UNESCO-IHE INSTITUTE FOR WATER EDUCATION

Hydraulic Design and Performance Assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

Ruaa Khalid Hamdan

MSc Thesis (WSE-LWD-08.10) April 2008

Hydraulic Design and Performance Assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

Master of Science Thesis By Ruaa Khalid Hamdan

Supervisors Prof. E. Schultz, PhD, MSc (UNESCO-IHE) F.X. Suryadi, PhD, MSc (UNESCO-IHE)

Examination committee Prof. E. Schultz, PhD, MSc (UNESCO-IHE), Chairman Ir. P.H.J. Hollanders (Principal Water-board of Delfland) F.X. Suryadi, PhD, MSc (UNESCO-IHE)

This research is done for the partial fulfillment of requirements for the Master of Science degree at the UNESCO-IHE Institute for Water Education, Delft, the Netherlands

Delft April 2008

The findings, interpretations and conclusions expressed in this study do neither necessarily reflect the views of the UNESCO-IHE Institute for Water Education, nor of the individual members of the MSc committee, nor of their respective employers.

This thesis is dedicated to my parents for their love and care.

Acknowledgements

Acknowledgements

All Praise is to Allah, the Lord of the Worlds.

To my Parents, Aunts, Sister and Brothers who support me and give me the power and the patience, to complete this study, I present this work to them.

Thanks and gratitude to Professor Bart Schultz for his valuable guidance and advices, thanks to Dr. Suryadi for his support and guidance.

Many thanks to the Director of Irrigation in Sulymania and the other staff members for providing me with information.

Special thanks to the entire support staff of UNESCO-IHE, my friends and my classmates for their support.

Ruaa K. Hamdan i Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

Ruaa K. Hamdan ii Summary

Summary

Design of irrigation systems is a complex process; it involves a large number of criteria. At any stage during the design phase feedback is necessary in order to optimize the final product. The optimization in the design phase requires an investment of time to get the most appropriate solution. In conventional design, this process of optimization was not really carried out because of lack of time. Nowadays with the enormous advance in computer techniques and with the support of powerful tools such as the DUFLOW and other computer programs, designers are able to find the most suitable solution by analyzing various alternatives in a much shorter period. At present, computer programs are available for the design of irrigation systems that allow the designer to evaluate and to check the hydraulic performance of each part of the irrigation system independently.

The present research was focused on the evaluation of the design of Malwan Irrigation Scheme in North Iraq (Kurdistan region). The specific objectives of the study were: • to assess the cropping potential of Malwan Irrigation Scheme and recommend possibilities for improvement of the scheme; • to assess the hydraulic sustainability of Malwan Irrigation Scheme, under the actual operation, maintenance and management condition; • to propose alternative solutions and determine to what extent the operational objectives of the irrigation agency can be fulfilled with the actual infrastructure; • to propose alternatives for improvement and analyze them by using DUFLOW modelling (the DUFLOW program is applied to investigate the impact of unsteady flow on the hydraulic performance of the irrigation canals, and to examine possible design and/or operational measures to improve the performance); • to recommend suitable design measures.

The research focuses on three topics and under Topic 1 on these scenarios as presented in the Tables below:

Topic Scenario 1- Water balance and 1 2 3 crop water requirements Without deficit Under deficit Changed cropping pattern

Topic Description 2- Canal capacity By using the hydrodynamic program DUFLOW 3- Sedimentation in the canal system By using the SETRIC program

Ruaa K. Hamdan iii Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

In Topic 1 the crop water requirement has been determined by using the program CROPWAT under different conditions. In both scenarios one and two of topic one five type of crops were selected (Cotton, Sunflower, Wheat, Barley and Small vegetables) according to the market of these crops in the area. The scenarios 1 and 2 are respectively without deficit and under deficit conditions. While in scenario three a new suggestion with respect to the cropping pattern and the irrigation scheduling has been made. Instead of planting five crops it will be eight different crops Potato, Tobacco and Beans will be added to the previous scenarios. These new crops will be planted after the harvesting of wheat and barley in the same tertiary unit, the peak discharge in this case will be a bit higher than the previous values, but with a higher income to the farmers from an economic point of view. Therefore scenario three of topic one is preferable for getting more chances to develop the cropping pattern as well as the economical benefits of the farmers.

The second topic concerns the hydraulic design from different points of view, including options that permit to introduce hydraulic energy and sediment transport concepts, both with one common goal, namely to obtain a design, which avoids sedimentation and erosion in the irrigation canal network. Another feature of Topic 2 includes the possibility to improve the preliminary design results (based on steady state computations) based on DUFLOW (unsteady flow computer program) and SETRIC (sediment transport program) for further analysis of the operation and maintenance. In topic two, the cross sectional dimensions which were obtained from the preliminary design are improved with the DUFLOW program, to get the final dimensions (bed width, water depth) for the main and secondary canals in Malwan Irrigation Scheme.

Further more in topic three the morphological performance of Malwan Irrigation Scheme has been checked with the SETRIC program. The link between the hydraulic design and the different programs for hydraulic and sediment transport modelling is a powerful element of analysis, because it combines two different approaches to solve the same problem: the steady and unsteady flow types in irrigation canals. In the simulation with SETRIC, the hydraulic design with “sediment control” option, showed to be appropriate. The incoming sediment load was transported through the whole canal system achieving the objective of the design. The result of the simulations showed that the hydraulic design with sediment criteria has the expected behaviour.

The SETRIC program is recommended for testing the behaviour of sediments in irrigation canal conditions, it can also be used to test different operation and maintenance conditions and to determine a sediment efficient operation and maintenance practice in an irrigation canal. Similarly various design alternatives can be analyzed to determine a sediment efficient design of irrigation canals and thus helps as a design tool. Further study is necessary to validate the boundary conditions of erosion and deposition calculated in the model.

An unsteady flow model would have to be applied to the system in order to support the decision- making process for improving operation and maintenance of the irrigation system. A short course for a number of engineers of the Malwan Irrigation Branch would have to be carried out in order to enable them to understand the software and to develop operation rules for all schemes. The DULOW program needs to be modified for irrigation networks and more types of control structures need to be added to the program in order to make the schematization simpler.

Ruaa K. Hamdan iv Summary

Executing the alternative scenarios during the irrigation season needs discussions with the farmers’ groups about the implications of the various operational options for changing the operational rules of the system in order to achieve the performance improvement goals.

Ruaa K. Hamdan v Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

Ruaa K. Hamdan vi Table of contents

Table of contents

ACKNOWLEDGEMENTS...... I SUMMARY...... III

TABLE OF CONTENTS...... VII List of symbols...... xi List of abbreviations ...... xiii List of tables...... xv List of figures...... xvii

1 INTRODUCTION...... 1 1.1 General...... 1 1.2 Background information of the country...... 4 1.2.1 Location ...... 4 1.2.2 Major geographical features ...... 5 1.2.3 Population ...... 6 1.2.4 Climate...... 7 1.2.5 Agriculture development and land use ...... 8 1.2.6 Water resources...... 9 1.2.7 Irrigation and drainage development ...... 12 1.3 Kurdistan region...... 12 1.3.1 Geography and location ...... 12 1.3.2 Land and population of Iraq Kurdistan...... 13 1.3.3 Climate of Kurdistan...... 14 1.3.4 Agriculture in Kurdistan ...... 15 1.3.5 Resources and small scale irrigation in Kurdistan...... 16 1.4 Malwan irrigation scheme...... 16 1.5 Problem identification...... 18 1.6 Objectives ...... 19 1.7 Methodology...... 20

2 LITERATURE REVIEW ...... 22 2.1 General...... 22 2.2 Performance studies review ...... 22 2.3 Application of computer models...... 27 2.4 Sediment Transport Predictors in Equilibrium Conditions...... 36 2.4.1 Ackers and White method...... 37 2.4.2 Engelund and Hansen method ...... 39 2.4.3 Brownlie method...... 40

3 DATA COLLECTION AND FIELDWORK ...... 41 3.1 Project background ...... 41 3.2 Field data collection...... 42

Ruaa K. Hamdan vii Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

3.2.1 Climate...... 43 3.2.2 Hydrology ...... 47 3.2.3 Soils...... 47 3.5.1 Water source and headwork...... 52 3.5.2 Main canal...... 52 3.5.3 Structures ...... 52 3.6 System management ...... 54

4 STUDY FRAMEWORKS...... 55 4.1 Need for performance assessment of irrigation systems...... 55 4.2 Current performance of irrigation systems ...... 56 4.3 Water delivery systems performance...... 57 4.4 Parameters describing water delivery performance...... 59 4.4.1 Adequacy ...... 60 4.4.2 Efficiency...... 61 4.4.3 Equity...... 62

5 COMPUTER MODELS...... 65 5.1 Unsteady flow model ...... 65 5.2 Application of the hydrodynamic program DUFLOW...... 66 5.2.1 Concept of water quantity in DUFLOW...... 67 5.2.2 Unsteady flow equations...... 68 5.2.3 Model setup...... 69 5.3 CROPWAT program ...... 72 5.3 .1 Input ...... 73 5.3 .2 Output ...... 73 5.3 .2 Calculation methods...... 74 5.4 Water flow and sediment transport theory in view of the SETRIC program ...... 75 5.4 .1 Governing water flow equation ...... 75 5.5 Governing sediment flow equation...... 78 5.5 .1 Continuity equation...... 78 5.5.2 Bed forms...... 81 5.5.3 Movable bed...... 82

6 SIMULATIONS AND EVALUATION OF RESULTS...... 85 6.1 Calculation of irrigation requirements...... 86 6.2 Modeling of alternative operational scenarios...... 92 6.2.1 Topic 1 ...... 93 6.2.2 Topic 2 ...... 96 6.2.3 Topic 3 ...... 102 6.2 Design criteria performance...... 106

7 CONCLUSIONS AND RECOMMENDATIONS...... 108

8 REFRENCES ...... 112

Ruaa K. Hamdan viii Table of contents

APPENDIXES...... 118

Appendix 1: Average evaporation and precipitation(mm) ...... 121 Appendix 2: Discharge of the suggested future reservoir in m3/year (1973-2007) ...... 124 Appendix 3: Checking the over turning and sliding of the canal wall...... 125 Appendix 4: Checking the reinforcement required at the canal base...... 126 Appendix 5 :Result of SETRIC program...... 128

Ruaa K. Hamdan ix Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

Ruaa K. Hamdan x List of symbols

List of symbols

% Percent A Area of a cross section (m2) Ea Application efficiency Ec Conveyance efficiency Ed Distribution efficiency Ha Hectare Kc Crop coefficient km Kilometre km2 Square kilometre m Metre m/s Metre per second m+MSL Metre above mean sea level m3 Cubic metre m3/s Cubic metre per second mg/l Milligram per litre mm Millimetre mm/month Millimetre per month mm/year Millimetre pear year oC Degree centigrade Qa Actual discharge (m3/s) R Rainfall (mm/day) Reff Effective rainfall (mm/day)

Ruaa K. Hamdan xi Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

Ruaa K. Hamdan xii List of abbreviations

List of abbreviations

CROPWAT Computer Program for Crop Water Requirements

CWR Crop Water Requirements (mm/day)

DPR Delivery Performance Ratio

DUFLOW DUtch FLOW package for unsteady open channel flow

FAO Food and Agriculture Organization

GDP Gross Domestic Product

GIR Gross Irrigation Requirement (mm/day)

IPTRID International Program for Technology and Research in Irrigation and Drainage

IWMI International Water Management Institute

Max Maximum

Min Minimum

NIR Net Irrigation Requirement (mm/day)

O&M Operation and Maintenance

RAM Readily Available Moisture (mm)

SIR Scheme Irrigation Requirement (mm/day)

Ruaa K. Hamdan xiii Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

Ruaa K. Hamdan xiv List of tables

List of tables

Table1-1: Temperature in different regions in Iraq (oC)...... 7 Table 2-1: Conveyance, field canal and field application efficiencies (adapted from FAO, 1992) ...... 33 Table 2-2: Farm irrigation efficiencies for sprinkler irrigation in different climates (adapted from FAO, 1982)...... 34 Table 2-3: Project efficiencies for localized irrigation systems (adapted from: Rainbird International, 1980) ...... 34 Table 2-4: Original coefficients of Ackers and White formula...... 37 Table 2-5: Coefficients for Modified Ackers and White formula...... 38 Table 3-1: Average monthly rainfall, 1973-2006 (mm)...... 43 Table 3-2: Average monthly temperature ◦C...... 44 Table 3-3: Average monthly humidity (%)...... 45 Table 3-4: Average daily evaporation, 1973-2006 (mm/day) ...... 45 Table 3-5: Average wind speed, 1973-2006 (m/s)...... 46 Table 3-6: Average daily sunshine hours, 1973-2006 (hrs/day) ...... 47 Table 3-7: Numbers of beneficiaries’ farmers and families before and after project implementation...... 49 Table 3-8: The returning families and farmers after establishing the project i.e. at 2001- 2002...... 51 Table 3-9: Main and secondary canal cross section characteristics ...... 52 Table 3-10: Vertical gate characteristics ...... 53 Table 4-1: Performance standards (Molden and Gates, 1990)...... 63 Table 5-2: Bed forms of van Rijn for lower regime...... 81 Table 5-3: Type of hydraulic regime as per van Rijn ...... 82 Table 6-1: Irrigation requirement for winter crops in mm/day...... 87 Table 6-2: Irrigation requirement for summer crops in mm/day ...... 88 Table 6-3: Cropping pattern and its calendar of Malwan Irrigation Scheme...... 89 Table 6-4: Assumed irrigation efficiencies in Malwan Irrigation Scheme...... 92 Table 6-5: Crop water requirement without deficit condition in m3/s...... 94 Table 6-6: Crop water requirement under deficit condition in m3/s ...... 95 Table 6-7: Crop water requirement with new suggested crops in m3/s...... 96 Table 6-8: Input parameters for the SETRIC program ...... 105

Ruaa K. Hamdan xv Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

Ruaa K. Hamdan xvi List of figures

List of figures

Figure1-1: General map of Iraq...... 5 Figure 1-2: Topographical map of Iraq ...... 6 Figure 1-3: Map of land use in Iraq ...... 9 Figure 1-4: Map of water resources in Iraq...... 11 Figure 1-5: Map of Iraqi Kurdistan...... 13 Figure 1-6: Location of Malwan Irrigation Scheme...... 18 Figure 3-1: Location of Malwan Irrigation Scheme...... 42 Figure 3-2: Average monthly rainfall, 1992 - 2006 ...... 43 Figure 3-3: Average monthly temperature in ◦C...... 44 Figure 3-4: Relative humidity in % ...... 45 Figure 3-5: Monthly average evaporation in mm...... 46 Figure 3-6: Average monthly wind speed in m/s ...... 46 Figure 3-7: Average daily sunshine hours...... 47 Figure 5-1: Main data manipulation screen at CROPWAT program ...... 72 Figure 5-2: Predictor corrector method for water flow ...... 78 Figure 5-3: Schematization of mass balance for total sediment transport...... 79 Figure 6-1: Water balance curve between crop evaporation and average rainfall...... 88 Figure 6-2: Cropping pattern and percentage of total grown area for each crop...... 90 Figure 6-3: Schematization of Malwan Irrigation Scheme in the DUFLOW program.... 97 Figure 6-4: Cross section dimensions of the main canal ...... 97 Figure 6-5: Discharge in the main canal of Malwan Irrigation Scheme ...... 98 Figure 6-6: Water level and velocity in the main canal of Malwan Irrigation Scheme ... 98 Figure 6-7: Cross section dimensions of the 1st secondary canal ...... 99 Figure 6-8: Discharge in the 1st secondary canal of Malwan Irrigation Scheme ...... 99 Figure 6-9: Water level in the 1st secondary canal of Malwan Irrigation Scheme ...... 99 Figure 6-10: Cross section dimensions of the 2nd secondary canal...... 100 Figure 6-11: Discharge in the 2nd secondary canal of Malwan Irrigation Scheme...... 100 Figure 6-12: Water level in the 2nd secondary canal of Malwan Irrigation Scheme .... 100 Figure 6-13: Cross section dimensions of the 3rd secondary canal ...... 101 Figure 6-14: Discharge in the 3rd secondary canal of Malwan Irrigation Scheme ...... 101 Figure 6-15: Water level in the 3rd secondary canal of Malwan Irrigation Scheme..... 102 Figure 6-16: Sediment concentration in the main canal of Malwan Irrigation Scheme 103 Figure 6-17: Change in bed level in the main canal of Malwan Irrigation Scheme...... 103 Figure 6-18: Scouring sluice ...... 104 Figure 6-19: The cross section of the main canal wall of Malwan Irrigation Scheme .. 106

Ruaa K. Hamdan xvii Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

Ruaa K. Hamdan xviii Chapter-1 Introduction

1 INTRODUCTION

1.1 General

Major civilizations of the world started in fertile river valleys, mainly due to the availability of land and water for agriculture. Civilizations in the past were able to survive on the average for only 40 to 60 generations before they declined, perished or were forced to move to new lands (Paudel, 2002). By human activity the quality of land deteriorated so badly that it became impossible to produce enough food to support the population. Human life continues to evolve around watercourses, and it is an absolute certainty that water will remain a vital ingredient for our general welfare. Disintegrating its importance and permitting a continued unregulated use and further deterioration of water quality could significantly reduce the quality of life. Alluvial plains of the Indus valley and the Nile valley are the only areas where we can find sustained crop production since the start of civilization. Other places have been either completely abandoned or become unfeasible for sustainable agriculture. In the Indus valley, at one stage, yearly 400,000 ha of land have become unusable due to salinity problems. Other causes of loss of agriculture land are soil erosion and water logging due to unregulated land and water use; it may be in the agriculture land itself or in the catchment.

Irrigation is an art that has been practiced for centuries (Bos and Nugteren, 1990). Irrigation is essential for agricultural production in arid and semi-arid regions where rainfall is inadequate to sustain crop growth. Indeed, in more humid areas irrigation has now become the primary tool to increase and stabilize agricultural production in view of uncertainties of rainfall and frequent droughts, and to feed an ever increasing world population (Schultz et al., 2005). Irrigation system objectives usually include such subjects as: economic return, augmenting crop production, betterment of the general population, rural development, etc., and more recently developing a sustainable agriculture and minimizing the impact of the system on the environment (i.e., water quality issues). Some of these objectives are relatively easy to evaluate, while other may be very difficult. In any case, the above types of objectives can only be viewed as long-term objectives. Measurements or indicators for evaluating these objectives can be measured seasonally or yearly at best (Biswas, 1990).

Worldwide, irrigation water consumes the bulk of the available renewable fresh water resources over 70%. Irrigated agriculture is practiced on 18% of total cultivable land in the world

Ruaa K. Hamdan 1 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

(approximately 267 million hectares) and produces more than 33% of the total agricultural production. Of these irrigated areas, 71% are in the least developed countries (Johansson, 2000). The aggregate result for the group of developing countries shows that the area equipped for irrigation in this group of countries will expand by 40 million ha 20% by 2030. This means that some 20% of the land with irrigation potential not yet equipped at present will be brought under irrigation by 2030 (FAO, 2003). The irrigation sector, which already consumes a large share of global water, will thus continue to increase its demand for water in the foreseeable future.

Population increase and the improvement of living standards brought about by development will result in a sharp increase in food demand during the next decades. Most of this increase will be met by the products of irrigated agriculture. Population growth will take place, in particular in the emerging and the least developed countries.

This implies that these countries will be confronted with the need to increase their food supply by a larger production in their own territory, maybe in combination with increased imports. From the point of view of food production there is a common feeling that in the coming decades about 90% of the required increase will have to be realized on existing cultivated land and about 10% on newly reclaimed land (Schultz, 2005).

There are more than 270 million ha of irrigated lands in the world of which most have poor irrigation efficiencies. In developing countries, many irrigation systems perform below their potential. Head-tail problems, leaky canals and malfunctioning structures because of delayed maintenance, leading to low water-use efficiency and low yields, are some of the commonly expressed problems. A large part of low performance may be due to inadequate water management at system and field level. It is therefore, imperative to strive for better management and utilization of water resources to meet the increasing competition for water.

Regarding the fact that efficient operation and maintenance (O&M) of an irrigation system plays an important role in the sustainability of irrigated agriculture therefore understanding the operational aspects that can help in improving the over all performance of these systems are important. Improving the system’s operation and maintenance can be carried out through better operational procedures and improved service delivery. The first stage of operational improvement process can be consisting of retrospective modelling analysis of the system to assess its operational performance.

Ruaa K. Hamdan 2 Chapter-1 Introduction

It is clear that the performance of the main system has a great impact on the performance of the whole system; therefore, assessment of water delivery performance is important to the managers of irrigation systems. The function of a main system is to deliver water needed by the crop to the farm turnout at the right amount, at the right time and for the right duration.

Performance of irrigated agriculture must improve to provide additional food to a growing and more affluent population (Burton and Molden, 2005). At the same time, the water input per unit irrigated area will have to be reduced in response to water scarcity and environmental concerns. Water productivity is projected to increase through gains in crop yield and reductions in irrigation water (Playan and Mateos, 2003). Expansion of worldwide food production during the twentieth century was closely associated with the expansion of irrigated land, and associated drainage. Yet the international community appears to be nervous about the prospects for the future increases in production that will likely be required to feed an expanding, more affluent world population, International Commission on irrigation and drainage (ICID, 2003). Improvements in the performance and productivity of existing irrigation systems are viewed as an important source for the needed expansion in world food production. Over the last several years, ICID had a Working Group on Performance Assessment. They have provided some useful guidelines on assessing the performance of irrigation and drainage systems. A recent issue of the ICID Journal Irrigation and Drainage discusses the need for benchmarking of irrigation and drainage systems (Malano et al., 2004a). In general, there are two types of indicators - external indicators of production, water use, or productivity and internal measures of operational performance (Malano et al., 2004b).

Various methods are available for measuring these indicators, which provide important diagnostic tools to determine how irrigation and drainage systems are operating (ICID, 2004). However, making a link between external performance and internal performance is not straightforward (Burt and Styles, 1999; Styles and Marino, 2002) Without a clear understanding of the link between irrigation system operations and the resulting system performance, one cannot develop a rational plan for implementing needed changes, nor where to start (Clemmens, 2006).

A water delivery system may be viewed as one of the components of an irrigated agriculture system. As such, it provides the water required to achieve farm-level agriculture production policies, such as maximizing net economic and social-welfare benefits. The production can be influenced by a very wide range of factors (e.g., climate, soil type, irrigation method, land

Ruaa K. Hamdan 3 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region) preparation and salt leaching, crop type, inputs, use of pesticides, financial arrangements, market price, market availability and so forth), and by no means have all of them anything to do with the quality of irrigation (Abernethy, 1986). For planning and management, the objectives of irrigation systems often are viewed in terms of desire to best meet agriculture water requirements (Molden and Gates, 1990). If the management is unsuccessful it will not be possible for agricultural management to succeed.

1.2 Background information of the country

1.2.1 Location

Iraq with a total area of 43.8 million ha including 92,400 ha of inland waters is surrounded by Iran to the East, Turkey to the North, Syria and Jordan to the West, Saudi Arabia and Kuwait to the South, and the Persian Gulf to the South-East. See Figure 1-1.

