended periods. Whilst the mean average flow values indicate the water taken for irrigation will range from 2.2 to 15.4 percent of the net river flow (Table 140) through the crop growth period, there will be times when natural river flow is below the actual required irrigation water demand. With the improved project and improved water use efficiency of 0.88%, it will still be necessary to have reserve water in storage to enable irrigation to continue uninterrupted during dry periods/years. With the storage, water can be diverted from the river when it is plentiful, to be held in storage for gradual release to the crops when the available main canal inflow is too low to meet full irrigation water demand.

Table 140: Available Water Discharge from Sugnugur River Irrigation Net Off-river River Water River Water Design Discharge for Main Water period Average water Withdrawals Withdrawals Supply Infrastructure a Available pond (with project) (without project) m3/s Water m3 Distributary from river Main Canal Field Pipes to m3/s Min Canal (140 ha) Irrigation m3/s % Avg m3/s % m3/s m3/s System May 1.16 - 0.07 2.7 0.18 15.4 0.75 0.55 Up to 0.16 June 1.20 - 0.09 3.1 0.21 17.5 July 2.11 - 0.08 2.3 0.20 9.6 August 3.41 - 0.07 1.3 0.16 4.7 September 3.29 - 0.03 0.9 0.07 2.2 a Design discharge capacity does not mean that this flow is taken all the time or at the maximum rate. Source: TA Consultant

811. To enable the full water requirement to be supplied, the main canal will need additional capacity to transfer water from the river when it is available, over and above matching the irrigation water demand at that time. It is therefore proposed, that with the balancing storage in place, the main canal conveyance capacity be 30% larger than the peak irrigation demand flow requirement, so that additional flow can be used to fill and/or replenish the storage. Therefore, design should allow for the main canal conveyance to be up to 0.75 m3/s. In the distributary canal, the peak capacity is set at 0.55 m3/s, for up to 140 ha. On that basis, the pipe and/or canal needed to supply the sprinkler system (40 ha) would have a flow capacity of 0.16 m3/s. These provisional estimates should be checked and revised at detailed design, in accordance with how the final design is organized and operated, to best provide supply for the differing crops and systems operating in parallel.

5. Civil Works

812. The main civil works for the diversion headworks from Sugnugur River, and conveyance of water to irrigation sprinkler/drip systems in the command area will include:

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(i) construction of a (up to 3 m high, u/s slope 2:1; d/s slope 2.5:1, top) rockfill barrier wall (with impermeable core) about 250 m across Sugnugur River channel, incorporating the intake structure, between natural abutments (east and south/southwest), at the location of the existing intake, actual length, height and alignment to be confirmed at detailed design stage; (ii) incorporation of a reduced level (- 1.0 m) reinforced concrete spillway section, up to 10 m wide, to control pool water level upstream, and pass moderate excess flows back to main river, over a concrete armored spillway over the rockface of the barrier wall; (iii) construction of a new intake structure in the barrier wall at the location of the existing intake and main canal, including a vertical screw lift sluice gate, with free release of the flow (up to 0.75 m3/s) into the reformed, graded and lined main canal; (iv) construction of a sediment sluicing channel in the box section of the new intake structure, with a sluice gate (0.3 x 0.25 m) to the right side of the intake structure, for periodic sediment sluicing; base of sediment collection chamber to be formed for effective guidance of sediment under flow toward sluice outlet; (v) construction as necessary (cutting, forming, shaping and protection) of a channel to carry sediment back toward the river on the downstream side of the barrier wall, away from the toe of the embankment; (vi) cutting and formation of an extended Soum road up to the barrier wall left abutment and main canal intake structure; (vii) as the barrier wall will form a shallow pool (up to 2 m deep), the ponded area will need to be cleared of vegetation and possible low saddles around the pool may need to be raised to mitigate any risk for overspill around the barrier wall; (viii) reformation and re-lining/repair of the trapezoidal section main canal to balancing storage (about 4,500 m, subject to actual start and finish location); suggested inclusion of pipe sections for runoff overspill with inlet and outlet transition structures, where there is risk for concentrated runoff to and across the canal line; inclusive of any necessary water guidance and protection earth embankment; canal depth 0.6 m, bed width 0.6 m, side slope 1.5:1 and water depth 0.3 m; (ix) construction of a controlled main canal discharge structure (capacity 0.75 m3/s, canal invert level 1,154 masl) into the balancing storage (eastern end) to steady inflow velocity from the main canal, and to minimize scour around the toe of this structure within the balancing storage when water level in the storage is low; the main canal inflow bed level should be set close to the full storage level in the storage to minimize backup of flow in the main canal (though it can be partially submerged without issue provided there is no risk for overtopping the canal banks (freeboard minimum 0.3 m at full discharge)); (x) construction of an outlet from the balancing storage to the distributary canal; a gated outlet to the distributary canal (Q = 0.55 m3/s) to be designed at detailed design stage; (xi) up to 10 field distributary pressure pipelines (various lengths and diameters to be determined at detailed design, up to PN 4) to be installed, to supply either open canal (sump) for sprinkler systems or to distributed drip irrigation intake, filter, pressure and control stations (up to 9 No.); (xii) reforming or building new U-shaped earth drains (up to 12 km) to protect the canals and command area, and enable clear drainage of rainfall runoff and any canal overspills; (xiii) installation of various flow control and outlet structures in the main and distributary canals, with outlet to pipes (up to 10 No.);

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(xiv) development of the windbreaks (5.2 km) on the north and south sides of the command area.

813. At this stage, the design and related details are preliminary, and as detail design and operational requirements are clarified, some additional works may be identified (e.g. additional protection measures for pipes, construction of field covered and protected valve boxes, minor earth checks in drains to support windbreaks), including installation of a protective fence around the command area (about 15 km) with posts at 5-m intervals and four strands of wire.

6. Equipment

814. Within the civil works, required equipment will be limited to gates, pressure pipes (HDPE) and associated fittings to the sprinkler system connection hydrants. The following specific equipment, some of which was mentioned for installation with civil works are: (i) The Water Intake – one vertical lift sluice gate with preliminary 1.5 m wide and a 0.75 m lift, with capacity up to 1 m3/s; (ii) Intake Sediment Sluice – vertical lift sluice gate, provisionally 0.75 m wide with 0.4 m opening, sufficient to flush rapidly at up to 1 m3/s, details to be finalized around operational and physical levels at site; (iii) Provision for overland flow crossing points in main canal, using either low pressure pipe sections (Up to 3 no., up to 5 m long) and/or box culvert section (one) giving at least 0.6 m2 free flow section (depth of flow), each up to 6 m long, at required locations to pass the canal under formed drainage overpass; (iv) Provision and installation, as may be required, of various gates, valves and fittings (No. and open diameter (mm)) to regulate flow from canal to irrigation subsystem (Table 141); (v) One self-propelled lateral move sprinkler set, 250 m spray width, single sided with either float suction intake (from canal/sump) or flexible hose reel connection to installed field hydrants (200 mm diam, up to 300 m centers) to track up and down the line of the buried field distributary pipe(s), all inclusive of power supply, flow controls, and associated spare parts, spray nozzles and drop pipes suitable for particular crops, all details to be discussed with potential suppliers before confirming detailed specifications (specifics of lateral drive to be discussed and agreed based on local electricity power available, and the operational convenience of available options; (vi) Up to 10 low pressure drip filtration, pump and control station, with sufficient associated main and connecting drip pipes, for up to 100 ha; (vii) Provisionally, one or more sets of low-pressure micro spray and/or drip systems for installation in greenhouses (size and number to be determined), should the option to develop such facilities at the eastern end of the header canal be approved; (viii) Provision of relevant power supply infrastructure, whether connection to main national or local electricity grid, inclusion of diesel power and generator sets, or provision of diesel power to drive irrigation systems (pumps, self-propulsion, etc.) [there is an expectation that adopted sprinkler equipment would include suitable on- board power controls and drive mechanisms if electric power supply and cabling is not viable].

Table 141: Gates, Valves and Fittings to Regulate Flow from Canal to Irrigation Subsystem Pipe Intake Outlet Scour Valve Filter Set* Emitters# Gate Valve

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or Valve Main 3 3 3 with drip Distributary 7 7 3 with drip Drip Systems (10) 1 x 50 with pipe end 1 x inline inline Sprinkler System 1 1 1 1 online Source: TA Consultant

7. Bill of Quantities

815. The cost estimation for Sugnugur subproject construction and equipment is in Table 142, which summarizes the cost for key components required for upgrading and modernization. The preliminary estimated cost for Sugnugur subproject is MNT5,377.81 million, equivalent to MNT38.41 million/ha.

Table 142: Bill of Quantities for Sugnugur Irrigation Scheme Modernization Budget No Item Unit Quantity (MNT million) Unit cost Total Civil Works Headworks Sluicing structure with intake sluice channel 1 piece 1 72.68 72.68 and outlet flushing channel 2 Rockfill Barrier and Water level Control Weir m 40 2.87 115.00 3 Headworks protection embankment m 500 0.04 18.48 4 Main Canal, reforming and lining m 3,300 0.14 467.32 5 Field pipe m 4,645 0.06 258.84 6 Header Canal – reforming and lining, in take sluice m 5,300 0.14 746.43 7 Drain m 1,000 0.004 4.41 8 Balancing storage m2 49,000 0.024 1,176.00 9 Roads – forming and grading m 11,000 0.003 35.97 10 Windbreaks – prepare land and install ha 4.9 42.27 207.12 11 Drain and protection bank m 200 0.03 6.37 12 Fence km 12.0 7.00 84.00 Subtotal 3,192.62 Equipment Head work Control Sluice Gate, Width 1.0 m x Height 0.6 13 piece 2 1.68 3.36 m, vertical screw Header Field Canal Flow Control Gate, Width 0.4 m, 14 – piece 38 1.05 39.76 height 0.3 m 15 PE400, SDR17, 1,0mpa, DN250mm, PN6 m 4,645 0.08 370.60 16 Self-propelled lateral move sprinkler set 1 77.16 77.16 17 low pressure micro spray set 2 1.22 2.45 18 3ha Water Efficient Drip Watering Advanced System set 3 28.36 85.07 19 10ha Water Efficient Drip Watering Advanced System set 10 79.00 790.00 20 Trees number 14700 0.00 58.80 21 Excavator for O&M piece 1 168.60 168.60 Subtotal 1,595.80 22 VAT % 29.52 478.84 23 Environmental baseline assessment number 1 42.67 42.67 24 Environmental impact assessment number 1 42.67 42.67 25 Design cost ha 140 0.18 25.20 Sub-Total 589.39 Grand total 5,377.81 Source: TA Consultants’ estimates

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N. Subproject 16 – Dulaanii Tal Irrigation and Drainage System Design

1. Site Description

a. Area and Crop Maps

816. Geomorphology: The Dulaanii Tal subproject area is located in the Eastern Region of Mongolia on the broad flat unprotected plain near to Kherlen river’s riparian zone, and 5-6 km east of Chinggis City. The subproject area is in the eastern steppe of Mongolia, at 740 masl to 760 masl, and is bounded on the north by Samballkundev mountain (1,280 m) and to the south by the Kherlen River.

817. The Dulaanii Tal irrigation scheme, owned by Kherlen Soum, is located in the middle reach of the Kherlen River (Figure 184). It was originally developed in the mid-1980s, with pumped sprinkler systems, but was stripped of everything during the 1990s. No sign of the civil works and equipment, or of previous crop production activities remain (Figure 185).

Figure 184: Location of Dulaanii Tal Irrigation Scheme

Source: Based on Google Map

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Figure 185: Current Situation at Dulaanii Tal Irrigation Scheme

Upper: headworks and pipe canal; Lower: crop fields) Source: Consultant’ field visits

b. Climate

818. The 34-year time series (1985-2018) of monthly mean air temperature, wind speed and monthly precipitation data observed at Underkhaan meteorological station was analyzed. The climate of the Khangai mountain region is sharply continental like other regions of Mongolia.

819. In the Dulaanii Tal irrigation subproject area, daily temperature throughout the growing season can exceed 40oC (maximum daily) between May and August, and humidity is about 40- 56%. Precipitation, when water is required for crop production, varies from an average of 16.5 mm in May to 39.7 mm in June, 66.5 mm in July, 62.4 mm in August, with an overall annual average of 235.6 mm. Of this, about 45% falls in June and July, and about 80% in May to August. Average annual wind speed is 3.9 m/s. Mean monthly climate data for the project area are in Table 143.

Table 143: Mean Monthly Climate Data in Dulaanii Tal Irrigation Subproject Area Month Average Absolute Absolute Humidity Wind Precipitation Temperature Maximum Minimum (%) speed (mm) (oC) Temperature Temperature, (m/s) (oC) oC January -23.6 -0.7 -44.3 73.8 3.5 2.0 February -18.8 10.6 -41.2 70.1 3.7 2.6 March -8.7 22.1 -38.0 58.6 4.0 3.7 April 3.1 31.2 -20.8 41.5 5.2 6.3 May 11.2 34.2 -13.7 39.2 5.3 16.5 June 17.1 39.0 -1.8 48.3 4.0 39.7 July 19.6 41.0 1.2 56.9 3.4 66.5 August 17.4 40.4 0.0 56.1 3.2 62.4 September 10.5 32.3 -10.8 54.9 3.6 22.7 October 1.0 31.7 -25.4 56.7 3.6 7.1 November -11.7 14.6 -38.1 66.0 3.4 3.4 December -20.2 7.5 -43.1 73.8 3.4 2.7

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Average -0.3 25.3 -23.0 58.0 3.9 235.6 Source: National Agency for Meteorology and Environment Monitoring

820. Air temperature. Figure 186 shows the trends for changes in monthly mean air temperature from April through to September. As April mean temperature is 3.1oC, and below 10oC, there is insufficient natural warmth in the air to support crop growth for most of that month.

821. Air temperature trends. Air temperature trends (Figure 186) indicate that monthly mean air temperature changes for the months from April to September have been occurring consistently. April mean temperature has increased by 2.8oC, May by 1.2oC, June by 2.5oC, July by 3.0oC, August by 2.2oC, and September by 2.0oC. On balance, there has been a shift in the mean annual growing season temperature, which will benefit crop production. With increased temperatures in the growing season, some increased irrigation will likely be required.

Figure 186: Trends of Monthly Air Temperature at Dulaanii Tal Irrigation Scheme

Source: National Agency for Meteorology and Environment Monitoring

822. Duration of hot days. One important climate factor that influences irrigated crop production is the number of hot days. Figure 187 shows the number of days each year with a daily average air temperature above 25oC has increased by 40 over the last 34 years. Despite this, the average number of days where air temperature exceeds 30oC has only increased by 10.

Figure 187: Trend in Hot Days with daily Mean Temperature More than 25oC and 30oC

Source: National Agency for Meteorology and Environment Monitoring

823. Precipitation. Annual average precipitation is 235.6 mm. Changes in precipitation for the months from April to September have not been consistent (Figure 188). Precipitation has increased by 9 mm in May, 12 mm in June and 6 mm in September, but has decreased by 16 mm in July and

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9 mm in August, with no change in April. However, overall precipitation from June to September has increasing since the beginning of the 2000s.

Figure 188: Trends in Monthly Precipitation at Dulaanii Tal Irrigation Scheme

Source: National Agency for Meteorology and Environment Monitoring

824. While precipitation has decreased for most months of the growing season, the number of days without precipitation has increased in June through September (Figure 189).

Figure 189: Trends in Number of Days Without Precipitation

Source: National Agency for Meteorology and Environment Monitoring

825. Wind. Mean monthly wind speed during the growing season tends to be higher than during other months (Table 143). The monthly average wind speed is 5.2 m/s in April, 5.3 m/s in May, 4.0 m/s in June, 3.4 m/s in July and 3.2 m/a in August, which is relatively high compared to other regions. The maximum wind speed can reach 20 m/s once a year. The number of days when wind speed has exceeded 10 m/s has increased by 150 days over the last 34 years (Figure 190). From, Forty percent of the wind comes from the south west and 24% from the south (Figure 190), indicating that windbreaks should be developed to the south-west and south.

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Figure 190: Trends in High Winds and Wind Direction

Source: National Agency for Meteorology and Environment Monitoring

826. Agro-climate. Over the period from 1995 to 2018, the growing season length has increased by a few days because of a shift in when the air temperature transitions above 10oC (earlier dates in spring) and below 10oC (later dates in autumn). The accumulated temperature that supports longer crop growth with more frost-free days has increased by about 5 days (Figure 191).

Figure 191. Agro-climate Characteristics

Source: National Agency for Meteorology and Environment Monitoring

827. Projections. Summer temperature is projected to increase by a further 1oC, and 2.0oC (Figure 4) and no change in precipitation (Figure 5) by 2035 and 2065, respectively, in the Dulaanii Tal subproject area. A continued increase in temperature and a no change in precipitation are the most likely combined future impacts necessitating more intense irrigation.

c. Soils

828. The Dulaanii Tal irrigation scheme area soils map (Figure 192) shows that the dominant soil types in the command area are kastanozem (silt loam) and alluvial meadowish.

