Fll.(B) TD201.P8 P45n.118 1983 REPUBLIC OF THE PHILIPPINES NATIONAL WATER RESOURCES COUNCIL 8th FLOOR, NIA BLOG .. E. DELOS SANTOS AVENUE, 0. C.
JESUS S. HIPOLITO, Chairman Minister Ministry of Public Works and Highways
MADAME I MELDA ROMUALDEZ-MARCOS TEODORO 0. PENA Minister Minister Human Settlements Ministry of Natural Resources
ARTURO R. TANCO, JR. VICENTE VALDEPENAS Minister Minister Ministry of Agriculture National Economic and Development Authority
GERONIMO Z. VELASCO ABER P. CANLAS Minister General Manager Ministry of Energy Metropolitan Waterworks and Sewerage System
GABRIEL P. ITCHON CESAR L. TECH President Administrator National Power Corporation National Irrigation Administration
FILE NO. sn, _rJ _,J~,f 4 SCANNED BY------ANGEL A. ALEJANDRINO Executive Director Q.A BY------ANA~BY------ EXTRACTED BY ---- UPLOADED BY-----
The National Water Resources Council (NWRC) is the body responsible for coordinating and integrating all activities related to water resources deve lopment and management. Its principal objective is to achieve a scientific and orderly development and management of all the water resources of the country consistent with the principles of optimum utilization, conservation and protect tion to meet present and future needs. ~(,.flf!C Lll:Ailll'luM:iih~ ~.:,L• !;'. .•,'. •.• 11' l!(ii, ~thvl0:3 DIVISIOil ICOlf;l'lc;' P~Ql'IOtlQ" M'l.Sflf.!ltH SOUTHERN MINDANAO PHl/77/S03 - UNITED NATIONS DEVELOPMENT PROGRAMME ASSISTANCE TO THE NATIONAL WATER RESOURCES COUNCIL f1 ., (.S,'
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I/lll/ll///lll /////l///ll///l//l ll/1 //ll////ll///lll ///// lll//ll/ - ST!-J 0-8638 REPUBLIC OF THE PHILIPPINES NATIONAL WATER RESOURCES COUNCIL REPORT NO. 24-11 B OECEMBER 1963 ... in cooperation with the REWARDS/MPW and NEDA S_CIENCE AND TECHNO · 0 · -~?GV TNFORMATION INSTITUf5 EPARrMENT O~ ::iC!l·.NCE AND TECHNOLOGY l r,, ""*"' .._,_, LIBRARY .... -a....:....
FOREWORD
The development and utilization of the country's water resources has evolved over a long period in a setting of abundant natural resources and practically without the benefit of a broad planning framework considering available resource supply and existing regional needs. With fixed water resources to serve the changing growth patterns and the increased use of water among a rapidly expanding population, the past trend of development should now be re-oriented to a broader perspective, if we are to avoid long-run water problems in the future.
Against this backdrop, the National Water Resources Council was created under Pres idential Decree 424 to carry out the policy of the government in encouraging the conserv ation, development and optimum utilization of water and related land resources on a comprehensive and coordinated basis in order to meet the present and future water needs of the country.
In pursuing its task, the Council undertakes comprehensive river basin and regional framework studies which serve as guides to detailed planning of water resources develop ment by concerned line agencies and help determine a reasonable starting point together with the factors and linkages which will have to be considered to make reasonably correct and meaningful decisions. The framework plan on Tagum-Libuganon Basins forms a part of the council's effort to establish the water and related land resources relationship on a basinwide approach for the framework study of Water Resource Region XI.
ANGEL A. ALE] ANDRINO Executive Director
v TABLE OF CONTENTS
PAGE
FOREWORD ...... v LIST OF TABLES ...... xiii LIST OF FIGURES...... xv CHAPTER I - SUMMARY ANO RECOMMENDATIONS ...... 1
A. General Characteristics ...... 1 B. Framework for Development ...... 3
B.1 Water Resources...... 3 B.2 Land Resources...... 4 B.3 Socio-Economic Aspects...... 4 B.4 Environmental Considerations...... 5
C. Sectoral Recommendations ...... 5 C.1 Water Supply and Sewerage...... 5 C.2 Irrigation...... 6 C.3 Flood Control...... 6 C.4 Land Use Management ...... 6 C.5 Power ...... 7 C.6 Fisheries ...... 7 C.7 Transportation ...... 7
CHAPTER II - INTRODUCTION'...... ·· .. ····· 9
A. Background ...... 9 B. Objective of the Study 9 c. Scope of the Study .. 9
CHAPTER Ill -OBJECTIVES OF DEVELOPMENT...... 11
A. Regional Development Objectives and Strategies...... 11 B. Development Objectives of the Basin ...... 11
CHAPTER IV - AREA PROFILE...... 13
A. Location and Description ...... 13 B. Archaeological, Historical and Cultural Characteristics...... 13 C. Settlement System ...... 13 D. Climate...... 13 D.1 Climate Type...... 13 D.2 Temperature and Humidity...... 17
vii CHAPTER V -WATER AND RELATED LAND RESOURCES ...... ···.:·· 19
A. Water Resources ...... · · · · · · · · · · · · · · · · · · · 19 A.1 Rainfall ...... · · · · · · · · · · · · · · · · · · 19 A.2 Surface Run-off ...... · . · · · · · · · · · · · · · · · · 20
A.2.1 Data Availability ...... · . · · · . . 20 A.2.2 Surface Water Availability...... 21 A.2.3 Dependability Analysis...... 21 A.2.4 Flood and Minimum Flow Frequency Analysis...... 21 A.2.5 Flood Control ...... 23
A.3 Groundwater ...... ······· 23
A.3.1 Data Availability...... 23 A.3.2 Groundwater Assessment ...... 36
A.4 Sedimentation and Water Quality...... 36 A.5 Evapotranspiration ...... 36
B. Land.. Resources...... 39
B.1 Topography and Drainage...... 39 B.2 Slope Complex ...... ·. · · ·.. 40 B.3 Geology...... 43 B.4 Soils and Capabilities...... 45
B.4.1 Soil Classification ...... 45 B.4.2 Land Capability...... 46
B.5 Soil Erosion Susceptibility ...... 47 B.6 Existing Land Use...... 47
B.6.1 Special Land Use ...... 48
B.6.1.1 National Parks/ Archaeological/ Recreational Sites...... 48 B.6.1.2: Forest Reserves ...... _ 48 B .6.2 Proposed Land Use ...... 48
CHAPTER VI PRESENT AND FUTURE DEVELOPMENT AND RESOURCE NEEDS ...... 57
A. Social Environment ...... 57 A.1 Demographic Characteristics...... 57 A.1.1 Population...... 57
viii A.1.2 Population Density ...... 57 A.1.3 Urban-Rural Population Structure...... 57 A.1.4 Age-Sex Structure, Dependency Ratio ...... 58 A.1.5 Household/Family Size...... 58 A.1.6 Demographic Projections...... 58
A.2 Income ...... 58
A.2.1 Income Levels...... 58 A.2.2 Per Capita Income...... 59 A.2.3 Income Profiles...... 60 A.2.4 Farm Income...... 60
A.3 Labor Force and Employment Structure...... 60
A.3.1 Labor Force...... 60 A.3.2 Employment...... 61 A.3.3 Employment Projections...... 62
A.4 Domestic and Municipal Water Use...... 62 A.5 Water Supply Facilities Sources...... 62
A.5.1 Water Supply Infrastructure ...... 63
A.6 Sewerage and Waste Disposal...... 64
B. Economic Sectors...... 65
B.1 General Economic Structure...... 65
B.1.1 Gross Domestic Product and Employment ...... 65 B.1.2 Sectoral Highlights ...... 67
B.1.2.1 Agriculture, Fishery, and Forestry ...... 67 B.1.2.2 Industry ...... 67 B.1.2.3 Services...... 69
B.2 Agriculture ...... 70
B.2.1 General ...... 70 B.2.2 Agricultural Area Distribution...... 70 B.2.3 Farm Features...... 70 B.2.4 Land Ownership and Distribution...... 70 B.2.5 Cropland Distribution...... 71 B.2.6 Production ...... 71
B.2.6.1 Temporary Crops ...... 71
ix Palay ...... · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 73 Corn ...... · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 75 Sugarcane ...... · · · · · · · · · · · 76 Tobacco ...... · · · · · · · · · · · · · · · · · · · · · · 77 Vegetables ...... · · · · · · · · · · · · · · · · · · 77 Rootcrops ...... · · . · · · · · · · · · · · · · · · · 77
B.2.6.2 Permanent Crops ...... ··········· 78
Coconut ...... · .. · · · · · · · · · · · · · · · 78 Fruits ...... · · · · · · · · · · 78 Coffee ...... ··········· 78 Abaca ...... · · · · · · · · · · · · · · · · · · · · 78
B.2.7 Irrigation ...... · · · · · · · · · · · · · · · · · · 79 B.2.8 Livestock and Poultry ...... ·.····· 80
B.2.8.1 Population ...... 80 B.2.8.2 Demand ...... 80
B.2.9 Agricultural Water Requirement ...... 81
B.3. Fisheries ...... 82 B.4 Industry ...... · ... · 82
B.4.1 Mining...... 83 B.4.2 Manufacturing...... 83 B.4.3 Construction and Electricity...... 86 B.4.4 Industrial Water Requirement...... 86
B.5 Transportation ...... 87
B.5.1 Highways and Road Transport ...... 87 B.5.2 Water Transport ...... 88 B.5.3 Air Transport ...... 89
B.6 Power ...... 90
B.6.1 Power Generation and Consumption ...... 90 B.6.2 Power Generating Facilities ...... 91
CHAPTER VII - WATER RESOURCE DEVELOPMENT FRAMEWORK ...... 97
A. Sectoral Indicators of Development ...... 97 A.1 Water Resources ...... 97
x A.1.1 Water Requirements ...... 97 A.1.2 Water Availability ...... 97
A.2 Land Resources...... 99 A.3 Agricultural Self-Sufficiency ...... 99 A.4 Social Indicators...... 100
A.4.1 Health...... 100 A.4.2 Education ...... 102 A.4.3 Income ...... 103
B. Project Profile...... 103
B.1 Potential Multi-Purpose Projects...... 103 8.2 Irrigation Projects...... 109 8.3 Water Supply Projects...... 109
B.3.1 Agency Proposals and Activities...... 109 B.3.2 Study Proposals ...... 109
B.4 Data Collection System...... 11 O
8.4.1 Water Resource Data...... 110
B.4.1.1 Rainfall Data...... 110 B.4.1.2 StreamflowData ...... 110 B.4.1.3 Evaporation and Other Climatic Data...... 110 B.4.1.4 Groundwater Data...... 111