Topographically Iraq is shaped like a basin, consisting of the great Mesopotamian alluvial plain of the Tigris and the Euphrates rivers. Mesopotamia means, literally, the land between two rivers. This plain is surrounded by mountains in the North and the East, which can reach altitudes of 3,550 metre above mean see level (m+MSL), and by desert areas in the South and West, which account for over 40% of the land area. For administrative purposes, the country is divided into 18 governorates, of which three are gathered in a region named as Kurdistan.

It is estimated that 11.480 million ha are cultivable or 26% of the total area of the country. The total area estimated to be used for agriculture is 8 million ha, which is almost 70% of the cultivable area. However, due to soil salinity, fallow practices and the unstable political situation it is estimated that only 3 to 5 million ha are actually cultivated annually (FAO, 1994).

Ruaa K. Hamdan 4 Chapter-1 Introduction

Figure1-1: General map of Iraq

1.2.2 Major geographical features

Most geographers, including those of the Iraqi government, discuss the country’s geography in terms of four main zones or regions: the desert in the West and South-West; the rolling upland between the upper Tigris and Euphrates rivers (in Arabic Dijla and Furat, respectively); the highlands in the North and North-East; and the alluvial plain through which the Tigris and Euphrates flow, as shown in Figure 1-2.

Ruaa K. Hamdan 5 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

Figure 1-2: Topographical map of Iraq

1.2.3 Population

The total population is about 28.8 million (2005), of which 25% is rural. Estimates for the population in 2025 and 2050 are respectively 44.7 and 63.7 million (United Nations Population Statistics Bureau, 2005). Average population density is estimated at (47 inhabitants/km2), but ranges from (5 inhabitants/km2) in the Anbar province, in the desert in the Western part of the country, to more than (170 inhabitants/km2) in the Babylon province, in the centre of the country. The average population growth was estimated at 3.6% during 1980-90, but emigration of foreign workers and severe economic hardship has reduced this growth rate since 1990. In 1989, the

Ruaa K. Hamdan 6 Chapter-1 Introduction

agriculture sector contributed only 5% to the Gross Domestic Product (GDP), which was dominated by oil (61%). About 20% of the labour force is engaged in the agriculture sector.

1.2.4 Climate

Roughly 90% of the annual rainfall occurs between November and April, most of it in the winter months from December through March. The remaining six months, particularly the hottest ones of June, July, and August, are dry. Except in the North and North-East, mean annual rainfall ranges between 100 and 170 mm. Data available from stations in the foothills and steppes South and South-West of the mountains suggest a mean annual rainfall between 320 and 570 mm for that area. Rainfall in the mountains is more abundant and may reach 1,000 mm/year in some places, but the terrain precludes extensive cultivation.

Cultivation on non irrigated land is limited essentially to the mountain valleys, foothills, and steppes, which have 300 mm or more of rainfall annually. Even in this zone, however, only one crop a year can be grown, and shortages of rain has often led to crop failures.

Mean minimum temperatures in the winter range from near freezing (just before dawn) in the Northern and North-Eastern foothills and the Western desert to 2 - 3 °C and 4 - 5 °C in the alluvial plains of Southern Iraq. They rise to a mean maximum of about 15.5 °C in the Western desert and the North-East, and 16.6 °C in the South. In the summer mean minimum temperatures range from about 22.2 °C to about 29 °C and rise to maximums between roughly 37.7 °C and 43.3 °C. Temperatures sometimes fall below freezing and have fallen as low as -14.4 °C at Ar Rutbah in the Western desert, (for more detail see Table 1-1. They are more likely, however, to go over 46 °C in the summer months, and several stations have records of over 48 °C.

Table0-1-1: Temperature in different regions in Iraq (oC)

Winter Summer Extremes Region Min Max Min Max Min Max Western/Southern Desert 9° 16° 20° 40° -14° 49° Rolling Upland 3° 13° 25° 40° -12° 49° Tigris/Euphrates Delta 4° 18° 25° 40° -7° 51° Mountains -4° 5° 15° 25° -30° 42°

Ruaa K. Hamdan 7 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

The summer months are marked by two kinds of wind phenomena. The Southern and South- Easterly sharqi, a dry, dusty wind with occasional dusts of 80 km/hr, occurs from April to early June and again from late September through November. It may last for a day at the beginning and end of the season but for several days at other times. This wind is often accompanied by violent dust storms that may rise to heights of several thousand metres and close airports for brief periods. From mid-June to mid-September the prevailing wind, called the shamal, is from the North and North-West. It is a steady wind, absent only occasionally during this period. The very dry air brought by this shamal permits intensive sun heating of the land surface, but the breeze has some cooling effect.

The combination of rain shortage and extreme heat makes much of Iraq a desert. Because of very high rates of evaporation, soil and plants rapidly lose the little moisture obtained from the rain, and vegetation could not survive without extensive irrigation.

Some areas, however, although arid do have natural vegetation in contrast to the desert. For example, in the Zagros Mountains in North-Eastern Iraq there is permanent vegetation, such as oak trees, and date palms are found in the South.

1.2.5 Agriculture development and land use

Since the beginning of recorded time, agriculture has been the primary economic activity of the people of Iraq. The land use pattern is shown in Figure 1-3. In 1976, agriculture contributed about 8% of Iraq’s GDP, and it employed more than half the total labour force. In 1986, despite a ten- year Iraqi investment in agricultural development that totalled more than 4 billion US$, the sector still accounted for only 7.5% of total GDP, a figure that was predicted to decline. In 1986 agriculture continued to employ a significant portion - about 30% of Iraq’s total labour force. Part of the reason the agricultural share of GDP remained small was that the sector was overwhelmed by expansion of the oil sector, which boosted total GDP.

Significant fluctuations year-to-year in Iraqi harvests, caused by variability in the amount of rainfall, made estimates of average production problematic. Statistics indicated that the production levels for key grain crops remained approximately stable from the 1960s through the 1980s, with yield increasing while total cultivated area declined. Increasing Iraqi food imports

Ruaa K. Hamdan 8 Chapter-1 Introduction

were indicative of agricultural stagnation. In the late 1950s, Iraq was self-sufficient in agricultural production, but in the 1960s it imported about 15% of its food supplies, and by the 1970s it imported about 33% of its food. By the early 1980s, food imports accounted for about 15% of total imports, and in 1984, according to Iraqi statistics, food imports comprised about 22% of total imports. Many experts expressed the opinion that Iraq had the potential for substantial agricultural growth, but restrictions on water supplies, caused by Syrian and Turkish dams building on the Tigris and Euphrates Rivers might limit this expansion.

Figure 1-3: Map of land use in Iraq

1.2.6 Water resources

River basins There is only one river basin in Iraq, the Shatt Al-Arab basin. The Shatt Al-Arab is the river formed by the confluence downstream of the Euphrates and the Tigris and flows into the Persian Gulf after a course of only 190 km. Before their confluence, the Euphrates flows for about 1,000 km and the Tigris for about 1,300 km respectively within the Iraqi territory. Nevertheless, due to the importance of the Euphrates and the Tigris, the country is generally divided into three river basins: the Tigris, the Euphrates, and the Shatt Al-Arab (referring to the part downstream of the confluence of the two rivers).

Ruaa K. Hamdan 9 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

Surface water resources Both the Tigris and the Euphrates are international rivers originating their source in Turkey. The Tigris river basin in Iraq has a total area of 23.6 million ha or 54% of the total river basin area. While Euphrates has 20.1 million ha or 46%. The average annual flow of the Euphrates as it enters Iraq is estimated at 951 m³/s, with a fluctuating annual value ranging from 317 to 1268 m³/s. Unlike the Tigris, the Euphrates receives no tributaries during its passage in Iraq. About 317 m³/s drained into the Hawr al Hammar (a marsh in the South of the country).

For the Tigris, average annual runoff as it enters Iraq is estimated at 672m³/s. All the Tigris tributaries are on its left bank, as shown in Figure 1-4. From upstream to downstream: • The Greater Zab, which originates in Turkey and is partly regulated by the Bakhma dam. It generates 412 m³/s at its confluence with the Tigris; • The Lesser Zab, which originates in Iran and is equipped with the Dokan dam. The river basin of 2.1 million ha (of which 74% is in Iraqi territory) generates about 222 m³/s, of which 159 m³/s of annual safe yield after the Dokan construction; • The Al-Adhaim (or Nahr Al Uzaym), which drains about 1.3 million ha entirely in Iraq. It generates about 25 m³/s at its confluence with the Tigris. It is an intermittent stream subject to flash floods; • The Diyala, which originates in Iran and drains about 3.2 million ha, of which 75% in Iraqi territory. It is equipped with the Darbandikhan dam and generates about 182 m³/s at its confluence with the Tigris; • The Nahr at Tib, Dewarege (Doveyrich) and Shehabi rivers, draining together more than 800,000 ha. They originate in Iran, and bring together in the Tigris about 32 m³/s of highly saline waters; • The Al-Karkha, whose course is mainly in Iran and, from a drainage area of 4.6 million ha, brings about 200 m³/s yearly into Iraq, namely into the Hawr Al Hawiza during the flood season, and into the Tigris river during the dry season; • The Karun River, originating in Iran flows with its mean annual flow of 783 m³/s into the Shatt Al Arab. It brings a large amount of fresh water into the Shatt Al-Arab.

The Euphrates and the Tigris are subject to large and possibly disastrous floods. The level of water in the Tigris can rise at the rate of over 0.3 m/hour. In the Southern part of the country,

Ruaa K. Hamdan 10 Chapter-1 Introduction

immense areas are regularly inundated, levees often collapse, and villages and roads must be built on high embankments. The Tharthar reservoir was planned inter alia in the 1950s to protect Baghdad from the ravages of the periodic flooding of the Tigris by storing extra water discharge upstream of the Samarra barrage.

Figure 1-4: Map of water resources in Iraq

Groundwater resources Good quality subterranean water has been found in the foothills of the mountains in the North- East of the country and in the area along the right bank of the Euphrates. The aquifer in the North-East of the country has an estimated sustainable discharge of between 10 and 40 m³/s, at depths of (5-50) m. Its salinity increases towards the South-East of the area, where it reaches 1 mg/1. The aquifers on the right bank of the Euphrates river are found at depths up to 300 m, and have an estimated discharge of 13 m³/s. Salinity varies between 0.3 and 0.5 mg/l. In other areas of the country, groundwater is also found, but always with a salinity level higher than 1 mg/l.

Ruaa K. Hamdan 11 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

1.2.7 Irrigation and drainage development

The history of irrigation started 7,500 years ago in the land between the Tigris and the Euphrates when the Sumerians built a canal to irrigate wheat and barley. Irrigation potential was estimated in 1990 at over 5.5 million ha, of which 63% in the Tigris basin, 35% in the Euphrates basin, and 2% in the Shatt Al-Arab basin. Considering the soil resources, it is estimated that about 6 million ha are classified as excellent, good or moderately suitable for flood irrigation. With the development of water storage facilities, the regulated flow has increased and changed the irrigation potential significantly, since it was estimated at 1.1 million ha only in 1976. However, irrigation development depends to a large extent on the volume of water released by the upstream countries.

1.3 Kurdistan region

1.3.1 Geography and location

The three Governorates Erbil, Dohuk, and Suleimanyiah are located in the Northern part of the republic of Iraq known as Kurdistan; see Figure 1-5.

The region lies between latitudes 34° 42’ and 37° 22’ N and between longitudes 42° 25’ and 46° 15’ E. The lowest point in the region is Kifri, which has an elevation of 140 m+MSL, and the highest point is the Peak of Hasarost Mountain in Erbil governorate, measuring 3,607 m+MSL. The Kurdistan region mainly extends across the Zagross Mountain up to the Taurus Mountains in Turkey. The region shares its borders with Syria in the West, Turkey in the North and Iran in the East.

Ruaa K. Hamdan 12 Chapter-1 Introduction

Figure 1-5: Map of Iraqi Kurdistan

1.3.2 Land and population of Iraq Kurdistan

The land has high latitudinal parallel mountain ranges and valleys. The soils in the mountain valleys, foothills and adjacent plains were formed from erosion. Several metres of fine textured sediment forming fertile deep soil lie on top of a bed of gravel. Litho soil, shallow and medium chestnut soils are dominant from the great soil groups in mountainous areas. Shallow to deep chestnut soils exist in the valleys, whereas the foothills have mainly brown soil. Rolling plains, found at the foot of high mountains are all suitable for large-scale farming.

Most of the cultivated land is rainfed, falling in different micro-climatic zones. The land holding system is a mixture of owner/operator farming, leaseholders and sharecroppers. The size of the land holdings is from 1 to 6 ha in rainfed agriculture, up to 25 ha in rainfed semi-arid areas with

Ruaa K. Hamdan 13 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region) more risky rainfall conditions and between 0.5 and 2.5 ha in irrigated areas. In the rainfed agriculture the farmers have been ignored and land was controlled by those with power.

The population of the three Northern governorates is around 4 million, mainly composed of Kurds with farming as their livelihood and major source of employment. The farming population resides in thousands of villages scattered all over the mountain areas. Women play an important role in agriculture but frequent political violence has displaced considerable numbers of women from their households that are now available as seasonal farm labour.

1.3.3 Climate of Kurdistan

The climate of Kurdistan is characterized by extreme conditions, with large temperature differences between day and night and between winter and summer. In summer, the temperature reaches beyond 45 ºC in daytime at the Southern boundaries of the three governorates, while in the Northern edges it goes down well below 20 °C at night. In winter the daily temperature ranges from about -15 °C to about 15 °C. Accordingly, the climate of Kurdistan has been classified as semi-arid continental, that is to say hot and dry in summer and cold and wet in winter. Spring and autumn are short in comparison to summer and winter.

In summer, the region falls under the influence of Mediterranean anticyclones, with dust storms carrying dust into the region, raising daily temperature to a maximum value of more than 45 ºC. Kurdistan experiences some of the highest temperatures anywhere in the world. These scorching conditions are often accompanied by a persistent dusty, North-Westerly wind, the shamal, which adds to the unpleasantness. Occasional droughts, heat exhaustion and even heatstroke are hazards. In winter, the region is invaded by cyclones from various sources, bringing an appreciable amount of rain and in higher elevations snow into the region.

Precipitation increases from South-West to North-East, with annual averages ranging from 200 mm in the Erbil area to more than 1,300 mm at Sherwan-Mazen. The annual rainfall in Kurdistan of Iraq is not much less than the annual rainfall in Europe, but the annual rainfall in Europe is well distributed.

Ruaa K. Hamdan 14 Chapter-1 Introduction

1.3.4 Agriculture in Kurdistan

Kurdistan is regarded as the most ancient place in the history to have known agricultural activities. The province of Germo; 11 km East of Chemchemal town, according to archaeological studies, is the first region to have practiced cultivation, 5000 BC.

Undoubtedly, Iraqi Kurdistan region possesses enormous agricultural potentials such as extensive arable land, convenient climate, water resources and manpower.

The major agricultural crops can be grouped as: • Cereal (wheat, barely, and rice); • Oil seeds and industrial crops (Sesame, Sunflower, Cotton and Tobacco); • Vegetables (Tomatoes, Cucumber, Watermelon, Melon, Onion, and Garlic); • Fruits (Grapes, Apple, Apricot, Peach, Pear, and Pomegranate); • Legumes (Chickpeas, Lentils and Green beans).

Two methods are used for land distribution amongst the farmers, which is stipulated in the land reform legislation: • Distribution; • Contracts; which is divided into sections: 9 permanent contracts; 9 Seasonal contracts.

Farmer’s share of land varies from region to region depending on: • Soil fertility; • Land location to the marketing centres; • Availability of water resources; • Number of farmers in the region.

There are two types of land in terms of ownership in Kurdistan of Iraq: • State ownership: lands owned by the state given to the farmers on contract bases or distributed on them; • Private sector ownership: owned by the farmers.

Ruaa K. Hamdan 15 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

Areas mentioned above cultivates various cash crops such as Wheat, Barley, Chickpeas, Lentils, Cotton, Rice, Tomato, Beans, Sunflower-seeds, Onions, Garlic etc, plus various types of seasonal vegetables and fruits to meet local consumption. For example wheat production in the provinces is estimated to be 150 to 500 thousand tons per annum. This figure could alter depending on sufficient rainfall and methods employed.

1.3.5 Resources and small scale irrigation in Kurdistan

In terms of average annual rainfall, and allowing for normal fluctuation, the region of Kurdistan can be divided into the following zones: • Zone 1. Areas in which rainfall is virtually guaranteed. These areas are those in which the annual average rain and snowfall is between, at least 500 mm and as much as 1,300 mm. A substantial feature of these areas, which are estimated to comprise of approximately 500,000 ha, is mountainous and forested terrain; • Zone 2. Areas in which rainfall is usually plentiful, in which average yearly rainfall ranges between 350 and 500 mm; such areas, which account for approximately 400,000 ha and are located in Suleimanyiah and Erbil provinces (along with some areas of Dohok that lie within the first rainfall zone) are counted as the principle areas of agriculture production in Kurdistan; • Zone 3. Areas in which rainfall is not reliable, where the yearly average is between 100-200 mm. In some years this can be the case with as much as 200,000 ha of land, mostly around the cities of Khaniqin, Mosul and Kirkuk.

Thus the total amount of arable land which is dependent upon winter rainfall is approximately 1.1 million ha, that is roughly 89% of the region’s total area. The remaining part 11% of Kurdistan’s terrain is therefore dependent upon irrigation.

1.4 Malwan Irrigation Scheme

Ruaa K. Hamdan 16 Chapter-1 Introduction

Malwan Irrigation Scheme was rehabilitated at 2001 under the supervision of food and agriculture organization / Sulaimaniyiah sub office/WRI sub-sector. The project is situated at Malwan village (at Sharazor area), Tanjaro Sub-district, Sulaimaniyah Centre districts about 35 km south of Sulaimaniyah City.

The old project was executed at 1973 by constructing an off take and about 1.5 km lined canal but the project was suffer from some damages that caused to not work in good condition. This was lead to need for repairing the project. Figure 1-6 shows the system location from Google earth.

The water supply is delivered form Tanjaro stream and the main canal extended to end of Malwan lands and its length about 11.0 km and the branch canals of about 8 km. This canal is used to irrigated the land located at down stream of the canal by the gravity action and can irrigating an area of about 750 ha.

Main source of water The main source of water for the project is Tanjaro main Stream located at the up stream of the off take site.

Quantity of water resources The quantity of the stream is estimated to be about 10 – 15 m3/s during the Flood discharge, but in normal condition is about 2 - 3 m3/s and the canal was derived its water from this sources and it will estimated to be 1.20 - 1.40 m3/s.

Quality of water resources Due to self-purification action of the water it cleaned from the disposal water and it’s quality is suitable for irrigation.

Ruaa K. Hamdan 17 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

Figure 1-6: Location of Malwan Irrigation Scheme

1.5 Problem identification

Development of any command area by construction of acquisition, conveyance and distribution networks, among others, is aimed to produce output of water from the irrigation system for a sustained level of agriculture. This is more productive than would be possible under rain fed conditions. Hence, irrigation is important. Increase in agriculture productivity leads to an increase in incomes in the rural sector, which, in turn, is a key to rural economic development. (Mishra, 2004). In order to ensure sustainable agriculture system, Kurdistan has introduced irrigation projects.

Many factors influence the performance of irrigated agriculture, including infrastructure design, management, climatic conditions, price, use of inputs and socioeconomic structures. Efficient and productive use of land and water is required to prevent degradation of natural resources and

Ruaa K. Hamdan 18 Chapter-1 Introduction

environmental problems such as high groundwater tables, Stalinisation, water logging, and flooding. Therefore, there is urgent need for increased efforts to achieve more efficient, productive and sustainable irrigation practices.

Most of the large scale irrigation systems in Kurdistan have a rather poor performance of the water delivery system in terms of water division which results in unequal and unreliable distribution. There are certain specific reasons for unreliable water distribution for each system, but the reason which is common to almost all systems is that unsteady flow phenomena in irrigation networks and their effect on the water delivery performance are often not well understood and contribute to poor delivery performance.

1.6 Objectives

The function of an irrigation canal system is conveyed and distributes irrigation water throughout an irrigation scheme. In many irrigation systems the water distribution performance is below expectation, which implies an unreliable and unequal supply.

One of the causes underlying a poor water distribution performance is the unsteady flow phenomena. As result of daily operation of the system is trouble some (Schuurmans, 1991). If the system would react instantaneously on change in gate setting, it would be much simpler to determine the proper timing and magnitude of gate adjustment. In reality, the water flow does not react instantaneously, but shows a retarded and diffusive response. The main objectives of the research are: • To assesses the cropping potential of Malwan Irrigation Scheme and recommendation for the system improvement; • To assesses the hydraulic sustainability of Malwan Irrigation Scheme, under actual operation, maintenance and management condition; • Propose alternative solutions. (To determine in what extent the operational objectives of the irrigation agency can be fulfilled with the actual infrastructure); • Propose alternatives for improvement and analyze them by using DUFLOW program (DUFLOW program is use to investigate the impact of unsteady flow on the hydraulic performance of irrigation canals, and to examine possible design and / or operational measures to improve the performance);

Ruaa K. Hamdan 19 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

• Recommend suitable design measures.

As one of the appropriate tools for understanding the hydraulic behaviour of irrigation systems is hydraulic models; therefore, DUFLOW program has been selected to simulate the flow in the main system.

This study is done to assess the performance with emphasis on research on the unsteady flow phenomena in irrigation networks in such away that the results can be evaluated to improve the performance.

1.7 Methodology

The research is oriented to fact-finding of the present status of the irrigation system and suggesting how to fulfil the objectives of the research, which can be done by efficient utilization of water resources. The study objective encompasses mainly four stages of the work: • Literature review; • Data collection; • Data processing and analysis; modelling, simulation and evaluation of the results.

Recommendations can be put for improvement in the form of better operation of the system, improved participation of the farmers, improved cropping calendar. The methodology of the study is presented in Figure 1-7.

Ruaa K. Hamdan 20 Chapter-1 Introduction

System data - Hydrology - Reservoir characteristics (Software) Run model - Water demands

No Optimization Report Yes Performance

- Urban water supply - Irrigation water supply Simulation - Flood control Optimal operation - Spillage losses policies

Figure 1-7: Flow diagram of the methodology in the study

Ruaa K. Hamdan 21

Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

2 LITERATURE REVIEW

2.1 General

The research is based on available literature, past studies and the data collected have addressed performance assessment for irrigation water delivery systems. A process of improving system performance requires its assessment and in this respect various parameters, measures and indicators should be used, which may assist in formulation of operational policies. The aspect of these indicators include external indicators, which concentrate more on the outputs (i.e., agricultural production, and economic and environmental impacts), and internal indicators (or water-delivery Indicators), which mainly focus on hydraulic processes of irrigation systems.

In addition to that a new cropping pattern will be suggested depending on how much water will be saved, the water requirements calculation will make use of the CROPWAT program.

2.2 Performance studies review

Irrigated agriculture is important in stimulating sustainable economic growth and rural employment and is the cornerstone for food security and poverty reduction. Most of the large- scale irrigation schemes appear to perform below expectation. Due to increasing water demands, accurate control of the water flow in the irrigation system is becoming more and more important, but in practice control of water flow in irrigation systems is still rather poor. This implies an inefficient, unreliable and/or inequitable water distribution, which may occur in main canal systems as well as in minor canal systems (Schuurmans, 1991).