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Figure 192: Soil Map of Dulaanii Tal Irrigation Scheme

Source: Institute of Geography and Geo-ecology

829. Eight soil samples at up to 1-m depth were taken. According to their analysis, the command area soil has low organic matter content, less than 1%, and is affected by a high rate of erosion. Originally the area was covered by steppe native grassland vegetation. The soil is neutral with a pH of 6.8 and electrical conductivity (EC) of 35-60 μS, meaning there is no salinity risk for crops.

830. The soil is mostly sandy loam with 65-70% sandy fraction. Volumetric water content was 12-14%. The fraction of stone and gravel greater than 2 mm is 15-18% (Table 144). Soluble nitrogen content is acceptable at about 9.2 mg/kg, plant available phosphorus level is very low at about 6-7 mg/kg, and exchangeable potassium levels are on the lower lever at about 30-35 mg/kg. Cation exchange capacity is low, at about 9.5 meq/100g, which means that cations are binding with clay particles and soil will deliver nutrients to plant roots. Detailed analysis is given in Annex 2 and 3.

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Table 144: Soil Profile and Analysis of Dulaanii Tal Irrigation Scheme Soil Depth, m Characteristic horizon 1 O 0- 0.1 Grass Root zone with slightly decomposed organic matter. Sandy loam

2 A 0.1- 0.4 Grey brown soil. sandy loam

3 E 0.4 - 0.6 Loamy sand /78-80 % is sand/ 4 B 0.6 -0.7 Sand and gravel.

5 C > 0.7 Grass Root zone with slightly decomposed organic matter. Sandy loam

Source: Integrated agricultural laboratory

d. Water Sources

831. The main water source for irrigation is the Kherlen river (Figure 193). The hydrological gauging station is located upstream of the subproject area. For water resources assessment for the Dulaanii Tal irrigation scheme, the 62-year of time series (1959-2017) of monthly data from Underkhaan gauging station has been used.

Figure 193: Kherlen River Basin

Source: TA consultant based on National atlas

832. Table 145 shows monthly mean flow data at Kherlen-Underkhaan river gauging station, which ranges from 17.7 m3/s to 55.3 m3/s during the growing season. As the environmental flow

314 requirement in the Kherlen River is 18.0 m3/s, there is an average monthly mean flow of at least 8.2 m3/s available to meet non-environmental flow demands in June, and more in other months through to August. There is no net water available in May as the long-term average of 17.7 m3/s is less than the environmental flow of 18.0 m3/s. While the monthly high flow can be 47.3 m3/s in May, the low discharge can be much less than the environmental flow requirement in all months. Even at 75% reliability of flow, there is insufficient water available in May and June, and more than enough water available for reliable irrigation at Dulaanii Tal during the July, August and September.

Table 145: Water Resources of the Kherlen River at Dulaanii Tal Subproject Area Mean Mean Net Water available for Mean Environ- Maximum Minimum % of Annual use Month Discharge mental flow Discharge Discharge 3 3 Discharge (m /s) (m /s) 3 (m3/s) (m3/s) (m3/s) (m /month) April 38.8 0.0 9.6 18.0 3.99 - May 47.3 4.1 17.7 18.0 7.37 - June 85.4 4.5 26.2 18.0 10.9 8.2 21,962,880 July 246.0 4.1 49.2 18.0 20.5 31.2 83,566,080 August 210.0 5.6 55.3 18.0 23.1 37.3 99,904,320 September 141.0 6.2 45.0 18.0 18.77 27.0 72,316,800 October 70.0 4.8 25.8 18.0 10.76 7.8 21,962,880 November 36.5 0.4 7.4 18.0 3.10 - December 17.8 0.0 1.5 18.0 0.62 - January 4.0 0.0 0.6 18.0 0.24 - February 3.0 0.0 0.3 18.0 0.14 - March 6.9 0.0 1.2 18.0 0.50 - Source: National Agency for Meteorology and Environment Monitoring

833. Kherlen river flow during the irrigation period from May to August at Kherlen-Underkhaan has decreased sharply since 1959 but has increased slightly since 2010 (Figure 194).

Figure 194. Kherlen River Flow at Kherlen-Buyant Gauging station (1965-2017)

Source: National Agency for Meteorology and Environment Monitoring

834. Kherlen River flow sensitivity related to climate change is shown in Table 146. If precipitation remains unchanged and average temperature increases by 1°C, 2°C, 3°C or 5°C, it is projected that river flow could decrease by 8.2% (+1oC) to 37.5% (+5oC). The impact of precipitation increasing by up to 20% is substantially more marked than if precipitation decreases by 20%, but a temperature increase of 5oC would almost eliminate any gains expected from additional precipitation. If precipitation has declined by 20%, then the reduction in river flow from increased temperature is relatively small. Overall, river flow is highly sensitive to reduced precipitation, but with unchanged or increased precipitation, the impact of increased temperature is more significant in moderating river flow.

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Table 146. Kherlen River Percentage Change in Flow Due to Climate Change Temperature Projected Percentage Change in Precipitation Increase (oC) -20% -10% 0% +10% +20% 0 -51.7 -29.9 39.4 89.6 1 -55.7 -35.7 -8.2 28.1 74.6 2 -60.0 -42.0 -17.3 15.6 57.7 3 -63.7 -47.6 -25.2 4.6 43.0 5 -69.5 -56.1 -37.5 -12.6 19.7 Source: TA consultant

835. Water quality. Water chemistry analysis for Kherlen river from 2013 to 2018 (Figure 195) 2+ 2+ indicates that, overall, the chemical composition is good. The concentrations of Ca , Mg , SO4 and Cl- do not exceed the irrigation water standards thresholds. Sodium adsorption ratio (SAR), which is a critical factor for sustainable irrigation, is also found to be within acceptable limits.45 Therefore, water from the Kherlen River is concluded to be well-suited for irrigation use.

Figure 195: Water Chemistry of the Kherlen River

Source: Central Laboratory of Environment and Metrology

836. Suspended solids in the Kherlen River water range from 0.8 to 129.1 mg/l (or 0.008 to 0.1 kg/m3), and often exceed 20 mg/l (0.02 kg/m3) (Figure 196) and can exceed 50 mg/l during floods.46 Thus, Kherlen river water may not be suitable for irrigation in terms of suspended solids according to the irrigation water standard. Therefore, there is a need for careful management of water diversions from the river to reduce suspended sediment discharge into the intake and canal/irrigation system, by providing additional sediment management measures at the intake or through settlement and flushing basins aligned with the main canal.

45 MNS-ISO-16075-1:2018 Guidelines for treated wastewater use for irrigation projects: The basis of a project for irrigation 46 MNS 4943: 2015: Mongolian standard on effluent water quality in the environment

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Figure 196: Suspended Solids in Kherlen River Water

Source: Central Laboratory of Environment and Metrology

837. Water quality in the Kherlen River the water is classified as “clean” with an index of 0.42, based on water quality analysis and assessment against the Water Quality Index (WQI).

2. Irrigation Water Requirement

838. The designed command area is 700 ha out of which 170 ha is for each of potatoes, vegetables, cereals and fodder, which will be grown in rotation, and 20 ha for fruits (Table 147). There is 7.0 ha for tree wind breaks to the west and south-west. The windbreak will be made up of three rows which will require nurturing from seedling to maturity. Leafy trees will be planted in two rows with one row of low fruit and/or nut bushes on the windward side. These windbreaks will be set along the north and northeastern boundary of the command area to contain the aggression of the prevalent strong winds, as determined in the wind direction data.

Table 147: Current and Planned Command Area Crop type Current allocation Irrigation method Planned allocation Irrigation of command area of command area method (ha) (ha) Potatoes No cultivation Furrow 170 Drip & sprinkler Vegetables 170 drip & sprinkler Cereals 170 Fodder 170 sprinkler Fruit trees and 27 drip wind break Source: Consultant’s estimate

839. Overall efficiency (Table 8) will be raised to 73% using piped systems, modern central pivot sprinkler irrigation machines for fodder, cereals and vegetable, low pressure drip systems for potatoes and windbreak (Table 148).

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Table 148: Scheme Irrigation Efficiency Characteristics Field irrigation Percentage Conveyance Field Scheme application of total efficiency application irrigation command (%) efficiency efficiency area (%) (%) Current for total Surface irrigation 100.0 60 60 36 command area (border, furrow, basin) Designed for Fodder, Sprinkler cereals, vegetables , 88.0 95 75 71 616 ha Designed for potatoes, Drip 12.0 95 90 86 84 ha Average for designed Combined sprinkler 100.0 95 75 73 command area and drip Source:TA Consultants

840. The total irrigation water use for the planned cropping area and crop mix is estimated to be 4,813,253 m3 (0.36 m3/s) in the with-project scenario and 4,959,810 m3 (0.37 m3/s) in the with- climate-change scenario based on an overall water use efficiency of 73% using piped system for primary supply, and central pivot sprinklers for fodder, cereals and vegetables, drip systems for potatoes. The total irrigation water requirement accounts for 1.7% of total available water in the in June through September or about 0.4-5.5 % of the river flow of the given months (Table 149), after meeting the environmental flow of 0.47 m3/s. Thus there is sufficient water is available to meet irrigation needs.

Table 149: Irrigation Water Requirements for Dulaanii Tal Irrigation period Item Total May June July August September Allocation of command area Potatoes (ha) 170 170 170 170 170 Vegetables (ha) 170 170 170 170 170 Cereals (ha) 170 170 170 170 170 Fodder (ha) 170 170 170 170 170 Fruit trees and wind break (ha) 27 27 27 27 27 707 Water requirement with project Gross irrigation norm (m3) 859,299 899,800 816,672 578,708 359,196 Irrigation Efficiency (%) 0.73 0.73 0.73 0.73 0.73 Total Irrigation Water Requirement (m3) 1,177,122 1,232,602 1,118,729 792,750 492,049 4,813,253 Water requirement with project and with climate change Increase in Evapotranspiration, (m3) 7,358 4,635 4,867 4,515 11,425 Projected water requirement (m3) 896,973 911,926 833,666 595,349 382,748 Irrigation Efficiency (%) 0.73 0.73 0.73 0.73 0.73 Projected total irrigation water requirement (m3) 1,228,730 1,249,214 1,142,008 815,547 524,312 4,959,810 Source: TA Consultants

Table 150: Water Availability for Irrigation Percentage Projected total of irrigation Monthly Environ- irrigation water water use Irrigation River ment Net available flow in the requirement with from net period Discharge, Flow, river project river flow m3/s m3/s m3/s m3/month m3/s m3/month % May 17.7 18.0 -0.3 -803,520.0 0.44 1,228,730 - June 26.2 18.0 8.20 21,962,880 0.48 1,249,214 5.80 July 49.2 18.0 31.2 83,566,080 0.42 1,142,008 1.34

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August 55.3 18.0 37.3 99,904,320 0.30 815,547 0.79 September 45.0 18.0 27.0 72,316,800 0.19 524,312 0.42 Total 276,946,560 4,959,810 1.79 Source: TA Consultants

841. The irrigation demand for the planned 700 ha of mixed cropping requires a peak flow of 0.45 m3/s (73% overall efficiency), which means that if conveyance and application losses can be further reduced through modernization, it may be possible to expand the overall command area. However, there is no water available in May when estimation is based on long-term average flow. Based on analysis of daily flow in April, May and June of the lowest flow year (Figure 197), there is sufficient water available for irrigation due to spring snow melt. Even though the monthly mean flow is low, the daily flow exceeds the environmental flow. Thus, more detailed water analysis is recommended when doing detailed design.

Figure 197: Kherlen River Daily Flow Hydrograph for May 75% Exceedance

60.0 Law flow year Environmental flow

50.0 /s 3 40.0

30.0

River River flow, m 20.0

10.0

0.0

Days

Source: National Agency for Meteorology and Environment Monitoring

3. Proposed System and Layout

a. Area Topography

842. The intake from the Kherlen River is located at elevation 1,019 masl (left riverbank level), at 47.21.6.33 N and 110.45.31.22 E. This intake will have a closure sluice gate. The boundary of the main fodder/cereal/potato command area is 700 ha at elevation 1,026 masl. The planned new irrigation system will include a pump irrigation system from source (Kharlen River) (Figure 198).

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Figure 198: Proposed Irrigation Scheme Layout

Source: TA Consultants

b. New Irrigation System

843. The overall irrigation design is summarized in Table 151 and detailed below.

844. Headworks Weir. The system will include a barrier across the river with a weir length equal to the width of the river plus the addition of abutments to both banks. The abutments will blend into any additional embankments that may be needed alongside the river to at least contain a peak river pool water level without overtopping. It is assumed (to be checked at detail design) that under normal flood flows, the water level with flow passing over the weir (at river width) would rarely, if ever, exceed the indicated top of bank height, but a detailed check for this should be undertaken, and the abutment and bank design height should be raised if necessary.

845. Headworks Intake. The new weir with gated intake and sediment sluicing arrangement (as shown in Annex 1) should be installed at the left abutment, with two sluice gates, suitably sized to pass the design peak flow for the canal (1.0 m3/s). This intake structure would be rectangular in general form and embedded as an integral part of the embankment in the right abutment. It would include: (i) An intake sluice gate of appropriate size for flow with minimal head loss when fully opened; (ii) A sediment trap chamber with a suitable alignment and formed floor to guide flow and encourage sediment removal when the flushing sluice gate is opened;

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(iii) An outlet sluice of sufficient size to engender high velocity discharge and flushing to an external channel that runs back to the river downstream of the river barrier/weir; (iv) An internal obliquely aligned side spill weir wall (to get length) where clean water (without the settled sediment) can flow over into the outlet chamber, be steadied in a pool area and released steadily into the canal (or pipe). The indications are an internal weir wall length of 4 to 6 m is required to pass the design flow at 0.4 m to 0.5 m depth over the weir wall; (v) An outlet basin to steady the flow prior to it exiting into the lined canal; (vi) The outlet canal to be set at a level (making use of level differential) to facilitate installation and functionality of the sediment excluding intake structure.

846. The intake with sediment exclusion feature will be maintained to protect pipes and pumps. Where pipes, pumps and mechanical sprinkler and drip systems are used, sediment is the enemy, and everything should be done to exclude sediment from the water before it enters into any closed pipe system.

Table 151: Irrigation Design Option No Irrigation Scheme Details and Value and Units Components 1 Gross irrigation scheme area 770.0 hectares 2 Irrigation scheme command area 700.0 hectares 3 Land use coefficient (1/2) 0.95 4 Main canal (lined) capacity Q = 2,000 l/s, L = 200 m, 5 Main canal intake structure and sediment Q = 2,000 l/s, see Annex 1 sluice 6 Settling basin, inlet structure and escape see Annex 1 outlet 7 Drains around command area up to L = 6,000 m, b = 1.0 + m, m = 1.5 8 Protection barriers around command area Up to L = 6,000 m, b = 2.0 m top, m = 1.5, h = up to 2 m 9 Pumping station intake pipework and 30 m x 20 m x 3.5 m filtration units 10 Pump Station, 4 pumps (one standby), Details to be developed power supply and control panels 11 Drip irrigation system for windbreaks and Q = 25 l/s, L = 13,900 m, A = up to 80 ha orchard/vegetable area 12 Pipes (HDPE or equivalent) to center pivot L = 6,606 m, Diam (ID) = 500 mm, irrigators (11) L = 2,600 m, Diam (ID) = 450 mm, L = 5,050 m, Diam (ID) = 355 mm, etc. Diameter will be to standard available, OD or ID, best next size 13 Center pivot machines (3) A = 56 ha, Radius = 422 m, App Rate = 8 mm/day 14 Road 12,900 m, with surface area of 3.87 ha 15 Windbreak/forest strip L = 13,900 m, b= 10 m, with area of 13.90 ha 16 Small sprinkler equipment sets Up to X sprinkler units - to be used in multiple 84 ha areas 17 Fence length Up to 14.000 m Source: TA Consultants

847. Settling Basin: The settling basin of size 30 m x 20 m x 3.5 m downstream of the head regulator will be constructed for the settling of sediment. The settled sediment will be hydraulically flushed to the river. This will be very useful while the system is using sprinkler and drip irrigation after modernization.