B.4.2 Land Resources Data ...... _ ...... _.... 111
B.4.2.1 Land Capability...... 111 B.4.2.2 Soil Fertility ...... _...... 111
C. Development I mp act Evaluation...... 111
C.1 Socio-Economic Impact Evaluation ...... - ...... - . . . . 111
C.1.1 General ...... 112 C.1.2 Effects in Basin Incomes...... 112 C.1.3 Possible Effects on Income Inequality ...... - ..... - . . . . . 112 C.1.4 Spin-off Impact on Land Reform and Development ...... 112 C.1.5 Effects on Employment Generation in the Agricultural Sector ...... - .... - . . . 113
C.2 Environmental Impact Evaluation ...... - ...... 113
xi 114 C.2.1 Natural Vegetation and Wildlife ...... · · · · · · 115 C.2.2 Fisheries ~nd Water Quality ...... ··· 115 C.2.3 Soils ...... · · · · · · · · · · · · · · · · · · · · · · · · · · · · · C.2.4 Mineral Resources ...... · ..... · · · · · · · · · · · · · 116 C.2.5 Historical and Archaeological Aspects ...... •...... 116 C.2.6 Vectors and Public Health ...... · . · .. . 116 C.2.7 Socio-Cultural Aspects ...... · · · .. . 118
D. Institutions ...... 119
D.1 National Organizations ...... 119
D .1.1 The National Economic and Development Authority (NEDA) ...... 119 D.1.2 The National Water Resources Council (NWRC) ...... 119 D.1.3 The National Irrigation Administration (NIA) ...... 121 D .1.4 The Ministry of Public Works and Highways ( MPWH) ...... 121 D .1.5 The National Power Corporation ( N PC) ...... 121 D .1.6 The Bureau of Forest Development (B FD) ...... •.. 122 D.1.7 The Bureau ofSoils(BS) ...... 122 D.1.8 The Ministry of Local Government and Community Development (MLGCO) ...... 122 D .1.9 The Farm Systems Development Corporation ( FSDC) ...... 122 D .1.10 The Local Water Utilities Administration ( LWUA) .....•... 122 D .1.11 The National Electrification Administration (NEA) ...... 123 D .1.12 The Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) ...... • 123
D .2 Regional Organizations ...... •...... 123
D.2.1 The Regional Development Council (RDC) ...... •.• 123 D .2.2 Regional Sectoral Agencies ...... 123
D.3 Local Governments ...... 123
D .3.1 Provincial Government ...... •...... • 123 D .3.2 Municipal and Barangay Government ...... •.. 123
APPENDICES ...... 125
Appendix A - Water Resources ...... 127 Appendix B - Power ...... •...•. 147 Appendix C - Economic Sector ...... 153 Appendix D - Land Resources Appendix E - Social Environm·e·n~ ...... •. 165 ...... 169 REFERENCES ...... 173
xii LIST OFT ABLES
TABLE NO. TITLE PAGE
1-A· 1 Summary of Current and Future Basin Characteristics ...... 2 V-A-1 Historical Rainfall Records ...... 19 V-A-2 Historical Streamflow Records ...... 20 V-A-3 Frequency Analysis of Peak Discharge of Rivers ...... 22 V-A-4 Minimum Flow Frequency Analysis of Rivers in the Tagum-Libuganon Basins ...... 23 V-A-5 Groundwater Statistical Data ...... 39 V-A-6 Estimated Monthly E vapotranspiration ...... 40 V-B· 1 Slope Categories, Characteristics and Area Coverage ...... 41 V-8-2 Geologic Formation Characteristics and Area Coverage ...... 43 V-8-3 Major Groups of Soils, Characteristics and Area Coverage ...... 45 V-B-4 Land Capability Classes, Characteristics and Area Coverage ...... 46 V-8-5 Soil Erosion Susceptibility and Area Coverage ...... 47 V-8-6 Existing Land Use Pattern and Area Coverage ...... 47 V-8-7 Area Requirement/Limitations on Land Use ...... 49 Vl-A-1 Actual and Projected Population, Density and Structure...... 57 Vl-A-2 Estimated Total Income and Per Capita Income Classified into Urban and Rural, 1975 ...... 58 Vl-A-3 Income Profile, 1975 ...... 59 Vl-A-4 Distribution of Fami!ies by Income Classes ...... 59 Vl-A-5 Selected Income Measures, 1961, 1965, 1971, and 1975 ...... 60 Vl-A-6 Farm Income Statistics, 1971 ...... , ...... 60 Vl-A-7 Labor Projections ...... 61 Vl-A-8 Employment Distribution by Industry Group ...... 61 Vl-A-9 Projected Water Withdrawals for Domestic Use ...... 62 Vl-A-10 Number of Households by Source of Water, 1970...... 63 VI-A· 11 Inventory of Water Supply Facilities ...... 64 Vl-8-1 Gross Domestic Product and Gross Value-Added by Industry Group, 1975-2000 ...... 67 Vl-8-2 Summary Statistics of Selected Industries ...... 69 Vl-8-3 Various Measures on Land Ownership and Distribution by Farm Size, All crops, 1971 ...... 70 Vl-8-4 Crop Distribution ...... 73 Vl-8-5 Rice Production - Sufficiency Analysis, Year 2000 ...... 74 Vl-8-6 Feedgrain Requirements ...... 75 Vl-8-7 Summary of Corn Demand and Supply ...... 76 Vl-8-8 Existing Irrigation Systems ...... 79 Vl-8-9 Proposed Irrigation Systems ...... 79 Vl-8-10 Livestock and Poultry Inventory ...... 80 Vl-8-11 Agricultural Water Requirements ...... 81 Vl-8-12 Fish Production, 1979 ...... 82 Vl-8-13 Mineral Reserves, 1978 ...... 83 Vl-8-14 Mineral Production,CY 1978 vs. CY 1977 ...... 84
xiii Vl-8-15 Summary Statistics for Large-Scale Manufacturing Establishments ...... 85 Vl-8-16 Summary Statistics for Small-Scale Manufacturing Es tab Iish men ts ...... •.. 85 Vl-8-17 Gross Value-Added in Manufacturing by Industry Group ...... 86 Vl-B-18 Industrial Water Requirements by Industry Group ...... 87 Vl-8-19 Industrial Water Requirements ...... 87 Vl-8-20 Road Inventories as of 1980 ...... •...... 88 Vl-8-21 Various Indices for Road Transport ...... 88 Vl-8-22 Port of Davao ...... 89 Vl-8-23 Airport Statistics ...... 89 Vll-A-1 Water Demand in MCM/Year...... 97 Vll-A-2 Estimated Water Resources ...... 97 Vll-A-3 Level of Land Resource Utilization ...... 99 Vll-A-4 Food Self-Sufficiency ...... 100 Vll-A-5 Morbidity and Mortality Rates of Water-Borne Diseases, Davao del Sur ...... 101 Vll-A-6 Morbidity and Mortality Rates of Water-Borne Diseases, Davao del Norte ...... 101 Vll-A-7 Population ( 1975) and Estimated Number of Schistosomiasis Cases by Municipality Including Estimated Snail Areas as of December 1980 ...... 102 Vll-A-8 Educational Attainment, 1975 ...... 103 Vll-B-1 Water Impounding Reservoir Projects ...... 104
xiv LIST OF FIGURES
FIGURE NO. TITLE PAGE
IV-A-1 Location Map, Tagum-Libuganon Basins ...... 14 IV-A-2 Provincial and Municipal Coverage ...... 15 IV-A-3 Drainage Map ...... 16 IV-D-1 Climate Map ...... 18 V-A-1 Hydrologic Map ...... 24 V-A-2 Minimum, Mean, Maximum Monthly Rainfall, Davao City, Davao del Sur ...... 25 V-A-3 Minimum, Mean, Maximum Monthly Rainfall, Bago Oshiro, Davao del Sur ...... 25 V-A-4 Minimum, Mean, Maximum Monthly Rainfall, · Tagum, Davao del Norte ...... 26 V-A-5 Minimum, Mean, Maximum Monthly Rainfall, Tagnanan, Mabini, Davao, Davao del Norte ...... 26 V-A-6 Mean Annual Rainfall ...... 27 V-A-7 Rainfall Intensity Chart, Davao City ...... 28 V-A-8 Mean Annual Runoff (mm) ...... 29 V-A-9 Flow Duration Curves, Tagum River, Higo River, Sibulan River and Matina River ...... 30 V-A-10 Dependable Stream flow ...... 31 V-A-11 Flood Frequency Curve, Higo River at Tipaz, Tagum, Davao ...... 32 V-A-12 Flood Frequency Curve, Tagum River at Pagsabangan, Tagum,Davao ...... 32 V-A-13 Flood Frequency Curve, Matina River at Pangi, Matina, Davao ..•...... 33 V-A-14 Flood Frequency Curve, Sibulan River at Sibulan, Sta. Cruz, Davao ...... 33 V-A-15 Minimum Flow Frequency Curve, Hija River at Tipaz, Tagum, Davao ...... 34 V-A-16 Minimum Flow Frequency Curve, Tagum River at Pagsabangan, Tagum, Davao ...... 34 V-A-17 Minimum Flow Frequency Curve, Matina River at Pangi, Matina, Davao ...... 35 V-A-18 Minimum Flow Frequency Curve, Sibulan River at Sibulan, Sta. Cruz, Davao ...... 35 V-A-19 Cyclogram Map ...... 37 V-A-20 Groundwater Mining Picture ...... 38 V.S-1 General Slopes ...... 42 V-B-2 Geological Formation ...... 50 V-B-3 Major Groups of Soils ...... 51 V-B4 Land Capability ...... •...... 52 V-B-5 Soil Erosion Susceptibility ...... 53 V-B-6 Existing Land Use ...... 54
xv V-B-7 Forest Reserves, Game Refuge and Bird Sanctuary ...... 55 Vl-B-1 GVA-Employment Distribution by Major Sector ...... 66 Vl-8-2 Agricultural Area Distribution ...... 68 Vl-8-3 Lorenz Curve for Land Ownership ...... 72 Vl-8-4 Irrigated Palay Area Demand vs. Supply ...... 92 Vl-B-5 Proposed National Irrigation Projects ...... 93 Vl-8-6 Mineral Map ...... · · ...... 94 Vl-B-7 Increase in Total System Kilowatt Demand Relative to Increase in Number of Consumers and Average Consumption ...... 95 Vl-8-8 Increase in House Connection Level and Number of Consumers From 1980 to 2000 Years ...... 96 VI l-A-1 Water Picture ...... 98 Vll-B-1 Water Impounding Reservoir Projects ...... 105 Vll-8-2 Area-Capacity Curve, Higo Dam, Lingdam, Davao del Norte ...... 106 VI l-B-3 Area-Capacity Curve, S imong Dam, Mabantao, Davao del Norte ...... 106 VI 1-8-4 Area-Capacity Curve, Kapalang Dam, Jaguimitan, Davao del Norte ...... 107 VI 1-8-5 Area-Capacity Curve, Davao Dam, Calinan, Davao del Sur ...... 107 Vll-B-6 Area-Capacity Curve, Siwawan Dam, Calinan, Davao del Sur ...... 108 VI l-B-7 Area-Capacity Curve, Langi tang Dam , Matuga, Davao del Norte ...... 108 VI l-C-1 Major Areas of Significant Ecological Interest ...... 120
xvi CHAPTER I
SUMMARY AND RECOMMENDATIONS
A. General Characteristics
The Tagum-Libuganon Basins is one of the three major basin groups in Water Resource Region XI. They occupy the eastern portion of the Mindanao Island with area of 7 ,901 square kilometers.