There are a lot of studies that have been done in the domain of performance assessment of irrigation and drainage systems; in this section some of these studies and researches are discussed while there are many more applications that one can refer to. The overseas development unit of hydraulics research (HR Wallingford) has collaborated with research institutes and irrigation departments in developing countries to gather performance data at smallholder systems. Long- term studies over several seasons, for example the five year’s of data collection at Kaudulla system in Sri Lanka described by Weller and Kumarasamy (1987), have highlighted the sorts of

Ruaa K. Hamdan 22 Chapter-2 Literature review problems which may occur: systematic undersupply to certain areas; poor rainfall utilization; and poor timing of water releases. But the time and resources required to mount such studies are not very practical for managers faced with the task of improving the operation of their system.

In recent years; several short, intense field studies have been conducted which have made a rapid assessment of the performance of large systems, e.g., the Gezira in Sudan (Francis et al., 1988) and a sub-district of the Punjab in India (Goldsmith and Makin, 1988). Molden and Gates (1990) as well as Depeweg et al. (2000) developed performance measures to facilitate the analysis of an irrigation water delivery system in terms of adequacy, efficiency, reliability and equity of water delivery. The measures provide practical and quantitative assessment not only of the overall system performance, but also of the contributions to the performance from the structural and management components of the system. Spatial and temporal distribution of required, scheduled, effective and supplied water can be used to calculate the performance measure. Clemmens (1990) describes a method of evaluating and understanding water delivery performance of a system before rehabilitation. The study seeks to separate conceptually the two components of water delivery performance at a delivery point. First, how accurate is the preparation of the water delivery schedule (delivery schedule performance) and second, how did the system deliver water with reference to the schedule (operation performance)? Clemmens’ approach is useful in determining the extent to which causes of poor performance relate to the inadequate estimation of water requirements and improper preparation of water delivery schedules or the inability of the physical or management system to operate according to the schedules to deliver the scheduled supply. However, it will not determine whether the main cause of poor performance is the physical system limitation, operational problems, or management.

Clemmens and Bos (1990) provide a more detailed exposition of the same concept and the use of statistical relations to express equity, adequacy and reliability from the measurements of actual to scheduled flows or to required flows.

A water management study of Warabandi in North-West India in 1983 developed a methodology for assessing the performance of large scale smallholder irrigation systems by observing irrigated areas and carrying out random crop cutting. A study of Warabandi in 1988 took a shorter amount of time and concentrated on direct measurements of flow and seepage in order to assess the performance of the physical conveyance system. The study contrasted these two approaches and

Ruaa K. Hamdan 23 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region) gave practical guidance on how to go about carrying out a rapid assessment of the performance of the physical conveyance system of an irrigation system (Smith and Makin, 1991).

Also, Bos et al. (1991) demonstrate the use of average seasonal values of the ratio of intended and actual volumes of water delivered to the tertiary units in a performance evaluation of a secondary canal. This ratio is useful in finding the deviation for any individual unit along a canal. But, the mean and standard deviation of the values along the canal are not useful as performance indicator if there is a large variation in size of tertiary units, because the ratios for small areas have an inordinately great influence on the mean and the standard deviation (Rao, 1993).

There are a number of methods that can be used for evaluating and comparing the water delivery performance of irrigation systems. Each methodology has its own advantages and disadvantages, and may be most relevant under particular conditions. Sakthivadivel et al. (1993) described a new methodology for assessing water delivery performance through the use of the concept of Cumulative Relative Water Supply (CRWS). Like the concept of Relative Water Supply (RWS), CRWS relates the supply to the demand for water. They concluded that the major advantage of CRWS compared to RWS is that it can be used to represent graphically the ratio of supply to demand meaningfully for the whole season, while RWS is useful for evaluating this ratio for a specific time period.

Malano et al. (1993) used combined monitoring and system modelling approach to analyze the operation of the Thup Salao system in Thailand and developed an improved operational strategy. The IMSOP model was used to simulate the operation of the irrigation canal system and reservoir. The operation of the system since commissioning was evaluated by comparing flow variables describing the operation at the systems headwork and dam outlet. The comparison between required irrigation supply and actual irrigation delivery reveals that the actual supply deviates significantly from the volume of delivery required to meet the crop water demand. Further, no regular pattern of deviation could be observed between these two variables although the deviations are greater in the wet season. The adequacy of planning the operation based solely on average climatic data was tested by comparing the planned irrigation supply and required irrigation supply variables. Deviations of up to 80% were observed in the wet season due to the variability of rainfall from year to year. Deviations of up to 20% are observed in the dry season. The real-time operation was simulated using the planned irrigation supply based on average climatic data and the required irrigation supply based on the year’s climatic data with a rainfall

Ruaa K. Hamdan 24 Chapter-2 Literature review correction factor. This improved the ability to match flow deliveries and the actual crop water requirement and to use rainfall more effectively.

Delivery performance ratio was used to assess the water delivery performance in an irrigation district in the Doroodzan irrigation system in Iran in a study done by Jahromi et al. (2000); in this study the measurements were applied to three selected irrigation canals and their tertiary outlets during five consecutive irrigation cycles. The canals were located at the head, middle and tail end of the irrigation district. Performance indicators reveal that the physical system and the management could respond to the delivery of the intended supply. In this study the indicators show a better performance than the equity performance in water delivery at the tertiary outlets. The results from the Doroodzan irrigation system reveal that the system could not deliver water according to the real crop water requirements. The actual overall efficiency was used to quantify the water delivery performance in terms of deficit and excess water. The equity and reliability performance was illustrated by using the spatial and temporal variation of the expected overall efficiency at the district level.

System performance monitoring, evaluation and diagnostic analysis are keys to appreciate the improvement or inefficiency in our irrigation systems. Irrigated lands’ baseline inventory in spatial and time domains using spatial information technologies (satellite remote sensing, digital image processing, GIS and GPS) provides an array of performance evaluation matrices to address this issue. Case study in Nagarjunasagar irrigation system in Andhra Pradesh, India is cited as a realization of this modern information technology tool in a research done by Chakraborti et al. (2002).

In the last decade, irrigation researchers have developed and applied computer tools to plan, schedule and monitor the operation of irrigation systems to improve their performance. Simple canal operation models are useful in generating irrigation demand based on evapotranspiration estimates and a realistic description of the delivery system and its characteristics (Turral et al., 2002). Researches have shown the capability of simple models for generating water demands at system level (Teixeira et al., 1996; George et al., 2002).

During a two-year field study the performance of the water delivery was evaluated in a large- scale irrigation system on the North coast of Peru. Flow measurements were carried out along the main canals, along two secondary canals, and in two tertiary blocks in the Chancay-Lambayeque

Ruaa K. Hamdan 25 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region) irrigation system. The most important finding was the unexpectedly high accomplishment rate of the actual delivery at field level compared with the on-request schedule (Vos, 2004).

A study carried out with the case study of Sunsari Morang irrigation system, Biratnagar, Nepal, which is a major irrigation system; net command area is 64,000 ha. The findings and recommendations of this study can be generalized to other similar systems in Nepal as well as neighbouring countries. The study intended to explore the present water service situation in the system, its constraints and possible solutions to improve the water service by modernizing the irrigation system. The water balance used to find the adequacy of the water availability at main canal level, a sensitivity analysis done to find the equity among the secondary canals drawing water from the main canal and farmer’s satisfaction was taken as an indicator of the present water service within the system (Tamrakar, 2004).

Another research has been carried out on Nepal by Acharya (2004), in this research work the performance evaluation of the two systems Vijayapur and Andhikhola is done by the benchmarking process. The data related to infrastructure, technology and institutions are collected. The internationally recognized and accepted performance indicators developed by IPTRID are taken for this research work. The data required for these indicators is collected and indicators are calculated. To evaluate the outside input of these projects the Rapid Appraisal Process (RAP) is used. By RAP process of Vijayapur and Andhikhola, necessary actions for improvements are identified. By the RAP, calculation of both internal and external indicators is possible (Acharya, 2004).

Under limited water resources, an efficient irrigation system must be attained. In developing countries, lack of financial resources and proper infrastructure are major obstacles in improving the efficiency of the system. The assessment of irrigation performance is clearly important to the managers of irrigation systems. This realization has shifted the focus on policy-makers and researchers to the improvement of canal irrigation performance through main system management. One of the appropriate tools for understanding the hydraulic behaviour of irrigation systems is hydraulic simulation models (Shahrokhnia and Javan, 2005).

Ruaa K. Hamdan 26 Chapter-2 Literature review

2.3 Application of computer models

A model only calculates the irrigation water requirement as well as the hydraulic behaviour of a canal system, which simultaneously identifies the impact of hydraulics to implicitly related aspects. In an irrigation system social, institutional, economical and technical aspects are involved. All these aspects are interrelated. This implies, for example, the institutional problems can be caused by technical shortcomings and, hence, paying attention to the technical aspects can sometimes solve them.

To use the model effectively, one should not only simulate the hydraulic behaviour of a system, but also interpret the results. In order to interpret the model’s output, namely water levels and discharges varying in time and space, performance indicators are indispensable. A well- performed irrigation system is the one that meets its objectives. Hence, objectives of irrigation should be reviewed to establish performance indicators.

The objective of irrigation is to guarantee the agricultural production in certain areas, in order to improve the quality of life (whose, and on what terms?). Since there are many participants involved in an irrigation enterprise, and it cannot be assumed that they all share the same view as to what constitutes a good performance, a viewpoint should be defined (Abernethy, 1989). Hence, it is impossible to specify the objective of irrigation, and consequently, the optimal water distribution does not exist. For, the optimal water distribution from an economic point of view might not be optimal from a social viewpoint.

Instead of looking to the objectives of irrigation another more narrow approach is followed: the hydraulic performance of the operation of the system is examined rather than the performance of system itself. This implies that, firstly, the deliveries to the water users (on farm, tertiary unit or secondary unit level) have to be defined in water supply schedule. This schedule should be the result of optimization of all different performance requirements of the irrigation system. Once a water supply schedule, in which hydrological, agronomical, social and economical factors have been incorporated, has been established the supply system should deliver the irrigation water according to this intended schedule. Thus, this study is not explicitly dealing with the determination of optimal water delivery schedule but with the realization of given delivery schedule.

Ruaa K. Hamdan 27 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

A perfect operational performance is achieved when the actual supplies match the intended supplies. This implies that the intended supply must have been agreed upon before the operation performance can be assessed. The objectives are encapsulated in the scheduled deliveries.

Good performance indicators should reflect to which extent actual supplies match intended supplies. Although some operation performance parameters do exist (Makin, 1986), International Water Management Institute (IWMI, 1987) and (Farncis and Elawad, 1989), new operation performance parameters have been developed mainly because the existing parameters appeared not suitable for the evaluation during unsteady flow condition (Schuurmans, 1991).

Once a model that is able to calculate the real life, non-uniform and unsteady flow phenomena in controlled canals, computation of operation performance indicators, can be made, which is used to improve the reliability, equity, and efficiency of the water distribution in every phase (Design phase, Operation phase and Modernization phase) of the life-cycle of irrigation projects. Strelkoff (1970) gave numerical solution of the St. Venant Equations describing in approximate, one- dimensional terms the unsteady flow in rough, rigid open channel. It is noted that explicit numerical schemes, which are simple, but require small steps in time because of stability problems, are contrasted with implicit schemes which permit a numerical solution over larger time steps but require the solution of large sets of simultaneous algebraic equations at each step. Paudy and Loof (1988) suggested that the improvement of irrigation systems can be done by understanding the hydraulic phenomena and operation that occur during the irrigation period by using mathematical models to solve the hydraulics of typical main systems particularly for the large scale irrigation systems in Thailand. Rabe (1991) estimated the roughness coefficient of a non-prismatic irrigation canal under steady and unsteady flow conditions by using three models: a geometric elements calculation model, a steady flow simulation model and unsteady flow model. The results showed that both steady and unsteady flow models gave relatively the same value of the roughness coefficient. He also suggested that for unsteady flow models, the boundary conditions to be used are water stage at both upstream and downstream boundaries. These gave better results than discharge and water stage as boundary conditions, upstream and downstream respectively.

Equity in the distribution of irrigation water has long been an operational objective for the management of the large canal systems in the North and West of the Indian subcontinent. How

Ruaa K. Hamdan 28 Chapter-2 Literature review well that operational objective continues to be met is the central concern of the research reported by Bhutta and Van der Velde (1992).

Baume (1993) developed a mathematical flow simulation model for the Kirindi Oya Right Bank Main Canal (RBMC) in Sri Lanka. The RBMC simulation model is intended to serve not only as a research and training tool to study the hydraulic behaviour of irrigation canals but also as a decision-support tool for managing a manually operated system. Fluctuations in discharge and water depth in a canal pool are due to two physical phenomena occurring in the flow: wave propagation (perturbation), mass transport (long waves). If gate movements are slow, water depth and discharge change slowly and the flow is unsteady gradually varied. Assume that the flow is one-dimensional, streamline curvature is small and velocity is uniform over the cross section, the flow can be modelled very accurately modelled by Saint Venant equations. These equations are not valid to model cross structure behaviour. There is a need for improvement in the operation and management of many irrigation and drainage systems worldwide. Computer models are used widely for better management. One of such models is HEC-RAS that was applied to Ordibehesht canal at the Doroodzan irrigation network, northwest of Fars province in Southern Iran. The model was calibrated and validated for two irrigation seasons during 2001 and 2002.

The present gate opening rules used to control the off-takes were simulated by the model and the discharge reductions were evaluated. Discharge reduction of off takes due to discharge reductions at system source were evaluated by the model. Results show that the present rule is not appropriate for the present system. Fluctuations of discharge at the beginning of canal show considerable and non-uniform changes in discharge of off takes along the Ordibehesht Canal. The head off takes show more reductions in the water delivered than middle and tail off takes. A new sensitivity indicator was defined and used to show the response of off takes due to discharge changes at system source. The study also shows that the HEC-RAS model can be used successfully for a large and complex irrigation system for evaluation of its performance in the absence of observed flow data and improvement of irrigation management plans.

Kumar et al. (2002) evaluated an irrigation canal by unsteady model, CANALMAN. They concluded that the model was valid for the command canal and the average water supply was about 13% higher than the model simulated required discharge.

Ruaa K. Hamdan 29 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

Crop water requirement versus irrigation requirements

It is important to make a distinction between crop water requirement (CWR) and irrigation requirement (IR). Whereas crop water requirement refers to the water used by crops for cell construction and transpiration, the irrigation requirement is the water that must be supplied through the irrigation system to ensure that the crop receives its full crop water requirement. If irrigation is the sole source of water supply for the plant, then the irrigation requirement will be at least equal to the crop water requirement and generally is greater to allow for inefficiencies in the irrigation system. If the crop is receiving some of its water from other sources (rainfall, water stored in the soil, underground seepage, etc.), then the irrigation requirement can be considerably less than the crop water requirement.

Net Irrigation Requirement (IRn) does not include losses that are occurring in the process of applying the water. IRn plus losses constitute the Gross Irrigation Requirement (IRg).

Whereas the estimation of crop water requirement, which is equal to crop evapotranspiration ETc, has been discussed in the previous part, the calculation of IR will be the subject of this chapter. It is important to realize that the estimation of crop water requirements is the first stage in the estimation of irrigation requirements of a given cropping program. Hence the calculation of crop water requirements and irrigation requirements must not be viewed as two divorced procedures.

Importance of estimating irrigation requirements

Estimating the crop water and irrigation requirements for a proposed cropping pattern is an essential part of the planning and design of an irrigation system.

The irrigation requirement (IR) is one of the principal parameters for planning, design and operation of irrigation and water resources systems. A detailed knowledge of the IR quantity, its temporal and spatial variability is essential for assessing the adequacy of water resources, for evaluating the need of storage reservoirs and for the determining the capacity of irrigation systems. It is a parameter of prime importance in formulating the policy for optimal allocation of water resources as well as in decision-making in day-to-day operation and management of irrigation systems.

Ruaa K. Hamdan 30 Chapter-2 Literature review

Incorrect estimation of the IR may lead to serious failures in the system performance and to the waste of valuable water resources. It may result in inadequate control of the soil moisture regime in the root zone; it may cause water logging, salinity or leaching of nutrients from the soil. It may lead to the inappropriate capacities of the irrigation network or of storage reservoirs, to low water use efficiency and to a reduction in the irrigated area. Over-estimating IR at peak demand may also result in increased development cost.

Net irrigation requirements

The net irrigation requirement is derived from the field balance equation:

IRn = ETc − (Pe + Ge + Wb) + LRmm ……………………………………………… (2.1)

Where:

IRn = Net irrigation requirement (mm)

ETc = Crop evapotranspiration (mm) Pe = Effective dependable rainfall (mm) Ge = Groundwater contribution from water table (mm) Wb = Water stored in the soil at the beginning of each period (mm)

LRmm = Leaching requirement (mm)

Irrigation efficiencies

There is an ever-growing demand on water resources, which emanates from an increasing human population. This means that there is increasing competition for the use of water for agricultural, industrial, domestic and environmental purposes. This needs for more efficient use of finite water resources in order to minimize conflict between the water users. This section provides some basic information that can be used by planners for the selection of an irrigation system based on levels of their efficiencies. In the process of applying irrigation water to crops, water losses occur. These losses have to be taken into account when calculating the gross irrigation requirements of an irrigation project. This can be done through the use of an efficiency factor, which has to be estimated at the design stage. Different types of irrigation systems have different levels of efficiency. The higher the irrigation efficiency, the larger the area that can be irrigated from a given finite water source, and the less the leaching of nutrients and damage to the soil the more environmentally friendly the irrigation system. The overall efficiency, also known as project

Ruaa K. Hamdan 31 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region) efficiency (Ep), comprises conveyance efficiency (Ec), field canal efficiency (Eb) and field application efficiency (Ea). According to FAO (1992): • Conveyance efficiency (Ec) is the ratio of the water received at the inlet of a block of fields to the water released at the headwork; • Field canal efficiency (Eb) is the ratio between water received at the field inlet and that received at the inlet of the block of fields; • Field application efficiency (Ea) is the ratio between water directly available to the crop and that received at the field inlet; • Project efficiency (Ep) is the ratio between water made directly available to the crop and that released from the headwork, or Ep = Ec x Eb x Ea.

Conveyance and field canal efficiencies are sometimes combined and called distribution system efficiency, Ed, where Ed = Ec x Eb. Field canal and field application efficiencies are also sometimes combined and called farm efficiency, Ef, where Ef = Eb x Ea.

The conveyance efficiency is affected by several factors among which are size of irrigated area, size of rotational unit, number and types of crops grown, type of conveyance system and the technical and managerial facilities for water control. The field canal efficiency is affected by the way the infrastructure is operated, type of soils in respect of seepage losses, size of canals and irrigated blocks.

Distribution system efficiency is particularly influenced by the quality of technical and organizational operations. Farm efficiency depends on the operation of the main farm delivery system and the irrigation skill of the farmers.

Table 2-1 shows the conveyance, field canal and field application efficiencies for different irrigation systems, as proposed by different institutions under different conditions of water conveyance and distribution infrastructure and management.

Ruaa K. Hamdan 32 Chapter-2 Literature review

Table 2-1: Conveyance, field canal and field application efficiencies (adapted from FAO, 1992)

Irrigation System and Type of Efficiency USDA US(SCS) ICID/ILRI

Conveyance efficiency (Ec) 1- Continues supply with no sustainable change in flow 0.9 2- Rotation supply in projects of 3,000-7,000 ha, with 0.8 effect water management 3-Rotational supply in large schemes(>10, 000) ha and small schemes(<10, 000) ha with respective problematic communication and less effective management : - Based on predetermined schedule 0.7 - Based on advance request 0.65

Field canal efficiency (Eb) 1- Blocks larger than 20 ha: unlined 0.8 Blocks larger than 20 ha: lined or piped 0.9 2- Blocks up to 20 ha: unlined 0.7 Blocks up to 20 ha: lined or piped 0.8

Field application efficiency (Ea) 1- Surface methods - light soils 0.55 - medium soils 0.7 - heavy soils 0.6 Graded border 0.6-0.7 0.53 Basin and level border 0.6-0.8 0.58 Contour ditch 0.5-0.55 Furrow 0.55-0.7 0.57 Corrugation 0.5-0.7 2- Sprinkler Up to 0.8 - hot dry climate 0.6 - moderate climate 0.7 0.67 -humid and cool 0.8 3- Rice 0.32

Ruaa K. Hamdan 33 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

Farm irrigation efficiencies of sprinkler irrigation systems vary under different climates. FAO (1982) proposed the figures of farm irrigation efficiencies provided in Table 2-2 on the basis of climate.

Table 2-2: Farm irrigation efficiencies for sprinkler irrigation in different climates (adapted from FAO, 1982)

Climate/Temperature Farm irrigation efficiency, Ef*

Cool 0.80 Moderate 0.75

Hot 0.70 Desert 0.65

Assuming no losses in the distribution system (Ec and Eb = 1)

Table 2-3 presents project efficiencies (Ep) that can be used for calculating gross irrigation requirements for localized irrigation systems.

Table 2-3: Project efficiencies for localized irrigation systems (adapted from: Rainbird International, 1980)

Climate Project efficiency, Ep*

Hot dry 0.85 Moderate 0.90

Humid 0.95

Assuming no losses in the distribution system (Ec and Eb = 1)

Each type of irrigation system affects the means used for water conveyance and distribution. For this, the conveyance (Ec) and the field canal efficiencies (Eb), and thus the distribution system efficiency (Ed), vary between pressurized and non-pressurized systems. It is, however, mainly the field application efficiency (Ea), which varies considerably from one type of irrigation system to another. Generally, localized irrigation systems are the most efficient (Ea is 85 - 95%), followed by sprinkler irrigation systems (Ea is 60 - 85%) and surface irrigation systems (Ea is 55 - 80%).

Ruaa K. Hamdan 34 Chapter-2 Literature review

On the basis of this, a localized irrigation system could irrigate 12 - 42% (95/85 x 100 to 85/60 x 100) more area than a sprinkler irrigation system and 19 - 55% (95/80 x 100 to 85/55 x 100) more area than the surface irrigation system.

However, differences among application efficiency values provided by different sources, especially for the surface irrigation systems. This is attributed to the different climatic, soils and management conditions prevailing in the different countries. It also makes the availability of local data very important.

Looking at the overall project efficiency (Ep) and assuming an Ec of 0.9 for lined canal and continuous flow and an Eb of 0.8 for lined canals, the Ep for surface irrigation systems would be between 0.40 (0.9 x 0.8 x 0.55) and 0.58 (0.9 x 0.8 x 0.8). The Ep for pressurized systems, assuming an Ec and Eb of 1, would be between 0.60 (1 x 1 x 0.6) and 0.85 (1 x 1 x 0.85) for sprinkler irrigation systems and between 0.85 (1 x 1 x 0.85) and 0.95 (1 x 1 x 0.95) for localized irrigation systems. This simple calculation shows that under localized irrigation the irrigated area can be doubled as compared to surface irrigation. The increase in area for sprinkler irrigation can be over 50%.

The efficiency of an irrigation system is dependent on the level of management during operation as well as on the level of built-in management in the system. Under surface irrigation it is often difficult to apply water with the same degree of precision as in the localized and sprinkler irrigation systems.