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848. Pumping Station. Due to the local topography, there is no natural hydraulic head available from the river for the operation of piped sprinkler and drip irrigation systems. It is therefore essential, if adopting these types of systems, to include sufficient pumping capacity to deliver water to the irrigation machines/systems at the required operating pressure. Water can be pumped using suitable centrifugal or combined axial/centrifugal pumps. Choice should depend on operational efficiency for the particular flow and capacity and costs. It is assumed that, for complete operational independence, there will be four separate center pivot systems, where each supplies water, on rotation to a movable center pivot with four operating positions (circles). The required flow rate is assumed at 8 mm/day equivalent across the 56-ha center pivot circle. Each pump would also be supplying water at the same rate to 25% more area, this being the infill areas between/around the circles, which will use smaller specific types of irrigation equipment. Thus, each pump is supplying sufficient water to irrigate 125 ha at 8 mm/day. It is also supposed that all four pumps might be connected at the pump station with common inflow and/or outflow manifolds, which would then also provide flow for the windbreak and orchard irrigation systems, and by virtue of connection, can equalize pressure and flow to all parts of the command area. The specifics for linking or not linking the separate irrigation systems from a common pumping arrangement, with valves and manifolds, will need to be discussed and finalized at detailed design. By linking the pumps and comparing combinations to meet expected output and pressure requirements, there may be possibilities to moderate overall equipment, energy and operating costs. For this analysis, it is assumed there will be four separate center pivot pump systems with outflow capacity of 125 to 130 l/s against an overall operating head up to 50 m (conservative as may need only about 40 m depending on pipe length, size and hydraulic friction loss).

849. A provisional estimate has been made for pumping costs, based on the arrangement outlined above in the scheme layout. A cost range has been developed using a net ‘norm’ on the assumption less water is needed when using sprinklers than if using surface irrigation, as is the general basis for derived ‘norms’. These are also allowing for the water losses that occur in the open canal systems, whereas with pumping, the costs are attributable to the net water actually pumped inclusive of direct on-field application losses, taken as 10%. On this basis, to operate three pumps to service the three central pivot units and other ancillary irrigation systems, the annual electricity costs (subject to actual applicable tariff) are in the order of MNT142.9 million per season (MNT204,200/ha) (Table 152).

Table 152: Operating cost of pumps S.No Item Unit Dulaanii Tal 1 Command area CA 700 2 Total Dynamic Head m 40 3 Total volume of water required m3/year 4,968,882 (Water pumped during May-Sep) 4 Total Water Requirement in June m3/month 1,256,251 5 Peak Pumping hours hrs 20 6 Quantity of water required m3/hr 2,093 7 Pump operation hours in a year hrs 2,373 8 Power requirement Kw 1,091,102 9 Motor efficiency % 0.88 10 Energy requirement for total command are Kw 764,521 11 Energy per ha Kwh/ha 1,558 12 Rate per Kwh MNT 131 13 Operation cost/ha MNT 204,203

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850. The pump station will directly draw water from settling basin to remove any suspended sediment that could otherwise be harmful to and might collect in the pipes, valves, sprinklers and drip emitters.

c. Proposed Layout

851. Distributary/Field canals. The new irrigation system design is based on the use of center pivots covering 58 ha each. A total of 11 circles are defined. The general land form is well suited to the use of center pivots, and as the soils are highly permeable with a sandy silt topsoil, low in organic matter, overlying a more permeable sand transitioning to gravelly sand at depth, it is best to use an irrigation system that more uniformly distributes and limits the depth of water application per path. This is not possible with surface irrigation, where much of the water would be lost to deep percolation close to the canal, limiting effective overland flow runs. By using center pivots, water can be spread more evenly, and can be applied at rates within the general water holding capacity of the topsoil, and thereby constrain overall loss of scarce water through deep percolation. However, allowance will be given for leaching of salts. Therefore, the prime means of distributing water over the land for the crops will be center pivot sprinklers, and this will be enhanced within the substantive blocks between the pivot circles that cannot be readily irrigated, by also deploying smaller localized sprinkler/spray/ drip solutions, supplied from the center-pivot buried supply pipes, to suit particular cropping requirements in those smaller areas.

852. Additionally, 1-3 drip systems are proposed with direct supply from the pumping station, sufficient to irrigate up to 13.9 ha of windbreaks.

853. Drains. the Dulaanii tal command area is large and lies on the alluvial flood plain slopes formed over many years. These slopes still carry runoff water from rain and snowmelt, and the route of this runoff can be seen in Google Earth across the command area. Once the irrigation system is in place, it will be preferable to ensure there is no overland flow crossing the cultivated areas and causing aggressive erosion, as such washouts are disruptive to both cultivation and the passage of the irrigation equipment. To avoid such risks, it is proposed that a combination of surface drains and raised banks are installed around the boundaries of the command area.

854. Drains and banks are needed to intercept and reliably direct excess runoff water and filter backwash water safely around and away from the command area. Drains will discharge to the Kherlen River. The estimated length of drains required within and around the command area is about 6,000 m. They will have a minimum width of 1.0 m, and a side slope of 1.5 to 1. They will be earth channels open to livestock, traffic and general runoff, and will therefore require periodic inspection and maintenance to ensure adequacy for purpose.

855. Constructing and forming the drains will provide material that can be used to form protective banks that are needed on the lower side of the drain. These banks would be nominally 2 m wide at the top, follow the grade line of the drain and be up to 2 m high across any localized depressions. Their purpose is to prevent runoff from crossing over the drain line and help redirect major runoff along the line of the drain. These banks could, if required, duplicate as part of the access road network. Some specific arrangements may have to be made to safeguard access to the command area with appropriate locations to cross the drains and the banks without disrupting flow in the drain or weakening the effectiveness of the banks. Where the drains are to cross the pumping main from the pump station, special attention will need to be given to set the pipe well below the drain bed level and provide added rockfill or concrete protection for the pipe and the drain banks.

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856. Command area fence. A fence will be designed and installed around the command area to protect the cropped area, forest strips and seedlings from livestock and other outside interference. The fence will be up to 14 km meters long and will comprise 4 lines of galvanized steel wire between wooden posts 5m apart.

857. Access road. Roads, with a minimum width of 3.0 m and total length of up to 15 km, will be formed and protected to the site and headworks, and within the irrigation command area. These will run along or on the protection banks, along the main canal, and between the central pivot connection hydrants. They will be formed as earth roads, suitably elevated where necessary, in conjunction with the pipe, canal, drain, protection bank and windbreak network.

858. Windbreak/Forest strip. Windbreaks are used as a means of checking aggressive winds locally to protect dry soils from erosion. These windbreaks are located in suitable alignments adjacent to the command area or canals, on the windward (approach) side. It is proposed that wind breaks be installed for about 13.9 km. The windbreak will consist of two rows of trees and 1 row of shrubs/bushes (for fruit and/or nuts). The distance between each tree will be 4 m, and between each bush 1 m. The distance between the tree lines will be 4 m and the shrub line will lie a further 3 m away from the second tree line. The general arrangement for setting out the windbreak lines is shown in Annex 1. At the initial development stage of these windbreaks, it is proposed that they be supplied with water via permanently installed dripper lines, with the intake located at and using filtered water from the main pump station. Specific design of drip systems – pump, filters, control valves, main supply lines, and dripper pipes to tree and/or bush base should be completed at detail design stage. It is assumed that up to 7,500 m of main supply pipe, and at least 24,000 m of small diameter in-line emitter drip pipe will be required to reach all trees and bushes. It is assumed for water demand estimation purposes, that the effective wetted area is the length of the tree line times an effective 10 m overall width. Alignment of the main pipes will, wherever possible, be downslope to provide some partial pressure recovery over distance. However, where lines run uphill, sufficient initial pressure can be provided from the pumping station to ensure operating lateral lines (there will be some rotation between blocks) will have sufficient pressure to ensure minimum outflow pressure at the furthest outlet.

859. Irrigation method. For Dulaani Tal, the modernized design uses center pivot irrigation machines. With 11 circles, the area can be covered with 3 units working on a 72-hour irrigation period per circle. On the assumption that each machine can deliver an equivalent of 8 mm per day over the circle, but take three days to complete the circle, the irrigation depth would be 24 mm per cycle. Given that the root zone soil depth is about 400 mm, and the water holding capacity (replenishment) is a minimum of 5%, then 24 mm represents 6% of the water holding capacity of the soil. This application rate reduces the risk for any excessive deep percolation, with a 12- to 15-day period between irrigations. Taking this approach, then within the 12- to 15-day period, the center pivot can be used sequentially on up to four circles, with relevant disconnection, moving and reconnection of the machine for each successive circle estimated to take from 3 to 4 hours. On this basis, the three center pivots would complete between 8 and 10 cycles each per season.

860. Additionally, the shortfall at the aggregated corner areas for each circle in the main command area are proposed to be irrigated with small subsystem sprinkler or drip as suited, either covering the main crop, or otherwise for smaller pockets of potatoes, vegetables, or fruit trees. The water would be source via connection from the main center pivot pressure lines, with strategically placed hydrants and movable irrigation infrastructure – pipelines and risers, rain guns or drip roll out. A four-corner block between four center pivots is effectively 15.33 ha of potentially unused land, so there is merit in considering how to utilize this as a small subunit, or as a supplementary area attached to the center pivot circles. In total, this could be four subunits totaling

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61.3 ha. Similarly, there are 10 double corner blocks and one triple, which would provide another 88 ha of irrigated land. Thus, whilst the center pivots are the main irrigation machines, it would still be feasible to arrange infill irrigation for up to another 150 ha.

861. Besides the main center pivot sprinkler systems, and any additional sprinkler or drip systems tapped to the center pivot pressure supply pipes, there is a need for drip systems for up to 13.90 ha of windbreak around of the command area. The drip systems would include a filtration unit on the main feedline, which would backwash through control valves and discharge to the escape drain to the river. These systems would operate on a rotational basis under lower pressure, with pressure compensating in-line emitters or otherwise higher head movable sprinkler/riser lines.

4. Design Discharge

862. The estimated maximum discharge capacity from the river intake headworks is 1.54 m3/sec (Table 153), which at 73% overall conveyance and application efficiency, equates to a net average water application rate of 0.77 l/s/ha for 700 ha. The peak water flow in the main canal can be designed to be up to 2.0 m3/s without the use of the balancing storage.

Table 153: Design Discharge from the Kherlen River Month Net available Water extracted Canal and Pipe Capacities Water a from river for m3/s m3/s irrigation with project Distributary m3/s % Main Canal Main Pipe Pipes May 9.60 1.0 10.40 1.0 0.47 0.16 June 14.0 1.0 7.10 1.0 0.48 0.16 July 20.10 1.0 4.90 1.0 0.44 0.16 August 24.0 1.0 4.10 1.0 0.31 0.16 September 18.40 1.0 5.40 1.0 0.20 0.16 a See Table 145 Source: TA Consultant

5. Civil Works

863. The main civil works for the diversion headworks on Kherlen River will include survey, detailed design and strengthening/raising of the cross-river barrier to maintain a river pool level for the diversion and conveyance of water to a pump station and irrigation sprinkler/drip systems. The works can be summarized as: (i) Construction of the rockfill barrier wall (with impermeable core) across Kherlen River to raise the pool water level to a reliable quantity; (ii) Construction of a settling basin (30 m x 20 m x 3.5 m) with outlet sluice gate flushing sediment back , via formed channel, to the river below the river barrier; (iii) construction of a new intake structure at the head of the previously used intake location during 1980. The head regulator with inlet sluice gate, internal flow control weir for discharge to the main canal, with outlet sluice gate for flushing sediment back, via a formed channel, to the river below the river barrier [this internal weir acts like a sidespill weir and has to be a minimum 5 m long to ensure depth of water over the weir does not exceed 0.4 m; assume with 0.1 m headloss through sluice gate and sediment settlement chamber, the weir sill level will be set at least 0.5 m below the set river pool water level]; (iv) construction of a safety protection embankment from the barrier wall;

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(v) reformation, realignment and lining of the main canal (200 m long), to discharge upstream of the settling basin; (vi) provision of piped/culvert outlet from to the pump station, to a suction sump, with coarse trash and sediment strainers on the inlets, whether one only inlet or several inlets, one per pump; (vii) provision of a pump house, to house up to 4 pumps, inclusive of suitable water filtration unit(s), pipe connections, valves and monitoring/control systems, and power connections, to supply 3 central pivots, and all associated small irrigation systems outlined for the windbreaks and infill areas between the central pivots; (viii) installation of main and subsidiary pressure pipes to deliver water from the pump house to all irrigation systems (central pivot, sprinkler/spray, drip) for the complete 700 ha command area, inclusive of pressure monitoring and warning systems for fault management; (ix) reforming and/or new drains (about 10.0 km) to protect the canals, associated infrastructure, windbreaks and command area, with clear effective drainage of rainfall runoff and any canal overspills to Kherlen River; (x) formation of relevant protection banks around the command area and other infrastructure, in conjunction with the development of drains and windbreaks; (xi) construction/formation of up to 13 km of access road; (xii) construction of up to 13.9 km of fence for stock proofing the command area.

864. At this stage, the design and related details are preliminary, and as detailed design and operational requirements are clarified, some additional works may be required (e.g. crossing points on the main canal at headworks, or at start of the command area).

6. Equipment

865. Within the civil works, required equipment will be limited to gates to be installed for: (i) Water intake – vertical lift sluice gate with preliminary 1.2 m wide and a 0.6 m lift; (ii) Intake Sediment Sluice – vertical lift sluice gate sufficient to flush rapidly at up to 1 m3/s, details to be finalized around operational and physical levels at site; (iii) Provision of 4 pumps and associated pipes, with up to 40 m operating head and output of at least 160 l/s, to supply all planned irrigation systems (center pivot, sprinkler/spray, drip) to cover the full 700 ha in a maximum 15-day cycle; (iv) Provision of all required pipework – HDPE or other as suitable – to distribute all pumped water around the command area to the designated center pivot anchor stations and other required offtakes for minor systems; (v) Provision of 3 56-ha center pivot sprinkler sets, with 420-m boom, inclusive of propulsion power supply, operating control, and associated spare parts, spray nozzles and drop pipes suitable for particular crops, all details to be discussed with potential suppliers before confirming detailed specifications; (vi) Provision of three drip system controlling stations and associated low-pressure drip pipework, with sufficient associated connections and control valves for up to 13.9 ha of windbreak and up to 80 ha of upgraded and revitalized orchard; (vii) Provisionally, one or more sets of low pressure microspray and/or drip systems for installation in greenhouses (size and number to be determined), should the option to develop such facilities be adopted; (viii) Provision of relevant power supply infrastructure, whether connection to main national or local electricity grid, inclusion of diesel power and generator sets, or provision of diesel power to drive irrigation systems (pumps, self-propulsion, etc.). There is an expectation that adopted sprinkler equipment would include suitable on-

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board power controls and drive mechanisms if electric power supply and cabling is not viable.

7. Bill of Quantities

866. The cost estimation for Dulaanii Tal irrigation scheme construction and equipment (Table 154) summarizes the cost for key components required for the upgrading and modernization. The estimated cost for Dulaanii Tal irrigation scheme is MNT9,608.79 million, equivalent to MNT13.73 million/ha.

Table 154: Bill of Quantities for Dulaanii Tal Irrigation Scheme Modernization Budget

No Item Quantity (MNT million) Unit Unit cost Total Civil Works 1 Headworks Sluicing structure with intake sluice piece 1 76.55 76.55 channel and outlet flushing channel 2 Rockfill Barrier and Water level Control Weir, Wall L= m 200 2.87 574.00 200 m 3 Headworks protection embankment m 200 0.04 7.39 4 Main Canal, construction and lining m 200 0.14 28.00 Sluiceway for outlet flushing channel piece 1 36.34 36.34 5 Main pipe m 4,776 0.07 334.32 6 Distribution pipe m 9,073 0.04 362.92 7 Drain well no 10 3.02 30.20 9 Roads – forming and grading m 12,900 0.003 42.18 10 Windbreaks – prepare land and install ha 7.0 46.27 323.89 11 Drain and protection bank m 6,000 0.03 180.00 12 Pump station number 1 100.00 100.00 13 Fence km 12.9 7.00 90.30 Subtotal 2,287.27 Equipment 14 Head work Control Sluice Gate, Width 1.0 m x Height piece 2 1.68 3.36 0.6 m, vertical screw Sluice gate in settling basin piece 1 0.84 0.84 15 Main PE: PE100, SDR11, 1,0mpa, DN500mm, PN10 m 4,776 0.40 1,910.40 16 Distributary PE: PE100, SDR11, 1,0mpa, DN500mm, m 1,500 0.40 600.00 PN10 17 Distributary PE: PE100, SDR11, 1,0mpa, DN450mm, m 2,538 0.34 862.92 PN10 18 Distributary PE: PE100, SDR11, 1,0mpa, DN355mm, m 5,035 0.27 1,359.45 PN10 20 Central pivot sprinkler, 56 ha set 3 195.94 587.83 21 10ha Water Efficient Drip Watering Advanced set 4 79.00 316.00 System 22 5ha Water Efficient Drip Watering Advanced System set 9 43.47 391.23 23 Trees, number piece 21000 0.004 84.00 24 Pump (diesel) piece 4 15.00 60.00 25 Excavator for O&M piece 1 168.60 168.60 Subtotal 6,313.13 26 VAT, 10% % 55.11 860.04 27 Environmental baseline assessment number 1 42.67 42.67 28 Environmental impact assessment number 1 42.67 42.67 29 Design cost ha 700 0.09 63.00 Subtotal 1,008.38 Grand total 9,608.79 Source: TA Consultants’ estimates

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III. TOTAL INVESTMENT AND FINANCIAL PLAN

1. Investment Cost

867. The project is estimated to cost $46.25 million (Table 155).

868. Detailed cost estimates by expenditure category and by financier are included in the project administration manual.47 The major expenditure items that constitute the project are civil works (68.21% of base costs) and equipment (22.13%). Consulting services account for 5.01% of base costs, subproject design and environmental impact assessment for 1.34% and PIU operation and project management for 3.31%.