In 1975, the planning area had a population of about 1 million representing 44 percent of the region's population. The Gross Domestic Product (GDP) amounted to 'P4,979 million and a per capita GDP of about :P4,900.
Computations for water requirement projections show that demand will increase from 1,730 million cubic meters (MCM) in 1980 to 2,061.96 MCM by year 2000. Marked increases in water demand are expected from the agricultural, industrial and domestic sectors. As expected, water for agricultural purposes wil I account for 9 5 per cent of the total water requirements by year 2000.
Changes in the economic structure of the basin are expected from the industrial and service sectors which will realize higher growth rates than the agricultural sector in the 25-year period. Thus, the agricultural share of the basins' gross value-added (GVA) will drop from 43 per cent in 1975 to 15 per cent in year 2000 while the industrial GV A contribution will move from 15 per cent to 65 per cent during the same period. On the other hand, the service sector will register a decrease from 86 per cent to 17 per cent.
The basins' population is forecasted to increase at an annual growth rate of 5 per cent from 1 million in 1975 to 2.8 million in year 2000. Average family income in the basin was P7 ,893 while per capita income average was :Pl ,275 i11 1975.
Despite some achievements in the economic and social spheres, the basin con tinues to face urgent problems and challenges. A relatively large segment of the popula tion continues to experience inadequate education, health, power and water supply facilities and shortages in some food items. Other problems that confront the basin are the worsening distribution of family incomes and the incidence of water-borne diseases particularly gastro-enteritis. The basin has important resources with great production potentials in which the development of these can be viewed more as an investment rather than as a final con sumption. However, only rice and corn showed surpluses. The presence of large labor force could, likewise, be tapped to meet the man power requirement of the basin. Most of its mineral resources, which at present remain underdeveloped could be harnessed to enhance the economic development in the area. There are areas open for expansion for irrigation purposes. Their land resources are ex tensive and can be utilized for productive purposes. (Refer to Table 1-1 for the summary; of the basin's characteristics). Table I - 1 SUMMARY OF CURRENT AND FUTURE BASIN CHARACTERISTICS Tagum -Libuganon Basins
1975 2000
Basin Area (Sq. Km.) 7,901 Water Resources Total Mean Annual Run-Off (MCM) 10,862 Dependable Flow ( 80% MCM/day) 15.42 Groundwater Storage 5,812 590 Year Groundwater "Mining" (MCM/Year) 976 "Safe Yield" Level ( MCM/Year) 859 Temperature and Humidity 0 Temperature ( c Mean) 27 Relative Humidity(% Mean) 81 Mean Annual Basin Rainfall (mm/year) 2,476 Social Environment Population 1,012,900 2,760,000 Urban 283,600 872,700 Rural 729,300 1,890,000 Labor Force (Economically Active) 303,000 860,500 Employment 291,000 843,200 Agriculture 197 ,900 279,100 Industry 24,600 185 ,500 Services 68,600 378,600 Income
Average Family Income ('P) 7,900 Per Capita Income (l>') 1,300 Economic Structure (GVA in 'PM) Agriculture 2,100 Industry 6,300 800 Services 27,100 2, 100 8,300 Food Demand Requirements (MT) Rice 96,800 Corn 286,100 43,500 Sugar 91,300 21,600 Vegetables 61,200 48,000 Rootcrops 177 ,800 25,900 Fruits 68,000 51,900 Pork 185,700 7,200 33,400
2 Table 1-1 (cont.)
1975 2000 Beef/Carabeef 4,000 18,700 Poultry Meat 4,800 19,600 Fish 39,100 145,100 Agricultural Prouduction (MT) Rice 122,400 568,500 Corn 329,100 728,600 Sugar 100 200 Vegetables 10,700 29,300 Rootcrops 10,200 20,700 Fruits 43,700 75,700 Pork 2,200 33,400 Beef/Car ab eef 2,400 19,800 Poultry Meat 600 19,600 Water Requirements (MCM/Year) Agriculture 1,703.86 1,968.84 Industrial 1.12 4.99 Domestic 24.26 88.13 Land Use(Sq. Km.) Riceland (Irrigated) 144 Riceland (Non-Irrigated) 211 Total Riceland 335 Diversified Cropland 733 Fruit-bearing Trees 1,000 Pasture/Rangeland 2,040 Forest 3,773 Power Peak Demand (MW) (1980) 56.402 168.354 Generated Power (MW) 167.990 1,032.347
Transportation Road Kilometerage 4,406.822 Kilometer/1,000 Population 2.302 Port (National) 1 Airport (Alternate International) 1
B. Framework of Development
B .1 Water Resources
The requirement for water is primarily dictated by the irrigation of agricul tural land, the direct use of domestic, municipal, industrial and other econ omic activities, the requirements of water-based sectors like fisheries and navi gation and the special requirements of hydro-power, recreation and wildlife.
3 Through the proper utilization of water, the basin, as a whole, can fulfill the total annual water requirement. However, it is also necessary to pursue water impounding and water distribution projects to assure a year-round supply of water. These projects will store water during the months of deficient flows. There are no major flood-prone municipalities in the basin. Flood problems are minor and localized. At present, there are 6 existing river control projects in the area. These consist of dikes/levees, revetments, cut-off channels/diversion channels and spur dikes.
B .2 Land Resources The basin has to consider agricultural area expansion either to intensify the surplus production of rice and corn or to utilize the available areas to attain sclf sufficiency in most of the other food items. Preliminary studies of optimal land use for the basin show that the present resources arc underutilized. This can be proven by the land capability studies where for instance, total land area suitable for rice cultivation amounted to 724 square kilometers while actual rice-pro ducing areas totalled to 355 square kilometers. It seems that the basin is not fully utilizing the area of cultivation for diversified crops {733 sq. km.) as against its land capability (996 sq. km.). Forest resources of the basin are not so extensive. They account for 48 per cent of the total land area of the basin. Extreme care must be taken in developing these resources to avoid harmful ecological consequences, to protect its water sheds and to prevent flooding and erosion problems (Figure 1-B-1 ).
B .3 Socio-Economic
The basins' future development efforts will have to be decisively directed towards a more equitable distribution of the benefits of economic progress. Development will engage the initiative and resources of the people as requi sites for success. As both the sources and objects of development, the people will be provided with adequate economic opportunities and social amenities in Iife to attain a dignified existence. However, efforts to increase family income will have to be based on present income sources, notably farming and land-based activities. Higher level of cropping techniques through the provision, enhancement and im proved delivery of essential agricultural inputs such as credit, extension work, marketing facilities and infrastructure (particularly irrigation and feed er roads among others) will have direct income increase effects.
To promote the physical aspects of human development, education, man power development and health programs should be expanded and urgraded.
The educational and training opportunities should be democratized to allow more people to participate productively in the development process. Health facilities should be accessible to the population and services must be adequate to provide the health needs.
4 B .4 Environmental Considerations
The attainment of development should consider the careful management of the environment. Natural vegetation, wildlife, feeding and habitat areas and archaeological sites have to be considered particularly with the proposed im pounding projects. These activities should be spatially located in conformity with the environmental standards for air, water and land. The river system within the basin still exhibits normal conditions which could sustain aquatic life and water impounding projects which will have good effects for fresh water aquaculture development. These conditions can contribute in maintaining the fish production in the basin. The rapid expansion of human settlements and accelerated development activities in agriculture, mining and forestry and manufacturing usually result in a number of environmental problems. These problems are soil erosion, floods and others which, although, to a small degree, exist in the basin. Special measures are required to ensure that the higher economic growth envisioned in the succeeding years will not impair the environment. Special consideration must be given to areas susceptible to erosion and flooding.
C. Sectoral Recommendations
C.1 Water Supply and Sewerage The availability of domestic water supply and the existence of sewerage and water disposal facilities are two of the most important indicators of household and community welfare. For areas of high urban density and complexity, a cen tralized water supply and sewerage system is practically a must so as to attain a desirable level of health, sanitation and well-being.
The NWRC, through the Rural Water Works Development Corporation, has defined three levels of service. The first two refer to point sources with limited service coverage and the third refers to large systems with extensive distribution networks covering urban communities of at least 20,000 inhabitants. The projected increase in population to year 2000, combined with the in creasing standard in per capita consumption as the level of urbanization and dev elopment rises, suggests that deliberate shifts should be made from Level I to Levels 11 and 111 water supply services. Level 111 systems will have to be cons tructed to serve new urban areas as soon as they reach the scale requirement of the service, particularly the municipalities of Davao City and Tagum. With regard to sewerage and waste disposal facilities, centralized systems may not be needed in the area for sometime. Instead, non-cer.tralized but modern sewerage facilities particularly the use of flush-type toilets should be promoted. These would, of course, depend on abundant water supply regardless of the level of service. To promote higher standards of household sanitation, water is still the basic need and its availability to adequately supply urban and rural households should be planned along the shortest time frame feasible.