Consequently, the systems are less efficient. However, their efficiencies can be greatly improved if fields are regularly well graded; the system operator applies correct flows and if building management is enhanced through system automation.

Ruaa K. Hamdan 35 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

SETRIC

The mathematical program SETRIC has been developed by Néstor Méndez V. in 1998 for the first time. So far only SETRIC (Sediment Transport in Irrigation Canals) program has been found which claims its suitability for the specific conditions of an irrigation canal sediment transport. Its earlier version was in QuickBasic and the input and output options were difficult to understand by general professionals. So in the past only limited persons used this model for their research purposes due to the problem of the working environment (Paudel, 2002). The latest version is in Visual Basic. The model is based on an uncoupled solution of the water flow and sediment transport equations. The model can be used for evaluating the effect of inter-relation between the irrigation practice and the sediment deposition. Moreover the effects of flow control structures, water delivery schedules and maintenance plans on the overall response of the canal with respect to sediment transport can be studied with this model. It has four options of sediment transport predictor, which are as follows: • Brownlie; • Engelund and Hansen; • Ackers and White; • Modified Ackers and White.

2.4 Sediment Transport Predictors in Equilibrium Conditions

Equilibrium condition means the amount of sediment for a certain flow condition that can be transported deposition or erosion. Sediment transport predictors are supposed to be in equilibrium condition. Ackers and White and Brownlie methods are the best to predict the sediment transport capacity under prevailing flow conditions and sediment characteristics in irrigation canals (Mendez, 1998).

Ruaa K. Hamdan 36 Chapter-2 Literature review

2.4.1 Ackers and White method The total sediment transport per unit width (m2/s) as per Ackers and White (1973) reads as:

n ⎛ V ⎞ q = G V d ⎜ ⎟ s gr 35 ⎜ u ⎟ ⎝ * ⎠ ……………………………………………………………….….….. (2-1)

m ⎛ F ⎞ G = c ⎜ gr − 1⎟ gr ⎜ A ⎟ ⎝ ⎠ ……………………………………………………………...….... (2-2)

1−n ⎡ ⎤ n ⎢ ⎥ u * ⎢ V ⎥ Fgr = g d (s - 1) ⎢ ⎛10 h ⎞⎥ 35 ⎢ 32 log⎜ ⎟⎥ ⎜ d ⎟ ⎣⎢ ⎝ 35 ⎠⎦⎥ …………………………………….……… (2-3)

1/ 3 ⎡(s − 1) g ⎤ D = d * ⎢ 2 ⎥ 35 ⎣ ν ⎦ ………………………………………………………..…….... (2-4)

The original coefficients of the Ackers and White formula are given in the following Table 2-4.

Table 2-4: Original coefficients of Ackers and White formula

Coefficients 1< D* < 60 D* ≥ 60 n 1.00 – 0.56 log D* 0 9.66 m +1.334 1.5 D *

0.025 c 2.86 log D**2−− log (D ) 3.53

10 0.23 A + 0.14 0.17 D *

Ruaa K. Hamdan 37 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

Where: D* = Dimensionless grain parameter s = Relative density g = Acceleration due to gravity (m/s2) d35 = Representative particle diameter (m) h = Water depth (m) ν = Kinematic viscosity (m2/s)

Fgr = Dimensionless mobility parameter

A = Value of Fgr at the nominal, initial movement

Ggr = Dimensionless transport parameter c = Coefficient in the transport parameter Ggr m = Exponent in the transport parameter Ggr n = Exponent in the mobility parameter Fgr u* = Shear velocity (m/s) V = Mean velocity (m/s)

The c and m coefficients were later modified (HR Wallingford, 1990). These modifications were necessary as the original relations predicted transport rates were considerably too large for relatively fine sediments (d50 < 0.2 mm) and for relatively coarse sediment. The coefficients for modified Ackers and White formula are given in the following Table 2-2.

Table 2-5: Coefficients for Modified Ackers and White formula

Coefficients 1< D* < 60 D* ≥ 60 n 1.00 – 0.56 log D* 0 6.83 m +1.67 1.78 D *

0.025 c 2.79 log D**2−− 0.98log (D ) 3.46

10 A 0.23 0.17 + 0.14 D *

Ruaa K. Hamdan 38 Chapter-2 Literature review

The results of the Ackers and White formula with the modified parameters, described in HR Wallingford (1990), are slightly worse than the predictions of the original formula (Sheer et al, 2002).

2.4.2 Engelund and Hansen method

This method is based on the energy balance concept. The Enguelund and Hansen (1967) function for the total sediment transport is calculated by: q φ = s (s - 1) g d 3 50 …………………………………………………..……………..…. (2-5)

u 2 θ = * (s − 1) g d 50 …………………………………………………………………..…. (2-6)

0.1 θ 2.5 C2 φ = 2g …………………………………………………………………...….. (2-7)

0.05 V 5 q = s (s − 1) 2 g 0.5 d C3 50 ……………………………………………………………... (2-8)

Where: 3 qs = Volumetric total sediment transport (m /s/m) θ = Dimensionless mobility parameter φ = Dimensionless transport parameter V = Depth averaged velocity (m/s) C = Chezy’s coefficient (m1/2/s) s = Relative density (density of particle / density of water) u* = Shear velocity (m/s) d50 = Mean diameter (m) g = Acceleration due to gravity (m/s2)

This method is not recommended for the median size less than 0.15 mm and the standard deviation greater than approximately 2. Also the relation does not account for the critical bed shear stress and is therefore, not accurate close to initiation of motion (van Rijn, 1993).

Ruaa K. Hamdan 39 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

2.4.3 Brownlie method

This Brownlie (1981) method is based on a dimensional analysis and calibration of a wide range of field and laboratory data, where uniform conditions prevailed. The transport (in ppm by weight) is calculated by:

−0.3301 ⎛ R ⎞ q = 727.6 c ()F − F 1.978 ⎜ ⎟ s f g gcr ⎜ d ⎟ ⎝ 50 ⎠ ………………………………………….…… (2-9)

V F = g [(s - 1) g d ]0.5 50 …………………………………………………………...….. (2-10)

F = 4.596 τ 0.5293 S-0.1405 σ −0.1696 gcr *0 g ………………………………………..…………. (2-11)

τ = 0.22 Y + 0.06 10 −7.7Y *0 () ……………………………………………………...…. (2-12)

Y = ( s - 1 R ) −0.6 g ………………………………………………………….…….... (2-13)

3 0.5 ()g d 50 R g = 31620 ν ………………………………………………………………….….. (2-14)

Where: cf = Coefficient for the transport rate (cf = 1 for laboratory and 1.268 for field conditions)

Fg = Grain Froude number

Fgcr = Critical grain Froude number

τ*0 = Critical dimensionless shear stress

σg = Geometric standard deviation S = Bottom slope g = Acceleration due to gravity (m/s2) d50 = Median diameter (m) s = Relative density

Rg = Grain Reynolds number R = Hydraulic radius (m) υ = Kinematic viscosity (m2/s

Ruaa K. Hamdan 40

Chapter-3 Data collection and field work

3 DATA COLLECTION AND FIELDWORK

A certain format of questionnaire was developed for the purpose of data collection on the basis of the objective of the study. During the field visit, the relevant information pertaining to the agricultural data of the study area and people involvement towards the system was assimilated. All this information was gathered from the central level, system level, district level and lower level offices of the related agencies, for more detail see Appendix 1.

3.1 Project background

The Malwan Irrigation Scheme has great benefits for the farmers that living in the (Rashed Ramazan, Ibrahim Kareem, and Malwan Hama aziz) villages; which they are located in Tanjaro Sub-district Sulaimaniyah centre district and this project were irrigating about 625 ha in summer cultivation. For that aim the establishing of irrigated project has a great importance for farmers, lead to increase their annual incomes in the way of increasing (production/ha) and increasing the irrigated land, and improvement of quality of crops. For all that a reason, studying of project from agricultural sides is very important, and finding out the weak points, disadvantages from agricultural domains and making some reformations by using scientific methods and after that to improvement of farmers level of life, subsequently to make progress and raising the production. The layout of this system is shown in Figure 3-1, and more details about it will be discussed in section 3.6.

Ruaa K. Hamdan 41 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

Malwan irrigation scheme

Figure 3-1: Location of Malwan Irrigation Scheme

3.2 Field data collection

A water-delivery system may be viewed as one of the components of an irrigated agriculture system. As such, it provides the water required to achieve farm-level agriculture production policies, such as maximizing net economic and social-welfare benefits. The production can be influenced by a very wide range of factors (e.g., climate, soil type, irrigation method, land levelling and grading, land area, irrigation demand, cultural practice on land preparation and salt leaching, crop type, inputs, use of pesticides, financial arrangements, market price, market availability and so forth), and by no means have all of them anything to do with the quality of irrigation (Abernethy, 1986). Therefore, relevant data for identification and analysis of water delivery performance of the system has been collected in the system area. Climatic, hydrologic, soil and crop data, maps, operational rules were included as well. During the fieldwork, interviews with farmers as well as irrigation agency have been done in order to clarify functions and concerns of the interested parties.

Ruaa K. Hamdan 42 Chapter-3 Data collection and field work

3.2.1 Climate

Climate differences between seasons are important in the area. Average temperature varies from 6.8 ◦C to 32.8 oC; total annual rainfall shows 646 mm/y. Data are collected from a nearby meteorological station for a period around 34 years. The main monthly meteorological data of the study area are presented below:

Rainfall The rainfall pattern in the study area is characterized by a long rainy period from October to the end of May. The mean total annual rainfall is about 646 mm, out of which about 400 mm concentrate in the period between December and April, and this is shown in Table 3-1 and Figures 3-2.

Table 3-1: Average monthly rainfall, 1973-2006 (mm)

Month J F M A M J J A S O N D total P 111 98 107 86 45 0 0 0 0 48 67.5 85 646

120.00

100.00

80.00

60.00 ave. precipetaion

40.00 precipitation

20.00

0.00 JFMAMJJASOND Months

Figure 3-2: Average monthly rainfall, 1992 - 2006

Ruaa K. Hamdan 43 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

Temperature

The mean temperature is about 20 oC over the year with mean daily maximum in

July(About 33 oC) and the minimum in January (7 oC), and this shown in Table 3-2 and Figure 3-3.

Table 3-2: Average monthly temperature ◦C

Month J F M A M J J A S O N D Tmean 7 9 12 18 24 29 33 32 28 22 14 9

.

35

30

25

20 Mean Temperature C 15

10

5

0 0 5 10 15 Months

Figure 3-3: Average monthly temperature in ◦C

Relative Humidity

The relative humidity varies from about 70% in the morning hours to about 40% in the afternoon and annual average is about 50.4%, and this shown in Table 3-3 and Figures 3-4.

Ruaa K. Hamdan 44 Chapter-3 Data collection and field work

Table 3-3: Average monthly humidity (%)

Month J F M A M J J A S O N D Tmean 75 71 62 56 45 31 28 29 31 43 61 73

80 70 60 50

% 40 30 20 10 0 02468 Months

Figure 3-4: Relative humidity in %

Evaporation

The average daily open water evaporation is highest in July (about 216 mm/day) and lowest in December (about 23 mm/day). The average daily evaporation over the year is about 102 mm/day and they are presented in Table 3-4 and Figure 3-5.

Table 3-4: Average monthly evaporation, 1973-2006 (mm/month)

Month J F M A M J J A S O N D Average 40 40 51 67 115 155 216 201 149 118 44 23

Ruaa K. Hamdan 45 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

250

200

150 Average monthly evaporation 100 Ev.(mm/d)

50

0 051015 Months

Figure 3-5: Monthly average evaporation in mm Wind speed

The average wind speeds range from 200 m/s (from August to December), this shown in the Table 3-5 and Figure 3-6. Table 3-5: Average wind speed, 1973-2006 (m/s) Month J F M A M J J A S O N D Average Umean 138 164 190 200 200 200 207 200 170 150 120 130 172.4

250

200

150 Wind speed (m/s)

Umean 100

50

0 0 5 10 15 Months

Figure 3-6: Average monthly wind speed in m/s

Ruaa K. Hamdan 46 Chapter-3 Data collection and field work

Sunshine hours

The average daily sunshine is lowest in almost (4.75 hrs/day) and highest in July around (12.4 hrs/day), this shown in Table 3-6 and Figure 3-7.

Table 3-6: Average daily sunshine hours, 1973-2006 (hrs/day)

Month J F M A M J J A S O N D Average n 4.8 5.7 6.2 7.3 9.4 12.4 12.3 11.6 10.5 8.0 6.2 4.8 8.3

14

12

10

8

n Sunshine hours 6

4

2

0 051015 Months

Figure 3-7: Average daily sunshine hours

3.2.2 Hydrology

The following discharges data of the future suggestion dam in the up stream of Malwan Irrigation Scheme site are available. For more detail see Appendix 3, the minimum discharge in this reservoir is 86.1*106 m3/year in 2007, while the maximum value is 273 m3/s.

3.2.3 Soils

The area is situated in a mountain valley and is pictographically differentiated. The following photographical units have been distinguished: mountains and hills, foot-hills, alluvial fans.

Ruaa K. Hamdan 47 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

The mountains and hills are of two types: • The higher mountain ranges and hills being generally bare or having only scanty vegetation. • Low hills having moderately steep slopes and covered with grass.

Soils in particular physiographical unite are widely differentiated. The mountains have shallow to negligible soils. The low hills support shallow to very shallow soils developed from fine texture material, mixed with stones and boulders. The foot hills in the project area consist of pebbles of differentiated mineralogical composition such as limestone, sand stone. Their surface is sloping and generally they are gravely and stony. Soils in the range of this physiographical unite are moderately deep to deep, fine textured and gravely. Soils of the foot-hills are subjected to slight erosion.

Soils are mostly cultivated forming poor arable land, and quite often they are used us pasture land. The alluvial fans or gravely uplands occur between foot-hills and alluvial plains, and consist of deposits of gravel and fine textured material. Generally they have gravely surfaces which are slightly slopping. Soils of this unite is moderate to very deep, fine textured relatively thick and rich in organic matter.

The soil of Malwan Irrigation Scheme area have mostly developed from alluvial which drive from limestone and partly from shells with sandstones. The soil is rich with organic matters which is not saline and not sodic.

Taking into consideration the above mentioned characteristics the soil of Malwan Irrigation Scheme area is suitable for intensive agricultural production under irrigation farming.

3.3 Agriculture development

Beneficiary farmer and family

The number of beneficiary farmers and families after the project implementation was increased as compared with years ago; this change will be discussed in two stages below: The number of beneficiary farmers and families from irrigated lands served by Malwan canal before making the project was low; the number of beneficiary farmers and families from this canal at year 1998 to 2001 had faced a little increasing.

Ruaa K. Hamdan 48 Chapter-3 Data collection and field work

In the year 1999 the number of beneficiary farmers was 82 farmers and the number of beneficiary families was 265 families also in the year 2000 the number of farmers was 85 farmers and the number of families was 270 families. That means before establishing the project the number of farmers and families, gradually increased in little amount because of: Loosing a big quantity of water due to seepage the water in the canal banks, for that the rate of water in the canal decreased, which caused to reducing the number of irrigated land and beneficiary farmers and their families.

After constructing the project the number of beneficiary farmers and families increased i.e. in the year 2002 the number of farmer was 140 and the number of families was 410 (i.e. 55 farmers and 140 families increased after making the project). This increasing in number of farmers and families those benefited from the canal is due to: Lining the canal and by this decreased the wastes or losses of water and the speed of flowing water was increased due to cleaning the canal and by doing this the canal water may go near the end of the captivated lands from that the number of irrigated land increased, which cause to increase the number of farmers and families as shown in Table 3-7:

Table 3-7: Numbers of beneficiaries’ farmers and families before and after project implementation

States years Number of farmer Number of family members

1999 82 265 Before the project 2000 85 270 2001

After the project 2002 140 410

total 140 410

Note: In 2001 the project was under construction.

Ruaa K. Hamdan 49 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

Land ownership The Malwan Irrigation Scheme is a government system; the lands were given to the farmers by contract, every year an amount of money was taken from the landowners according to the type of crops grown and the year income of the farmer; but because of the systematic politic events that happened in Iraq, now the farmers are free from this money and most of the lands have been sold to companies because of suitability of land in obtaining building materials such as gravel and sand.

Farm size Farm plots vary from 1.25 - 7.5 ha; the stronger farmers have more than one plot and vary from 12.5 - 19 ha, especially in the downstream part of the area where the topography is much helpful in distributing the land.

Settlement The irrigated lands of these villages (Rasheed Ramazan, Ibrahim Kareem, and Malwan Hamma Aziz) situated among Malwan Irrigation Scheme, the farmers of these villages’ benefits from canal water in summer cultivation. But all those farmers and families do not in habit “dwell” in their villages because in 1989 established Shahrazoor-district that called “Halabjay Taza” in the area, and settled all inhabitants of those villages in this city from that year up to now. They did not come back to their obvious places; because their lands are very near from Halabja. After establishing the project the area of their lands increased which benefited from canal from 375 ha to 750 ha that means increased about 250 ha from the irrigated lands. Due to increasing the irrigated land was leaded to increase number of farmers and families; those came back to their lands for summer cultivation. Also the change in the water quantity, irrigated land was caused to increasing their annual incomes and especially in same block of the land that planted in summer and winter subsequently Thus we can say that the farmer incomes was increasing as comparing with year before establishing the project and this an important factor to resettlement the farmer and there families. The number of farmers and families those returned to their lands to summer planting after the project as the following Table:

Ruaa K. Hamdan 50 Chapter-3 Data collection and field work

Table 3-8: The returning families and farmers after establishing the project i.e. at 2001-2002

No. of returning No. of returning farmers families

55 140

Cropping policy The cropping policy is free selection of crops. Crops with good market price are preferred. The main crops that are grown in the agriculture lands surrounding the area are oil crops (Sunflower, Sesame), Cotton, Pea, Nut, Beans, Wheat, Barley, Tobacco, Small vegetable crops.

3.4 Tertiary units and field irrigation system

Tertiary off takes The tertiary off take is the place where the agency and the users bound responsibilities. In the case of Malwan Irrigation Scheme the tertiary off take consist of a manual gate and a pipe which diverts water from the main canal and transfer it under a road to the lateral canals (secondary canals), the size of flow is controlled by the size of the pipe, which is nearly proportional to the served area. Then from the lateral canal water will be taken by farmers to their fields. Water master men are responsible for opening and closing these gates. There is no device for measuring water that has been given to the farmers, so there is no information about water consumption, the main reason may be that there is no fee on water.

Tertiary units The size of the tertiary units varies from 75 - 225 ha, all the tertiary units have a surface irrigation system (furrow and basin), inside the tertiary unit a farm plot is defined as an area that is irrigated at the same time.

Ruaa K. Hamdan 51 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

3.5 Main irrigation system

3.5.1 Water source and headwork

The water source of Malwan Irrigation Scheme is Tanajro river, springs and deep wells. Tanjaro river is 66.7 km long coming from Sulymania restrict in the up stream towards Darbandikhan reservoir on Dyala river in the downstream. This river provides more than 49% of the water required for irrigation in the region; the mean annual discharge of this stream is around 9.5 m3/s.

3.5.2 Main canal

The main canal has a total length of 8.5 km; this canal takes water from the Tanjaro river source and irrigates nearly 750 ha of agriculture land, the characteristics of the cross sections of the main canal and secondary canals are shown in Table 3-9. The discharge of the main canal is 2.7 m3/s and the three secondary canals taking it’s water from the main canal to irrigate each block of different crops. In the scheme the lengths of the three secondary canals are (996.4, 1,209.8, 1,540) m respectively then flowing into Tanjaro river again; details are shown in Table 3-9.

Table 3-9: Main and secondary canal cross section characteristics

Characteristic unite Main canal 1st secondary 2nd sec. 3rd sec. Base width m 1.3 0.5 0.7 0.5 Side slope - - - - - Bottom slope m/m 0.0025 0.003 0.008 0.007 Manning s/m1/3 0.015 0.015 0.015 0.015 coefficient Water depth m 1 0.7 1 0.7 Free board m 0.13 0.13 0.13 0.13 Total depth m 1.13 0.83 1.13 0.83

3.5.3 Structures

Some important structures in the alignment of the main and secondary canals are: 1. Regulator structure (intake):

Ruaa K. Hamdan 52 Chapter-3 Data collection and field work

A special type of headwork structure provided at the head of the canal alignment and its proposed at the river or stream where the natural water surface is high enough to produce head casing flow through the canal by gravitational action.

In any intake the two major principles must be occupy: 1- Occupy high flood entering and safety exit it from the silt excluder or flood passages and 2- Sufficiently providing maximum demand of water during flood season and low flow season. The intake of Malwan Irrigation Scheme is taking the water from Tanjaro river to the main canal in the scheme this intake is far 2,000 m in the up stream of the first secondary canal.

2. Weirs: there are four weirs in the main canal of Malwan Irrigation Scheme. The first three weirs are far 5 m in the down stream of each secondary canal, the last weir is about 1m before the end of the main canal, all the weirs has a crown width of 0.8 m.

3. Vertical gate: They are constructed on the secondary canals about 5 m from the beginning of each secondary canal, the properties of the vertical gate is shown in Table 3-10.

Table 3-10: Vertical gate characteristics

Crown Shape Sharp Width Whirlpool (m) 0.6 Height Whirlpool (m) 0.15 Gate Level (m) 515.03 Mu free surface flow pos. 1 Mu free surface flow neg. 1 Mu submerged flow pos. 1 Mu submerged flow neg. 1

4. Scouring sluice: The shunt sluice with an open front has been used in the main canal in three positions just behind each weir in order to cleanup the canal from any sediment deposition and prevent any blocking which may effect later on the water requirements of the crops in the scheme.

Ruaa K. Hamdan 53 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

3.6 System management

Irrigation agency, but this management is not under a legal framework that state by the government. Main interest groups are:

Users Management of the system at tertiary level is the responsibility of individual farmers. They have free selection of crops and continuous flow with variable discharge, relatively constant frequency and variable irrigation duration relative to their farms.

Water is delivered from lateral canals to farm plots through pipes with metal cover; farmers open their pipes whenever they want to irrigate their field without any schedule or consultation with irrigation agency but with some arrangements among themselves without any legal document. Lack of irrigation schedule and good plan for operation at the tertiary level cause an inefficient use of water, especially in the dry season (summer). Water has to be divided among the farmers according to type and stage of crop growing, size of farms and farness from the lateral offtake.

Irrigation agency

The irrigation agency is Sulaimanya irrigation and dams directorate. They are in charge of operation and maintenance of the main canal, their main responsibilities are: • Deliver water from the headwork to lateral off takes; • Supervise the operation of the system at main level; • Organize and execute maintenance works at the main level.

Because there is no fee on water that is delivered to the farmers no device been installed for measuring water consumption at the lateral off takes along the operation time of the system, this considered as one of the system’s shortcomings.