Table 155: Summary Cost Estimates ($ million) Item Amounta A. Base Costb 1. Efficient and climate-resilient irrigation infrastructure and management systems installed 32.89 2. Environmentally sustainable agriculture production systems improved 2.01 3. Technical, institutional, and management capacity and coordination strengthened 4.52 Subtotal (A) 39.42 B. Contingenciesc 5.21 C. Financial Charges During Implementationd 1.62 Total (A+B+C) 46.25 a Includes taxes and duties of $3.7 million. Such amount does not represent an excessive share of the project costs. The Government will finance value-added tax and duties for goods and materials through exemption from value- added tax. b Prices as of 30 September 2019. c Physical contingencies computed at 7.5% for civil works and goods, and at 5.0% for all other costs for the ADB loan and at 5% for the proposed JFPR grant. Price contingencies computed average of 1.58% on foreign exchange costs and 8.0% on local currency costs; includes provision for potential exchange rate fluctuation under the assumption of purchasing power parity exchange rate. d Includes interest and commitment charges. Interest during construction for the ordinary capital resources loan has been computed at the 5-year LIBOR swap rate plus an effective contractual spread of 0.50% and maturity premium of 0.1%. Interest during construction for the concessional loan has been computed at 2.0%. Commitment charges for the ordinary capital resources loan are 0.15% per year to be charged on the undisbursed loan amount. Source: Asian Development Bank estimates.

869. The government has requested a $14.7 million regular loan from ADB’s ordinary capital resources to help finance the project. The loan will have a 25-year term, including a grace period of 5 years; an annual interest rate determined in accordance with ADB’s London interbank offered rate (LIBOR)-based lending facility, a commitment charge of 0.15% per year; and such other terms and conditions as are set forth in the draft loan and project agreements. Based on the straight-line repayment method, the average maturity is 15.25 years, and the maturity premium payable to ADB is 0.1%. The government has also requested a $25.3 million concessional loan from ADB’s ordinary capital resources to help finance the project. The loan will have a 25-year term, including a grace period of 5 years; an annual interest rate of 2%. The government has also requested a grant of $2 million from the Japan Fund for Poverty reduction.

2. Financing Plan

870. The summary financing plan is in Table 156. ADB will finance the expenditures in relation to civil works, goods, consulting services, and taxes and duties of $2.6 million for eligible ADB- financed expenditures amounting to 92.0% of the total project costs through a regular loan

47 Project Administration Manual (Appendix 5).

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(33.8%) and a concessional loan (58.2%). The Japan Fund for Poverty Reduction (JFPR) will provide grant cofinancing equivalent to $2.00 million to be administered by ADB. The grant will finance 4.3% of the total project costs, including expenditures relating to irrigation and farming equipment for CGGs and facilitation support for establishing and formalizing CGGs. Central and local governments will contribute 9.2% of the total project costs covering office space at the central level, counterpart staff at the central and soum level, and the cost of taxes and duties on goods and works financed through tax exemption.

Table 156: Summary Financing Plan Amount Share of Total Source ($ million) (%) Asian Development Bank Ordinary capital resources (Regular loan) 14.70 31.8 Ordinary capital resources (Concessional loan) 25.30 54.7 Cofinancing (Grant) 2.00 4.3 Central and local governments 4.25 9.2 Total 46.25 100.0 Source: Asian Development Bank estimates.

IV. IMPLEMENTATION AND OPERATING ARRANGEMENTS

A. Implementation Schedule

871. The Project Implementation Plan is set out in the Project Administration Manual.48

B. Operation and Maintenance of Irrigation Systems

872. Some key aspects of operation and maintenance of the irrigation systems are outlined below. Further details are in the Asset Management and Operation and Maintenance Arrangements.49

1. Main System Infrastructure

873. The various priority subprojects have quite varied configurations in terms of the main system components, for capturing and diverting water from the source (river, stream or spring) and subsequently conveying and distributing that water to the irrigated land (command area). The specific infrastructure and layout details for each of the 13 schemes are described in the respective design sections above (III. B to R), but all will require oversight, monitoring and maintenance to keep the respective works in good operating order. Every year, after the irrigation season, the Soum Government irrigation systems managers will need to inspect and implement appropriate measures to ensure the system is fully drained and will not suffer adverse effects due to the harsh winter. All pipes will need to be free of water, and gates should ideally be set open and free of standing water whenever possible, inferring that all open canals, lined or not, should be empty of standing water. However, once the snow falls, it may not be possible to keep open infrastructure free of snow and ice.

874. At the beginning of each season, soum government managers should organize soum labor and equipment, together with WUA labor, to work through the complete system from headwork to last water outlets to make sure all canals are free of wind-blown debris and sediment, that all canal

48 See Appendix 5 of the Main Report, Project Administration Manual 49 See Appendix 30 of the Main Report, Asset Management and Operation and Maintenance Arrangements

329 banks and lining are in good order, and that before any water is released into the system that all ice and snow has melted, gates are greased and operating freely, and that all necessary pumps, filters and equipment are in place and ready to operate and function as required. This likely will include re-installing any removed equipment put into store for winter and making sure all power and pipe connections are all connected properly with appropriate seals and safety measures.

875. Besides implementing O&M on the main system infrastructure, soum government, together with support and agreed responsibilities from the water user associations (WUAs), will need to periodically review and implement maintenance on and drainage and/or flood protection works included within the overall irrigation systems system. This could involve routine but periodic removal of collected sediment (or flushing from settlement basins if the layout supports this), inspection on banks and drainage canals, removal of any erosion or debris obstructions and repairs to relevant channel and protective dyke banks as and when these may be required.

876. Soum Government and/or WUAs will require finance, equipment, tools, labor and materials (fuel, cement, etc.) to enable the relevant maintenance as well as operations activities to be implemented. To the extent possible, such work could be delegated to WUA members, particularly if they have relevant training and skills. Some finance could and should be recouped from beneficiary farmers, but it is probable the O&M of sophisticated equipment, and the larger fixed infrastructure, will require more specific skills and appropriate financing. Arrangements will need to be made for Soum Government, with Aimag and National support as may be necessary, to establish a financial account for the O&M of the irrigation systems – routine and periodic, or even emergency, expenditures. Actual costs will be dependent on the specifics of each irrigation systems, and where the irrigation systems is more sophisticated with pumps, pipes and specialist equipment, the provisions for O&M will have to be more substantive, possibly requiring a rolling maintenance contract with particular equipment suppliers (irrigation and construction equipment which could be retained for on-going maintenance activities). In way of initial provisions, an annual O&M financial budget of about 3% of the capital works and equipment costs may have to be considered and established through appropriate channels.

877. To help overcome this major constraint to development and long term sustainable operation of the irrigation systems, it is proposed that for implementation of the subproject, the local government will be provided with the machinery for construction that will then become the basic mechanical resources for the long term operation and maintenance of the irrigation systems infrastructure (headworks, dams, canals, drains, protection banks, irrigation equipment). Within an Aimag, some of the major equipment might also be assigned for multiple irrigation systems rather than specifically for one small irrigation systems, but this will depend on establishment of roles and responsibilities between Aimag and Soum Governments.

2. Institutions

878. The social and institutional context (organization, coordination, cooperation) for effective irrigation O&M is extremely critical to ensure the ultimate performance of an irrigation scheme. In the past, the implementation process for irrigation projects, especially when spearheaded by governments and some donors, has involved a top-down approach – instruction to do rather than participation to secure ownership. However, experience has shown that if farmers are not involved in all project development stages, then they lack any sense of ownership and obligation to ensure project functionality, performance and success, reducing the chances for project sustainability. A project that is planned with its beneficiaries, rather than just being provided to them, will generally have more acceptance, participation and overall long-term sustainability.

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879. Whilst the government has initiated the upgrading and modernization of these subprojects, it is intended that through Soum Government involvement (major works ownership) and direct interaction with the project participants and beneficiaries (field works ownership), the schemes will be successful and sustainable. To that end, it will be essential that the Soum and participating farmers (individuals, enterprise or combination) work together and mutually operate and maintain all the system works. The involved parties will need to establish and maintain regular and close consultation (i.e. participatory irrigation management – PIM) to not only ensure effective development of the modernized scheme, but to also share responsibilities for its long term O&M, including ensuring there is sufficient finance and resources for regular supervision, inspections, operations and maintenance, and that scheduled activities are undertaken as planned, in accordance with agreed and assigned responsibilities.

539. During discussions with farmers it was understood that WUAs, in principle, are self- managed and governed by their members. However, in the irrigation schemes, irrigation institutions are not fully autonomous and self-managed. The highest supervisory bodies in the existing irrigation institutions are government administrative offices. Interviewers indicated the following features of WUAs that make them different to earlier cooperatives and other associations, including: (i) WUAs are public legal organizations and their mandate is of a public interest; (ii) membership of WUAs are farmers; (iii) WUAs operate on a non-profit/non-commercial basis, but they nevertheless provide services to their members, namely the provision of irrigation water, (iv) WUAs are self-managed organizations governed by their members but due to the public interest nature of their tasks, they are subject to some form of supervision by the state.

880. The development of irrigation institutions through a pragmatic and socially embedded process, rather than by imposing Farmer Groups (FG), would work better for the management of irrigation schemes by encouraging participant interest and willingness to work for and secure common outcomes. However, a clear-cut distinction between the role of the FGs and WUAs needs to be established to minimize any confusion over the governance processes and responsibilities for an irrigation scheme. The tasks of irrigation management institutions in Mongolia are often limited to providing irrigation services and activities. Therefore, it is proposed that more simple and collaborative institutions should be established, consisting of Central Government (MOFALI), Local Government (Soum Administration) and WUAs (consisting of farmers with some external technical support (e.g. scheme waterman) (Figure 199)). The process should not be too prescriptive but context specific. A farmers group and a WUA could be one and the same.

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Figure 199: Irrigation Management Institutions

MOFALI Central Irrigation Management Institution

Soum administration Local Irrigation Management Institution

WUA 1 WUA 2 WUA n

Source: TA Consultant

881. In addition to the institutional structure, issues with membership are another major hurdle to be clarified. Membership of water users in the WUA should ideally be compulsory and is linked to the presence of irrigable land (land use rights) within the service area of the irrigation scheme. Membership of WUAs should be compulsory because in surface irrigation systems where water flows in canals, illegal diversion and hence free riding can be totally avoided. It was found during interview that there are non-member farmers that come only in the growing season from other soums.

882. It is proposed that WUAs are mandated to implement operation and maintenance for the irrigation infrastructure within the hydraulic boundaries of the irrigation distribution systems. The operational management of WUAs includes the day-to-day activities to ensure good functioning of the irrigation scheme. The activities will include planning seasonal operations, operating control systems, monitoring water distribution, and generally taking care of and implementing routine maintenance works for the irrigation system during the growing season (pre, during and post as necessary).

3. Supplies and Services

883. The "Crop Farming Support Fund” operated under MOFALI aimed at increasing domestic food production, in the form of wheat price support and subsidized soft loans for the purchase of machinery, fuel, seeds, and plant protection chemicals.

C. Capacity Building

884. Capacity building refers, in general terms, to the long-term investment in people and their institutions, that will then enable them to effectively and efficiently carry out specific duties to achieve specific development and on-going operational objectives. It involves much more than the narrower

332 purpose for training, which merely imparts essential knowledge, skills and attitude change. For the subprojects, the main target group will be the newly established WUAs (or WUG; FWUG) and the Soum Governments administrative group responsible to oversee the irrigation systems, irrigated agriculture and agricultural product storage, processing and marketing. This Soum group will have assigned staff with direct responsibility to oversee and work with WUAs to implement effective O&M for sustainable use of the irrigation systems.

885. With respect to WUAs, due to the many roles and functions expected of them, the concept of capacity building takes a broader context to encompass the following aspects: • Building of social capital, • Improved access to production resources, • Strengthening WUAs’ capacity to determine their own values and priorities, • Strengthening WUAs’ capacity for decision making, • Improving understanding and needs for planning, implementing and monitoring, and • Enhanced access to information and support services.

886. Local community members have various capacities that should be identified and built upon when implementing capacity building programs. To facilitate informed decision making by WUAs, information and support services should be strengthened. These include: (i) technical information through extension services, farmer field schools; (ii) information on policy issues; (iii) marketing information; (iv) meteorological information; and (v) early warning systems.

887. Even though the capacity building is more than a training, it cannot be achieved without training. The provision of knowledge and development of skills for effective planning, implementation, operation, maintenance, monitoring and evaluation, will require formal training activities directed to the appropriate recipients that will have future responsibilities in the respective areas. Training can be implemented in a classroom setting or through seminars, workshops, exposure visits, or video conferencing.

888. Terms of Reference for the capacity development consultants are in Appendix 1 of the Project Administration Manual.50

V. PROJECT OUTCOME AND IMPACTS

A. Project Monitoring

889. Project Monitoring is described in the Project Administration Manual.51

B. Social Impact Assessment

890. The social impact assessment is detailed in the Poverty, Gender and Social Analysis.52

C. Environmental Impact Assessment

891. The environmental impact of the irrigation subprojects is detailed in the Initial Environmental Examination.53

50 See Appendix 5 of the Main Report, Project Administration Manual. 51 See Appendix 5 of the Main Report, Project Administration Manual. 52 See Appendix 20 of the Main Report, Poverty, Gender and Social Analysis. 53 See Appendix 13 of the Main Report, Initial Environmental Examination.

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VI. CRITICAL RISKS

A. Extreme Climate

892. The planned 17 irrigation systems will have to exist under extreme climatic conditions – with harsh freezing winters, hot and dry arid spring/summers and occasional intense rainfall with potential for localized flooding. These extremes can be damaging to infrastructure – freezing- thawing, wind erosion, and washouts – so designs are planned to cope with these potential extremes. However, despite sound planning and design, there will be risks for unexpected events – early severe frosts, heavy intense storms, longer droughts. Designs will be prepared for these potential eventualities, but more crucially, O&M will include plans for potentially emergency responses should such extremes occur and disrupt irrigation operations, putting crops and livelihoods at risk. O&M planning should include for having appropriate stocks of necessary materials and other resources to hand, and the relevant O&M personnel will need to have been trained (or at least alerted) for responding to any sudden or unexpected emergencies. This will be important also to maintain the goodwill and interest of irrigation systems beneficiaries who will be dependent upon the regular supply of irrigation water.

B. Alignment with Interests and Expectations of Farmers and Other Stakeholders

893. There is a risk that planned modernization and upgrading of irrigation schemes could proceed without properly taking into account the particular interests, needs and expectations of the participating farmers and local impacted communities. To mitigate this risk, it is proposed that all stakeholders – government, farmers, local business and others directly linked to or potentially affected by the project development – will be invited to participate in consultative meetings to effect broader understanding and acceptance of the project, including the requirements for all beneficiaries to participate in the decision making, implementation and longer term O&M of the project.

894. A key factor for ensuring sustained farmer interest and participation in the irrigation systems will be timely and reliable, as well as equitable distribution of available water through the growing season. Design will assess which type of irrigation system is appropriate based on area, crops and more crucially the certainty for water supply (quantity and quality) to support agricultural operations through the season. By involving farmers (as WUAs) in the management of the irrigation systems, with direct responsibilities for some O&M tasks, it is anticipated that the key objectives – timely, reliable, equitable – for water supply and distribution will be established and maintained into the future. The development of an active participatory O&M plan, and its implementation through agreement with all participants, is expected to reduce the potential risk to irrigation systems operations over the long term, ensuring project sustainability and improved beneficiary outcomes.

C. Water Quality Especially Salinization

895. Nearly all water will be sourced from surface rivers and streams. Consequently, there are no identified water quality risks, nor any apparent salinity risks for the 17 prioritized subprojects. There is also no identified salinization risk identified as a result of high water-table present in any irrigation systems areas. However, it is noted that some surface salinity encrustation can be seen where any ponded surface water has remained and evaporated, which suggests that a net positive water flow into the ground may be needed to mitigate risks in some limited areas. Any specific risk areas have still to be identified.

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D. Operations and Maintenance

896. The number one risk for O&M and project sustainability is that of having the resources organized and available to carry out O&M in accordance with plans and any emergency needs. Whilst it is planned that O&M responsibilities and requirements are defined, the assigned personnel will be unable to deliver if the necessary finance, equipment, materials and labor are unavailable when required. It is proposed that this overall risk will be mitigated by careful planning, establishment of a coordinated and cooperative O&M technical and irrigation systems based team of people (from Soum and WUAs), establishment of irrigation systems fees (ISF) (or similar), establishment of major resource (equipment, spare parts, finance) supply procedures, and general adoption of a pre-emptive rather than reactive approach to O&M.