5 C.2 Irrigation The National Irrigation Administration statistics for 1975 indicate a combined potential service area of 24,800 hectares for all types of existing irrigation systems. Around 27 per cent of this area is served by communal i~riga tion systems and 73 per cent by national irrigation systems. There are no private irrigation systems present. While statistics are not immediately available, the apparent problem in the field is the low ratio of areas actually served to the targeted potential service areas. Causes that have been identified by NIA include, among others, the decreas ing supply of water in national structure and canalization, poor maintenance and operation of the system and poor management of irrigation water on the part of the farmers. The close relationship between the infrastructural, management and socio economic aspects of the problem requires an integrated approach that should include the following major components: ( 1) rehabilitation and improvement of existing irrigation systems; (2) improvement and expansion of water distribution facilities including turn-outs, main canals and laterals; (3) improvement of organ ization for planning, maintenance and operation of systems; ( 4) extension services to farmers in water management; (5) improvement of collection of water rates and ( 6) strengthening of the watershed conservation program to maintain reliable water supply levels in dams and reservoirs during low-flow periods. The completion of the NIA's on-going and proposed irrigation projects would greatly expand the irrigated areas and increase substantially the agricultural production, hence, the income of the rural households. The development of these projects should be accompanied by proper management training and other instit utional measures to maximize project efficiency. C.3 Flood Control
The Bureau of Public Works {now the Ministry of Public Works and High ways), the agency in charge of the Flood Control Program of the government has no estimate of flood damage in the basin. There are 6 existing flood control measures in the area.
C.4 Land Use Management
The protection of forest areas from indisciminate developmental activities is the main concern of the basin to preserve these areas for present and future gener ations. Also, a considerable focus must be placed on watersheds and forest re serves which serve special functions for the ecological life of the basin.
, . . Likewise,. preventive measures have to be undertaken against soil erosion within the basin. Proper rangeland management and planting of permanent crops to steep areas are some of the steps to mitigate and prevent the soil erosion pro blem of the area.
Land capability studies indicate that agricultural land is both underutilized and misused. Transformation of large tracts of grass and shrublands can provide
6 additional areas for other uses. This expansion should be focused on the produc tion of its deficit flood items and/or on the increased production levels of its meat supply. C.5 Power The estimated number of households with electric power connection in 1980 was almost 100 per cent of the total basin households. Considering the present level of development of the basin and the projected population growth for the next 20 years, it is estimated that by 1990 and 2000, the service shall reach almost 100 per cent of the total households. The National Power Corporation and the National Electrification Adminis tration are engaged in power development in Mindanao and will utilize different sources of energy namely: hydro, geothermal and diesel power. These plants are located in the Agus River Complex, lligan Bay, Davao City, Pulangi River and Aplaya. The success of the time table to fill the power requirement for year 2000 shall depend on the program of implementation of the Mindanao Grid of the NPC, and the general power market. In this sense, the planning and implementation have to be continually integrated with the other sectoral plans for the development of the basin. C.6 Fisheries The fishing area of the Tagum-Libuganon Basins covers an approximate area of 2,795 hectares. Commercial fishing ranks first among the three sources of fish production in the basin, The role that the basin is expected to play in the future is concerned with self-sufficiency in its fish requirements. C.7 Transportation The insular characteristic of the Tagum-Libuganon Basins points to the strong need for a complementation of land, water and air transport. At present, the basin is served by an a!ternate international airport in Davao City. The Port of Davao handles the shipping activities of the basin. A total of 4,406.822 kilometers of national, provincial, municipal, city and barangay roads connect the major set tlements within the basin. The improvement of airport and port facilities is an important support to the development of the basins' agricultural, fishery and other exports to the con sumption centers of the country. Likewise, the improvements will allow the basin to be supplied of the products they are deficient in. The focus of concern for an accelerated basin development should be the in crease in rural roads through the construction of more farm-to-market roads.
7 CHAPTER II
INTRODUCTION
A. Background
The growing importance of water resources as a key sector in the national dev elopment effort has dictated the need for a nationwide water resource development framework plan that is both integrated and should be integrable into the national and regional development programs of the country. This is one of the basic purposes for which the National Water Resources Council was created by virtue of Presidential Decree No. 424. To achieve its mandated objectives, the Council continually evolves planning approaches and conducts studies relevant to the preparation of water resource develop ment µlans. The initial step in the planning process adopted by the Council is the pre paration of framework plans for the country's twelve water resource regions. Each regional plan consists of the integration of the multi-sectoral development framework of the major basins, sub-basins or contiguous basin areas of the region. The basin then or in some instances important sub-basins or an integrated group of minor basins, is the adopted unit of analysis and planning of the water needs and potentials of the region. Water Resource Region XI consists of the Davao Oriental, South Cotabato and Tagum-Libuganon Basins.
As a planning area, the Tagum-Libuganon 1 Basins cover the southeastern part of Mindanao Island with a total drainage area of 7,901 square kilometers. B. Objective of the Study The study hopes to establish a sufficient analytical framework on which to base concrete recommendations of the development of the basin area including, where necessary, measures to improve the data base for subsequent planning efforts for basin wide water resource development.
C. Scope of the Study As a long-range development planning exercise, this study covers the following areas of analysis.
1. Existing situation and trends in water resources and related developments. 2. Potentials in terms of land and water resources. 3. Projection of demand for water and related resources up to year 2000. 4. Water supply projections and evaluation of capacity to meet future demands. 5. Identification and profiling of water resource development projects. 6. Environmental and social impact assessments of future development. 7. Determination of development thrust of sectors with high potentials. 8. Determination of areas for improvement in basic data.
9 CHAPTER Ill
OBJECTIVES OF DEVELOPMENT
A. Regional Development Objectives and Strategies The development of water resources is basically intended to support the overall strategies for achieving the regional development objectives. The Five-and Ten-Year Development Plan of Southern Mindanao (Regional XI) prepared by the National Economic Development Authority and adopted by the Regional Development Council spells out the objectives of development for the next ten years which may, for the purposes of this study, represent the long-range objectives up to year 2000. The objectives include the following: 1. Optimize the food production capability. 2. Develop agri-based, labor-intensive and export-oriented industries. 3. Provide adequate infrastructure/utilities support. 4. Develop manpower to meet sector needs. 5. Promote a participatory delivery system of health and social services. 6. Participate actively in the regional development efforts. 7. Preserve the region's ecological balance. To achieve the above-mentioned objectives, the NED A plan, likewise, outlines broad development strategies to which the following seem vital: 1. Provide facilities to the secondary service centers, in order to meet Davao City's capacity to serve the region. 2. Broaden the industrial base by providing the necessary growth stimulant in order to complement the agricultural activities. 3. Adopt an outward-looking strategy for the producing sectors. 4. Upgrade regional manpower skills which will be directed towards the un employed, underemployed and the out-of-school youth. 5. Strengthen local institutions in terms of expertise, budget, and decision making capabilities to insure a universal participation policy in development programs. B. Development Objectives of the Basin
As a significant areal component of Water Reso·• .. t;e Region XI, the development of the Tagum-Libuganon Basins shall be geared to the pursuit of the following objectives: 1. To enhance the surplus production of some of its agricultural products and the achievement of self-sufficiency in food and other basic needs for the basins' population; 2. To increase per capita and family income and reduce income inequality by developing to the fullest extent the basins' agricultural, industrial and human resource potentials;
11 3. To raise the level of social services and facilities particularly those related to health and nutrition, education and domestic water supply. 4. To conserve the basins' watershed and extensive forest resources; 5. To protect its archaeological sites and to develop significant recrea tional areas; and, 6. To maximize the utilization of the basins' water and land resources.
12 CHAPTER IV
AREA PROFILE
A. Location and Description The Tagum-Libuganon Basins lie at the northern part of Water Resource Region XI. It is bounded on the west by the North Cotabato, on the east by Davao Oriental, on the north by Agusan del Sur and on the south by the Davao Gulf.
Eight sub-basins, namely Matibo (172 sq. km.), Hija (700 sq. km.), Tuganay (666 sq. km.), Davao ( 1,623 sq. km), and Tagulaya-Sibulan ( 158 sq. km) plus watersheds amounting to 674 sq. km. make up the 4,837 square kilometer minor basin area of Tagum-Libuganon 8 as ins. Influence area totals to 7 ,901 square kilometers. The topography of the basin area is characterized by limited lowlands, Hilly areas that gradually rise into mountains border the coastal plains. The Tagum-Libu ganon basin proper is drained by many creeks and rivers. Libuganon River is its major water artery with Tagum river as its main tributary. B. Archaeological, Historical and Cultural Characteristics Davao province or Davao del Norte in terms of number of municipalities, makes up most of this planning area. Majority of its population is Christian, though several indigenous tribes inhabit the area. These are the Calagones, Tabacaoles, Aetas, Samalese, B agobos, and the Mandayas. About 70 per cent of the basin population speak Cebuano and 88 per cent prac tice Roman Catholicism. C. Settlement System Major settlements in the Tagum-Libuganon Basins are generally situated near or along the coast. The most densely populated municipality is Davao City. About 72 per cent of the basin population reside in the rural areas. As of 1980, there are 4,407 kilometers of road length in the basins. Of this, 14 per cent comprise national roads, 28 per cent provincial roads, 11 per cent municipal roads, 6 per cent city roads and 41 per cent barangay roads. The only airport found in the basin is located in Sasa, Davao City, and is classified as an alternate International Airport. The only existing port is the port of Davao.
D. Climate D .1 Climate Type The Philippine Atmospheric Geophysical and Astronomical Service Adminis traction ( PAGASA) employs three climate classification system namely: Coronas, Hernandez, and Koppen. The Coronas classification gives emphasis on the sea sonal type; the Hernandez on the number of wet and dry months; and the Kop pen on the temperature range and the amount of rainfall in the driest month.
13 REPUBLIC of the PHILIPPINES ~ [)cP p
q
LUZON
. I I
r'
0
.:o {1
i
1 I :I
SUL~ I ~ I a f A
Tlill 1-;_;J:J- ... 0
Figure IY-A-1 LOCATION MAP TAG UM-LI BUG ANON BASINS
0 5 IO 15 20
Scale in K1lomeTers
14 11!11011 II
e•oo'
LOC.t.TIOll ......