Ruaa K. Hamdan 54 Chapter-4 Study framework

4 STUDY FRAMEWORK

4.1 Need for performance assessment of irrigation systems

The performance of a system is represented by its measured levels of achievements in terms of one, or several, parameters, which are chosen as indicators of the systems goals (Snellen, 1993). Performance is assessed for a variety of reasons: to improve system operations; to assess progress against strategic goals; as an integral part of performance-oriented management, to assess the general health of a system; to assess impacts of interventions; to diagnose constraints; to better understand determinants of performance; and to compare the performance of a system with others or with the same system over time. The type of performance measures chosen depends on the purpose of the performance assessment activity (Molden et al., 1998).

One of the most important factors in terms of sustainability of irrigation systems is monitoring and evaluation plans (performance assessment programs), which keep it on track towards the objectives and do corrections if necessary (Bird, 1990).

Performance assessment is an activity that supports the planning and implementation process. The ultimate purpose of performance assessment is to achieve an efficient and effective use of resources by providing relevant feedback to the system management at all levels. As such, it may assist the system management in determining whether the performance is satisfactory and, if not, which and where corrective or different actions need to be taken in order to remedy the situation (Burton and Molden, 2005).

The performance of an irrigation system can be viewed from a number of different perspectives. This view depends upon the background and experience of those conducting the evaluation, and the objectives of the irrigation system that are evaluated. If the irrigation system is a single, large farming operation, system objectives should be relatively easy to define. However, for irrigation systems those are publicly funded and operated to distribute water to a large number of independent farmers, the objectives may not be so easy to define (Clemmens and Bos, 1990).

Performance assessment can be used in a variety of ways, including operational performance assessment by system managers to determine how the operational processes are performing. The

Ruaa K. Hamdan 55 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region) processes studied could relate to the overall production, or they could be broken down into sub- processes such as main system water delivery, on-farm water delivery, crop production, etc. depending on the level at which the analysis is required (Burton and Molden et al., 2005).

4.2 Current performance of irrigation systems

Nowadays most of the irrigation systems in Kurdistan are performing below their potential. Murry-Rust and Snellen (1993), based on multiple experiences mentioned that in the recent years there has been a growing concern that performance of irrigation systems is less than expected. Some of reasons that are mentioned by (Helfgott, 2002) in his research (evaluation of hydraulic performance of irrigation sector in Peru) are: • Unrealistic hydraulic designs; • Low overall water use efficiency; • Deficiencies in irrigation management and poor maintenance programs; • Environmental hazards.

Combination of the latter factors resulted in non-sustainable systems and in the typical cycle of construction-deterioration-modernization of irrigation systems. Thus, investments since the 70’s have been directed to modernization instead of to new systems like in the 50’s and 60’s.

According to his ideas the problem originates in a missing management framework, which will enable to identify the real cost of the operation and maintenance service. The process to revert the situation includes improvement of both hardware (canal lining, structures, gates) and software (institutional and policy reforms, capacity building, training, credits, marketing) components of the system.

Barnett (1977); Pant (1983); Repetto (1986); Plusquellec et al. (1990); Postel (1992); Bottrall (1995) declared that most large-scale irrigation systems in the world are considered to exhibit low degrees of management performance. This includes low cost recovery and low water use efficiencies induced by area-based water allocation and poor water delivery performance.

A solution currently widely promoted to increase the performance of these systems is volumetric allocation, charging, and delivery of water Grimble (1999). Generally, volumetric charging is

Ruaa K. Hamdan 56 Chapter-4 Study framework supposed to increase water use efficiency, because it gives an incentive for the farmers to save water. It is also supposed to raise fee recovery, because payments can be enforced by only supplying the volume of water paid for. Nevertheless, most irrigation experts believe volumetric water allocation, charging and delivery will not function in a large-scale system with many smallholders and open canals in poor countries, because of high costs, and technical and social difficulties in water distribution (Plusquellec et al., 1994; Horst et al., 1998).

For more than 6000 years man has used water to his advantage in many different ways. At the same time he also protects himself against the harmful effects of water in order to improve his living conditions. Tremendous successes have been realized, but in many regions water management systems function significantly below their potential. Schultz, et al. (2005) explained how improvements in water management may contribute to the requisite developments. Within this framework their study shows how irrigation and drainage may contribute to the required increase in food production and sustainable rural development.

Shahrokhnia and Javan (2005) emphasized on the reality that there is a need for improvement in the operation and management of many irrigation and drainage systems worldwide.

The performance of large-scale irrigation systems worldwide has been disappointing to the international community. Continued poor performance could limit our ability to provide food and fibre for a growing, more affluent world population. Improvement in the productivity of large irrigation systems is a key component to assuring future adequate food and fibre supplies (Clemmens, 2006). He discussed in a study the reasons for poor performance of these systems and proposed a method to improve their performance.

4.3 Water delivery systems performance

The success of a water delivery system can be measured by how well it meets the objectives of delivering an adequate, while not excessive, and dependable supply of water in an equitable manner to users served by the system. Hence, there is need for performance measures, in a quantitative manner, which is associated with the evaluation, planning and design of water delivery system. Furthermore, to assess the need for improvement in structural and institutional

Ruaa K. Hamdan 57 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

(i.e., management) elements, it is logical to evaluate separate contributions of these elements to overall performance of the water delivery system. The operation and management of irrigation systems play a major role in the performance of each part. The performance of the main system has a great impact on the performance of the whole system. The function of a main system is to deliver water needed by the crop to the farm turnout at the right amount, at the right time and for the right duration.

Schuurmans (1991) declared that in many irrigation systems the water distribution performance is below expectation, which implies an unreliable and unequal supply. There are certain specific reasons for unreliable water distribution for each system, but the reason which is common to almost all systems is that unsteady flow phenomena in irrigation networks and their effect on the water delivery performance are often not understood and contribute to poor delivery performance; as a result the daily operation of the system is troublesome. If the system would react instantaneously on changes in gate setting, it would be much simpler to determine the proper timing and magnitude of gate adjustments. In reality, the water flow does not react instantaneously, but shows a retarded and diffusive response. Hence it is impossible to specify the objective of irrigation, and consequently, the optimal water distribution does not exist. For the optimal water distribution from an economic point of view might not be optimal from social view point. It can be stated that one of the causes of poor performance of water distribution in irrigation canal systems is the inability to control the regulators in such away that actual supply matches with the intended supply. To improve the real life of non-uniform and unsteady flow phenomena rather than the simplified uniform steady flow phenomena should be taken into account. The non-uniform unsteady flow a phenomenon in controlled irrigation canals is rather complex and can only be calculated by using a model. This model can be mathematical, a scale or a numerical one. Due to progressive development of one-dimensional unsteady flow models and computer resources, a numerical model is most suitable to study the non-uniform unsteady flow phenomena in controlled irrigation canals (Schuurmans, 1991).

Although a lot of efforts have been done all over the world for improving the performance of irrigation systems with emphasizing on tertiary level management and on-farm development by assuming that the main system is functioning according to the design to deliver water needed by the crop; it soon became clear that main systems are performing below the expected level and cause the on-farm activities to be ineffective.

Ruaa K. Hamdan 58 Chapter-4 Study framework

Baume (1993) has commented that “in efficient management of the conveyance and distribution of water in the main system often negates even the best efforts of farmer’s organizations and irrigation agencies to achieve equitable water supply below turnouts”. Kamolrantana (1993) also commented that “no strategy for improving water control at tertiary level will work unless there is an adequate, reliable flow of dry season water at the farm turnout”. Chambers et al. (1988) have concluded that “main system management is considered to hold the key to improving canal irrigation performance”.

A logical alternative is to improve the system’s operation and management through better operational procedures and improved service delivery. Critical elements to achieve the goal of improved water management are an efficient operation of the main delivery system and effective maintenance of irrigation and drainage infrastructure (Schultz and de Wrachien, 2002). Furthermore, large investment in irrigation infrastructure has not met the planners’ expectations. This realization has forced policy makers and researchers to focus on improving irrigation system performance at different levels. Lack of financial resources and adequate infrastructure are the major obstacles to improving the performance of the system through physical development.

4.4 Parameters describing water delivery performance

A water-delivery system may be viewed as one of the components of an irrigated agriculture system. As such, it provides the water required to achieve farm-level agriculture production policies, such as maximizing net economic and social-welfare benefits. The production can be influenced by a very wide range of factors (e.g., climate, soil type, irrigation method, land levelling and grading, land area, irrigation demand, cultural practice on land preparation and salt leaching, crop type, inputs, use of pesticides, financial arrangements, market price, market availability and so forth), and by no means have all of them anything to do with the quality of irrigation (Abernethy, 1986). For planning and management, the objectives of irrigation systems often are viewed in terms of desire to best meet agriculture water requirements (Molden and Gates 1990). If the management is unsuccessful it will not be possible for agricultural management to succeed. The objectives of delivering an adequate and reliable supply of water in an equitable and efficient manner (i.e., delivery of water where and when it is wanted for crop

Ruaa K. Hamdan 59 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region) production, efficiently and in the right quantities) to users served by the system are the key to merit irrigation-water-delivery system. To evaluate how well an irrigation water-delivery system is functioning in its present state relative to its objectives, and to make decisions about designing or modernizing a system, requires defining of measures of system performance and prescribing standards for assessing the values of those measures. Performance measures should be functions of state variable that is used to indicate the state of system performance relative to system objectives, should be intuitively easy to interpret, and should be relatively easy to measure or predict. Once performance measures have been estimated for a given state of the system, their values must be assessed, or evaluated (Molden and Gates 1990).

4.4.1 Adequacy

A fundamental concern of water delivery systems is to deliver the amount of water required to adequately irrigated crops. Adequacy of delivery is dependent on water supply, specified delivery schedules, the capacity of hydraulic structures to deliver water according to the schedules, and the operation and maintenance of the hydraulic structures. A measure of performance relative to this objective for a region R served by the system (or the number of measuring points) over a time period T is proposed as:

1 ⎛ 1 ⎞ PA = ∑∑⎜ p A ⎟...... (4 −1) T ⎝ R ⎠

QD p A = ...... (4 − 2) QI

For QD ≤ QI

Where: PA = the performance measure relative to adequacy; pA = the point performance function relative to adequacy; QD = the actual amount of delivered water; QI = the intended (required) amount of water. R = a region served by the system

Ruaa K. Hamdan 60 Chapter-4 Study framework

Delivery performance ratio (DPR) is defined as the ratio of delivered discharge or volume to intended discharge or volume. It is similar to the point performance function relative to adequacy (pA). The values lower than 1 show the inadequate delivered water whiles the values higher than 1 show that the delivered water is more than enough.

4.4.2 Efficiency

The system performance relative to efficiency PF represents the desire to conserve water while matching water deliveries with water requirements. Principally, it is reverse of system performance relative to adequacy. Water saved may play vital role in less expenditure on existing infrastructure in terms of operation and maintenance and in possibility to fully meet crop water requirement or in irrigating more land.

System water-delivery efficiency is embodied by conveyance efficiency and by other overuse or loss of water not directly reflected in the concept of conveyance efficiency as in, change in in- canal storage due to the delivery of more than adequate supply of water to bifurcation points within the system. Conveyance efficiency indicates relative amount of water lost in a canal reach due to canal seepage or overflow. Change in in-canal storage defined as change in the volume of water within a reach after a new steady state is achieved. A water delivery system which supplies more than adequate amount of water instigates water logging and salinity to farms. The performance indicator is read as:

1 ⎛ 1 ⎞ PF = ∑∑⎜ pF ⎟...... (4 − 3) T ⎝ R R ⎠

pF = water-delivery system efficiency indicator

Qa p = ,ifQ ≤ Q ...... (4 − 4) F Qr r a

PF = 1, otherwise all other terms are as specified above.

Ruaa K. Hamdan 61 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

From the boundary of the function PF equal to 1, when Qr ≥ Qa, indicates system is efficient. However, no information is retrieved about the extent of under-delivery. This information can be retrieved from PA ≤ 1. Further, as PF approaches to 1 there is an increasing compatibility with the goal of efficient water delivery for the hydraulic level or reaches. The value of PF less than 1 indicates inefficient and over-adequate water delivery

Where: PF = the performance measure relative to efficiency; pF = the point performance function relative to efficiency; Qa = the actual amount of delivered water; Qr = the intended (required) amount of water.

4.4.3 Equity

Equity as related to a water delivery system can be defined as the delivery of a fair share of water to users throughout a system. Equity of water delivery is a difficult objective to measure because of the interpretation of fair share. The researchers have suggested several alternative definitions of water delivery equity. One of them is interpreted as spatial uniformity of the relative amount of water delivered. Therefore, it can be the average relative spatial variability of the ratio of the amount delivered to the amount required over the time period of interest.

1 ⎛ Q ⎞ ⎜ D ⎟ PE = ∑CVR ⎜ ⎟...... (4 − 5) T T ⎝ QI ⎠

Where: PE = the performance measure relative to equity; CVR (QD/QI) = Spatial coefficient of variation of the ratio (QD/QI) over the region R.

If the value of PE is close to zero the greater degree of equity will exist. Once the values of performance measures are estimated for a given state of a system, those values can be used to analyze the system for the purposes of evaluation and planning. If the performance is not in acceptable range, action may be taken to investigate alternatives for system rehabilitation. Table 4-1 shows the performance standards proposed by Molden and Gates (1990).

Ruaa K. Hamdan 62 Chapter-4 Study framework

Bos (1997) summarized about 40 multidisciplinary performance indicators. Using these indicators water delivery, water use efficiency, maintenance, irrigation sustainability, environmental aspects, socio-economics and management can be evaluated in irrigation systems. Furthermore; in this domain Clemmens and Bos (1990) described the performance of water delivery service and they emphasizes on the reality that there are several different parameters that can be measured and used to describe the performance of water delivery service; flow rate, volume, duration, pressure, and frequency as well.

Table 4-1: Performance standards (Molden and Gates, 1990)

Performance classes Measure Good Fair Poor

PA 0.9-1.0 0.8-0.89 0.8 PF 0.85-1.0 0.7-0.84 0.7 PE 0-0.1 0.11-0.25 0.25

The proper one(s) to consider depends on the systems conditions and objectives. The overall performance of an irrigation water delivery system can be broken down into two components; the delivery schedule and operations.

The performance of the delivery schedule can be evaluated by looking at the ratio of intended to required water (volume, rate, duration, etc.) and the performance of operations by the ratio of actual to intended water. The overall performance is expressed by the product of these two ratios; the actual divided by the required water. Statistical relations are provided to express equity, adequacy and reliability from measurement of these ratios.

Past evaluations of delivery performance have identified the concepts of adequacy, equity and dependability as being important considerations (Mohammed, 1987). Dependability and consistency can also be considered as word descriptions of performance.

At any point in time, one can measure the discharge, Q, or the pressure, P, at various delivery points within the system. Over specified periods of time, one can examine the duration of a delivery, D, the total volume of water supplied, V, and the frequency with which water is delivered, F, at a given farm turnout or off take. These are the usual quantities of interest that can be measured. The question is how can these measurements be made into expressions of adequacy,

Ruaa K. Hamdan 63 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region) efficiency and equity? In addition one might ask, ‘how can these expressions be related to overall system performance?’ and ‘how can one establish target values for these expressions that can be used by system management to improve performance?’ (Clemmens and Bos, 1990). In the initial stages of system formulation, decisions should be made regarding: • The method for allocating water; • The method for physically distributing water.

The method for allocating water is often referred to as the delivery schedule. Examples include demand, arranged, and rotation schedules (Zimbelman, 1987). The method for distributing water (operations) is a combination of the physical facilities, the physical water control strategy and the operating plan (management). Examples of control strategies and physical facilities are upstream control in canals with manually operated check gates and pressurized closed pipe deliveries with regulated pressure (Zimbelman, 1987). The conditions (both in system operation and in farm irrigation) assumed during system development may be considerably different from those which currently exist. Changes in irrigation practices and crops may suggest changes in this plan.

Evaluation of system water delivery performance would have to focus on evaluating these two parts of the water delivery plan. The first, an evaluation of the delivery schedule, should be done periodically (e.g., every ten years) or when major rehabilitation is being planned. The second, an evaluation of water delivery operations, can be an on-going activity (Seckler et al., 1988). Unfortunately, the data needed for these evaluations is not typically collected during routine irrigation system operations (Clemmens and Bos, 1990).

Johnson et al. (1993) present a framework irrigation managers can use in assessing performance of irrigation, and recommend a specific set of indicators for measuring performance that the authors believe are practical, useful, and generally applicable. Although the primary focus is on the management of canal systems for agricultural production, they also discuss indicators that can be used for assessing longer term performance, including physical, economic and social sustainability. Finally, they highlight the crucial importance of strategic, as well as operational management performance, and the necessity of having an incentive system that encourages managers to improve performance.

Ruaa K. Hamdan 64 Chapter-5 Computer models

5 COMPUTER MODELS

Computer model applications are widely used throughout the water management sector. Most of them are successors of previously used laborious conventional method but some have introduced new methodologies and concepts (Smedema et.al., 2004).

In this study, the quickest way of getting insight of how best the system can be run is through the use of computer models. For performance assessment, evaluation is made for the existing operation of the system. For this purpose two models were used for the research: DUFLOW and CROPWAT.

5.1 Unsteady flow model

There is a need for improvement in the operation and maintenance of many irrigation and drainage systems worldwide. Irrigation canals are complex hydraulic systems difficult to control (Malaterre et al., 1998). The behaviour of water flow in an irrigation canal can be steady or unsteady. This behaviour can be described by the Saint Venant Equations. In the past three cades, research on open canal hydraulics has been done to obtain a more complete understanding of the dynamics of the transient conditions.

Emphasis was placed numerical schemes by using mathematical models. Selection of the appropriate models; which can be divided into unsteady and steady models, depends on the hydraulic regimes of the irrigation system (Clemmens et al., 1993); (Schuurmans, 1993); (Merkley and Roger et al., 1993); (Holly and Parish, 1993) evaluated hydraulic models such as DUFLOW, MODIS, CANAL, CARIMA, and USM, respectively.

The Rijkswaterstaat (Public Works Department) in the Netherlands in the 1970s developed a main-frame-based FORTRAN program “IMPLIC” for simulating one dimensional unsteady flow in open-canal systems. The program was designed for simple networks of canals with simple structures. Later, the Delft University of technology, the international Institute for Infrastructural, Hydraulic and Environmental Engineering (IHE), and Rijkswaterstaat collaborated in developing IMPLIC to produce a more user-friendly, free-surface program for general use. The program is intended for use in all types of open canals, not just irrigation canals. The IMPLIC computation

Ruaa K. Hamdan 65 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region) code was combined with a user interface written in MS-BASIC to produce a new microcomputer software package called DUFLOW (Dutch Flow).

Water levels and discharges are determined by solving the St. Venant equations of continuity and momentum with the Preissmann scheme. The set of equations is solved by Gaussian elimination so that any network or loop configuration can be included. The program has a user interface for entering a description of the network conditions.

DUFLOW is professional software and is distributed at a nominal cost. The DUFLOW computer program is relatively inexpensive. Data entry and presentation of results are handled. DUFLOW was not designed to specifically handle irrigation canals, thus some of the structures are not handled as conveniently as in other irrigation canal models. However, DUFLOW can be also used for other applications.

5.2 Application of the hydrodynamic program DUFLOW

DUFLOW gives regional water manager a quality tool for modelling irrigation systems, drainage systems and natural streams in low lands. The application can be typically related to optimizing agriculture production through the water quantity control, such as automation of irrigation canal, flood control, reservoir operation, and the water quality, except sediment, control. DUFLOW offers the support, which is needed for effective planning, design and operation of new and existing water system. The software simulates the unsteady flow in branched and looped networks configuration, consisting of number of reaches having cross-sections and structures. Definition of types of boundary conditions, as well as defining lateral inflow and out flow using time series and standard formulae is possible. In the study, use of water quantity control in line with DUFLOW modelling programmed has helped to find out how the performance of the irrigation system can be improved by a better operation of the gates and weirs. Version 2.05 of DUFLOW program is used in simulating water quantity in the study of SS9B, SS9F and SS9J canal network. As the part of DUFLOW that deals with water quality process is not used in the study, so this aspect is not outlined. Version 3.6 of DUFLOW program is used in simulating water quantity in the study of Malwan Irrigation Scheme main canal. As part of DUFLOW that leads with water quality is not used in the study so this aspect will not be outlined.

Ruaa K. Hamdan 66 Chapter-5 Computer models

5.2.1 Concept of water quantity in DUFLOW

DUFLOW works with the complete de St Venant equation for unsteady flow that includes transient flow phenomena as well as backwater and drawdown profiles. The assumptions for deviation of St Venant equation for unsteady flow follow as the flow is one-dimensional, i.e., velocity is uniform over the cross section (so the energy line is constant) However in reality, velocity varies (a) in depth from the bottom of cross section (b) from the side (wall) boundary of cross section (c) along length of canal and (d) in time. This means either the water level should not be constant in a cross section for no uniform velocity distribution, given the constant energy level or the energy level shouldn’t be constant in a cross section on account of non-uniform velocity distribution, given the water level. The contradiction in energy level or water level terms, however, it is not present while flow is steady and uniform. Departure from hydrostatic pressure due to streamline curvature so formed between the variable cross section in a canal is small. Hence, the centripetal (i.e., vertical) acceleration is negligible.

In reality, variation in irrigation canal cross section depends not only on design but also on maintenance conditions. Hence variation in cross section of the canal may be arbitrary. The assumption also means that there must be a continuous water surface between the canal cross section so as not to have stream line curvature effect of significance. That is flow should be unsteady and gradually varied without abrupt changes. However, the reality may violate the assumption in the neighbourhood of discontinuity, for example hydraulic jump, sudden operation (closure or opening) of control gate and sharp variation in boundary flow creates significant discontinuity in the water surface at a cross section. In solution, if discontinuity is assumed as simple with infinitesimal length then use of moving hydraulic jump relations to link the region upstream and downstream can be made in which the Saint Venant assumption is valid. However, in an irrigation canal with mild slope hydraulic jump is mostly associated within downstream of control structure, so the operation of a control gate and variation of boundary flow is more gradual.

The effects of canal boundary friction and turbulence can be accounted for through resistance laws analogous to those used for steady state flow. This is true for uniform velocity over a cross section, along canal length and in time. However, the velocity of flow is unsteady and non- uniform in irrigation canals when the operation of control structures and/or the change in boundary condition of flow is activated. This means that the effect of boundary resistance on non-

Ruaa K. Hamdan 67 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region) uniform velocity of flow, from the canal bed and from the sidewalls over the cross sections, is significantly different from that of steady state of flow.

The average canal bed slope is small so that the cosine of the angel it makes with horizontal may be replaced by unity. But in case of irrigation canal in hilly region the bed slope may depart significantly from horizontal.