897. Many of the irrigation systems will require the introduction and use of specialist irrigation equipment – sprinkler systems, drip systems, and possibly micro-spray systems for greenhouses. The necessary equipment required for these systems will need to be bought from manufacturers, directly or through their Mongolian agents. In some cases, this equipment could be imported. A key requirement besides installation and commissioning, will be to ensure there is a ready supply of any critical consumable parts, and that the manufacturer and/or agents can provide supply and service as per warranty and in accordance with an agreed schedule to keep the equipment in top working order for the whole of its expected life. To that end, it is proposed that the government, or subsidiary irrigation systems owners, will be able to establish appropriate contracts to ensure there is appropriate support services, parts availability, and technical support available through the life of the project. Equally, within irrigation systems O&M plans, appropriate financing and succession planning for field operatives and technicians should be established, to ensure such equipment is fully maintained and ready for service through each irrigation season.

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Annex 1: Schematic Designs

Figure A1.1: Schematic Layout for Rock-fill Barrier and Concrete Water Level Control Weir

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Figure A1.2: Schematic Layout for Headwork

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Figure A1.3: Schematic Layout for Pumpstation

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Figure A1.4: Schematic Layout for Windbreak

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Annex 2: Soil Analysis Results by Subproject

Table 1: General Information of the Soils Test of the Subprojects

Field size, soil density, A horizon EC, Salinity IS name soil texture soil classification, WRB № hectare g/cm3 depth, m µS/cm level

1 Tsakhir 200 sandy clay loam 1.41 0.40 156.0 1.48 leptic kastanozem 2 Yolton 320 sandy loam 1.39 0.40 129.0 1.81 light kastanozem 3 Erdenburen 2000 sandy loam 2.20 0.30 62.8 0.88 4 Boomiin am 380 sandy loam 1.34 0.30 150.0 2.10 leptic kastanozem 5 Khoid gol 290 Loam 1.08 0.65 226.0 2.15 6 Tsul-Ulaan 160 sandy clay loam 1.45 0.35 315.0 2.71 kastanozem 7 Ulaandel 400 sandy loam 1.59 0.25 96.0 1.34 leptic kastanozem 8 Khurental 500 sandy loam 1.41 0.30 184.0 2.58 dark kastanozem 9 Nogoonkhashaa 64 sandy loam 1.25 0.30 170.0 2.38 Fluvisol 10 Iven Gol 240 silty clay loam 1.09 0.50 183.5 1.58 Fluvisol 11 Okhindiin tal 2680 silt loam 1.09 0.40 183.0 2.48 dark kastanozem 12 Sugunugur 140 silt loam 1.26 0.50 136.0 1.29 Fluvisol 13 Dulaanii tal 700 sandy loam 1.50 0.45 50.0 0.70 Arenosol

Soil salinity classification Criteria low salinity 0-2 low-meduim salinity 2.0-4.0 plants affected salinity 4.0-8.0 tolerant plant affected 8.0-16 High salinity >16

340

A2.2: Subproject 1 Tsakhir IS

INTEGRATED AGRICULTURAL LABORATORY SOIL TESTING LABORATORY

Customer: Mongolian water forum Field location: Govi-altai aimag, Jargalan soum Irrigation scheme: Tsakhir Field size: 200 hectare Datum: 2019.07.30

Table 2.1: Soil Agronomic Parameters Mineral Sample Lab P, K, Ca, K, Mg, Na, CEC EC, pH pH SOM, Carbonate, Sample Nitrogen, name no mg/kg mg/kg % % % % meq/100g H2O CaCl2 % % depth, mg/kg μS/cm m Interpretation 1 2 3 4 5 6 7 8 10.0- 60- 3.0- 10.0 6.0 - 5.5 - Optimal value 25-50 60-90 <5 15-25 <200 >2 15.0 75 8.0 -20.0 7.0 6.5 GS265 Р45 0.25 4.36 9.23 76.71 89.7 3.0 6.6 0.6 36.69 100.1 8.8 7.5 1.7 0.60 GS266 Р46 0.25 3.45 16.14 123.24 91.0 3.5 5.1 0.3 31.53 113.7 8.68 7.33 1.6 0.77 GS267 Р46а 0.25 2.02 3.64 6.67 92.4 1.1 5.7 0.8 25.58 79.4 8.99 7.37 1.1 0.25 GS268 Р46б 0.40-0.6 2.91 1.30 1.00 91.7 1.8 5.6 0.9 9.22 56.3 9.3 7.45 GS269 Р47 0.25 4.45 5.97 85.02 91.0 2.9 5.6 0.5 31.64 102.3 8.89 7.47 1.5 0.75 GS270 Р48 0.25 14.24 11.70 88.61 90.2 3.3 5.9 0.5 36.17 122.4 8.78 7.5 1.29 1.38 GS271 Р49 0.25 95.45 8.30 40.89 90.5 1.9 6.2 1.5 33.31 523 8.2 7.4 1.3 1.20 Average 0.25 24.39 10.27 82.90 90.48 2.93 5.89 0.69 33.87 192.30 8.67 7.44 1.48 0.94

341

Table 2.2: Soil Physical Parameters Coordinates Soil particle size distribution Gravel, Sample Lab Soil Moisture, Density Sand, % Silt, % Clay, % % name no Х Ү utilisation % g/cm3 Texture >2000 2000-63 63-2 <2 μm μm μm μm Interpretation 9 10 11 sandy GS265 46.880001 96.211498 pasture 1.45 1.41 9.54 Р45 clay loam sandy GS266 pasture 1.49 1.41 20.95 69.91 7.42 22.67 Р46 clay loam sandy GS267 46.881528 96.206752 pasture 1.00 1.41 46.21 72.73 8.08 19.19 Р46а loam sand GS268 pasture 0.27 1.41 60.52 Р46б loam sandy GS269 46.883494 96.198903 pasture 1.20 1.41 19.89 Р47 clay loam sandy GS270 46.886291 96.189124 pasture 1.71 1.41 3.73 50.73 23.15 26.11 Р48 clay loam sandy GS271 46.890438 96.175009 pasture 1.21 1.41 10.84 Р49 clay loam

342

A2.3: Subproject 2 Yolton IS

INTEGRATED AGRICULTURAL LABORATORY SOIL TESTING LABORATORY

Customer: Mongolian water forum Field location: Govi-Altai, Khaliun soum Irrigation scheme: Yolton Field size: 320 hectare Datum: 2019.07.30

Table 3.1: Soil Agronomic Parameters

Mineral Sample Lab P, K, Ca, K, Mg, Na, CEC EC, pH pH SOM, Carbonate, Sample Nitrogen, name no mg/kg mg/kg % % % % meq/100g H2O CaCl2 % % depth, mg/kg μS/cm m Interpretation 1 2 3 4 5 6 7 8 10.0- 60- 3.0- 10.0 6.0 - 5.5 - Optimal value 25-50 60-90 <5 15-25 <200 >2 15.0 75 8.0 -20.0 7.0 6.5 GS272 Р50 0.25 10.08 4.38 141.14 90.8 1.8 5.9 1.4 33.34 136.5 8.63 7.41 0.5 0.50

GS273 Р51 0.25 42.71 4.28 24.67 90.8 1.6 6.5 1.1 36.84 171.6 8.59 7.45 0.7 0.50

GS274 Р51а 0.4-0.8 2.88 1.13 0.00 89.8 1.1 7.8 1.3 38.61 128.6 8.75 7.51 0.4 0.76

GS275 Р52 0.25 11.16 6.70 132.80 91.5 2.7 5.2 0.6 33.01 98.4 8.92 7.46 0.59 0.60

GS276 Р53 0.25 4.59 3.26 5.40 90.9 1.1 6.4 1.7 35.03 105.6 9.15 7.5 0.5 0.50

GS277 Р54 0.25 7.18 4.31 1.03 90.6 1.2 6.9 1.4 38.66 134.3 8.74 7.51 0.65 0.70

Average 0.25 15.14 4.58 61.01 90.90 1.68 6.18 1.24 35.38 129.28 8.81 7.47 0.59 0.56

343

Table 3.2: Soil Physical Parameters Coordinates Soil particle size distribution Sample Lab Soil Moisture, Density Gravel, % Sand, % Silt, % Clay, % name no Х Ү utilisation % g/cm3 Texture >2000 μm 2000-63 μm 63-2 μm <2 μm Interpretation 9 10 11 GS272 Р50 45.904149 96.428007 Oat 1.80 1.39 0.07 sandy clay GS273 Р51 Oat 1.90 1.39 1.46 54.09 19.52 26.39 45.910804 96.421507 loam GS274 Р51а Oat 2.76 1.39 0.79 71.35 12.75 15.89 sandy loam GS275 Р52 45.909587 96.411251 Oat 1.43 1.39 1.79 GS276 Р53 45.910575 96.40535 pasture 1.92 1.39 2.22 sandy clay GS277 45.913207 96.396325 pasture 2.48 1.39 0.68 54.76 22.34 22.90 Р54 loam

344

A2.4: Subproject 3 Erdeneburen IS

INTEGRATED AGRICULTURAL LABORATORY SOIL TESTING LABORATORY

Customer: Mongolian water forum Field location: Khovd aimag, Erdeneburen soum Irrigation scheme: Erdeneburen Field size: 2000 hectare Datum: 2019.07.30

Table 4.1: Soil Agronomic Parameters Mineral Sample Lab P, K, Ca, K, Mg, Na, CEC EC, pH pH SOM, Carbonate, Sample Nitrogen, name no mg/kg mg/kg % % % % meq/100g H2O CaCl2 % % depth, mg/kg μS/cm m Interpretation 1 2 3 4 5 6 7 8 10.0- 60- 3.0- 10.0 6.0 - 5.5 - Optimal value 25-50 60-90 <5 15-25 <200 >2 15.0 75 8.0 -20.0 7.0 6.5 GS293 Р68 0.25 6.57 3.13 23.36 83.8 5.7 8.8 1.7 7.40 62.3 8.6 7.14 0.38 0.04 GS294 Р68а 0.3-0.5 11.55 2.86 5.62 87.4 4.0 7.2 1.4 11.54 73.7 8.51 7.08 0.3 0.04 GS296 Р69 0.25 7.42 7.12 42.33 85.1 7.2 7.0 0.7 4.97 68.2 8.98 7.25 0.5 0.04 GS297 Р70 0.25 8.28 7.37 84.58 85.5 7.9 6.3 0.3 9.99 76.2 8.84 7.28 0.5 0.04 GS298 Р71 0.25 8.24 2.21 30.04 81.3 7.5 10.2 1.0 4.17 56.4 8.92 7.22 0.6 0.04 GS299 Р72 0.25 9.04 1.00 26.21 82.6 8.3 8.2 0.8 3.43 62.8 8.76 7.27 0.5 0.04 GS300 Р73 0.25 10.96 2.41 57.22 94.7 2.4 2.8 0.2 19.70 100.1 8.74 7.41 0.8 0.04 GS301 Р74 0.25 11.55 5.63 25.82 80.1 5.8 12.5 1.5 3.45 37.8 7.01 5.95 0.8 0.04 GS302 Р75 0.25 13.69 3.52 20.33 82.6 4.7 11.0 1.7 3.74 38.6 7.13 6.2 1 0.03 Average 0.25 9.47 4.05 38.74 84.47 6.19 8.35 0.99 7.11 62.80 8.37 6.97 0.64 0.04

345

Table 4.2: Soil Physical Parameters Coordinates Soil particle size distribution Sample Lab Soil Moisture, Density 3 Gravel, % Sand, % Silt, % Clay, % name no Х Ү utilisation % g/cm Texture >2000 μm 2000-63 μm 63-2 μm <2 μm Interpretation 9 10 11 sandy GS293 pasture 1.10 2.29 9.71 79.95 1.05 19.00 Р68 loam 48.57485 91.461858 sandy clay GS294 pasture 2.12 2.29 1.83 62.87 11.93 25.20 Р68а loam GS296 Р69 48.565503 91.476848 pasture 0.30 2.29 6.26 GS297 Р70 48.556349 91.491156 pasture 0.92 2.29 25.79 GS298 Р71 48.548054 91.504102 pasture 0.47 2.29 9.91 GS299 Р72 48.593643 91.420278 pasture 0.43 2.29 5.67 GS300 Р73 48.575478 91.420178 pasture 0.56 2.29 20.51 GS301 Р74 48.564991 91.434906 pasture 0.48 2.29 5.79 loamy GS302 48.548479 91.426711 watermelon 0.65 2.29 9.57 85.76 2.83 11.41 Р75 sand

346

A2.5: Subproject 4 Boomiin am IS

INTEGRATED AGRICULTURAL LABORATORY SOIL TESTING LABORATORY

Customer: Mongolian water forum Field location: Khovd Aimag, Altai soum Irrigation scheme: Boomiin am Field size: 300 hectare Datum: 2019.07.30

Table 5.1: Soil Agronomic Parameters

Mineral Sample Lab P, K, Ca, Mg, Na, CEC EC, pH pH SOM, Carbonate, Nitrogen, K, % name no Sample mg/kg mg/kg % % % meq/100g μS/cm H2O CaCl2 % % depth, m mg/kg

Interpretation 1 2 3 4 5 6 7 8 10.0- 3.0- 10.0 - 6.0 - 5.5 - Optimal value 25-50 60-90 60-75 <5 15-25 <200 >2 15.0 8.0 20.0 7.0 6.5 GS286 Р62 0.25 14.24 4.54 124.41 91.1 4.2 4.1 0.5 21.71 108.3 8.68 7.31 1.8 0.40

GS287 Р63 0.25 4.62 2.91 84.90 93.0 3.1 3.4 0.4 22.21 81.7 9.01 7.42 1.4 0.45

GS288 Р64 0.25 12.51 5.24 94.61 91.2 3.3 4.0 1.5 26.11 180.7 8.68 7.39 1.19 0.46 GS289 Р64а 0.3-0.7 12.52 2.32 73.10 92.0 3.2 4.4 0.4 27.72 105.1 8.78 7.41 1 0.60

GS290 Р65 0.25 9.97 3.22 76.86 92.7 3.2 3.2 0.9 24.69 106.6 8.92 7.42 1.3 0.50

GS291 Р66 0.25 12.10 5.35 255.70 85.1 5.9 3.3 5.7 30.50 316 9.67 7.6 1.5 0.50

GS292 Р67 0.25 39.78 9.27 435.70 81.3 8.3 3.8 6.6 31.24 800 8.95 7.75 0.8 0.94 Average 0.25 15.80 5.20 118.26 88.66 4.76 3.54 3.04 26.95 297.00 9.05 7.52 1.24 0.57

347

Table 5.2: Soil Physical Parameters Coordinates Soil particle size distribution Gravel, Sample Soil Moisture, Density Sand, % Silt, % Clay, % Lab no % name utilisation % g/cm3 Texture Х Ү >2000 2000-63 63-2 μm <2 μm μm μm Interpretation 9 10 11 sandy GS286 46.019053 92.527352 Vegetable 0.97 1.34 13.20 65 15 20 Р62 loam sandy GS287 46.002319 92.504598 pasture 0.47 1.34 7.01 65 15 20 Р63 loam sandy GS288 pasture 0.86 1.34 3.94 66.10 14.74 19.16 Р64 loam 45.997535 92.49701 sandy GS289 pasture 0.96 1.34 19.01 60.58 20.23 19.18 Р64а loam sandy GS290 45.991942 92.490804 pasture 0.73 1.34 10.03 70 10 20 Р65 loam sandy GS291 45.987179 92.479486 pasture 0.86 1.34 12.34 70 10 20 Р66 loam sandy GS292 45.983392 92.467595 pasture 0.71 1.34 22.10 72.18 8.68 19.14 Р67 loam

348

A2.6: Subproject 5 Khoid gol IS

INTEGRATED AGRICULTURAL LABORATORY SOIL TESTING LABORATORY

Customer: Mongolian water forum Field location: Khovd aimag, Darvi soum Irrigation scheme: Khoid gol Field size: 400 hectare Datum: 2019.07.30