1•4e•
7•30'
1•1&'
LEGEND: •--• REGIONAL BOUNDARY -··- MAJOR BASIN BOUNDARY -·- MINOR BASIN BOUNDARY --- PROVINCIAL BOUNDARY ------MUNICIPAL BOUNDARY ~ RIVER, CREEK @ PROVINCIAL CAPITAL e CHARTERED CLTY O MUNICIPALITY ~- ~~ Figure IV-A-2 PROVINCIAL AND MUNICIPAL COVERAGE TAGUM-LIBUGANON BASINS 'stALE IH KILOMETER
10 IS 20 2!! 30 1<11111.
12!!• 1!1' 12e•30' 12&•4&'
15 LEGEND: RY BOUNOA ..-- REGIONAL N BOUNDARY ··- MA.JOR BASl N BOJNDARY - • - MINOR BASI BOUNDARY =--PROVINCIAL EK ~ RIVER ' CRE CAPrTAl... """- PROVINCIAL TY v- CHARTERED Cl ~ MUNIOPALITY
Figure I V-A-3AP
TAG UM-LIDRAINAG~~N BUGA BASINS
~CALE "' •LOMETE1'~ " 2'0 ~ ]() ... I()
12e• 1s· •·30'
16 The eastern half of the basin falls under the second climate type (Coronas) and the western half side under the fourth type. The second type is characterized by an absence of a dry season and a pronounced maximum rainfall occurring from November to January while the fourth type, by an evenly distributed rainfall. A similar division occurs under the Hernandez classification. The eastern half section is wet (Type A) while the western half side is humid (type B ). Under the Koppen scheme, the entire basin falls under the tropical wet climate (AF climate). A map of the basin with the areas under the different types of climatic con ditions is shown in Figure IV-D-1. The different climatic classification systems =!re described in Appendix A. D .2 Temperature and Humidity Aside from other climatic considerations the synoptic station of PAGASA in Davao City provides information on atmospheric temperature and relative humid ity. Available data covering a period of 32 years {1949-1980) are found in Ap pendix A. Data indicate that monthly average temperature ranges from a minimum of 22°c to a maximum of 33°C. The mean monthly temperature, on the other hand, does not vary considerably as values fluctuated from 26°C to 28°C. Tem perature is fairly uniform throughout the year as can be seen from Figure A-1 (Appendix A), which plots the monthly minimum, mean and maximum values respectively. The mean monthly relative humidity is, likewise, plotted on Figure A-2. Values range from 78% to 82% with the months of March and April experiencing relatively low humidity of 78% while the rest of the year averages 81 %.
17 CLIMATIC CLASSIFICATION (Island of Mindanao) T AGUM-LI BUGANON BASINS
KOPPEN's CLASS! Fl CATION
DAf [!IlfiljJAm
~Aw
0 Oo t::;:J --- RIVER BASIN o• O BOUNDARY 0 .~ 0 0
CORONA'S CLASS I Fl CATION
m 2ndType E 3rd Type
- 4th Type --- RIVER BOUNDARY
0.
HERNANDEZ CLASSIFICATION
f:!tz=-j Type A CJ TypeB
-TypeC
~TypeD --- RIVER BASIN BOUNDARY
Figure IV-D-1
18 CHAPTER V WATER AND RELATED LAND RESOURCES
A. Water Resources
The development of a region's water resources requires the scientific and orderly management of its resources consistent with the principles of optimum utilization, conservation and protection to meet present and future needs. Pr
A.1 Rainfall In the Tagum-Libuganon Basins, rainfall observation by PAGASA started in 1961. There are four stations presently operating within the area situated in Davao City and 8ago Oshiro in Oavao del Sur, and in Mabini and Tagum in Davao del Norte. Their coo rd in ates as well as periods of record are listed in Table V-A-1 while their approximate points locations are shown in Figure V-A-1.
Table V-A-1 HISTORICAL RAINFALL RECORDS Tagum-Libuganon Basins
Station Location of Station Latitude Longitude Type11 Period of ID Record K01 Davao City, Davao del Sur 7°05'00" 125°37'00" SY NOP 1961-76, 79-81 K02 Bago Oshiro, Davao City, Davao del Sur 7°02'00" 125°31 '00" AGRO '1976-80 K09 Tagum, Davao del Norte 7°23'00" 125°50'00" cc 1966-76 K10 Tagnanan, Mabini Davao de! Norte 7°17'00" 125°51 '00" CR 1966-79 ------1./Rainfall Station Type Classification
SY NOP - Synoptic Station AGRO - Agrometeorological Station CR - Cooperative Rain Station re - Cooperative Climatological Station
19 The minimum, mean, and maximum monthly rainfall values for the four ( 4) stations are plotted in Figures V-A-2 to V-A-5 and tabulated in Appendix A. Rainfall in the basin is more or less evenly distributed throughout the year. 8 y applying the reciprocal distance method of interpolation to the mean annual data of the rainfall stations in and adjacent to the basins, the spatial variation of the annual rainfall was obtained. Figure V-A-6 exhibits the rainfall map of the basin. Based on the mapped values, the mean annual basin rainfall is 2,476 millimeters. PAGASA prepared the rainfall depth-frequency-duration analysis ( 5, 15, and 30 minutes and 1, 6, ·12, and 24 hours) using Gumbel's method on rainfall records of Davao City. The illustrations and the summary arc given in Figure V-A-7 and in Appendix A, respectively.
A.2 Surface Runoff A.2.1 data availability The former Bureau of Public Works has established only four streamflow gaging stations in the basin, one of which had been abandoned in 1969. This abandoned station, though, (at Tagum River in Pagsabangan, Tagum, Davao del Norte) had a long and fairly good record and was, therefore, included in the analysis of runoff. The other stations are located in the Hijo, Matina and Sibulan Rivers. The coordinates and periods of record of these stations are given in Table V-A-2 and their approximate point locations are shown in Figure V-A-1.
Table V-A-2 HISTORICAL STREAMFLOW RECORDS Tagum-Libuganon Basins
Station Drainage Period of 1[).1/ Location Latitude Longitude Area Record (Sq. Km.) 1107 HijoR: Tipaz, Tagum, Davao 7°27'00" 125°49'00" 617 1963-64, del Norte 66-70
1108 Tagum R: Pagsabangan, Tagum, 7°28'00". 125°45'00" 2326 1949-69 Davao de! Norte
1109 Matina R: Pangi, Matina, Davao 7°07'16" 125°32'21" 48 1959-64, del Sur 66-70
1110 Sibulan R: Sibulan, Sta. Cruz, 6°58'05 125°22'40" 128 1955-64, Davao del Sur 66-70
J}Station ID Nos. are based on Reg. 11 NWRC listing.
20 The mean monthly and annual runoff values, as well as, the other statistical parameters are contained in Appendix A.
A.2.2. surface water availability The mean annual runoff volumes observed at the gaging stations were con verted to equivalent depths of runoff. These runoff depths served as inputs in plotting the spatial variation of the basins' runoff using the reciprocal distance method of interpolation. The basin has a mean annual runoff of about 1,375 millimeters or approximately 10,862 million cubic meters ( MCM) with the Tagum-Libuganon, Davao and Hija River Basins contributing 4,212 MCM, 2,231 MCM and 962 MCM respectively. Figure V-A-8 shows the areal variation of the basins' annual runoff.
A.2.3 dependability analysis The daily streamflow records of the gaging stations in and around the basin was subjected to flow duration analysis. Flow duration curves {Figure V-A-9) plot the percentage of time a certain flow is equalled or exceeded. Dependable streamflow can be derived from these curves by reading off values for the parti cular percentage of time, say 80 per cent, and applying the reciprocal distance method of interpolation to the values read to obtain the average vaiue for the basin. Figure V-A-10 presents the spatial variation of the basins' 80 per cent dependable streamflow indicating an average flow of 15.42 MCM/day. Eighty ( 80) per cent dependability is adopted by NWRC as the limit in its granting of water rights.
A.2.4 flood and minimum flow frequency analysis The annual peak discharges (details shown in Appendix A) of the Hija, Tagum, Matina, and Sibulan rivers were subjected to frequency analysis assum ing a Log Pearson Type 111 D istribution.11 The analysis was based on the length and acceptability of available streamflow records. The results of the flood frequency analysis are shown in Table V-A-3. The computed frequency curves together with the 5 per cent and 95 per cent confi dence curves as well as the observed annual peak flows are drawn in Figures V-A-11 to V-A-14. The number of recorded peak flows at the various gaging stations ranges from seven ( 7) to eighteen ( 18) years. Sibulan and Tagum Rivers with eleven and eighteen years of record, respectively, manifest higher reliability of flood estimates. This is shown by the narrower range of probable values in the estimated peaks defined by the 90 per cent confidence band. The annual minimum flows of the rivers were, likewise, subjected to fre quency analysis assuming a Type 111 Extremal Distribution (refer to Appendix A for details). Table V-A-4 shows the results of the minimum frequency analysis while Figures V-A-15 to V-A-18 plot the computed values.
1J. Method used as recommended by the U.S. Water Resources Council in Bulletin No. 37, March 1976.
21 Table V-A-3 FREQUENCY ANALYSIS OF PEAK DISCHARGE OF RIVERS Tagum-Libuganon Basins Discharge in CMS
Return Period: HIJO RIVER TAGUM RIVER MATINA RIVER SIBULAN RIVER
5% 237.30 814.69 58.38 15.21 100 yea7 82.40 624.06 15.43 11.45 95o/~ 28.61 478.03 4.08 8.61
5% 134.58 691.75 29.89 14.42 50 years 65.69 555.14 10.70 11.35 95% 31.97 445.51 3.83 8.93
5% 73.61 551.68 12.83 13.12 25 years 49.28 467.99 6.50 11.11 95% 32.99 396.99 3.29 9.41
5% 54.31 460.10 7.07 11.95 . 10 years 40.24 404.01 4.39 10.78 95% 29.81 354.75 2.72 9.72
5% 44.01 378.00 4.12 10.83 5 years 33.33 340.10 2.89 10.23 95% 25.24 306.00 2.03 9.66
5% 30.95 272.88 2.01 9.74 2 years 26.80 248.97 1.53 8.67 95% 23.21 227.14 1.16 7.72 Scale Parameter ALPHA 0.36 0.05 0.41 0.24 Characteristic Drought BETA 0.55 57.87 2.88 1.49 Lower Limit, GAMMA 3.19 2.80 -0.63 1.72
1f Expected flow is less than or equal to the indicated flow in 5 out of 100 observations. 1J Expected flow is greater or equal to the indicated flow in 95 out of 100 observations.