5.2.2 Unsteady flow equations

DUFLOW is based on the one-dimensional partial differential equations that describe non- stationary flow in open channels. These equations, which are mathematical translations of the laws of conservation of mass and of conservation of momentum, respectively read:

∂H ∂Q B + = 0...... (5 −1) ∂t ∂x

And

∂Q ∂H ∂()αQv g Q Q + gA + + = bγw2 cos()Φ −φ ...... (5 − 2) ∂t ∂x ∂x C 2 AR

While the following relation holds:

Q = vA...... (5 − 3)

Where: t = time in second x = distance as measured along the channel axis in metre H(x,t) = water level with respect to the datum of reference (in location, x and in time, t) in metre v(x,t) = cross section averaged velocity in metre/second Q(x,t) = discharge (in location, x and in time, t) in m3/s

Ruaa K. Hamdan 68 Chapter-5 Computer models

R(x,H) = hydraulic radius (the characteristic length) of a cross section in metre A(x,H) = cross section area of flow in m2 b(x,H) = width of free water surface flow over a cross section in metre B(x,H) = width of storage flow over a cross section in m g = acceleration due to gravity in m/s2 C(x,H) = coefficient of De Chezy in m (1/2)/s w (t) = wind velocity in m/s Φ (t) = wind direction in degrees φ (x) = direction of channel axis, measured clockwise from North in degrees γ (x) = wind conversion coefficient

The water level with reference to datum of reference embodies channel slope and water depth in a cross section of channel. In the derivation of these equations it has been assumed that the fluid is well mixed and the density of fluid is considered as constant. The letter C in equation 6.2, which stands for the Chézy coefficient relates to the Manning coefficient n as

1 1 C = R 6 ...... (5 − 4) n

5.2.3 Model setup

The setup preparation for the DUFLOW program involves specifications of canal cross-sections, layout of the canal network, regulators, upstream and downstream boundary conditions.

Schematization of the network

Nodes The DUFLOW program was applied to the whole project area with the relevant collected data in order to design the main and secondary canals. For this purpose schematization of Malwan Irrigation Canal is done as first step. The schematization consists of number of canals defined as section that connects nodes and number of structure is defined between the nodes. The main canal is divided into 8 cross sections and 5 nodes according to the location of laterals, structures and change in the cross sections. The maximum length of a section is 1530 m while the minimum

Ruaa K. Hamdan 69 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region) length of a section is 600 m. The design discharge in the main canal is 2.7 m3/s while in the secondary canals is (0.085, 0.136, 0.131) m3/s all over the canal sections. Bottom elevations of a section connecting two nodes is defined in the network, of which elevations of structures defined between the nodes is automatically accounted for, the schematization shown in Figure 6-3.

Boundary roughness A single valued boundary roughness, given by Manning’s coefficient n, in respective sections, both in the positive direction of flow and in the negative direction of flow (i.e., reverse flow), is specified from the data collected for corresponding canal network. However, in reality the roughness coefficient varies from bottom to sidewall due to variation of velocity and maintenance condition in a cross section. So, the actual value representative to a section model could be obtained from field measurements, for example using slope area method.

Cross section Cross section profile at respective nodes in the network under schematization is taken at different intervals from canal bottom so as to have better representative at nodes. This is because in reality the profile of cross section in irrigation channel of earthen material is not regular as implemented due to adjusted boundary of flow cross section having experienced different operational flow condition and due to irregular maintenance condition.

Structures

The structures with all the relevant data such as location, width, diameter, length, inside level, and sill elevation, depending upon type of structures, are specified in the network of DUFLOW from collected data.

The discharge correction factor, which includes correction for streamline curvature and velocity distribution due to shape and size of structure, correction for crest-referenced energy, and type of material and its maintenance condition, and correction for bottom and/or side contraction, is taken by default as 1 for both free flow and submerged flow condition in DUFLOW program. However, for a given structure the discharge correction factor depend on water level in canal both upstream and down stream of structure, on maintenance condition and on the flow condition. So, the actual discharge correction factor for the structure should be ascertained by calibration in the field or in the laboratory.

Ruaa K. Hamdan 70 Chapter-5 Computer models

Initial conditions The model requires initial condition of water level at respective nodes and discharge at corresponding sections and structures defined in schematization of canal under study before it starts computation of flow across the boundary of network. The normal water depth and the water level has been input in the model to start with computation procedures.

Boundary conditions The boundary condition of flow has been input as average monthly water level in front of main canal off take over the period of computation at extreme node 0 of upstream boundary, and discharge-water level relation ships at extreme node 4 of downstream boundary. Further, discharge-water level relation ships at extreme nodes of downstream of lateral canals have been input to the DUFLOW.

Calculation definition The period of computation has been taken as 6 months with the start of output one month later than start of computation so as to dampen irregular waves of initial flow through network. The time step of flow computation over the period is input as 1 second, with time step of flow output (or result) at an interval of 1 second.

Sensitivity analysis With lack of observed values of discharge and water levels; calibration and validation of the model is difficult. As these two processes needs two sets of measured discharge and water surface elevation at various locations along the canal to make comparison with the simulated results. Sensitivity analysis carried out for the model by choosing Manning’s roughness coefficient “n”, the results showed that the model is not sensitive for this coefficient as by increasing and decreasing this value, the water level in the canal does not change significantly.

Ruaa K. Hamdan 71 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

5.3 CROPWAT program

CROPWAT for Windows is a program that uses the FAO (1992) Penman-Monteith methods for calculating reference crop evapotranspiration. These estimates are used in crop water requirements and irrigation scheduling calculations. The methods supersede the older FAO 24 procedures published in 1977 which are no longer recommended as they over estimate evapotranspiration (Derek Clarke, 1998).

CROPWAT is a computer program for irrigation planning and management, it is a decision support system developed by the Land and Water Development Division of FAO for planning and management of irrigation, the manipulating screen is presented in Figure 5-1. The main functions of the program are: • To calculate reference evapotranspiration, crop water requirements and crop irrigation requirements; • To develop irrigation schedules under various management conditions and scheme water supply; • To evaluate rain fed production and drought effects and efficiency of irrigation practices.

Figure 5-1: Main data manipulation screen at CROPWAT program

Procedures for calculation of the crop water requirements and irrigation requirements are based on methodologies presented in FAO Irrigation and Drainage Papers No. 24 "Crop water requirements" and No. 33 "Yield response to water”. The development of irrigation schedules and evaluation of rain fed and irrigation practices are based on a daily soil-water balance using various options for water supply and irrigation management conditions.

Ruaa K. Hamdan 72 Chapter-5 Computer models

CROPWAT uses the same FAO (1992) Penman-Montieth method for calculating the reference crop evapotranspiration. These estimates are used in crop water requirements and irrigation scheduling calculations.

5.3 .1 Input

Calculations of the crop water requirements and irrigation requirements are carried out with inputs of climatic, crop and soil data. For crop water requirements (CWR) estimation, Reference Crop Evapotranspiration (Eto) values measured or calculated using the FAO Penman-Montieth equation based on the following climatic data: minimum and maximum air temperature, relative humidity, sunshine duration, wind speed, and Rainfall data, in addition to, the cropping pattern, which consist of the planting date, crop coefficient, root depth, depletion fraction and the area planted; a set of typical crop coefficient data files are provided in the program.

For irrigation scheduling the required data are soil type, scheduling criteria (several options available regarding the calculation of application timing and application depth.

5.3 .2 Output

Once all the data is entered, CROPWAT automatically calculates the results as tables or plotted in graphs. The time step of the results can be any convenient time step: daily, weekly, decade or monthly. The output parameters for each crop in the cropping pattern are: - Reference crop evapotranspiration Eto (mm/period); - Crop Kc - average values of crop coefficient for each time step; - Effective rain (mm/period); - Crop water requirements CWR (mm/period); - Irrigation requirements IWR (mm/period); - Total available moisture TAM (mm); - Readily available moisture RAM (mm); - Actual crop evapotranspiration Etc (mm); - Ratio of actual crop evapotranspiration to the maximum crop evapotranspiration Etc/Etm (%); - Daily soil moisture deficit (mm); - Irrigation interval (days) and irrigation depth applied (mm);

Ruaa K. Hamdan 73 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

- Lost irrigation (mm); - Estimated yields reduction due to crop stress (when Etc/Etm falls below 100%).

5.3 .2 Calculation methods

The values of decade or monthly Reference Crop Evapotranspiration (Eto) are converted into daily values using four distribution models (the default is a polynomial curve fitting). The model calculates the Crop Water Requirements using the equation: Etc = Eto*Kc CWR=Eto*Kc*area planted.

The average values of crop coefficient for each time step are estimated by linear interpolation between the Kc values for each crop development stage. The “Crop Kc” values are calculated as Kc*Crop Area, so if the crop covers only 50% of the area, the “Crop Kc” values will be half of the Kc values in the crop coefficient data file.

For crop water requirements and scheduling purposes, the monthly total rainfall has to be distributed into equivalent daily values. The program has available four Effective Rainfall methods (the USDA SCS method is the default). The Irrigation Scheduling option shows the status of the soil moisture every time new water enters the soil, either by rainfall or irrigation application. For the scheduling calculations two options can be selected:

Daily Soil Moisture Balance option shows the status of the soil moisture every day during the growing season.

User defined irrigation events and other adjustments to the daily soil moisture balance can be made when the Scheduling Criteria are set to “user-defined”.

Total Available Moisture (TAM) in the soil for the crop during the growing season is calculated as Field Capacity minus the Wilting Point times the current rooting depth of the crop. Readily Available Moisture (RAM) is part of the total available moisture, and it is calculated as TAM * P, where P is the depletion fraction, the calculated soil moisture deficit should not fall bellow the

Ruaa K. Hamdan 74 Chapter-5 Computer models readily available moisture. The manual explains the use of the program, and elaborate on calculation procedures and applications in irrigation planning and management.

5.4 Water flow and sediment transport theory in view of the SETRIC program

5.4 .1 Governing water flow equation

The computer program is based on sub-critical, quasi-steady uniform or non-uniform flow (gradually varied flow).

Continuity Equation (ignoring compressibility)

∂A ∂Q + = 0...... (5 − 9) ∂t ∂x

-Dynamic Equation (Prismoidal Channel)

∂h V ∂V 1 ∂V + + + S − S = 0...... (5 −10) ∂x g ∂x g ∂t f 0

To simplify the above equation, following assumptions can be made for irrigational canal without introducing appreciable error: • One dimensional flow along x-axis; • Horizontal level across the flow section; • Averaged velocity over the section; • Practically parallel and straight flow stream lines; • Quasi-steady water flow.

Based on above assumptions, simplified form of the equation is:

∂Q = 0...... (5 −11) ∂x and

Ruaa K. Hamdan 75 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

dh S0 − S f = 2 2 dx 1− F 2 Q T r and F = ...... (5 −12) r gA3

At points of confluences and/ or bifurcations:

Q ± ql = 0………………………………………………..…………….……….…… (5-13)

Where: A =Area of cross section (m2) g =Acceleration due to gravity (m/s2) h =Water depth (m) Q =Discharge of water (m3/s) t =Time co-ordinate (s) 3 ql =Inflow/outflow discharge (m /s)

S0 =Bottom slope

Sf =Energy line slope

Fr =Froude number

In SETRIC, water flow calculations for irrigation canals are based on a sub-critical, quasi-steady, uniform or non-uniform (gradually varied flow). Several methods are available to solve the dynamic equation of gradually varied flow for prismatic canals but Mendez uses predictor corrector for this model. The steps involved for this method are described underneath.

Calculations start from the boundary point. In sub-critical flow the boundary will be at the downstream end of the canal. Let the end point be xi as shown in Figure 5-2 compute the derivative (dh/dx) at point x = xi (S0, Sf1, and Fr12 are known).

dh (S0 - Sf ) ( ) = i dx i (1 - 2) Fr i …………………………………………………….……….…….. (5-14)

Calculate the water depth at point x = xi+1 with (dh/dx)i:

(hi+1)1 = hi + (dh/dx)i (xi+1 – xi)……………………………………………..….…(5-15)

Ruaa K. Hamdan 76 Chapter-5 Computer models

With the new water depth value ((hi+1) calculate (Sf)i+1, (Fr)i+1

Calculate the derivative at point x = xi+1:

dh (S0 - Sf )i + 1 ( )i + 1 = 2 ...... (5 −16) dx (1 - Fr )i +1

Calculate the mean derivative:

dh dh ( ) + ( ) dh i i+1 ( ) = dx dx ...... (5 −17) dx mean 2

Calculate the new value of hi+1 by:

dh h(i+1)2 = hi + ( ) (xx+1 - xi)...... (5 −18) dx mean

Check the accuracy of predicted value:

| - | ≤ e hh(i+1)1 (i+1)2 e = degree of accuracy desired

The procedure given above can be repeated if necessary, and may also be used for short sections of channels with changing width and shape (non-prismatic channels).

Hydraulic computation of a water surface profile in the canal is uncoupled with the computations of the structures. A specific hydraulic equation is required to calculate the water surface elevation at the upstream side of the structure. Water level at the upstream side of the structure will be used as downstream boundary condition for computing water profile in the upstream reach of the canal.

Ruaa K. Hamdan 77 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

Figure 5-2: Predictor corrector method for water flow

5.5 Governing sediment flow equation

5.5 .1 Continuity equation

A schematization of the mass balance equation for the total sediment transport in open canal is shown below.

From the mass balance, in each control volume, it can be found that for suspended load:

∂ h c ∂ q s s + s = c ()E - D ...... (5 −19) ∂ t ∂x a

For bed load:

∂z ∂ a c ∂ q ()1− p + b + b = - c ()E - D ...... (5 − 20) ∂t ∂x ∂x a

By summing both above equations, mass balance equation for the total sediment transport reads:

Ruaa K. Hamdan 78 Chapter-5 Computer models

∂z ∂ a c ∂ ()q + q ∂ h c ()1− p + b + s b + s s = 0...... (5 - 21) ∂t ∂x ∂x ∂t

Suspended load (qs , cs) hs

Bed load (qb , cb) a

dx E

Sediment Sediment Sediment Sediment inflow outflow inflow D outflow

E D Control volume Control volume bed load layer suspended load layer

Figure 5-3: Schematization of mass balance for total sediment transport

Expressing for the total cross section and for the steady sediment concentration, the equation becomes:

∂z ∂Q ()1− p B + s = 0...... (5 − 22) ∂t ∂x

The term (1-p) is sometimes called packing factor.

The term ∂Qs/∂x is called entrainment rate (E if θ ≥  θcr) or deposition rate (D) depending upon the flow condition and can be expressed as-

Ruaa K. Hamdan 79 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

∂Q Q ∂C Q ()C − C E or D = = = i+1 i ...... (5 - 23) ∂x s ∂x s Δx

The total entrainment and deposition rate is then:

Et = E Δx …………………….…………………………………………..………..…….… (5-24)

Dt = D Δx ……………………………………………………………………………….… (5-25)

-Friction factor and Sediment transport equation, which can be given as function of (Mendez)

C = f (d50, V, h, S0) ...………………………..…………………………....………....… (5-26) and

Qs = f (d50, V, h, S0)...... (5-27)

Where: A = Area of cross section (m2) C =Chezy’s coefficient (m1/2/s) d50 =Median diameter of sediment (m) h =Water depth (m) p =Porosity (sand porosity ≈ 0.4) Qs =Sediment discharge (m3/s) t =Time co-ordinate (s) V =Mean velocity (m/s) x =Length co-ordinate (m) z =Bottom level above datum (m) B = Bottom width (m) a,hs = Depth of the bed load layer and suspended load layer respectively (m) cs,cb = Suspended load and bed load concentration respectively (kg/m3) ca = Reference concentration at the boundary of the bed load layer z = Bottom level (m) qs,qb = Suspended load and bed load discharge per unit width (m2/s) E, D = Upward flux and downward flux respectively (m3/ms) Et,Dt = Total entrainment rate and total deposition rate respectively (m3/s) s = Relative density

Ruaa K. Hamdan 80 Chapter-5 Computer models

5.5.2 Bed forms

Bed forms are relief features, which results from the interaction of the flow and sediment, and are extremely complex. Theory developed by van Rijn behaves the best among others in irrigation canal (Mendez, 1998). The range described by van Rijn for the lower regime, which is expected in the irrigation canal, is shown in the following Table 5-1.

Table 5-0-1: Bed forms of van Rijn for lower regime

Particle Size Transport Regime 1 ≤ D* ≤ 10 D* > 10 Lower 0 ≤ T ≤ 3 Mini-Ripples Dunes 3 < T ≤ 10 Mega-Ripples Dunes 10 < T ≤ 15 Dunes Dunes

2 / ⎛ V ⎞ / τ = ρg⎜ ⎟ τ −τ 0 / T = 0 cr with ⎝ C ⎠ and ……………………………….……….. (5-28) τ cr

/ ⎛ 12h ⎞ C = 18log⎜ ⎟...... (5 − 29) ⎝ 3d90 ⎠

Where: T = Bed shear stress parameter V = Depth averaged velocity (m/s) τ/0 = Grain-related bed shear stress (N/m2) C/ = Grain-related Chezy-coefficient (m1/2/s)

In general, the prediction of the resistance to flow for a rigid boundary is done by assuming a flat bed and only skin friction (skin resistance). The bed forms, if they exists, have also influence on the flow resistance and that part is called form loss or form drag or form roughness. Thus the total shear stress can be expressed as:

τ = τ / +τ // 0 0 0 ………………………………………………………………………. (5-30)

Ruaa K. Hamdan 81 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

// 2 τ 0 = Bed form shear stress (N/m ) / 2 τ 0 = Skin friction shear stress (N/m )

The effect of bed form is particularly substantial with ripples and dunes. The bed-load transport / must be related to the effective bed shear stress (τ 0) and not to the form roughness and for

/ // suspended load to τ0 (τ 0 = τ 0 +τ 0 ) (Chanson, 2001).

Most of the existing predictors consider the bed form development on the resistance to flow implicitly, while some of them require explicitly the type and characteristics of the bed form.

5.5.3 Movable bed

In this case, flow conditions might change the roughness characteristics of the bed by developing bed forms. The development of the bed forms plays an important role in the hydraulic resistance of the flow. The best method among various other methods to determine the friction factor in irrigation canals on the bed as per van Rijn (van Rijn, 1984) is described below.

As per van Rijn (1993), the Chezy’s coefficient is calculated according to the type of flow regime as shown in the following Table 5-2.

Table 5-0-2: Type of hydraulic regime as per van Rijn

Type of Regime Classification Parameter u*ks/ν

Smooth u*ks/ν < 5

Transition 5 < u*ks/ν < 70

Rough u*ks/ν > 70

The flow regime types for no motion of sediment on the bottom (considered plane bed) are: smooth and transition and Chezy’s coefficient can be calculated by (van Rijn, 1993):

Ruaa K. Hamdan 82 Chapter-5 Computer models

⎛ ⎞ ⎜ ⎟ 12h C = 18 log ⎜ ⎟ Smooth flow regime………………………..…...…. (5-31) ⎜ ν ⎟ ⎜ 3.3 ⎟ ⎝ u* ⎠

⎛ ⎞ ⎜ ⎟ 12 h C = 18 log ⎜ ⎟ Transition flow regime………………..…. (5-32) ⎜ ν ⎟ ⎜ k sb + 3.3 ⎟ ⎝ u * ⎠

Once the sediment on the bottom of an irrigation canal comes into motion, the flow regime converts into rough one. This type of regime is most frequently found in irrigation canal for all practical ranges of sediment sizes (Mendez, 1998) and is given by the following equation as per van Rijn-

⎛ 12h ⎞ C = 18 log ⎜ ⎟ Rough flow regime…………………………. (5-33) ⎝ k sb ⎠ Where:

C = Chezy’s coefficient (m1/2/s) h = Water depth (m) ν = Kinematic viscosity (m2/s) u* = Shear velocity (m/s) / // ksb = Total equivalent roughness height (m) = ks + ks / ks = Equivalent height related to the grain (m) =3 d90 ≅ 4.5 d50 // ks = Equivalent height related to the bed form (m)

// For a plane bed with no motion, ks = 0 and according to van Rijn-

/ ksb = ks = 4.5 d50 ...... (5-34)

For mobile beds, according to van Rijn-

⎛ Δ ⎞ // ⎜ r ⎟ (For ripples)………………………… (5-35) k s = 20 *γ r * Δ r * ⎜ ⎟ ⎝ λr ⎠

Ruaa K. Hamdan 83 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

Δ ⎛⎞−25 d k1.1// = **γ Δ− *⎜⎟ 1e λd s dd⎜⎟ ⎝⎠ (For dunes)………………..…………... (5-36) Where:

γr = Ripple presence (γr =1 for ripples alone)

γd = Form factor (γd = 0.7 for field condition and 1.0 for laboratory conditions)

Δr = Ripple height (Δr =50 to 200 d50)

Δd = Dune height (m)

λr = Ripple length (λr = 500 to 1000 d50)

λd = Dune length (λd = 7.3 * h)

Ruaa K. Hamdan 84 Chapter-6 Simulations and evaluation of results

6 SIMULATIONS AND EVALUATION OF RESULTS

Based on the previous studies on CWR, and the water balance in the selected area, the undertaken project is Malwan Irrigation Scheme, Kurdistan to investigate and give alternatives for improving the system’s operational performance. The research focused on the application of computer modelling to guide the operation of the irrigation system within the frame work of existing institutional arrangements. DUFLOW unsteady hydraulic program is used for this purpose and the results obtained from this model is complied with respect to performance measures (adequacy, efficiency, and equity) at defined off takes of water delivery system of irrigation canal. These performance measures need comparison of actual supply and required demand. For calculating the required demand CROPWAT program is used which determines net irrigation requirement as will be explained in section 6.1. In contrast the actual supply can be determined by simulating flow with the existing operational performance of the main canal using DUFLOW program. The model can be used in two ways: • To check the preliminary design of Malwan Irrigation Scheme; • To simulate and analyze alternative operational scenarios to enhance system operational performance.

In the last decade, irrigation researchers have developed and applied computer tools to plan, schedule and monitor the operation of irrigation systems to improve their performance. Based on this reality the first stage of the operational improvement process consisted of a retrospective modelling analysis of the system to assess its operational performance. In this process, the monthly irrigation demand of the system is estimated using CROPWAT program for 34 year (1974- 2006), deepening on the water requirements for the selected crops to design Malwan Irrigation Scheme and check this design by DUFLOW program. The analysis is carried out for summer and winter cropping season during 2007 and crop information was collected on a seasonal basis by conducting farmers’ interviews to determine the proportion of different crops planted in each lateral off take and to determine the planting dates of each crop.

Ruaa K. Hamdan 85 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

6.1 Calculation of irrigation requirements

Net Irrigation Requirement This is the depth of water required at the location where the crops grow for meeting evapotranspiration minus contribution by precipitation. To avoid crop water stress, rainfall and irrigation must be sufficient to meet the crop's ET requirement. This means that for any period of time during the crop growing season, the net irrigation requirement (NIR) is the amount of water which is not effectively provided by rainfall:

NIR = ET − ERAIN...... (6 −1)

Where: NIR = Net irrigation requirement (mm/day) ET = Evapotranspiration (mm/day) E RAIN = Effective rainfall (mm/day)

E RAIN is that portion of rainfall which can be effectively used by a crop, that is, rain which is stored in the crop root zone. Therefore, E RAIN is less than total rainfall due to interception, runoff and deep percolation (or drainage) losses. NIR is irrigation water which is delivered to the field and available for the crop to use. This is primarily water which is stored in soil in the crop root zone, although some of the water which is evaporated from water, soil, and plant surfaces during application also effectively reduces climate demand.

"Crop water requirements" is defined as the total water needed for evapotranspiration, from planting to harvest for a given crop in a specific climate regime, when adequate soil water is maintained by rainfall and/or irrigation so that it does not limit plant growth and crop yield. Source "AQUASTAT Glossary". The irrigation requirement for crop production is the amount of water, in addition to rainfall, that must be applied to meet a crop's evapotranspiration needs without significant reduction in yield. Evapotranspiration (ET) includes water that is needed for both evaporation and transpiration. Evaporation is the change of water from liquid to vapour form. Evaporation occurs from all moist or wet surfaces, including soil, water, plant, and other surfaces. Transpiration is evaporation from plant leaves through small openings in the leaves called stomata.