Table 6.1: Soil Agronomic Parameters Mineral Sample Lab P, K, Ca, K, Mg, Na, CEC EC, pH pH SOM, Carbonate, Sample Nitrogen, name no mg/kg mg/kg % % % % meq/100g H2O CaCl2 % % depth, mg/kg μS/cm m Interpretation 1 2 3 4 5 6 7 8 10.0- 60- 3.0- 10.0 6.0 - 5.5 - Optimal value 25-50 60-90 <5 15-25 <200 >2 15.0 75 8.0 -20.0 7.0 6.5 GS278 Р55 0.25 77.58 8.35 482.60 84.3 8.3 5.5 1.8 28.72 307 8.45 7.45 5.06 0.43 GS279 Р55а 0.5-0.8 15.09 1.12 93.60 90.3 2.0 6.1 1.6 35.36 181.7 8.63 7.46 2.5 0.56 GS280 Р56 0.25 24.14 3.33 121.89 87.8 4.0 4.9 3.3 22.35 323 8.51 7.41 4.5 0.50 GS281 Р57 0.25 24.99 2.14 157.15 89.1 3.4 6.0 1.5 31.63 180.8 8.63 7.55 4.5 0.50 GS282 Р58 0.25 59.38 2.77 153.83 89.0 3.2 6.4 1.4 36.59 272 8.28 7.45 4 0.50 GS283 Р59 0.25 20.99 2.84 229.63 88.6 5.3 4.3 1.8 30.33 165.7 8.92 7.51 4.2 0.34 GS284 Р60 0.25 12.12 2.83 94.06 92.9 2.6 3.6 0.9 24.00 139.1 8.83 7.49 3.5 0.35 GS285 Р61 0.25 24.46 1.84 198.97 90.0 3.5 5.5 1.0 33.45 242 8.33 7.43 3.5 0.35 Average 0.25 34.81 3.44 205.45 88.82 4.35 5.17 1.66 29.58 232.80 8.56 7.47 4.18 0.42

349

Table 6.2: Soil Physical Parameters Coordinates Soil particle size distribution Sample Lab Soil Moisture, Density Gravel, % Sand, % Silt, % Clay, % name no Х Ү utilisation % g/cm3 Texture 2000-63 >2000 μm 63-2 μm <2 μm μm Interpretation 9 10 11 GS278 Р55 Rye 1.78 1.08 0.28 42.15 31.72 26.13 loam 47.020082 93.300671 GS279 Р55а Rye 1.92 1.08 0.83 16.25 60.98 22.77 silt loam GS280 Р56 47.017343 93.306265 Potato 0.98 1.08 25.90 GS281 Р57 47.025014 93.305719 Tillage 1.94 1.08 0.10 GS282 Р58 47.026641 93.310976 pasture 2.49 1.08 0.18 sandy GS283 47.027566 93.318638 pasture 1.36 1.08 3.50 57.85 19.50 22.64 Р59 clay loam GS284 Р60 47.015155 93.317284 Vegetable 1.03 1.08 10.41 GS285 Р61 47.016761 93.310707 Rye 2.30 1.08 1.47

350

A2.7: Subproject 6 Tsul-Ulaan IS

INTEGRATED AGRICULTURAL LABORATORY SOIL TESTING LABORATORY

Customer: Mongolian water forum Field location: Bayan-Ulgii aimag, Bayannuur soum Irrigation scheme: Tsul-Ulaan Field size: 161 hectare Datum: 2019.07.30

Table 7.1: Soil Agronomic Parameters

Mineral Sample Lab P, K, Ca, Mg, Na, CEC EC, pH pH SOM, Carbonate, Nitrogen, K, % name no Sample mg/kg mg/kg % % % meq/100g H2O CaCl2 % % mg/kg μS/cm depth, m

Interpretation 1 2 3 4 5 6 7 8 10.0- 3.0- 10.0 - 6.0 - 5.5 - Optimal value 25-40 60-90 60-75 <5 15-25 <200 >2 15.0 8.0 20.0 7.0 6.5 GS311 Р84 0.25 11.03 18.84 130.52 81.3 3.9 11.7 3.2 31.81 206 9.07 7.79 1.8 0.25

GS312 0.25 14.48 49.74 30.32 84.9 1.5 9.0 4.5 39.04 300 8.96 7.88 0.34 Р85 2.31 GS313 Р85а 0.3-0.5 6.44 4.12 0.00 81.2 1.8 15.1 1.9 14.99 69.8 8.03 6.94 1.2 0.04

GS314 Р86 0.25 157.73 4.85 280.50 82.5 5.8 5.0 6.7 32.62 492 9.29 7.7 2 0.58

GS315 Р87 0.25 65.50 5.76 295.33 71.3 5.3 10.9 12.4 40.62 587 9.75 8.06 1.8 0.50

GS316 Р88 0.25 6.76 2.62 241.74 86.2 6.6 5.2 2.0 30.34 168.1 9.46 7.7 1.2 0.50

GS317 Р89 0.25 4.86 2.23 279.14 81.3 5.1 10.1 3.4 37.97 387 9.26 8.13 1.2 0.50

Average 0.25 20.53 14.01 209.59 81.25 4.71 8.67 5.37 35.40 356.68 9.30 7.88 1.72 0.45

351

Table 7.2: Soil Physical Parameters Coordinates Soil particle size distribution Sample Lab Soil Moisture, Density 3 Gravel, % Sand, % Silt, % Clay, % name no Х Ү utilisation % g/cm Texture >2000 μm 2000-63 μm 63-2 μm <2 μm Interpretation 9 10 11 GS311 Р84 48.935572 91.168373 pasture 3.92 1.45 16.54 loam GS312 Р85 pasture 4.70 1.45 7.28 35.96 38.16 25.88 loam 48.934609 91.171944 GS313 Р85а pasture 5.26 1.45 28.55 31.31 39.13 29.55 clay loam sandy clay GS314 48.920446 91.187451 pasture 1.03 1.45 32.71 65.81 12.63 21.56 Р86 loam sandy clay GS315 48.922869 91.192865 pasture 4.58 1.45 9.46 Р87 loam sandy clay GS316 48.923638 91.184139 pasture 0.88 1.45 12.68 Р88 loam sandy clay GS317 48.928081 91.18124 pasture 1.20 1.45 5.26 Р89 loam

352

A2.8: Subproject 7 Ulaandel IS

INTEGRATED AGRICULTURAL LABORATORY SOIL TESTING LABORATORY

Customer: Mongolian water forum Field location: Bayan-Ulgii aimag, Sagsai soum Irrigation scheme: Ulaandel Field size: 400 hectare Datum: 2019.07.30

Table 8.1: Soil Agronomic Parameters Mineral K, CEC EC, pH pH Sample Lab P, Ca, K, Mg, Na, SOM Carbonate Sample Nitrogen mg/k meq/100 H2 CaCl name no mg/kg % % % % μS/c , % , % depth, , mg/kg g g m O 2 m Interpretation 1 2 3 4 5 6 7 8 10.0- 60- 3.0- 10.0 6.0 - 5.5 - Optimal value 25-50 60-90 <5 15-25 <200 >2 15.0 75 8.0 -20.0 7.0 6.5 GS303 Р76 0.25 11.85 4.15 44.77 93.5 2.0 4.2 0.3 26.17 89.1 8.82 7.38 0.9 0.20

GS304 Р77 0.25 21.75 8.90 25.08 94.0 1.6 3.9 0.5 23.04 123.4 8.61 7.39 0.83 0.27 GS305 Р78 0.25 13.77 10.94 27.34 94.6 1.7 3.5 0.3 21.68 99.6 8.61 7.34 0.85 0.15 GS306 Р79 0.25 10.63 27.74 97.29 92.6 3.4 3.8 0.2 22.43 91.6 8.62 7.27 0.9 0.15 GS307 Р80 0.25 9.67 10.98 76.98 91.0 4.2 4.6 0.2 13.56 84.4 8.68 7.3 1 0.15 GS308 Р81 0.25 12.96 19.34 31.80 93.7 2.2 3.8 0.3 19.95 97.5 8.58 7.3 1 0.14 GS309 Р82 0.25 8.98 15.23 47.82 88.9 3.9 6.9 0.4 13.13 93.6 8.55 7.28 1 0.15 GS310 Р83 0.25 9.73 8.72 35.38 94.6 1.7 3.4 0.2 29.23 93.2 8.65 7.37 1 0.15 Average 0.25 12.42 13.25 48.31 92.86 2.57 4.27 0.30 21.15 96.55 8.64 7.33 0.93 0.17

353

Table 8.2: Soil Physical Parameters Coordinates Soil particle size distribution

Sample Lab Soil Moisture, Density Gravel, % Sand, % Silt, % Clay, % 3 name no Х Ү utilisation % g/cm Texture 2000-63 >2000 μm 63-2 μm <2 μm μm Interpretation 9 10 11 GS303 Р76 48.856759 89.596616 pasture 1.28 1.59 25.19 GS304 Р77 48.84968 89.585732 pasture 1.13 1.59 38.70 73.70 11.47 14.83 sandy loam GS305 Р78 48.842395 89.5745 Rapeseed 1.25 1.59 35.08 GS306 Р79 48.834735 89.562494 Rapeseed 1.22 1.59 31.67 GS307 Р80 48.836913 89.556857 Rapeseed 0.75 1.59 33.04 GS308 Р81 48.843901 89.56783 Rapeseed 1.25 1.59 40.33 78.85 2.92 18.23 sandy loam GS309 Р82 48.851051 89.578805 pasture 0.88 1.59 26.01 GS310 Р83 48.857998 89.589574 pasture 1.35 1.59 19.90

354

A2.9: Subproject 9 Khurental IS

INTEGRATED AGRICULTURAL LABORATORY SOIL TESTING LABORATORY

Customer: Mongolian water forum Field location: Zavkhan aimag, Telmen soum Irrigation scheme: Khuren tal Field size: 500 hectare Datum: 2019.07.30

Table 9.1: Soil Agronomic Parameters Mineral Sample Lab P, K, Ca, Mg, Na, CEC EC, pH pH SOM, Carbonate, Nitrogen, K, % name no Sample mg/kg mg/kg % % % meq/100g μS/cm H2O CaCl2 % % depth, m mg/kg Interpretation 1 2 3 4 5 6 7 8 10.0- 60- 3.0- 10.0 - 6.0 - 5.5 - Optimal value 25-50 60-90 <5 15-25 <200 >2 15.0 75 8.0 20.0 7.0 6.5 GS331 Р101 0.25 35.95 5.50 91.96 74.08 11.28 13.67 0.97 7.00 58.6 6.7 5.83 1.5 0.10 GS332 Р102 0.25 28.19 2.63 22.64 79.03 5.91 13.91 1.16 6.28 40.2 6.91 6.09 1.5 0.10 GS333 Р103 0.25 35.32 3.77 48.97 76.21 10.52 12.44 0.82 6.52 171 8.55 7.37 1.5 0.10 GS334 Р104 0.25 38.92 9.40 80.57 77.92 5.05 12.25 4.78 11.88 47.6 7.16 6.27 1.5 0.10 GS335 Р105 0.25 46.01 8.91 136.28 72.73 3.79 20.12 3.37 29.16 246 9.13 7.81 1.42 0.19 GS336 Р105а 0.3-0.6 36.84 2.17 3.31 52.12 2.14 35.78 9.96 18.32 346 9.36 8.18 0.9 0.09 GS337 Р106 0.25 50.19 5.58 4.36 77.19 3.54 14.66 4.61 6.99 193.4 7.28 6.58 1.5 0.10 GS338 Р107 0.25 53.93 7.02 51.18 71.95 6.12 18.88 3.05 8.52 158.7 8.33 7.24 1.5 0.10 GS339 Р108 0.25 49.21 79.56 26.04 88.74 2.34 7.20 1.72 17.53 185 8.35 7.37 1.5 0.10 GS340 Р109 0.25 46.58 116.81 181.50 70.57 6.15 19.51 3.77 20.36 401 8.87 7.95 1.5 0.10 average 0.25 42.70 15.30 71.50 76.49 6.08 14.74 2.69 12.69 166.83 7.92 6.95 1.49 0.11

355

Table 9.2: Soil Physical Parameters Coordinates Soil particle size distribution

Sample Lab Soil Moisture, Density Gravel, % Sand, % Silt, % Clay, % 3 name no Х Ү utilisation % g/cm Texture 2000-63 >2000 μm 63-2 μm <2 μm μm Interpretation 9 10 11 sandy GS331 48.717973 97.712461 Oat 1.80 1.41 22.30 80.5 4.5 15 Р101 loam sandy GS332 2 48.726993 97.70494 pasture 1.04 1.41 27.80 75-80 3.0-5.0 15-20 Р10 loam sandy GS333 48.717862 97.702803 pasture 1.77 1.41 29.24 75-80 3.0-5.0 15-20 Р103 loam sandy GS334 4 48.724685 97.693115 pasture 1.08 1.41 3.08 75-80 3.0-5.0 15-20 Р10 loam sandy GS335 Oat 2.40 1.41 22.88 81.36 3.62 15.03 Р105 loam 48.715205 97.693943 sandy GS336 Oat 3.37 10.66 77.07 7.75 15.18 Р105а loam sandy GS337 48.708052 97.692352 Oat 1.38 1.41 13.95 75-80 3.0-5.0 15-20 Р106 loam sandy GS338 7 48.709617 97.701414 Oat 1.72 1.41 24.94 75-80 3.0-5.0 15-20 Р10 loam sandy GS339 48.70507 97.703228 Oat 2.47 1.41 27.20 75-80 3.0-5.0 15-20 Р108 loam sandy GS340 9 48.702832 97.694796 Potato 4.46 1.41 28.64 79 5.65 15.35 Р10 loam

356

A2.10: Subproject 10 Nogoonkgashaa IS

INTEGRATED AGRICULTURAL LABORATORY SOIL TESTING LABORATORY

Customer: Mongolian water forum Field location: Zawkhan aimag, Uliastai soum Irrigation scheme: Nogoonksashaa Field size: 64 hectare Datum: 2019.07.30

Table 10.1: Soil Agronomic Parameters

Mineral Sample Lab P, K, Ca, Mg, Na, CEC EC, pH pH SOM, Carbonate, Nitrogen, K, % name no Sample mg/kg mg/kg % % % meq/100g H2O CaCl2 % % mg/kg μS/cm depth, m

Interpretation 1 2 3 4 5 6 7 8 10.0- 60- 3.0- 10.0 - 6.0 - 5.5 - Optimal value 25-50 60-90 <5 15-25 <200 >2 15.0 75 8.0 20.0 7.0 6.5 GS324 Р95 0.25 44.63 50.54 59.72 85.5 4.1 8.9 1.6 13.91 133.8 7.46 6.76 4.35 0.04

GS325 Р95а 0.3-0.5 24.18 47.50 32.82 87.2 2.3 9.4 1.1 16.17 60.4 7.41 6.6 2.5 0.04

GS326 Р96 0.25 47.41 38.67 15.91 86.1 2.3 9.9 1.8 17.10 172.7 7.57 6.84 3.8 0.03

GS327 Р97 0.25 58.76 26.64 30.12 86.3 2.6 9.7 1.4 17.66 150.4 7.56 6.84 3.8 0.05

GS328 Р98 0.25 40.33 25.81 26.13 87.5 2.8 8.6 1.0 13.00 102.6 7.81 6.95 3.8 0.05

GS329 Р99 0.25 72.51 10.56 15.41 87.5 2.0 9.1 1.4 15.87 204 6.91 6.44 3.8 0.05

GS330 Р100 0.25 94.97 26.24 3.62 86.2 1.0 7.5 5.3 32.83 384 8.24 7.38 3.8 0.08

Average 0.25 59.77 29.74 25.15 86.52 2.46 8.95 2.08 18.39 191.25 7.59 6.87 3.89 0.05

357

Table 10.2:Soil Physical Parameters Coordinates Soil particle size distribution

Sample Lab Soil Moisture, Density Gravel, % Sand, % Silt, % Clay, % name no utilisation % g/cm3 Х Ү Texture 2000-63 >2000 μm 63-2 μm <2 μm μm Interpretation 9 10 11 sandy GS324 Vegetable 5.23 1.25 2.62 64.29 20.23 15.48 Р95 loam 47.743177 96.836174 sandy GS325 Vegetable 7.36 1.25 0.00 58.00 26.16 15.83 Р95а loam GS326 Р96 47.744254 96.829307 Vegetable 5.09 1.25 1.17

GS327 Р97 47.743643 96.821925 Vegetable 5.03 1.25 0.84

GS328 Р98 47.73991 96.817783 Vegetable 3.54 1.25 2.95

GS329 Р99 47.739545 96.831242 Vegetable 5.26 1.25 0.31

GS330 Р100 47.746428 96.820554 Vegetable 8.92 1.25 0.66 41.57 38.66 19.76 loam

358

A2.12: Subproject 12 Iven Gol IS

INTEGRATED AGRICULTURAL LABORATORY SOIL TESTING LABORATORY

Customer: Mongolian water forum Field location: Selenge aimag, Sant Soum, Iven river Irrigation scheme: Iven Gol Field size: 500 hectare Datum: 2019.07.30