22 Table V-A-4 MINIMUM FLOW FREQUENCY ANALYSIS OF RIVERS IN THE TAGUM-LIBUGANON BASINS (Discharge in CMS)
RETURN PERIOD HIJO TAGUM MA TINA SIBULAN
X +SE 10.20 23.12 0.22 2.83 100 Years 6.91 14.70 0.11 1.90 X-SE 3.62 6.29 0.00 0.97 X +SE 10.41 23.61 0.22 2.96 50 Years 7.65 16.47 0.13 2.18 X-SE 4.90 9.33 0.04 1.41 X +SE 11.09 25.44 0.24 3.25 20 Years 8.94 20.07 0.17 2.65 X-SE 6.80 14.69 0.10 2.05 X +SE 12.08 28.70 0.27 3.62 10 Years 10.23 24.29 0.21 3.11 X-SE 8.38 19.88 0.15 2.59 X +SE 13.65 35.11 0.34 4.16 5 Years 11.92 30.71 0.28 3.69 X-SE 10.19 26.32 0.22 3.22 X +SE 17.07 52.18 0.50 5.28 2 Years 15.37 46.56 0.42 4.84 X-SE 13.68 40.94 0.35 4.40 Scale Parameter, ALF A 3.18 1.95 2.15 3.59 Characteristic Drought, BET A 16.78 53.99 0.49 5.30 Lower Limit, GAMMA 3.88 10.59 0.06 0.59 Function A (ALF A) 0.34 0.24 0.26 0.36 Function B (ALFA) 3.23 2.12 2.30 3.59
A.2.5 flood contra I The Tagum-Libuganon Basins has no major flood prone area. However, the southern tip of the basin area is subjected to occasional flooding brought about by inundation on limited scale and bank scourging. It covers approximately 6.0 sq. kms. Established within the basin are river control projects that will prevent destruction of properties and disruption of economic activities. So far, there are six ( 6) river control projects situated in Davao del Sur and Davao del Norte. A list of the existing flood damage protection measures is provided in Table A-16 (Appendix A). Structures constructed consist of dikes/levees, revetments, cut off-channels/diversion channels and spur dikes.
A.3 Groundwater
A.3.1 data availability Groundwater development in the basin can hardly be quantified since
23 12!1°30' 12'94!1' REGION II
e•oo'
LOCATION MAP
T911'
LEGEND: EXISTING @ RAINFALL GAGING STATION
A STREAM GAGING STATON
Figure V-A-1 HYDROLOGIC MAP TAGUM-LI BUGANON BASINS SCAU IH ~l..OlolETEJI
1211•1&' 12&•30' .. .,
24 RAINFALL IN THE BASIN RAINFALL IN THE BASIN (MILLIMETERS) (MILLIMETERS)
1,000 1,000
900 900
8::: 800
700 700
60- 600
e E .§. .§. 500 500 ~ ~ t-..,) ~ VI ~
400 400
300 300
200 200 ~ - .....
100 100
~ ;,; ,., -- ,,,,...._ .... 0 0 ~·~ F M A M A s 0 N D F M A M A S 0 N D KOi DAVAO CITY, DAVAO DEL SUR K02 BAGO OSHIRO, DAVAO DEL SUR PERIOD OF RECORD: 1961-71,1976-81 PERIOD OF RECORD: 1976 - 80
r::::J.. MINIMUM JI_ MEAN _LMAXIMUM .r:::::l.MINIMUM JI_ MEN; _LMAXIMUM
Figure V-A-2 Figure V-A-3 RAINFALL IN THE BASIN RAINFALL IN THE BASIN (MILLIMETERS) (MILLIMETERS) TAGUM-LIBUGANON BASINS TAG UM-LI BU CANON 3ASI NS 1,00011-.--,--.,--.-.--.-.--.--,---.,,--,.---, 1,000-r--r--r---ir---,--,--....--r---r---.--~--r--,
800
700 700
600 600
E E' ..s E 500 500 ~ tv c 'E °' ~ ~ 400 400
300 300
g .~ 200 ··' ·; ;) ~~ ;'. ·t d PJ' .... ~ -':..··• ~·· ~ .. ·.;: t.; ,, ' •! ;; :·:' I~ . ~N ~! ,...... ~; }. 100-- J; -~ ~ :. ~ ,; ·,. 1'..;, .\ t. ··''. ,.. ·' r- r:, L:_: " ,.. ,... .· ,...... - - ~~ ~ n ,.. ,, .... ' ;;, i,:.\ ...... ,__ ...... ·...... iii: ..;... ~. 0 k~ ~· to '·. ~ F M A M A 0 N D KO 9 TAGUM, DAVAO DEL NORTE KIO TAGNANAN, MABIN!, DAV,\O, DAVAO DEL ~ORTE PERIOD OF RECORD· 1966 · 76 PERIOD OF RECORD 1966 79
r:::I.MINIMUM _._MEAN J_MAXIMUM r=:J. MINIMU\I ..II .. \l[,\N _L \1AXIMU\I Figure V-A-4 Figure V-A-5 125•30' 12!!1.4!!1' 1~00'
REGION II
8"1!!1'
11•00'
LOCATION MAP
7•30'
7•115•
LEGEND: ~'i@J 2300 7•00' -r-od ~ 2300- 2400 flllil 2400-2500 ~ 2500- 2600 C:J 2600-2700
8"415' Figure Y-A-6 MEAN ANNUAL RAINFALL (mm) T AGUM-LI BUGANON BASINS
SCALE IN ~ILOMfTER I I I I I I -r=-1 5 0 5 10 15 20 25 30 ~Id
s•30' 12!!1• 1!!1' 12!!1•30' 1~·4&'
27 6Q01o------r-....,..----r-----,----,-----1--1-1
500L---+---+---+----r----n1 RAINFALL INTENSITY CHART For DAVAO CITY Based on 1949 -1971
'L:" 100 :::l 0 ..t:: 90 ~ 80 (!.) +..> (l) 70 E .E 60 .:.:::-c: 50 >-f- Vlz 40 l.J..J zf- -I 30 -I <( w.. z :;: ~ 20
101------+----.l------+------+------+----+------+.--~--~~~~rl gL------+----~-----+------+------+----+------~----~~~~~rl 81------+----1------+------+------+----+------+.----__;'-+---lii~~r-llli~ 7.______-+----1~-----+------+------+---~------+------+--r-~-"1;1'1 61------+-----11---~---+------+------~----+------+------+---'~~-t
51------...-----1~-----+------+------+----+------+------+-----~~
3~ _____., __ __. ______.... ______-'------~--_... ______-1... ______..J..~~~~ 5 minutes i 0 15 30 60 2 hours 3 6 12 24 DURATION Figure V-A-7
28 1264'00' REGION 11
11·00·
LOCATION MAP
1"30'
1•1&'
LEGEND: 1•00' "feo<1 ~-= 1100 ~1100-1200 ms1200-1300 IIIIlil 1300 - 1400 ~1400-1500
11111500 - 1600 8"45' 6°4!!' EB ==- 11500 Figure V-A-8 MEAN ANNUAL RUNOFF (mm) TAG UM-LI BUGANON BASINS
SCALE IH KU..OMETER I I I I - I I +---. 5 0 ' 10 15 20 25 30 Kid. e•!O' 6°30' 125°15' 1211• '30° 12!5°4&' 1ie•OO' 12&• 1&'
29 900 I 80 0 I 701() ~ 60 0 FLOW DURATION 500 \ CURVES \ I 40 0 I I I \ I TAGUM RIVER (1949-1969) 300 '\ [/1 at Pagsabangan, Tagum Davao del Norte D.A. = 2,326 Sq. Km. I / I I 20 0 ~ . ' ~ v TAG UM-LI BUGANON BASINS 100 -...... 9 0 "~ ...... ~ 80 -...... 7 O' -- •r ~ 60 . \ i HIJO RIVER ('51-'61,'63-'64,'66-'70) ...... ""'- 5 0 at Tipaz, Tagum, Davao del Norte \ / D.A. = ll 7 Sq. Km. ~ 4 0 !/ 3 0 ·-. I "'~ I ' ~ 2 O I ------"\ \ -· -- -·-- 1 VJ -- ~----.. ~ u SI BULAN RIVER (1955-1970) r--...... z \ at Sibulan, Sta. Cruz, Davao del Sur / D.A. = 128 Sq. Km. ~ 10 ...... O' 9 ~ ...... _/ UJ 8 c..? a:'. 7 <( ---- ....___ - 6 - I ---- u i--_ (./") 5 :~ cs --- .---...... _ 4 \ ""'-
3 \ ~ ... \ ' \ 2 \ "'"" \ I 'NATINA RIVER (1959-1970) /i at Ma~ina, Pangi, Davao del Sur r\.,, D.A. - 48 Sq. Km. 1 .9 / .8 """" 111.._ """ ...... 7 -...... ,...._,_ .6 .5 ~ ...... _ .4 --. ", .3 ~ ·~ .2
.1 ' 0 10 20 30 40 50 60 70 80 90 100 PERCENT OF TIME FLOW IS EQUAL OR GR=:.r\TER THAN Q Figure V-A-9 30 12~· 1~· 125•30' 1~00'
11(010" II
· e•oo·
- 1••0'
7•30'
7•19' 7•10'
LEGEND: -1•00' UNIT: LPS/SQ. KM mJ-:18 Ill 18-20 mm 20-22 .. 23-24 ~ 24-26 ~:::-25 s••o' Figure V-A-10 DEPENDABLESTREAMFLOW (80 PERCENT) TAG UM-LI BUGANON BASINS SCALE IN KILOMETER FWWf --- I I --+~ 5 0 5 10 15 20 25 30 KMS
6°30' 125°15'
31 '1 - ' ' I LEGEND: 0 OBSERVED ANNUAL PEAK FLOW _ COMPUTED FREQUENCY CURVE (CFC) ----- C.F.C. + S.E. ---- C.F.C. -S.E.