Ruaa K. Hamdan 86 Chapter-6 Simulations and evaluation of results

Both evaporation and transpiration occur in response to climate demand. ET is greatest on hot, dry days and lowest on cool, humid days. ET must occur to avoid plant water stress. Plant water stress will occur if ET is limited because water is not available to plants. Water stress will occur quickest on high climate demand days. Water stress is avoided by rainfall or by irrigating to provide a crop with the water needed for evaporation and transpiration.

Calculations of crop water requirements and irrigation requirements are carried out with inputs of climatic and crop data into CROPWAT version 7.2; and the results are shown in Tables 6-1, 6-2, and Table 6-3.

Table 6-1: Irrigation requirement for winter crops in mm/day

Winter crops Wheat Potato Tobacco Months 1st Oct – 8th Feb 1st Feb - 11th Jun 1st Feb - 22nd May Jan 0.00 0 0 Feb 0.00 4.14 1.03 Mar 0.00 4.84 1.61 Apr 0.00 4 1.33 May 0.00 3.87 0.65 Jun 0.00 0 0 Jul 0.00 0 0 Aug 0.00 0 0 Sep 0.00 0 0 Oct 0.00 0 0 Nov 0.00 0 0 Dec 0.00 0 0

The irrigation requirement for the winter crops varies between (1-5) mm/day as shown in Table 6-1. That is because of the quite amount of rainfall in the period between October and May.

For the purpose of making a water balance or determination of the period of analysis, a comparison curve has been made between crop evapotranspiration and average rainfall from the results that have been gotten from the CROPWAT program, as shown in Figure 6-1.

Ruaa K. Hamdan 87 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

Table 6-2: Irrigation requirement for summer crops in mm/day

Summer Cotton Sunflower Small Barley Green Beans crops vegetable Months 1st Apr – 1st Apr- 1st Mar- 1st Jul- 1st March- 13th Oct 9th Aug 4th Jun 29th Oct 30th May Jan 0 0 0 0.00 0 Feb 0 0 1.03 0.00 0 Mar 0 0 1.61 0.00 1.29 Apr 1.33 4 1.33 0.00 1.33 May 5.16 7.74 0 0.00 0.97 Jun 6.67 6 0 0.00 0 Jul 5.16 3.87 0 0.00 0 Aug 6.45 0 0 0.00 0 Sep 5.33 0 0 0.00 0 Oct 3.87 0 0 0.00 0 Nov 0 0 0 0.00 0 Dec 0 0 0 0.00 0

250

200

150

100 mm

50

0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec -50

Average crop evaporation Average precipitation

Figure 6-1: Water balance curve between crop evaporation and average rainfall

From Figure 6-1, it is obvious that from beginning of May until one-third of October crop evaporation is higher than effective rainfall, so irrigation water need to be applied in order to meet crop’s evapotranspiration. This result emphasis on the farmer’s information that in most period on the year the main canal off take gates will be closed. So nearly six months have been selected for the purpose of analysis beginning from May and ends at November.

Ruaa K. Hamdan 88 Chapter-6 Simulations and evaluation of results

Cropping schedule The following cropping pattern is used for the simulation of the main canal of Malwan Irrigation Scheme with total irrigated area about 750 ha. Information about Type of crops, date of planting of each type, as well as percent of land grown per each crop are obtained by interviewing with farmers and managers, more detail shown in Figure 6-2 and Table 6-3.

Table 6-3: Cropping pattern and its calendar of Malwan Irrigation Scheme

Ruaa K. Hamdan 89 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

20 20

20 15

10 15 30 25

Cotton Sunflower Small vegetables Wheat Barley Potato Tobacco Beans

Figure 6-2: Cropping pattern and percentage of total grown area for each crop

Gross Irrigation Requirement

Some water is lost while transporting it from its source to the crop root zone. Losses occur due to such causes as leakage from pipelines, seepage and evaporation from open channels, and evaporation from droplets sprayed through the air. Because of these losses, more water must be pumped than that required to be stored in the crop root zone. The gross irrigation requirement (GIR) is the amount that must be pumped. GIR is greater than NIR by a factor which depends on the irrigation efficiency (Ea):

GIR = NIR / Ea...... (6 − 2)

GIR = Gross irrigation requirement (mm/day) NIR = Net irrigation requirement (mm/day) Ea = Application efficiency (decimal fraction)

From the above definition, a crop's irrigation requirement does not include water applied for leaching of salts, freeze protection, crop cooling, or other purposes, even though water for these purposes is required for crop production and is applied through an irrigation system. Total crop water requirements would be determined by adding water needed for these uses to the irrigation requirement calculated from equation (6-1).

Ruaa K. Hamdan 90 Chapter-6 Simulations and evaluation of results

From Equation (6-1), the irrigation requirement may be calculated for any time period; however, for water (consumptive) use permitting purposes, it is normally calculated for monthly and seasonal or annual time periods.

Tertiary Turnout Requirement The Tertiary Turn out Requirement is the net irrigation requirement plus all the water losses downstream of the tertiary off take; from here onto the place where the crops grow (Depeweg, 1997). This amount of water required at the unit’s off takes in the system.

TTR= GIR/Ed …………………………………………….………………….…...... … (6-3)

Where: TTR = Tertiary Turnout Requirement (mm/day) GIS = Gross Irrigation Requirement (mm/day) Ed = Distribution Efficiency

Scheme irrigation requirement The Scheme irrigation requirement is the tertiary turnout requirement plus all the water losses upstream of the off takes up to the headwork. The assumed irrigation efficiencies are shown in Table 6-8.

SIS = TTR/Ec ……………………………………………………………...………… (6-4)

Where: SIS = Scheme Irrigation Supply (mm/day) TTR = Tertiary Turnout Requirement (mm/day) Ec = Conveyance efficiency

For the purpose of calculating irrigation requirement at lateral off takes irrigation (application, distribution, conveyance) efficiencies should be taken into account for including the losses which can occur because of evaporation or leakage or both, this shown clearly in Table 6-4.

Ruaa K. Hamdan 91 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

Table 6-4: Assumed irrigation efficiencies in Malwan Irrigation Scheme

Item Efficiency % Remarks Ratio of the volume of water needed (and made Application available) for the crops in the field for 75 Efficiency evapotranspiration and the volume of water supplied from the field inlet (feeder canals). Ratio of the volume of water reaching the field Distribution inlet and the volume of water taken from the 85 efficiency distribution system at the off take/turnout (main feeder canals in the units). Ratio of the volume of water reaching the unit Conveyance 75 turnout and the volume of water diverted from efficiency the headwork (branch and main canals). Ratio of the volume of water needed (and made available) for evapotranspiration by crops in Overall irrigation the field and the volume of water diverted from 60 efficiency the headworks. This efficiency is estimated and assumed for this study according to the previous studies of similar schemes.

6.2 Modelling of alternative operational scenarios

DUFLOW gives regional water manager a quality tool for modelling irrigation systems, drainage systems and natural streams in low lands. The application can be typically related to optimizing agriculture production through the water quantity control, such as automation of irrigation canal, flood control, reservoir operation, and the water quality, except sediment, control. DUFLOW offers the support, which is needed for effective planning, design and operation of new and existing water system.

In topic one the crop water requirement determined by using CROPWAT program under different situation and depending on these requirements of the selected crops the preliminary design is done and checked with DUFLOW program.

In topic two, the cross sectional dimensions which determined from the preliminary design in topic one are improved by DUFLOW program, to get the final dimensions (bed width, water depth) for the main and secondary canals in Malwan Irrigation Scheme.

Ruaa K. Hamdan 92 Chapter-6 Simulations and evaluation of results

The schematization of the DUFLOW program is presented in Figure 6-3 and the bed elevation of the main canal varies from 519.4+MSL to 514.4+MSL at the front of the canal.

Further more in topic three the sediment deposition in the main canal of Malwan Irrigation Scheme is checked with SETRIC program Executing these alternative scenarios during irrigation season needs discussions to be carried out with farmers’ groups about the implications of the various operational options for changing the operational rules of the system in order to achieve the performance improvement goals.

6.2.1 Topic 1

This topic has been modelled in three parts with CROPWAT program, to determine the crop water requirement for the selected crops (Cotton, Sunflower, Small vegetables, Wheat, Barley, Potato, Tobacco, Beans)

Scenario one: In scenario one of Topic one crop water requirement was computed for (Cotton, Sunflower, Small vegetables, Wheat, Barley) only, without deficit condition, the peak discharge is 0.22m3/s and the result is shown in Table 6-5 below.

Ruaa K. Hamdan 93 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

Table 6-5: Crop water requirement without deficit condition in m3/s

Crops Cotton Sunflower Small Spring Barley vegetables wheat

1st Apr – 1st Apr- 1st Mar- 1st Oct – 1st Jul- Total Months 13th Oct 9th Aug 4th Jun 8th Feb 29th Oct (m3/s)

Jan 0.00 0.00 0.00 0.00 0.00 0.00 Feb 0.00 0.00 0.02 0.00 0.00 0.02 Mar 0.00 0.00 0.00 0.00 0.00 0.00 Apr 0.11 0.04 0.00 0.00 0.00 0.15 May 0.14 0.08 0.00 0.00 0.00 0.22 Jun 0.14 0.08 0.00 0.00 0.00 0.21 Jul 0.07 0.00 0.00 0.00 0.00 0.07 Aug 0.00 0.00 0.00 0.00 0.00 0.00 Sep 0.00 0.00 0.00 0.00 0.00 0.00 Oct 0.00 0.00 0.00 0.00 0.00 0.00 Nov 0.00 0.00 0.00 0.00 0.00 0.00 Dec 0.00 0.00 0.00 0.00 0.00 0.00 Qp (m3/s) 0.22

Scenario two: In the second scenario; the crop water requirement is also computed for the same crops in the 1st scenario, but under deficit condition, therefore the peak discharge in this case is 0.19 m3/s, the result shown in Table 6-6 below:

Ruaa K. Hamdan 94 Chapter-6 Simulations and evaluation of results

Table 6-6: Crop water requirement under deficit condition in m3/s

Crops Cotton Sunflower Small Spring Barley vegetables wheat Months 1st Apr – 1st Apr- 1st Mar- 1st Oct – 1st Jul- Total 13th Oct 9th Aug 4th Jun 8th Feb 29th Oct (m3/s) Jan 0.00 0.00 0.00 0.00 0.00 0.00 Feb 0.00 0.00 0.01 0.00 0.00 0.01 Mar 0.00 0.00 0.01 0.00 0.00 0.01 Apr 0.02 0.05 0.01 0.00 0.00 0.09 May 0.09 0.10 0.00 0.00 0.00 0.19 Jun 0.12 0.00 0.00 0.00 0.00 0.12 Jul 0.09 0.05 0.00 0.00 0.00 0.14 Aug 0.11 0.00 0.00 0.00 0.00 0.11 Sep 0.09 0.00 0.00 0.00 0.00 0.09 Oct 0.07 0.00 0.00 0.00 0.00 0.07 Nov 0.00 0.00 0.00 0.00 0.00 0.00 Dec 0.00 0.00 0.00 0.00 0.00 0.00 Qp (m3/s) 0.19

Scenario three: The last scenario in crop water requirement computation there are three suggestion crops (Potato, Tobacco and Beans these crops will plant in Malwan Irrigation Scheme after the harvesting of Wheat and Barley crops, to get more benefits from the irrigated land, the peak discharge will increase a little bit (0.27 m3/s) higher than scenario one but with more incomes to the farmers. The result is shown in Table 6-7 below:

Ruaa K. Hamdan 95 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

Table 6-7: Crop water requirement with new suggested crops in m3/s

Crops Cotton Sunflower Small Potato Green Tobacco vegetables Beans Months 1st Apr – 1st Apr- 1st Mar- 1st Feb – 1stMarch- 1st Feb – Total 13th Oct 9th Aug 4th Jun 11th June 30th may 22nd May (m3/s) Jan 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Feb 0.00 0.00 0.01 0.05 0.00 0.02 0.08 Mar 0.00 0.00 0.01 0.06 0.02 0.03 0.13 Apr 0.02 0.05 0.01 0.05 0.02 0.02 0.19 May 0.09 0.10 0.00 0.05 0.02 0.01 0.27 Jun 0.12 0.08 0.00 0.00 0.00 0.00 0.19 Jul 0.09 0.05 0.00 0.00 0.00 0.00 0.14 Aug 0.11 0.00 0.00 0.00 0.00 0.00 0.11 Sep 0.09 0.00 0.00 0.00 0.00 0.00 0.09 Oct 0.07 0.00 0.00 0.00 0.00 0.00 0.07 Nov 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Dec 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Qp 0.27 (m3/s)

6.2.2 Topic 2

This topic modelled with DUFLOW program, the cross sections of the main and secondary canals which was computed in the preliminary design is improved by DUFLOW program, comparison has been done between the peak discharges obtained from Topic 1 (CROPWAT program) and the discharges determined by DUFLOW program, in order to get sufficient design for the main and secondary canals in Malwan Irrigation Scheme. The schematization of Malwan Irrigation Scheme is shown in Figure 6-3.

Ruaa K. Hamdan 96 Chapter-6 Simulations and evaluation of results

Secondary canal

The main canal

Figure 6-3: Schematization of Malwan Irrigation Scheme in the DUFLOW program

For the main canal in Malwan Irrigation Scheme the discharge, water level and the velocity (2.7 m3/s, 524 m + MSL, 1.3 m/s) respectively are shown in Figures 6-5, 6-6; with the cross section dimensions (1.3*1) m, Figure 6-4.

Figure 6-4: Cross section dimensions of the main canal

Ruaa K. Hamdan 97 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

Figure 6-5: Discharge in the main canal of Malwan Irrigation Scheme

Figure 6-6: Water level and velocity in the main canal of Malwan Irrigation Scheme

The discharge and water level of the 1st secondary canal are 0.085 m3/s, 520m respectively and cross section dimensions 0.5*0.7m shown in Figures 6-7, 6-8, 6-9.

Ruaa K. Hamdan 98 Chapter-6 Simulations and evaluation of results

Figure 6-7: Cross section dimensions of the 1st secondary canal

Figure 6-8: Discharge in the 1st secondary canal of Malwan Irrigation Scheme

Figure 6-9: Water level in the 1st secondary canal of Malwan Irrigation Scheme

Ruaa K. Hamdan 99 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

For the second secondary canal the values of the discharge, water level and the velocity 0.136 m3/s, 507.5, 0.55 m/s respectively and cross section dimensions 0.7*1 m, shown in Figures 6-10, 6-11,6-12.

Figure 6-10: Cross section dimensions of the 2nd secondary canal

Figure 6-11: Discharge in the 2nd secondary canal of Malwan Irrigation Scheme

Figure 6-12: Water level in the 2nd secondary canal of Malwan Irrigation Scheme

Ruaa K. Hamdan 100 Chapter-6 Simulations and evaluation of results

The cross section dimensions for the last third secondary are 0.5*0.7 m, Figure 6-13, these dimensions were improved by DUFLOW program depending on the crop water requirement of the selected crops in Malwan Irrigation Scheme. The discharge, water level and the velocity values are(0.131 m3/s, 507 m, 0.55 m/s) respectively, shown in Figures 6-14 and 6-15.

Figure 6-13: Cross section dimensions of the 3rd secondary canal

Figure 6-14: Discharge in the 3rd secondary canal of Malwan Irrigation Scheme

Ruaa K. Hamdan 101 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

Figure 6-15: Water level in the 3rd secondary canal of Malwan Irrigation Scheme

6.2.3 Topic 3

Part A: This part of the third topic has been modelled with SETRIC program, it is observed in the simulation result at the end of the simulation period that there is deposition before each weir, the deposition quantity around 5 cm for a period of 6 months, in a realistic situation in Iraq the maintenance of the main canals in a such an irrigation schemes is yearly. So the deposition in the main canal of Malwan Irrigation Scheme will be 10 cm just before each weir without any erosion situation, to prevent the sediment deposition which may block the main canal later by using a scouring sluice, shown in Figure 6-18.

It is seen that the actual concentration increased towards each weir. This may be due to the scouring at the head reach. The result of the sediment concentration is shown in Figure 6-16 and the change in bed level due to sedimentation has been shown in Figure 6-17. The water depth, water level and sediment volume tables have been shown in Appendix 6.

Ruaa K. Hamdan 102 Chapter-6 Simulations and evaluation of results

Figure 6-16: Sediment concentration in the main canal of Malwan Irrigation Scheme

Figure 6-17: Change in bed level in the main canal of Malwan Irrigation Scheme

Ruaa K. Hamdan 103 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

Figure 6-18: Scouring sluice

In this context the modelling of sediment transport in this canal is very useful in predicting the quantity of sediment deposition and scouring and also to assess the effectiveness of the installations of sediment removal.

Based on field observation the canal system seems not much affected by the side vegetation. Therefore the type of maintenance chosen for simulation was decided well maintenance with all weed factors and parameters as default value as shown in Table 6-8.

Ruaa K. Hamdan 104 Chapter-6 Simulations and evaluation of results

Table 6-8: Input parameters for the SETRIC program

Parameters Value

Growing time of weeds for maximum obstruction (days) 90 Periodic maintenance interval (days) 45 Weed factor for 0 to 5 % obstruction, fwmax 1 Weed factor just before the periodic maintenance, fwtx 0.7 Kinematic viscosity of water, ν (m2/s) 1* 10-6 Acceleration due to gravity, g (m/s2) 9.81 Sediment division ratio at off-takes, fd 1 ( no change of concentration) Density of water, ρ (kg/m3) 1000 Specific gravity of sediment particle, s 2.65 Porosity of the sediment deposition 0.4 Modelling condition Field Minimum roughness height in the bed (mm) 10

The piece of information that is usually not available, mainly because it is more difficult to measure in the field is the actual roughness of the canals. The common practice is to assume the values of the roughness of the canals based on experience or as recommended in standard texts and then refine the assumptions if possible, e.g. by model calibration. In this simulation the Chezy’s coefficient was taken 40 as an initial assumption.

Part B: In the second part of topic 3 the over turning and sliding of the main canal wall has been checked under wet and dry conditions based on the stability equations by using Bishop method to be sure that the design has a good factor of safety.

Mf F.S = M

Ruaa K. Hamdan 105 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

Mf = resisting moments M = driving moments

The most critical situation is under dry condition in this case the factor of safety is 1.52, so the design is quite safe, the cross section of the main canal wall of Malwan Irrigation Scheme under dry condition shown in Figure 6-19. For more details see Appendix 4.

0.5m

0.1m W3

0.60m W2 W4

0.3m 0.90m W1 0.60m F=8.1Kn

A P=1.8T/m 0.5m

Cross Section of canal wall

Figure 6-19: The cross section of the main canal wall of Malwan Irrigation Scheme

6.3 Design criteria for performance

In order to achieve the objectives of the Malwan Irrigation Scheme, the design has been checked with some performance indicators namely Adequacy, Efficiency and Equity. These indicators show that the amount of actual water supply as designed was higher than the water requirement for the selected crops, according to the range of the indicators shown in Table 4-1. Both the adequacy and efficiency of Malwan irrigation system are good. While the spatial coefficient of variation CVR (QD/QI) was calculated as 20%, hence by the performance criteria on Equity is

Ruaa K. Hamdan 106 Chapter-6 Simulations and evaluation of results fair. Thus the combination of above makes operational performance of Malwan Irrigation project apparently better.

Ruaa K. Hamdan 107

Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

7 CONCLUSIONS AND RECOMMENDATIONS

This study mainly focused on the design of an irrigation scheme. The following conclusions and recommendations for improvement of the water delivery irrigation system are summarized.

CROPWAT program: • In Topic 1 in scenarios one and two five different crops were already selected (Cotton, Sunflower, Wheat, Barley and Small vegetables) according to the market of these crops in the area. Under two conditions without deficit and deficit, the maximum value of the determined peak discharge is 0.22 m3/s; • In topic one In scenario three a new suggestion with respect to the cropping pattern and the irrigation scheduling has been made, so instead of planting five crops it will be eight different crops (Potato, Tobacco and Beans) will be added to the previous scenarios. These new crops will be planted after the harvesting of Wheat and Barley in the same tertiary unit, the peak discharge in this case will be a bit higher than the previous value 0.27 m3/s, but with a higher income to the farmers from an economic point of view.

Hydraulic programs DUFLOW and SETRIC: • Support to the design is estimated by the DUFLOW program in the second topic. It also gives a possibility to check the operation and maintenance of such irrigation schemes; • The analysis with the programs define: - whether a structure is required or not, if so it’s type and operation, in order to get the required water levels or to reduce/avoid sediment deposition during the lifetime of the system; - a suitable water allocation system and an appropriate frequency for the maintenance works along the canal; • the link between the hydraulic design and the different programs for hydraulic and sediment transport modelling is a powerful element of analysis, because it combines two different approaches to solve the same problem: the steady and unsteady flow types in irrigation canals; • the morphological performance of Malwan Irrigation Scheme has been checked with SETRIC program;

Ruaa K. Hamdan 108 Chapter-7 Conclusions and recommendations

• in the simulation with SETRIC, the hydraulic design with “sediment control” option, shown to be appropriate. The incoming sediment load was transported through the whole canal system achieving the objective of the design; • the results obtained with both programs are satisfactory; • Adequacy, efficiency and equity criteria were checked against the design performance for Malwan Irrigation Scheme show a proper result.

The most important recommendations for the improvement of the design of Malwan Irrigation Scheme are: • scenario three from Topic 1 is preferable for getting more chances to develop the cropping pattern as well as the benefits and the incomes of the farmers; • a better data collection from the area which lead to more optimal cropping calendar by knowing the surplus and the shortage seasons; • an unsteady flow model should be implemented to the scheme in order to support decision- making process for improving operation and management of the irrigation system. Short course for a number of engineers of Malwan Irrigation Branch should be carried out in order to understand the software and to develop operating rules for all schemes; • the DULOW program needs to be modified for irrigation networks and more types of control structures needs to be added to the program in order to make the schematization simple; • further study is necessary to validate the boundary conditions of erosion and deposition calculated in the model. Here an empirical formula has been used for the calculation of deposition and erosion; • SETRIC program can simulate only one running of irrigation canal. Generally the long term behaviour of sedimentation in the canal should be observed. This program should be extended to the long term simulation. Also simulation for different flow control methods can be added at the same time; • SETRIC program is recommended for testing the behaviour of sediments in irrigation canal conditions; • from hydraulic point of view in order to have stable canal cross sections, rectangular cross sections are suggested. This suggestion should not be only for this particular scheme, but should also be valid generally in north of Iraq;

Ruaa K. Hamdan 109 Hydraulic design and performance assessment of Malwan Irrigation Scheme in North Iraq (Kurdistan Region)

• scouring sluice with a front opening is suggested as a good solution for the sediment deposition problem in the main canal of Malwan Irrigation Scheme; • Implementation of Malwan irrigation scheme should always be assessed with performance indicators to ensure optimal operations of the scheme.