Table 11.1: Soil Agronomic Parameters Mineral Sample Lab P, K, Ca, K, Mg, Na, CEC EC, pH pH SOM, Carbonate, Sample Nitrogen, name no mg/kg mg/kg % % % % meq/100g H2O CaCl2 % % depth, mg/kg μS/cm m Interpretation 1 2 3 4 5 6 7 8 10.0- 3.0- 10.0 6.0 - 5.5 - Optimal value 25-50 60-90 60-75 <5 15-25 <200 >2 15.0 8.0 -20.0 7.0 6.5 GS233 Р17 0-0.3 24.16 2.09 19.24 88.2 2.1 9.1 0.6 48.22 135.9 8.15 7.33 3.70 0.49 GS234 Р17а 0.3-0.5 0.00 1.46 0.00 88.5 1.3 9.5 0.6 49.34 116.8 8.41 7.51 2.5 1.40 GS235 Р18 0.25 44.24 16.29 29.49 89.7 2.1 7.5 0.8 44.45 212 8.21 7.49 3.50 0.40 GS236 Р19 0.25 45.21 124.56 451.36 80.3 10.1 9.0 0.6 36.07 204 8.04 7.09 3.00 0.40 GS237 Р20 0.25 35.87 14.45 59.78 88.8 3.0 7.5 0.7 33.44 165.3 8.18 7.31 3.00 0.40 GS238 Р21 0.25 2.36 13.96 60.89 90.5 2.5 6.6 0.4 40.55 129.6 8.27 7.39 2.70 0.40 GS239 Р22 0.25 32.60 13.94 77.29 90.6 2.5 6.4 0.5 37.80 165.4 8.17 7.41 2.80 0.40 GS240 Р23 0.25 100.25 8.94 56.37 89.4 2.2 7.7 0.7 44.60 379 7.88 7.42 3.00 0.40 GS241 Р24 0.25 19.11 5.58 34.39 89.7 2.1 7.3 0.8 46.69 180.2 8.14 7.39 3.00 0.40 GS242 Р25 0.25 8.61 4.98 83.09 82.7 5.2 11.6 0.5 32.96 136.5 8.09 7.24 3.00 0.25 GS243 Р26 0.25 32.72 8.52 74.29 88.1 3.0 8.1 0.7 45.63 192.3 8.06 7.34 5.40 0.16 GS244 Р27 0.25 16.84 4.68 48.44 88.1 3.0 8.2 0.7 41.78 139.2 8.12 7.38 2.2 0.25 Average 0.25 31.68 9.34 54.33 88.58 2.77 7.99 0.65 41.61 183.54 8.13 7.37 3.23 0.36

359

Table 11.2: Soil Physical Parameters Coordinates Soil particle size distribution

Sample Lab soil Moisture, Density Gravel, % Sand, % Silt, % Clay, % 3 name no Х Ү utilisation % g/cm Texture 2000-63 >2000 μm 63-2 μm <2 μm μm Interpretation 9 10 11 silty clay GS233 Vegetable 4.37 1.09 0.80 6.57 57.88 35.55 Р17 loam 49.252116 105.319017 silty clay GS234 Vegetable 4.21 1.09 0.74 4.55 66.22 29.23 Р17а loam silty clay GS235 49.252373 105.327729 Vegetable 3.03 1.09 2.04 5.0-10 55-70 25-35 Р18 loam silty clay GS236 49.250811 105.338437 Vegetable 3.34 1.09 4.15 5.0-10 55-70 25-35 Р19 loam silty clay GS237 49.249618 105.347624 Vegetable 3.82 1.09 1.99 5.0-10 55-70 25-35 Р20 loam silty clay GS238 49.245815 105.356873 Vegetable 2.61 1.09 2.22 5.0-10 55-70 25-35 Р21 loam silty clay GS239 49.249066 105.317437 Vegetable 2.45 1.09 0.37 5.0-10 55-70 25-35 Р22 loam silty clay GS240 49.251968 105.307516 Vegetable 3.84 1.09 0.00 5.0-10 55-70 25-35 Р23 loam silty clay GS241 49.244972 105.319402 Vegetable 3.18 1.09 0.00 5.0-10 55-70 25-35 Р24 loam silty clay GS242 49.238937 105.327243 Vegetable 3.59 1.09 0.00 5.0-10 55-70 25-35 Р25 loam silty clay GS243 49.23479 105.334313 Vegetable 4.96 1.09 0.00 9.19 57.84 32.97 Р26 loam GS244 Р27 49.236213 105.356134 Cereals 3.79 1.09 1.42 28.19 48.94 22.87 loam

360

A2.14: Subproject 14 Sugnugur IS

INTEGRATED AGRICULTURAL LABORATORY SOIL TESTING LABORATORY

Customer: Mongolian water forum Field location: Tuv aimag, Batsumber soum, Sugnugur Irrigation scheme: Sugnugur Field size: 140 hectare Datum: 2019.07.30

Table 12.1: Soil Agronomic Parameters

Mineral Sample Lab P, K, Ca, Mg, Na, CEC EC, pH pH SOM, Carbonate, Nitrogen, K, % name no Sample mg/kg mg/kg % % % meq/100g H2O CaCl2 % % mg/kg μS/cm depth, m

Interpretation 1 2 3 4 5 6 7 8 90- 3.0- 10.0 - 6.0 - 5.5 - Optimal value 15-20 18-20 60-75 <5 15-25 <200 >2 110 8.0 20.0 7.0 6.5 GS259 0.25 41.56 129.14 106.44 88.1 4.2 7.4 0.3 31.91 168.5 7.79 7 0.08 Р40 5.37 GS260 Р41 0.25 36.93 123.40 59.80 88.1 3.8 7.7 0.4 21.23 150 7.7 6.88 3.67 0.02

GS261 Р42 0.25 29.23 67.14 62.03 83.5 5.0 10.7 0.8 19.11 86.3 7.42 6.7 3.35 0.03

GS262 Р42а 0.6-0.8 17.45 15.31 108.88 79.7 3.9 14.9 1.5 33.79 179.8 8.71 7.67 2.00 0.17

GS263 Р43 0.25 46.58 51.32 118.01 78.9 7.3 13.4 0.3 19.28 115 7.21 6.55 2.5 0.04

GS264 Р44 0.25 10.74 72.32 32.73 78.9 7.3 13.4 0.3 17.64 120.5 8.12 7.13 2.5 0.04

Average 0.25 33.01 88.67 75.80 83.53 5.53 10.54 0.41 21.83 128.06 7.65 6.85 3.48 0.04

361

Table 12.2: Soil Physical Parameters Coordinates Soil particle size distribution

Sample Lab Soil Moisture, Density Gravel, % Sand, % Silt, % Clay, % name no utilisation % g/cm3 Х Ү Texture 2000-63 >2000 μm 63-2 μm <2 μm μm Interpretation 9 10 11

GS259 Р40 Vegetable 3.51 1.26 0.16 12.02 67.25 20.73 silt loam 48.394428 106.868575 GS260 Vegetable 2.52 1.26 0.16 33.85 49.47 16.68 silt loam Р41 48.392593 106.848835 GS261 Р42 Vegetable 2.15 1.26 0.33 38.14 43.47 18.40 loam 48.392203 106.835437 GS262 Р42 Vegetable 2.01 1.26 0.21 41.63 35.92 22.45 loam а GS263 Vegetable 2.97 1.26 0.98 33.91 49.03 17.06 silt loam Р43 48.392503 106.820449 GS264 Vegetable 2.24 1.26 1.30 38.00 42.00 20.00 loam Р44 48.398429 106.796649

362

A2.16: Subproject 16 Dulaanii tal IS

INTEGRATED AGRICULTURAL LABORATORY SOIL TESTING LABORATORY

Customer: Mongolian water forum Field location: Khentii aimag, Chingiss city Irrigation scheme: Dulaanii tal Field size: 700 hectare Datum: 2019.07.30

Table 13.1: Soil Agronomic Parameters

Mineral Sample P, K, Ca, K, Mg, Na, CEC EC, pH pH SOM, Carbonate, Lab no Sample Nitrogen, name mg/kg mg/kg % % % % meq/100g H2O CaCl2 % % depth, mg/kg μS/cm m Interpretation 1 2 3 4 5 6 7 8 10.0- 60- 3.0- 10.0 6.0 - 5.5 - Optimal value 25-50 60-90 <5 15-25 <200 >2 15.0 75 8.0 -20.0 7.0 6.5 Р1 GS213 0-0.4 11.33 3.74 34.38 77.1 6.4 14.7 1.9 9.63 71.6 6.92 6.06 1.59 0.26

Р2 GS214 0.4-0.6 7.30 2.43 9.13 80.6 4.2 13.8 1.3 10.37 47.7 6.83 5.85 1.00 0.35

Р3 GS215 0.25 5.55 4.34 43.37 78.6 7.5 13.3 0.7 6.25 42.2 6.77 5.86 0.70 0.34

Р4 GS216 0.25 5.95 3.53 31.95 77.0 7.6 13.3 2.1 5.77 28.4 6.83 5.67 0.50 0.36

Р5 GS217 0.25 15.17 21.23 57.93 91.5 2.5 5.6 0.3 23.96 113 8.26 7.16 0.99 0.47

Р6 GS218 0.25 9.21 3.34 0.00 82.3 4.7 12.4 0.6 6.99 30.6 6.53 5.59 0.62 0.31

Р7 GS219 0.25 7.38 2.63 10.00 80.0 5.6 13.7 0.7 6.91 24.8 6.76 5.71 0.62 0.35

Р8 GS220 0.25 9.80 2.63 47.88 76.7 9.1 13.5 0.8 7.15 34.8 6.78 5.84 0.87 0.33

Average 0.25 9.20 5.92 32.22 80.45 6.20 12.35 0.99 9.52 49.34 6.98 5.98 0.84 0.35

363

Table 13.2: Soil Physical Parameters Coordinates Soil particle size distribution

Sample Soil Moisture, Density Lab no Gravel, % Sand, % Silt, % Clay, % name utilisation % g/cm3 Х Ү Texture 2000-63 >2000 μm 63-2 μm <2 μm μm Interpretation 9 10 11 sandy GS213 47.351099 110.74697 fallow 1.12 1.50 13.05 66.65 19.20 14.16 Р1 loam sandy GS214 47.351099 110.74697 fallow 1.39 1.50 16.73 64.17 19.60 16.23 Р2 loam Loamy GS215 47.344801 110.73447 Vegetable 0.86 1.50 21.78 78.54 7.34 14.12 Р3 sand sandy GS216 47.338179 110.72363 Vegetable 0.79 1.50 16.19 78.92 4.95 16.13 Р4 loam sandy GS217 47.338257 110.70692 Vegetable 1.09 1.50 22.50 72.72 9.08 18.20 Р5 loam sandy GS218 47.345136 110.71421 pasture 1.16 1.50 10.98 76.68 7.13 16.19 Р6 loam sandy GS219 47.353865 110.72479 pasture 1.04 1.50 23.11 77.25 8.60 14.15 Р7 loam sandy GS220 47.366167 110.74492 pasture 1.00 1.50 13.17 75.74 10.12 14.14 Р8 loam

364

Annex 3: Fertilizer Application Recommendations by Subproject

A3.1: Subproject 1 Tsakhir

INTEGRATED AGRICULTURAL LABORATORY SOIL TESTING LABORATORY

FERTILIZER RECOMMENDATION

Customer: Mongolian water forum Field location: Govi-altai aimag, Jargalan soum Irrigation scheme: Tsakhir Field size: 200 hectare Datum: 2019.07.30

Table 1. Nutrient level for different type of crop Soil test result for Nutrients level

Nutrients Very low Low Acceptance High Very high

Mineral Nitrogen, NO3-N+NH4-N <25 25.0-45.0 45.0-75.0 >75 Mg/kg Plant Available phosphorus <10 10.0-15.0 15.0-25.0 >25 P, mg/kg Exchangeable Potassium <60.0 60.0-90.0 90.0-120.0 >120 K, mg/kg

Soil Organic matter, % 1.48 >2

P.S. Red colour cells are indicating the soil test level

Table 2. Fertilizer recommendation, kg/hectare Fertilizer recommendation, kg/hectare

Crop Organic matter Nitrogen, N Phosphorus, P Potassium, К (Compost or humus)

wheat 60.0 0.0 0.0 limitless Rapeseed 70.0 0.0 0.0 limitless Potato 125.0 25.0 35.0 limitless Vegetables 70.0 18.0 20.0 limitless

365

A3.2: Subproject 2 Yolton

INTEGRATED AGRICULTURAL LABORATORY SOIL TESTING LABORATORY

FERTILIZER RECOMMENDATION

Customer: Mongolian water forum Field location: Govi-Altai, Khaliun soum Irrigation scheme: Yolton Field size: 320 hectare Datum: 2019.07.30

Table 1. Nutrient level for different type of crop Soil test result for Nutrients level

Nutrients Very low Low Acceptance High Very high

Mineral Nitrogen, NO3-N+NH4-N <25 25.0-45.0 45.0-75.0 >75 Mg/kg Plant Available phosphorus <10 10.0-15.0 15.0-25.0 >25 P, mg/kg Exchangeable Potassium <60.0 60.0-90.0 90.0-120.0 >120 K, mg/kg 0.59 Soil Organic matter, % >2 P.S. Red colour cells are indicating the soil test level

Table 2. Fertilizer recommendation, kg/hectare Fertilizer recommendation, kg/hectare

Crop Organic matter Nitrogen, N Phosphorus, P Potassium, К (Compost or humus)

wheat 25.0 5.0 0 limitless Rapeseed 36.0 5.0 0 limitless Potato 88.0 35.0 20.0 limitless Vegetables 34.0 30.0 5.0 limitless

366

A3.3: Subproject 3 Erdeneburen

INTEGRATED AGRICULTURAL LABORATORY SOIL TESTING LABORATORY

FERTILIZER RECOMMENDATION Customer: Mongolian water forum Field location: Khovd aimag, Erdeneburen soum Irrigation scheme: Erdeneburen Field size: 2000 hectare Datum: 2019.07.30

Table 1. Nutrient level for different type of crop Soil test result for Nutrients level

Nutrients Very low Low Acceptance High Very high

Mineral Nitrogen, NO3-N+NH4-N <25 25.0-45.0 45.0-75.0 >75 Mg/kg Plant Available phosphorus <10 10.0-15.0 15.0-25.0 >25 P, mg/kg Exchangeable Potassium <60.0 60.0-90.0 90.0-120.0 >120 K, mg/kg 0.64 Soil Organic matter, % >2 P.S. Red colour cells are indicating the soil test level

Table 2. Fertilizer recommendation, kg/hectare Fertilizer recommendation, kg/hectare

Crop Organic matter Nitrogen, N Phosphorus, P Potassium, К (Compost or humus)

wheat 40.0 0.0 0.0 limitless Rapeseed 50.0 5.0 0.0 limitless Potato 100.0 30.0 25.0 limitless Vegetables 50.0 25.0 10.0 limitless

367

A3.4: Subproject 4 Boomiin am

INTEGRATED AGRICULTURAL LABORATORY SOIL TESTING LABORATORY

FERTILIZER RECOMMENDATION Customer: Mongolian water forum Field location: Khovd Aimag, Altai soum Irrigation scheme: Boomiin am Field size: 300 hectare Datum: 2019.07.30

Table 1. Nutrient level for different type of crop Soil test result for Nutrients level

Nutrients Very low Low Acceptance High Very high

Mineral Nitrogen, NO3-N+NH4-N <25 25.0-45.0 45.0-75.0 >75 Mg/kg Plant Available phosphorus <10 10.0-15.0 15.0-25.0 >25 P, mg/kg Exchangeable Potassium <60.0 60.0-90.0 90.0-120.0 >120 K, mg/kg

Soil Organic matter, % 1.24 >2 P.S. Red colour cells are indicating the soil test level

Table 2. Fertilizer recommendation, kg/hectare Fertilizer recommendation, kg/hectare

Crop Organic matter Nitrogen, N Phosphorus, P Potassium, К (Compost or humus)

wheat 40.0 0.0 0.0 limitless Rapeseed 50.0 5.0 0.0 limitless Potato 100.0 35.0 0.0 limitless Vegetables 50.0 30.0 0.0 limitless

368

A3.5: Subproject 5 Khoid gol

INTEGRATED AGRICULTURAL LABORATORY SOIL TESTING LABORATORY

FERTILIZER RECOMMENDATION Customer: Mongolian water forum Field location: Khovd aimag, Darvi soum Irrigation scheme: Khoid gol Field size: 400 hectare Datum: 2019.07.30

Table 1. Nutrient level for different type of crop Soil test result for Nutrients level Nutrients Very low Low Acceptance High Very high Mineral Nitrogen, NO3-N+NH4-N <25 25.0-45.0 45.0-75.0 >75 Mg/kg Plant Available phosphorus <10 10.0-15.0 15.0-25.0 >25 P, mg/kg Exchangeable Potassium <60.0 60.0-90.0 90.0-120.0 >120 K, mg/kg Soil Organic matter, % >2 4.2 P.S. Red colour cells are indicating the soil test level

Table 2. Fertilizer recommendation, kg/hectare Fertilizer recommendation, kg/hectare