./ / l / j .... ~ E ... ~ 2 1 ~ 10 ~ c 9 / ~ ...... ~ 7 / l.,...-o- L--"'" 6 .,, __,,.- L.._ ... 5 ... -1~ - -~ _. ~ 4 --;;,;;.- ~ i,...... ~ ~ ...... ~ ~ 3 -- - i.- (....--0 ~ 0 ~ -- 0 t> r.---- - 2
1 10 1.1 1.2 1.31.4 1.5 3 4 5 ~ '0 20 30 40 50 I 00 RECURRENCE INTERVAL (in years) FLOOD FREQUENCY CURVE 1107 HIJO RIVER AT TIPAZ, TAGUM, DAVAO DA= 617 Sq. Km, Period Of Record 7 Yrs. Figure V-A-11
104 1 9 LEGEND: 8 0 OBSERVED ANNUAL PEAK FLOW --- COMPUTED FREQUENCY CURVE (CFC) ---- C.F.C. + S.E. ---- C.F .C. - S.E.
'g" § ] E 3 ~ 10 10 c 9 8 7· 1.- --- 6 - ~ -· L,...- 5 ~ - ~ ...~ .__.._ 4 """' . ---~ - ...._.... ~ .... ~ ;Jl. _i- .... 3 ~ -""~~- 00 0 ~ 2 r 0 c 0 D o
02 1. 1.2 1.31.41.5 2 3 4 5 6 7 910 20 30 40 so 1 ()() RECURRENCE INTERVAL (in years) 1108 TAGUM R. AT PAGSABANGAN, TAGUM, DAVAO FLOOD FREQUENCY CURVE DA= 2326 Sq. Km. Period Of Record 18 Y~. Figure V-A-12
32 102 1 9 8 7 / _L / ~ / , ,' / / 1 / ~ 10 ~/ 10 c 9 / ~' 8 -- ~ / /' ,,,,;' .J, J, I~ / iv ~v .,,i; ~~ :-- ~ - ~ ./ - / 0 ,,,,.,,,,,,..... v ,...i.- -- / --v ... ,,,,,,, 1 .... /" LEGEND: 0 OBSERVED ANNUAL ---- COMPUTED FREQUENCY CURVE {CFC) ) ----- C.F.C. + S.E. 5 ---- C.F.C. - S.E. 1.1 1.2 1.3 1.41.5 3 4 5 6 7 8. 910 20 30 40 50 100 RECURRENCE INTERVAL {in years) 1109 MATINA RIVER AT PANGI, MATINA, DAVAO FLOOD FREQUENCY CURVE Figure V-A-13 DA= 48 Sq. Km. Period Of Record 9 Yrs.
102 10 9 LEGEND: 0 OBSERVED ANNUAL PEAK FLOW --- COMPUTED FREQUENCY CURVS: {CFC) ----- C.F.C. + S.E. ---- C.F.C.- S.E.
I ] ..... E _.. --s-- .. - --- I I -- 101 -· ..... - 10 ~ - .r-_ ~n----' - - c 9 I~ u .,, w (.,;) -- p "':% I~ ~ 0 0
1.1 1.2 1.3 1.4 1.5 3 4 5 6 7 8 9'10 20 30 40 50 foo RECURRENCE INTERVAL {in years) 1110 SI BULAN RIVER ATSIBULAN, STA, CRUZ, DAVAO FLOOD FREQUENCY CURVE Figure V-A-14 DA = 128 Sq. Km. Period Of Record 11 Yrs 33 10 102 9 LEGEND: 8 0 OBSERVED ANNUAL MINIMUM FLOW - COMPUTED FREQUENCY CURVE (ere) ----- C.F.C. + S.E. ---- C.F.C. - S.E.
0 p 0 (~ I'-- .... p..- i-- ~ r--r--. r--"'- ...... r--J- ...... 1 - """' ------•1 - --- .__ 7 I"'-.. 6 -...... s ~ 4 ......
3
2
10 \) 1.1 1.2 1.31.41.5 3 4 5 6 7 8 910 20 30 40 50 I ()() RECURRENCE INTERVAL (in years) 1107 HIJO RIVER AT TIPAZ, TAGUM, DAVAO MINIMUM FLOW FREQUENCY CURVE DA= 617 Sq. Km. Period Of Record 7 Yrs. Figur~ V-A·lS
2 10 u I 9 8 LEGEND: ) 0 OBSERVED ANNUAL MINIMUM FLOW v v \J - --- COMPUTED FREQUENCY CURVE (CFC) In C.F.C. + S.E. u u ----- ~-...... ---- C.F.C. - S.E. ~ ...... ~ ,.., ~ r-- - ~~~ -- ~ I'"" r". la- -- - .r-. """' .... ~ ---- r-- ~~ -- r-...... r----_ ~ 1 ...... 10 I'......
s
4
3
2
100 1 .1 1 .2 1.3 1.4 1 .5 3 4 5 6 7 8 9 1 0 20 30 40 50 100 RECURRENCE INTERVAL (in years) l lOSTAGUM R. AT PAGSABANGAN, TAGUM, DAVAO MINIMUM FLOW FREQUENCY CURVE DA= 2326 Sq. Km. Period Of Record 18 Yrs. Figure V-A-16
34 1 9 8 LEGEND: ) 7 0 OBSERVED ANNUAL MINIMUM FLOW 0 6 COMPUTED FREQUENCY CURVE (CFC) 0 --- 5 ----- C.F.C. + S.E. 0 (' ...... _ C.f.C. - S.E. 4 ---- r- ...... "'" ... _ 3 ~ ro...... ~ ,...... ~ ..... r-..... lo-...__ ...... ~ ~ ~ ~k: .._ .. ~ - ~- ~-- "O ~~. -- c -- 0 r--.:-0.. ~ ~~ ...... ~ r----...... E 1 r---- 10 ~ 109 .... c .. ' "' ~ "I\. \. \ \ \
1.1 1.2 1.31.41.5 3 4 5 6 7 8 910 20 30 40 50 100 RECURRENCE INTERVAL (in years) 1109 MA TINA RIVER AT PANGI, MATINA, DAVAO MINIMUM FLOW FREQUENCY CURVE DA = 48 Sq. Km. Period Of Record 9 Yrs. Figure V-A-17
101 1 9 LEGEND: .. 0 OBSERVED ANNUAL MINIMUM FLOW I COMPUTED FREQUENCY CURVE (CFC) i.J ) ...._ --- 0 ------C.F.C. + S.E. (~ C.F.C. - S.E. :::-- .~ ---- ~ ...... ~-- ...... __~ ).....,-·- ... I ------~ ... ~ ------'---.... ·- ...... , --~ .._ "O c ...... 0 ", -- f"... E 0 1 ~ 10 c
..;.J v c<: :;: "' ~ 0
I I 10 7 8 9 10 20 30 40 50 1U 1.1 I .2 1.3 1.4 1.5 4 5 6 RECURRENCE INTERVAL (in years) MINIMUM FLOW FREQUENCY CURVE 1110 SI BULAN RIVER AT SI BULAN. STA. CRUZ, DAVAO Figure V-A-18 D<\ = 128 54. Km. Pr1iod 01 R,·cord 11 Yr" 35 there had been no efficient system of registering groundwater data. It was just re cently that the National Water Resources Council ( NWRC) h~s endeavored to consolidate all water resource developments ancJ the corresponding data through out the country. Well drillers and well owners are require~ to submit well-l_og data from their wells prior to their application of water permits. However, despite NWRC's rigid campaign on the registration of water users, the resp.onse from the private sector has been far from sufficient. Thus, only the qua.nt1ty of ground water utilization by the government sector can somehow be described. In the Tagum-Libuganon Basins, the former Bureau of Public Works has developed 406 wells for domestic supply purposes.
A.3.2 groundwater assessment The macro-picture of the groundwater resources of the basin is shown in a cyclogram map describing the borehole data, the specific capacity, static water level, etc., and is presented in Figure V-A-19. Specific yields of five per cent (5%) for permeable layers and three per cent (3%) for semi-permeable layers of aquifer system were assumed. As to the estimated inflow to the groundwater reservoir system, it is assumed that ten per cent ( 10%) of the average annual rainfall penetrates to the bearing formation. The averages of the groundwater parameters of the different municipalities within the Tagum-Libuganon Basins is presented on Table V-A-5. The average drilling depth is about 38 meters with an average specific capacity of 0.74 liters per second per meter ( 1 ps/m). Of the 406 wells considered, average static water level is approximately 11.54 meters below the ground surface ( mbgs) with 178 wells having a static water level of less than or equal to 6 mbgs. Furthermore, the groundwater mining picture for the entire influence area depicting the relationship of the parameters with the life of the aquifer system is exhibited in Figure V-A-20. Total groundwater storage is estimated at 5,812 MCM with an inflow to the groundwater reservoir system of 859 MCM/year. Recommended safe yield level is also set at 859 MCM/year. If a 50-year ground water mining is allowed, a total of 976 MCM/year is available for the area. Groundwater mining pictures of the contributing basins are in Appendix A.
A.4 Sedimentation and Water Quality No sedimentation studies can be performed since no data are available for the basins. Also, water quality or surface and ground water cannot be determined due to the absence of data.
A.5 Evapotranspiration
. There is no evaporation station operating within the basins. A synoptic station however, located in Davao City, collects climatic data for the area. Using t~mp.erature data. from the said station, average monthly and annual evapotrans p1rat1on were est1m.ated ~o.r a thirty-year period. Estimates were made using the Blaney Method which ut1l1zes temperature data in computing consumptive use or evapotranspiration.