Ruaa K. Hamdan 110

Ruaa K. Hamdan 111

REFRENCES

Abernethy, C.L., 1986, Performance measurement in canal water management: discussion. ODI- IWMI Irrigation Management Network Paper, No. 86/2d: Overseas Development Institute, London, UK.

Acharya, S.C., 2004, Performance Evaluation and Benchmarking in Two Hill Irrigation Schemes in Nepal, MSc Thesis (155), International Institute for Infrastructural, Hydraulic and Environmental Engineering (IHE ), Delft, the Netherlands.

Baltzer, R.A and Lai, C., 1968, Computer simulation of unsteady flows in waterways, ASCE Proc, J of Hydraul div, Vol 94, No hy 4, Pap 6048, PP 1083-1117.

Bhutta, M.N. and Velde, E. J.V.D., 1992, Equity of water distribution along secondary canals in Punjab, Pakistan, Irrigation and Drainage Systems 6: 161-177.

Bird, J.D., 1990, Introducing monitoring and evaluation into main system management a low investment approach, journal irrigation and drainage systems, Springer, the Netherlands, Overseas Development Unit, Hydraulics Research, Wallingford, UK.

Biswas, 1990, Statistical methods for irrigation system water delivery performance evaluation, www.springerlink.com/index/H46512X833W12252.pdf.

Bos, M.G. and Nugteren, J., 1990, on irrigation efficiencies. 4thedition: International Institute for Land Reclamation and Improvement, Wageningen, the Netherlands

Bottrall, A.F., 1995, Assessment of Different Irrigation Management Models in Vietnam, International Journal of water resources development, Volume 21, Issue 3 September 2005, pages 525 – 535.

Celik, I. and Rodi, W., 1988, Modelling Suspended Sediment Transport in Non Equilibrium Situations, Journal of Hydraulic Engineering, Vol. 114, No. 10, ASCE, New York, USA.

Ruaa K. Hamdan 112

Chakraborti, R., 2002, Structural basis of gating by the outer membrane transporter FecA. PMID: 11872840 [PubMed - indexed for MEDLINE], School of Molecular Biosciences, Washington State University, Pullman, USA.

Chambers, R., 1988, Managing Canal Irrigation: Practical Analysis from South Asia, books.google.com.

Clemmens, A.J. and Bos, M.G., 1990, Statistical methods for irrigation system water delivery performance evaluation, u.s. Water Conservation Lab, USDA/ARS, Phoenix, AZ 85040, USA; International Institute for Land Reclamation and Improvement (ILRI), 6700 AA, Wageningen, the Netherlands.

Clemmens, A.J; Holly, F.M.Jr., ASCE, and Schuurmans, W., 1993, Description and evaluation of program: DUFLOW, This paper is part of the Journal of Irrigation and Drainage Engineering, Vol. 119, No. 4, July/August, 1993.

Depeweg, H. and Bekheit, K.H., 1997, Evaluation of proposed mesqa improvements, Irrigation and Drainage Systems 11: 299–323, 1997 Kluwer Academic Publishers, Printed in the Netherlands, International Institute for Infrastructural, Hydraulic and Environmental Engineering (IHE), Delft, the Netherlands; Ministry of Public Works and Water Resources, Irrigation Department, Cairo, Egypt.

Ertsen, M., 2005, Irrigation design in the Netherlands East Indies: the Tjipoenegara system in West Java. In: Coopey R., Fahlbusch H., Hatcho N. and Jansky L. (eds) 2005 A History of Water Issues. Lessons to Learn. United Nations University, Tokyo, Japan, pp 133-150. Faculty of Agricultural and Applied Biological Sciences, Katholieke Universities Leuven, 3000 Leuven, Belgium, Department of Irrigation, University of Shiraz, Shiraz, Iran.

FAO, 1977, Crop water requirements, FAO Irrigation and Drainage Paper 24. FAO, Rome, Italy.

Food and Agriculture Organization (FAO), 1992, CROPWAT, a computer program for irrigation planning and management, Irrigation and Drainage Paper 46. Rome, Italy: FAO.

Ruaa K. Hamdan 113

Francis, M.R.H., Hinton, R.D. Makin, I.W., El Daw, A.K., Ali, Y.A.M. and O.E. Hamad, 1988, Minor canal management in the Gezira Irrigation Scheme, Sudan. Report OD 106, Hydraulics Research, Wallingford, UK.

Ghimire, P.K., 2003, Non-equilibrium Sediment Transport in Irrigation Canals, M. Sc. Thesis, IHE Delft, Delft, the Netherlands.

Grimble, R.J., 1999, Economic instruments for improving water use efficiency, theory and practice, agricultural Water Management 40 (1): 77–82.

Guo, Q and Jin, Y., 1999, Modelling Sediment Transport Using Depth-Averaged and Moment Equations, Journal of Hydraulic Engineering, Vol. 125, No. 12, ASCE, New York, USA.

Helfgott, 2002, evaluation of hydraulic performance of Chavimochic irrigation scheme in Peru, Msc study at IHE, Delft, the Netherlands.

IRRIGATION DESIGN STANDARDS, 1986, HEADWORKS, republic of Indonesia

Jahromi, S.S., Feyen, J. Wyseure, G. and Javan, M., 2000, Approach to the Evaluation of Undependable Delivery of Water in Irrigation Schemes, journal irrigation and drainage systems, Springer Netherlands, Institute for Land and Water Management, Belgium,

Kumar, M., Raghuwanshi, N.S., Singh, R., Wallender, W.W., 2002, Estimating evapotranspiration using artificial aeural artwork, journal of Irrigation and Drainage Engineering, 2002 - link.aip.org. Dept. of Agricultural and Food Engineering, Indian Institute of Technology, Kharagpur, India.

Malano, H.M., Boonlue, C. and Mcmahon; T.A., 1993, developing an improved operational strategy for the Thup-Salao irrigation system, Thailand, Irrigation and Drainage Systems 7: 205- 220.

Manz, D. H., 1990. “Systems analysis of irrigation conveyance systems.” Proceedings of International Symposium on Water Resource Systems, Dept. of Civil Engineering, University of Manitoba, Winnipeg, Canada, June 1990, pp. 388-400, 1990. “Irrigation and Drainage Research:

Ruaa K. Hamdan 114

A proposal for an internationally-supported program to enhance research on irrigation and drainage technology in developing countries,” Volume 1.

Manz, D.H., 1991, “Eastern Irrigation District water delivery management/operation improvement project.” Vol. I-B Proceedings of the Special Technical Session at the42nd EIC Meeting of the International Commission on Irrigation and Drainage, pp. 147-157, Beijing.

Martin B., Molden, D., Skutsch, J., 2000, Benchmarking Irrigation and Drainage System Performance, Position Paper, Working Group on Performance Indicators and Benchmarking.

Merrey, D.J.; Valera, A. and Dassenaike, L., 1994, does assessing performance make a difference? Results from a comparative study of three irrigation systems. Quarterly Journal of Irrigated Agriculture 33 (3):276_293.

Molden, J.D., Sakthivadivel, R., Christopher, Perry, J. and Charlotte de Fraiture, 1998, Indicators for comparing performance of irrigated agricultural systems, Research Report 20: International Water Management Institute, Colombo, Sri Lanka.

Murray-Rust, D.H. and Snellen, W.B., 1993. Irrigation system performance assessment and diagnosis. (Jointly published by IIMI, ILRI, IHE), international Irrigation Management Institute, Colombo, Sri Lanka.

Mendez, N.V., 1998, Sediment Transport in Irrigation Canals, PhD Thesis, Delft, the Netherlands.

Paudel, K.P., 2002, Evaluation of the Sediment Transport Model SETRIC for Irrigation Canals, M.Sc. Thesis, IHE, Delft, the Netherlands

Playán, E. and Mateos, L., 2004, Modernization and optimization of irrigation systems to increase water productivity, "New directions for a diverse planet". Proceedings of the 4th International Crop Science Congress, Brisbane, Australia. Published on CDROM. Web site www.cropscience.org.au

Ruaa K. Hamdan 115

Plusquellec, H., Burt, C. and Wolters, H.W., 1994. Modem water control in irrigation. World Bank Technical Paper No. 246.

Rao, P. S. 1993, Review of selected literature on indicators of irrigation performance.

Sakthivadivel, R., Charlotte, D.F.; Molden, D.J., Perry, C.; Kloezen, W., 1999, Indicators of Land and Water Productivity in Irrigated Agriculture, International Journal of Water Resources Development.

Schultz, B., 2001, Irrigation and drainage and flood protection in a rapidly changing world, International Institute for Infrastructural, Hydraulic and Environmental Engineering (IHE ), Delft, the Netherlands Directorate-General for Public Works and Water Management, Utrecht, the Netherlands. Irrig. and Drain. 50: 261–277 (2001) DOI: 10.1002/ird.35.

Schultz, B., Thatte, C.D., Labhsetwar, V.K., 2005, Irrigation and drainage main contributors to global food production, Irrig. And Drain. 54: 263–278 (2005), Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/ird.170.

Schuurmans, W., 1991, A model to study the hydraulic performance of controlled irrigation canals, Thesis, Delft, Netherlands.

Shahrokhnia, M.A. and Javan, M., 2005, Performance assessment of Doroodzan irrigation network by steady state hydraulic modelling, Research Center for Agriculture and Natural Resources of Fars Province; Irrigation Department, Shiraz, Shiraz, Iran,

Singh, R., Kroes, J.G., Van Dam J.C., Feddes, R.A., 2006, Distributed ecohydrological modelling to evaluate the performance of irrigation system in Sirsa district, India: I. Current water management and its productivity, Journal of Hydrology (2006) 329, 692–713, available at www.sciencedirect.com.

Smedema, L.K, Vlotman, W.F. and Rycroft, D.W., 2004, Modern land drainage. Planning, design and management of agricultural drainage systems. A.A. Balkema Publisher, London, UK.

Ruaa K. Hamdan 116

Simons, D.B. and Senturk, F, 1992, Sediment Transport Technology, Water Resources Publications, Colorado, USA

Tamrakar, J. K., 2004, providing the poor with secure access to land in the hills of Nepal, Director General, Department of Forests, Ministry of Forest and Soil Conservation, His Majesty’s Government of Nepal.

Van Rijn, L.C., 1993. Principles of Sediment Transportation in Rivers, Estuaries and Coastal Seas, Aqua Publications, Delft, the Netherlands

Vos, J., 2004, Understanding water delivery performance in a large-scale irrigation system in Peru, Department of Environmental Sciences, Irrigation and Water Engineering Group, Wageningen University and Research Centre, Wageningen, the Netherlands.

Weller, J.A., 1991, an evaluation of the Porac River irrigation system, journal of irrigation and drainage systems, Springer Netherlands.

Zimbelman, D.D., 1987, Planning, Operation, Rehabilitation and Automation of Irrigation Water Delivery Systems. Proceedings of a 1987 Symposium sponsored by the Irrigation and Drainage Division of the American Society of Civil Engineers and held in Portland, OR, ASCE, New York, USA.

Ruaa K. Hamdan 117

APPENDIXES

Ruaa K. Hamdan 118

Ruaa K. Hamdan 119

Ruaa K. Hamdan 120

Appendix 1: Average evaporation and precipitation(mm) Average evaporation (mm)

Months J F M A M J J A S O N D Total Average 1973 29 42 75 93 131 143 27 16 556 70 1974 35 71 140 163 216 625 125 1975 67 114 158 207 546 137 1976 24 47 122 172 236 214 184 131 1130 141 1977 136 184 328 361 267 171 1447 241 1978 53 92 152 155 452 113 1979 50 47 67 84 124 45 30 447 64 1980 41 48 77 85 106 70 34 21 482 60 1981 53 103 171 272 216 115 930 155 1982 50 67 105 148 250 124 744 124 1983 44 51 85 107 147 167 69 38 25 733 81 1984 20 55 142 243 186 50 696 116 1985 40 60 93 231 230 146 101 901 129 1986 23 40 81 155 241 184 724 121 1987 27 42 85 126 198 175 112 765 109 1988 16 37 101 179 206 539 108 1989 83 132 177 78 470 118 1990 74 101 48 19 242 61 1991 33 22 62 82 46 24 269 45 1992 28 36 56 64 73 42 25 18 342 43 1993 24 47 122 172 129 214 184 131 1023 128 1994 49 45 67 83 121 145 219 207 139 124 55 34 1288 107 1995 40 41 81 100 134 158 233 216 158 30 22 1213 110 1996 44 47 70 29 20 210 42 1997 48 128 145 321 107 1998 134 225 155 514 171

Ruaa K.Hamdan 121

1999 127 169 122 418 139 2000 158 216 198 146 718 180 2001 122 216 198 146 682 171 2002 162 155 64 381 127 2003 150 162 155 64 531 133 2004 228 265 186 679 226 2005 35 62 111 145 219 207 138 101 38 1056 117 2006 35 62 111 145 231 212 146 101 38 1081 120 NO.days 31 29 31 30 31 30 31 31 30 31 30 31 23155 681 Total 358 395 921 1475 2640 3093 4095 4028 3137 2125 659 229 Average 40 40 51 67 115 155 216 201 149 118 44 23

Average precipitation (mm)

Months J F M A M J J A S O N D Total Average 1973 118 100 113 91 32 0 0 0 0 31 64 84 632 53 1974 116 98 114 84 40 0 0 0 0 47 52 79 630 53 1975 114 106 112 92 36 0 0 0 0 28 54 90 631 53 1976 121 102 118 84 34 0 0 0 0 43 48 80 630 53 1977 102 88 96 80 28 0 0 0 0 41 47 96 577 48 1978 108 100 106 84 34 0 0 0 0 36 66 94 626 52 1979 114 96 115 78 36 0 0 0 0 48 68 90 646 54 1980 119 100 84 79 42 0 0 0 0 60 72 84 640 53 1981 120 102 118 90 58 0 0 0 0 67 78 96 729 61 1982 118 103 114 86 50 0 0 0 0 48 66 84 670 56 1983 112 100 94 84 40 0 0 0 0 36 54 69.6 588 49 1984 115 96 109 90 55 0 0 0 0 34 54 60 613 51 1985 108 100 91 72 28 0 0 0 0 30 48 64 540 45 1986 110 96 102 84 34 0 0 0 0 20 43 42 532 44 1987 118 101 116 91 40 0 0 0 0 28 60 72 625 52

Ruaa K. Hamdan 122

1988 112 100 118 60 34 0 0 0 0 17 72 48 559 47 1989 102 89 100 72 32 0 0 0 0 20 66 67 548 46 1990 108 96 116 85 40 0 0 0 0 36 48 72 601 50 1991 112 102 115 84 48 0 0 0 0 36 54 81.6 632 53 1992 112 100 118 92 58 0 0 0 0 48 66 94 686 57 1993 102 95 96 84 48 0 0 0 0 42 60 85 612 51 1994 84 78 91 77 30 0 0 0 0 12 50 84 506 42 1995 100 88 106 84 46 0 0 0 0 36 60 78 596 50 1996 119 103 102 101 53 0 0 0 0 58 90 96 721 60 1997 125 116 108 102 70 0 0 0 0 68 84 102 775 65 1998 96 92 95 86 42 0 0 0 0 59 89 84 643 54 1999 100 88 102 90 42 0 0 0 0 72 88 92 673 56 2000 112 96 104 85 52 0 0 0 0 85 94 107 734 61 2001 104 90 96 84 48 0 0 0 0 82 80 102 686 57 2002 128 110 124 109 44 0 0 0 0 102 113 120 850 71 2003 112 96 112 94 60 0 0 0 0 59 77 96 704 59 2004 112 98 108 84 65 0 0 0 0 56 74 100 697 58 2005 108 102 115 91 62 0 0 0 0 72 74 96 721 60 2006 106 100 108 86 68 0 0 0 0 60 82 97 707 59 NO.days 31 29 31 30 31 30 31 31 30 31 30 31 Average 111 98 107 86 45 0.00 0.00 0.00 0.00 48 67 85 646

Ruaa K.Hamdan 123

Appendix 2: Discharge of the suggested future reservoir in m3/year (1973- 2007) Annual discharges of Qara ali reservoir

Number Year Discharge (m3/y) *106 1 1973 273 2 1974 262 3 1975 250 4 1976 248 5 1977 241 6 1978 228 7 1979 209 8 1980 202 9 1981 201 10 1982 199 11 1983 195 12 1984 190 13 1985 189 14 1986 188 15 1987 188 16 1988 187 17 1989 178 18 1990 176 19 1991 174 20 1992 163 21 1993 160 22 1994 159 23 1995 159 24 1996 156 25 1997 154 26 1998 152 27 1999 152 28 2000 148 29 2001 143 30 2002 135 31 2003 130 32 2004 118 33 2005 118 34 2006 112 35 2007 86

Ruaa K. Hamdan 124

Appendix 3: Checking the over turning and sliding of the canal wall

2 2 2 Ka = 1.0 γ = 20 Kn/m γc = 24 Kn/m γw = 10 Kn/m Taking moment about point A

Case 1: Dry condition

W = ρ * g * h = γ * A

W1= 0.5*0.6*24 = 7.2 Kn 0.5m M1 = 0.72*0.25 = 1.8 Kn.m 0.1m W3

W2 = 0.4*0.6*24 = 5.76 Kn 0.60m W2 W4 M2 = 0.576*0.20 = 1.2 Kn.m 0.3m 0.90m 0.60m W1 W3 = 0.1*0.5*24 = 1.2 Kn F=8.1Kn M = 0.12*0.20 = 0. 24 Kn.m 3 A

P=1.8T/m W4 = 0.4*0.1*20 = 0. 8 Kn M4 = 0. 8*0.45 = 0. 4 Kn.m 0.5m

P = Ka*γ∗h = 1.0*20*0.90 = 18 Kn/m Cross Section of canal wall F1 = p*h/2=18*0.9/2=8.1 Kn M = 8.1*0.90/3 = 2.4 Kn.m Factor of safety against sliding (f.o.s) = Σ Mr/Σ Mo Σ Mr = 1.8+1.2+0. 24+0. 4 = 3.64 Kn.m 0.5m Σ Μο = 2.4 Kn.m W3 Σ Mr/Σ Mo = 3.64/2.4 = 1.52 > 1.5 o.k, Safe W2 W4

0.3m 0.90m W1 Case 2: Wet condition F1=8.1Kn

W = ρ * g * h A P=1.8T/m = γ * A 0.5m A = 1*10 =1.0 Kn/m F2 = A*h/2=10*1/2 =5 Kn Cross Section of canal wall M = 5*1/3= 1.66 Kn.m

Factor of safety against sliding (f.o.s) = Σ Mr/Σ Mo ΣMr = 1.8+1.2+0. 24+0. 4+ 0.166 = 5.3 Kn.m

Ruaa K. Hamdan 125

P = Ka*γ∗h = 1.0*20*0.90 = 18 Kn/m F1 = p*h/2 = 1.8*0.9/2 = 8.1 Kn M = 8.1*0.90/3 Kn = 2.4 Kn.m

ΣMo= 2.4 Kn.m

Σ Mr/Σ Mo = 5.3/2.4 = 2.2 > 1.5 o.k, Safe

Appendix 4: Checking the reinforcement required at the canal base

Ruaa K. Hamdan 126

Total load per m2 of canal base

Foundation = 0.25*2.4*2.4 = 1.44 T

Wall = 2*(0.5*0.6+0.4*0.6)*2.4 = 2.59 T Cover = 2*0.1*0.5*2.4 = 0.24 T Water = (1*1.0)*1.0 =1 T Total =5.27 T =51.4 KN q contact = 51.4 /2.4*1.0 =21.4 KN/m2

0.65m

Applied shear stress =21.4*0.50/1.0*0.25 =42.8 KN/m2 0.25m 1/2 Allowable shear stress =0.17φ(fc) = 0.17*0.65*(21)1/2 q cont=21.4 kN/m2 = 0.506Mpa Load on canal base

=506 KN/m2 >>42.8 KN/m2 very safe No Shear reinforcement required

Applied bending moment 21.4*0.50*(0.50/2) = 2.675 Kn.m

Applied tensile stress = M c/I = M (t/2)/(bt3/12) = M/(bt2/16) = 2.675*6/1*0.25 2 = 276 KN/m2

1/2 Ultimate tensile stress =φ*0.4*(fc) =0.65*0.4(21)1/2= 1.19MP =1190KN/m2>>276 KN/m2 No reinforcement required

Ruaa K. Hamdan 127

Appendix 5 :Result of SETRIC program

Sediment transport result (initial)

Y Actual Sediment X- Water Equilibrium Initial Bed Moderate actual concentration volume coordinate(m) level.(m) concentration(ppm) level.(m) Bed level.(m) (m) (ppm) (m3) 0 1 525 4125 750 524 524 0 100 1 525 4125 750 524 524 0 200 1 525 4125 750 524 524 0 300 1 525 4125 750 523 523 0 400 1 524 4125 750 523 523 0 500 1 524 4125 750 523 523 0 600 1 524 4125 750 523 523 0 700 1 524 4125. 750 522 522 0 800 1 523 4125 750 522 522 0 900 1 523 4126 750 522 522 0 1000 1 523 4125 750 522 522 0 1100 1 523 4127 750 521 521 0 1200 1 522 4128 750 521 521 0 1300 1 522 4131 750 521 521 0 3540 1 516 3765 750 515 515 0 3550 1 516 3740 750 515 515 0 3550 1 515 4190 750 514 514 0 3650 1 515 4197 750 514 514 0 3750 1 515 42010 750 514 514 0 3850 1 514 4233 750 513 513 0 3950 1 514 4276 750 513 513 0 4050 1 514 4356 750 513 513 0 4150 1 514 4509 750 513 513 0 4150 1 514 3629 750 512 512 0 4160 1 514 3594 750 512 512 0 4160 1 513 4248 750 512 512 0 4260 1 513 4280 750 512 512 0

Ruaa K. Hamdan 128

Sediment transport result (final)

Y Actual Sediment X- Water Equilibrium Initial Bed Moderate actual concentration volume coordinate(m) level.(m) concentration(ppm) level.(m) Bed level.(m) (m) (ppm) (m3) 0 1 525 4126 750 524 524 0 100 1 525 4125 750 524 524 0 200 1 525 4125 750 524 524 0 300 1 525 4125 750 523 523 0 400 1 524 4125 750 523 523 0 500 1 524 4125 750 523 523 0 600 1 524 4125 750 523 523 0 700 1 524 4125 750 522 522 0 800 1 523 4125 750 522 522 0 900 1 523 4126 750 522 522 0 1000 1 524 4125 750 522 522 0 1100 1 523 4127 750 522 521 0 1200 1 522 4128 750 521 521 0 1300 1 522 4131 750 521 521 0 1400 1 522 4136 750 521 521 0 3440 1 516 4444 750 520 520 0 3540 1 516 3765 750 515 515 0 3550 1 516 3740 750 516 515 0 3550 1 515 4190 750 514 514 0 3650 1 515 4197 750 514 514 0 3750 1 515 42010 750 514 514 0 3850 1 514 4233 750 513 513 0 3950 1 514 4276 750 513 513 0 4050 1 514 4356 750 513 513 0 4150 1 514 4509 750 513 513 0 4150 1 514 3629 750 512 512 0 4160 1 514 3594 750 512 512 0 4160 1 513 4248 750 512 512 0 4260 1 513 4280 750 512 512 0

Ruaa K. Hamdan 129