Crop Phosphorus, Organic matter (Compost or Nitrogen, N P Potassium, К humus)

wheat 5.0 5.0 0 limitless Rapeseed 10.0 12.0 0 limitless Potato 60.0 40.0 0 limitless Vegetables 10.0 36.0 0 limitless

369

A3.6: Subproject 6 Tsul-Ulaan

INTEGRATED AGRICULTURAL LABORATORY SOIL TESTING LABORATORY

FERTILIZER RECOMMENDATION Customer: Mongolian water forum Field location: Bayan-Ulgii aimag, Bayannuur soum Irrigation scheme: Tsul-Ulaan Field size: 161 hectare Datum: 2019.07.30

Table 1. Nutrient level for different type of crop Soil test result for Nutrients level

Nutrients Very low Low Acceptance High Very high Mineral Nitrogen, NO3-N+NH4-N <25 25.0-45.0 45.0-75.0 >75 Mg/kg Plant Available phosphorus <10 10.0-15.0 15.0-25.0 >25 P, mg/kg Exchangeable Potassium <60.0 60.0-90.0 90.0-120.0 >120 K, mg/kg Soil Organic matter, % 1.72 >2 P.S. Red colour cells are indicating the soil test level

Table 2. Fertilizer recommendation, kg/hectare Fertilizer recommendation, kg/hectare

Crop Organic matter Nitrogen, N Phosphorus, P Potassium, К (Compost or humus)

wheat 25.0 0 0 limitless Rapeseed 35.0 0 0 limitless Potato 87.0 7.5 0 limitless Vegetables 33.5 3.0 0 limitless

370

A3.7: Subproject 7 Ulaandel

INTEGRATED AGRICULTURAL LABORATORY SOIL TESTING LABORATORY

FERTILIZER RECOMMENDATION Customer: Mongolian water forum Field location: Bayan-Ulgii aimag, Sagsai soum Irrigation scheme: Ulaandel Field size: 400 hectare Datum: 2019.07.30

Table 1. Nutrient level for different type of crop Soil test result for Nutrients level

Nutrients Very low Low Acceptance High Very high Mineral Nitrogen, NO3-N+NH4-N <25 25.0-45.0 45.0-75.0 >75 Mg/kg Plant Available phosphorus <10 10.0-15.0 15.0-25.0 >25 P, mg/kg Exchangeable Potassium <60.0 60.0-90.0 90.0-120.0 >120 K, mg/kg Soil Organic matter, % 0.93 >2 P.S. Red colour cells are indicating the soil test level

Table 2. Fertilizer recommendation, kg/hectare Fertilizer recommendation, kg/hectare

Crop Organic matter Nitrogen, N Phosphorus, P Potassium, К (Compost or humus)

wheat 55.0 0.0 0.0 limitless Rapeseed 65.0 0.0 0.0 limitless Potato 110.0 13.0 90.0 limitless Vegetables 60.0 8.5 77.5 limitless

371

A3.9: Subproject 9 Khurental

INTEGRATED AGRICULTURAL LABORATORY SOIL TESTING LABORATORY

FERTILIZER RECOMMENDATION Customer: Mongolian water forum Field location: Zawkhan aimag, Telmen soum Irrigation scheme: Khuren tal Field size: 500 hectare Datum: 2019.07.30

Table 1. Nutrient level for different type of crop Soil test result for Nutrients level

Nutrients Very low Low Acceptance High Very high

Mineral Nitrogen, NO3-N+NH4-N <25 25.0-45.0 45.0-75.0 >75 Mg/kg Plant Available phosphorus <10 10.0-15.0 15.0-25.0 >25 P, mg/kg Exchangeable Potassium <60.0 60.0-90.0 90.0-120.0 >120 K, mg/kg Soil Organic matter, % 1.5 >2 P.S. Red colour cells are indicating the soil test level

Table 2. Fertilizer recommendation, kg/hectare Fertilizer recommendation, kg/hectare

Crop Organic matter Nitrogen, N Phosphorus, P Potassium, К (Compost or humus)

wheat 0.0 0.0 0.0 limitless Rapeseed 0.0 0.0 0.0 limitless Potato 30.0 10.0 30.0 limitless Vegetables 0.0 5.0 15.0 limitless

372

A3.10: Sub-project 10 Nogoon Khashaa

INTEGRATED AGRICULTURAL LABORATORY SOIL TESTING LABORATORY

FERTILIZER RECOMMENDATION Customer: Mongolian water forum Field location: Zawkhan aimag, Uliastai soum Irrigation scheme: Nogoonksashaa Field size: 64 hectare Datum: 2019.07.30

Table 1. Nutrient level for different type of crop Soil test result for Nutrients level

Nutrients Very low Low Acceptance High Very high Mineral Nitrogen, NO3-N+NH4-N <25 25.0-45.0 45.0-75.0 >75 Mg/kg Plant Available phosphorus <10 10.0-15.0 15.0-25.0 >25 P, mg/kg Exchangeable Potassium <60.0 60.0-90.0 90.0-120.0 >120 K, mg/kg Soil Organic matter, % >2 3.89 P.S. Red colour cells are indicating the soil test level

Table 2. Fertilizer recommendation, kg/hectare Fertilizer recommendation, kg/hectare

Crop Organic matter Nitrogen, N Phosphorus, P Potassium, К (Compost or humus)

wheat 0.0 0.0 0.0 limitless Rapeseed 0.0 0.0 0.0 limitless Potato 0.0 0.0 150.0 limitless Vegetables 0.0 0.0 130.0 limitless

373

A3.12: Subproject 12 Iven Gol

INTEGRATED AGRICULTURAL LABORATORY SOIL TESTING LABORATORY

FERTILIZER RECOMMENDATION Customer: Mongolian water forum Field location: Selenge aimag, Sant Soum, Iven river Irrigation scheme: Iven Gol Field size: 500 hectare Datum: 2019.07.30

Table 1. Nutrient level for different type of crop Soil test result for Nutrients level

Nutrients Very low Low Acceptance High Very high

Mineral Nitrogen, NO3-N+NH4-N <25 25.0-45.0 45.0-75.0 >75 Mg/kg Plant Available phosphorus <10 10.0-15.0 15.0-25.0 >25 P, mg/kg Exchangeable Potassium <60.0 60.0-90.0 90.0-120.0 >120 K, mg/kg

Soil Organic matter, % >2 3.2 P.S. Red colour cells are indicating the soil test level

Table 2. Fertilizer recommendation, kg/hectare Fertilizer recommendation, kg/hectare

Crop Organic matter Nitrogen, N Phosphorus, P Potassium, К (Compost or humus)

wheat 5.0 0.0 0.0 limitless Rapeseed 12.0 0.0 0.0 limitless Potato 65.0 25.0 80.0 limitless Vegetables 10.0 20.0 65.0 limitless

374

A3.14: Subproject 14 Sugnugur

INTEGRATED AGRICULTURAL LABORATORY SOIL TESTING LABORATORY

FERTILIZER RECOMMENDATION Customer: Mongolian water forum Field location: Tuv aimag, Batsumber soum, Sugnugur Irrigation scheme: Sugnugur Field size: 140 hectare Datum: 2019.07.30

Table 1. Nutrient level for different type of crop Soil test result for Nutrients level

Nutrients Very low Low Acceptance High Very high

Mineral Nitrogen, NO3-N+NH4-N <25 25.0-45.0 45.0-75.0 >75 Mg/kg Plant Available phosphorus <10 10.0-15.0 15.0-25.0 >25 P, mg/kg Exchangeable Potassium <60.0 60.0-90.0 90.0-120.0 >120 K, mg/kg

Soil Organic matter, % >2 3.48 P.S. Red colour cells are indicating the soil test level

Table 2. Fertilizer recommendation, kg/hectare Fertilizer recommendation, kg/hectare

Crop Organic matter Nitrogen, N Phosphorus, P Potassium, К (Compost or humus)

wheat 0.0 0.0 0.0 limitless Rapeseed 0.0 0.0 0.0 limitless Potato 50.0 0.0 0.0 limitless Vegetables 0.0 0.0 0.0 limitless

375

A3.16: Subproject 16 Dulaanii tal

INTEGRATED AGRICULTURAL LABORATORY SOIL TESTING LABORATORY

FERTILIZER RECOMMENDATION Customer: Mongolian water forum Field location: Khentii aimag, Chingiss city Irrigation scheme: Dulaanii tal Field size: 700 hectare Datum: 2019.07.30

Table 1. Nutrient level for different type of crop Soil test result for Nutrients level

Nutrients Very low Low Acceptance High Very high

Mineral Nitrogen, NO3-N+NH4-N <25 25.0-45.0 45.0-75.0 >75 Mg/kg Plant Available phosphorus <10 10.0-15.0 15.0-25.0 >25 P, mg/kg Exchangeable Potassium <60.0 60.0-90.0 90.0-120.0 >120 K, mg/kg Soil Organic matter, % 0.84 >2 P.S. Red colour cells are indicating the soil test level

Table 2. Fertilizer recommendation, kg/hectare Fertilizer recommendation, kg/hectare

Crop Organic matter Nitrogen, N Phosphorus, P Potassium, К (Compost or humus)

wheat 55.0 5.0 0 limitless Rapeseed 70.0 5.0 0 limitless Potato 120.0 30.0 120.0 limitless Vegetables 65.0 25.0 110.0 limitless

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Annex 4: Output of ESTIMATOR PRO54 for Estimation of Construction Civil work for Tsul-Ulaan Irrigation scheme

Table 4.1: Overall budget for civil work, in MNT Items Quantity Labor Material Technics Transportation Others Benefit Total

Headwork’s Sluicing structure with 2,286,505 53,021,810 1,055,687 6,001,418 872,623 9,437,157 72,675,201 intake sluice channel and outlet 1 flushing channel Rock fill Barrier and Water level 49,909,786 60,244,956 47,044,709 4,004,732 19,047,590 25,908,807 206,160,581 Control Weir, Wall L = 60 m, h = 1.5 1 m, Weir L = 10 m, h = 1.0 m 10,521 2,409,814 18,480,197 Headwork’s protection 500m 2,027,567 6,002,012 7,837,451 192,833 embankment Main Canal – reforming and lining 5700m 148,745,062 385,292,116 29,773,865 44,119,172 56,767,124 96,339,990 761,037,329 Header Canal reforming and 69,692,711 182,462,876 13,991,624 20,560,677 26,597,553 45,419,369 358,724,810 – 2554m lining Field Canals reforming and 49,454,975 13,445,016 29,542,330 437,278 18,873,956 15,644,365 127,397,921 – 14047m shaping Drains – reforming and grading 2936m 65,107 0 11,174,570 0 24,848 1,688,206 12,952,731 Bridge 5 piece 515,369 7,533,610 1,041,316 2,333,006 196,686 8,681,849 20,301,836 Roads – forming and grading 6600m 172,751 0 18,532,800 0 65,929 2,811,813 21,583,293 Windbreaks prepare land and 79,000,271 46,072,960 0 3,406,055 30,149,694 - 137,666,822 – 3.1 ha install 20,962,158 Drain and protection bank 2900m 137,833 0 80,160,960 0 52,603 12,048,991 92,400,387 Fence 6.6 km 46,200,000 Grand total of civil works 1,875,581,108

54 This is the software for estimation a budget for construction as per Building Norm and Standards:81-10-13 for Preparation of Budget for Construction Woks. This norm was updated in 2010. The software was certified by the Minister of Urban development and Construction on 23 February 2008.

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Table 4.2: Budget for Headworks Sluicing structure with intake sluice channel and outlet flushing channel, in MNT Code in the Building Norms and Volume of work Quantity unit Labor Material Technics Transportation standard number reinforced concrete wall for 06-060-10 20 m3 961,029 8,002,244 759,936 870,209 gate reinforced concrete for gate 06-010-19 74 m3 1,267,875 42,491,058 295,672 4,814,139 basement 06-050-12 Assemble gate frame 1 set 57,680 2,528,508 317,070

Total 2,286,584 53,021,810 1,055,687 6,001,418

Table 4.3: Budget for the Rockfill Barrier and Water level Control Weir, in MNT Code in the Building Norms and Volume of work Quantity unit Labor Material Technics Transportation standard number 08-020-04 Rock preparation, 3 transportation 1350 m 45,038,968 34,762,500 44,649,407 1,118,432 reinforced concrete wall 06-060-06 54 m3 3,986,322 21,096,286 2,306,331 2,399,191 06-010-05 reinforced concrete 24 m3 884,496 4,386,170 88,971 487,109 basement

Total 49,909,786 60,244,956 47,044,709 4,004,732

Table 4.4: Budget for the Headworks protection embankment Code in the Building Norms and Volume of work Quantity unit Labor Material Technics Transportation standard number Stone preparation, 01-220-07 3 transportation and shaping 250 m 2,027,567 6,002,012 7,837,451 192,833

Total 2.027,567 6,002,012 7,837,451 192,833

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Table 4.5: Budget for the Main Canal – reforming and lining Code in the Building Norms Volume of work Quantity unit Labor Material Technics Transportation and standard number Excavation 01-360-02 5700 m3 124,328 13,338,000 Dumping of the excavated 01-220-08 5472 m3 soils 91,421 15,690,851 Dig, smoothing 01-040-02 1368 m3 and shaping the 18,799,231 canal by hand 08-030-04 Underlay sand on the 598.5 m3 7,872,967 9,875,250 320,644 2,762,304 bottom 3 06-230-09 Reinforced concrete lining 1938 m 105,453,219 181,309,590 35,950,882 Install the biddings 06-050-12 0.06 ton 8,652 307,276 21,187 12-060-10 Underlay water proof 19380 m2 15,253 779 193,800,000 5 384 799 plastics Installation of gates 22-110-10 3 piece 1,141,477 424,359

Total 148,745,062 385,292,116 29,773,865 44,119,172

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Table 4.6: Budget for the Header Canal – reforming and lining Code in the Building Norms Volume of work Quantity unit Labor Material Technics Transportation and standard number Excavation 3 01-360-02 2730 m 59,547 6,388,200 Dumping and shaping of 01-220-08 2621 m3 43,789 7,515,665 the excavated soils Dig, smoothing 01-040-02 700 m3 9,619,489 and shaping the canal by hand 08-030-04 Underlay sand on the 163.8 m3 2,154,707 2,702,700 87,755 755,999 bottom 06-230-09 Reinforced concrete lining 928.2 m3 50,506,542 86,837,751 17,218,580 Install the biddings 06-050-12 0.02 ton 2,880 102,425 7,062 12-060-10 Underlay water proof 9282 m2 7,305,757 92,820,000 2,579,035 plastics

Total 69,692,711 182,462,876 13,991,624 20,560,677

Table 4.7: Budget for the Field Canals – reforming and shaping Code in the Building Norms Volume of work Quantity unit Labor Material Technics Transportation and standard number Excavation 01-220-08 8428 3 140,807 24,167,121 m Dig, smoothing 01-040-02 2528 m3 34,740,099 and shaping the canal by hand Install control gates 06-050-12 38 piece 115,360 4,097,016 282,488 Reinforced concrete well piece 22-110-10 38 14,458,709 9,348,000 5,375,209 154,789 for control gates

Total 49,454,975 13,445,016 29,542,330 437,278

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Table 4.8: Budget for the Drains – reforming and grading Code in the Building Norms Volume of work Quantity unit Labor Material Technics Transportation and standard number Excavation, dumping and 01-220-08 3897 m3 65,107 11,174,570 shaping

Total 65,107 11,174,570

Table 4.9: Installation of the Bridge Code in the Building Norms Volume of work Quantity unit Labor Material Technics Transportation and standard number Excavation 01-220-08 6 3 100 17,205 m 01-040-02 Dig, smoothing 2 27,484 m3 and shaping the canal by hand 08-030-04 Sand underlay 1 13,154 16,500 536 4,615 m3 33-090-24 Install the culverts 0.03 km 374,093 7,452,000 1,006,200 2,324,560 11-120-04 Stone embankment 14.4 m2 100,537 65,110 17,376 3,831

Total 515,369 7,533,610 1,041,316 2,333,006

Table 4.10 Earth road Code in the Building Norms Volume of work Quantity unit Labor Material Technics Transportation and standard number Excavation, dumping and 01-360-02 7920 m3 172,751 18,532,800 shaping 172,751 18,532,800 Total

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Table 4.11: Budget for the Windbreaks – prepare land and install Code in the Building Norms Volume of work Quantity unit Labor Material Technics Transportation and standard number Dig the (deep)hole and

underlay the fertile soil m3 37-040-12 2072 53,007,954 30,914,240 2,285,410 for 75% for threes Dig the hole and underlay

the fertile soil for 75% for m3 37-080-12 1016 25,992,317 15,158,720 1,120,645 bushes Total 79,000,271 46,072,960 3,406,055

Table 4.12: Fence Code in the Building Norms Volume of work Quantity unit Labor Material Technics Transportation and standard number

Fence cost is 7,000,000 MNT/h including all costs. This the cost of from, MOFALI project for fencing implemented in 2018.