36 124°45' 125°00' 125°15' 125°45' 126°00' 12s 0 15' 12s0 30' 12s 0 4s' 8°45'
9•30' 0°30'
a•rs· 0°15'
a•oo' 8°00'
,-.-.'"'- 7•45' 7°45' ~
7°30' 7°30'
7°15' 7°15'
70 7°00'
LEGEND:
6°45'
6°30'
Fl~ure V-A-19 s0 15 6°15' CYCLOGRAM MAP TAGUM-LIBUGANON BASINI IHI• I• ICll••etero
11 O 11 10 II 10 ~I IO llMI. 6-00 6°00·
126°00' 12s0 15' 126"30' 12s•45' 124°45'
37 Figure V-A-20 GROUNDWATER MINING PICTURE T AGUM-LI BUGANON BASINS
7000
6000 ad >- ~ -u 5000 ~ z ESTIMATED GW STORAGE = 5812 MCM - ESTIMATED SAFE YI ELD = 859 MCM/YR. 0 ESTIMATED 50.YR GWM YIELD = 976 MCM/YR. ....f ESTIMATED 50.YR GWM 2 <{ WELL DENSITY = 0.12 MCM/KM ~ 4000 oc 0 :r: I- ~ ~ 3000 z 5812 ~ ~Q- t +-859 ~ 2000 \( ~ 1000
0 0 20 40 60 80 100
PERIOD OF EXHAUSTION Tin years
38 Table V-A-5 GROUNDWATER STATISTICAL DATA Tagum-Libuganon Basins
No. of Average Ave. Normal Average Specific No. Towns Wells Well Depth Static Water Capacity Considered (M) Level (L/S/M) (MBGS) ------1. Sto Tomas 3 47.87 1.62 0.83 2. Tagum 21 33.68 2.97 0.91 3. Asuncion 2 43.45 17.38 1.29 4. Babac 29 42.53 29.02 0.72 5. Sta. Cruz 14 26.58 13.20 1.82 6. Kapalong 9 25.85 9.55 0.50 7. Mabini 9 18.75 3.53 0.92 8. Maco 2 15.55 1.83 0.06 9. Nabunturan 6 18.33 2.23 0.43 10. New Corella 1 25.61 0.91 0 11. Panabo 35 17.32 4.05 0.63 12. Pantukan 39 20.99 3.31 0.78 13. Sam al 32 55.91 37.70 0.71 14. Davao City 189 49.67 24.67 1.01 15. B unawan 1 41.16 41.16 16. Sasu 11 24.15 2.63 0.28 17. Dona Alicia 1 79.57 0.61 0 18. Mampising 2 94.97 11.28 1.68
Table Y-A-6 presents the computed values. Mean monthly evapotranspira tion ranges from a minimum of 101 millimeters (mm) for the month of February to a maximum of 125 mm. for May. Average annual evapotranspiration is approx imately 1,390 millimeters. B. Land Resources
B .1 Topography and Drainage Located in the eastern portion of the island of Mindanao, the Tagum-Libu ganon Basins lie between the provinces of Davao del Norte, Davao Oriental and Bukidnon. Bounded on the north by Agusan del Sur and by the Davao Gulf on the south, they encompass the western side of Davao del Sur. With 8 minor and one major river basin, they measure a total of 7 ,901 square kilometers. Mt. Ampaoid and Mt. Olagusan, both situated on the north are the major landforms of the area. Lowlands are very limited. The coastal plains are bordered mostly by hilly areas that gradually rise into mountains. Although the entire area of Davao is exceedingly mountainous, the Tagum Libuganon Basins proper is somewhat level and drained by many creeks and rivers. Libuganon River is its major water artery with Tagum river as its main tributary. Originating from the eastern slope of Mt. Ampaoid, they flow south easterly and discharge into Davao Gulf.
39 Table V-A-6 ESTIMATED MONTHLY EVAPOTRANSPIRATION (BLANEY METHOD) in millimeters Tagum-Libuganon Basins
Station: DAVAO CITY Lat. 07°18'00" Long. 125°35'00"
DEC YEAR JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV
112 1 108 99 115 116 126 123 124 119 115 115 112 2 110 101 115 115 124 122 124 119 113 116 109 111 3 108 101 115 118 128 123 123 121 115 117 110 112 4 111 101 115 114 124 121 123 122 114 115 112 113 5 110 103 117 118 123 121 124 121 114 116 113 112 6 113 99 112 115 123 122 123 120 116 117 110 113 7 107 101 115 115 122 121 121 121 117 117 112 113 8 108 100 114 115 124 141 123 121 117 115 111 113 9 112 101 114 114 125 123 122 120 113 114 1i2 115 10 113 105 120 119 129 123 126 121 117 118 113 116 11 109 102 120 119 124 120 122 119 114 115 110 112 12 112 99 118 119 125 119 122 120 113 115 110 109 13 108 101 118 118 123 118 120 119 114 115 111 112 14 108 98 116 118 124 119 121 120 114 118 110 111 15 111 98 116 119 126 120 122 120 116 116 111 113 16 112 100 116 117 124 119 122 120 115 116 110 112 17 109 101 117 117 124 119 121 120 115 116 111 110 18 108 101 120 120 124 120 122 121 114 116 111 112 19 112 102 118 120 128 122 125 123 117 116 111 113 20 110 101 119 120 124 121 124 122 116 117 111 114 21 108 101 117 119 126 121 122 120 115 117 110 112 22 111 102 116 118 125 120 121 118 115 115 109 109 23 110 102 120 121 125 120 123 121 116 115 111 111 24 111 101 115 118 124 119 124 120 114 117 111 112 25 113 103 119 116 124 120 123 119 115 119 109 113 26 108 99 116 116 125 120 123 121 116 115 111 111 27 111 101 116 115 124 118 123 122 116 117 111 108 28 110 100 116 118 144 120 124 123 114 117 111 118 29 110 100 115 119 126 119 122 119 113 117 112 112 30 115 106 120 122 126 122 124 122 117 119 113 112
MEAN 110 101 117 118 125 121 123 120 115 116 111 112
B.2 Slope Complex Five general slope classifications are used to define the total cultivable land areas which can be improved through proper irrigation systems and soil conserva-
40 tion practices. The table below shows the general slope categories from nearly level areas to steeply sloping terrain. Their corresponding areas and percentages to the total basins' area are also shown.
Table V-8-1 SLOPE CATEGORIES, CHARACTERISTICS, AND AREA COVERAGE Tagum-Libuganon Basins
Slope Area Percentage Category Description (Sq. Km.) (%) A Includes all level to nearly level lands with slope ranging from 0 to 3 per cent. Areas belonging to this category are the most suitable for irrigation because of their flat terrain. Depending on soil physical condition, 3 per cent slope is about the maximum slope if the land is to be used for lowland rice production. 3,816.0 48.0 B Consists of gently sloping and gently un dulating lands with slope ranging from 3 to 8 per cent. Gently sloping lands are suitable for irrigation but require slight terrain modi fication in terms of contouring or terracing. Depending on soil and climatic conditions in the area, 8 per cent is about the maximum slope for upland crop production that will require more complex and expensive soil conservation practices. 1,122.0 14.0 c Consists of moderately sloping and moder ately undulating lands with slopes ranging from 8 to 15 per cent. Due to terrain restric tion, irrigatjon for purposes of lowland rice production will not be feasible. Intensive soil conservation measures are necessary to keep the soil in place when necessary. 1,556.0 20.0 D Includes steeply sloping, rolling and undulat ing lands between 15 to 25 per cent. On these lands cultivated crops cannot be pro duced continuously over an extended period of time. Tree crops, however, can be grown. 1,146.0 15.0 E Includes those that are steeply sloping to hilly and mountainous terrain. It includes all lands with a slope greater than 25 per cent. This slope category is not suited to any type of cultivated crops and should be left as forest cover. 261.0 3.0 TOTAL 7,901.0 100.0% 41 126"oo'
- a·oo·
LOC,t.TIO" W,t.,.
- 7°40'
7•30' 7•30'
1•1!!'
---- REGIONAL BOUNDARY -··-MAJOR BASIN BQ..;NDARY -·-MINOR BASIN OOUNDARY --- PROVINCAL.BOONDMY -1•00' ~ RIVER, GREEK @ PROVINCIAL CAPITAL • CHARTERE:D CrTY O MUNICIPALITY
~ ~~~~OF~~L6 ~~~L WITH Sl..0'€ ~ ~m~L~PIR~~~~ OM~JP3~~~ATIOO
lillllllllllill ~~mfkJ ~~tfP~R~~~81~ 8· l&"Ao
~ ~p~~~~~a.J.m&l,i~ 2~~LAT1Ng. .. " ~ ~lrW'sk~~ci1~ 1,\k~A~g:~~~~~S GENERAL SLOPES TAG UM-LI BUGANON BASINS
10 15 ?0 75 30 KW! Figure V-B-1 s•30' 120• 1!1' 12!1°30' 12!5°40' 12fl"OO' 12a• 1e·
42 B .3 Geology
The rugged western and eastern mountain ranges are mainly exposed to lava flows of impervious tuffaceous mudstone and graywacke of metamorphic origin. Recent alluvium deposits of river and coastal deposits and other marine carbonates are found mostly in the level areas in the central part, making them some of the best productive agricultural lands. The southern and eastern sides are conformably overlain by sedimentary for mations, also of hornblende andesite, lava agglomerate and ash flows and volcanic ash.
Table V-B-2 GEOLOGIC FORMATION, CHARACTERISTICS AND AREA COVERAGE Tagum-Libuganon Basins
Area Percentage Symbol Age Lithology (Sq. Km.) (%)
R Recent Consists of outwash, valley fill, river and coastal deposits of clay, silt, sand, gravel, corals, and other marine carbonates. The detritals are derived from older rock formations. A considerable portion of the Davao City lowlands is covered with clay, possibly shallow coastal deposits. 1,243.0 16.0 Pliocene to Consists of limestone, marly, cora Pleistocene line, bedded and non-bedded with sinkholes and underground channel ways. 546.0 7.0 Nll Late Oligocene Consists of the upper dense lime to Middle stone member of the Mangagoy for Miocene mation in B islig, Surigao del Sur and second uppermost member of the Kalagutay group which is distributed west of the peridodite intrussive in Western Davao. These sedimentary formations conformably overlie the basin basement metavoicanic and metased imentary rocks. They are partly folded and faulted. 134.0 2.0 N2S Late Miocene Consists of tuffaceous conglomerate, to Pliocene sandstone and shale. The elastic rocks are porous and moderately in durated with loamy clay as main cementing material. The basal con glomerate and sandstone are derived from basaltic rocks. 292.0 4.0
43 Table V-B-2 (cont.) Area Percentage (Sq. Km.) (%) Symbol Age Lithology Pgl Paleocene These are granodioritc, quartz dio rite, dolerite and dacite. The grano d iorite is gray and holocrystalline. It altered the adjacent andesite. 241.0 3.0 NI Middle Miocene Consists of hornblende andcsitc plugs, basalts, dacite, andecite lava, agglo- 40.0 0. merate as in flow. Pliocene to This unit consists of conglomerate, Pleistocene sandstone, siltstone, shale, tuff and thin limestone. In Davao City, those derived from the late Miocene to Pleistocene volcanics are likely to be grayish. These rocks weather to brownish and reddish soil. They are partly folded and faulted. 734.0 9.0 QV Pliocene to The volcanic core central areas are Pleistocene reported to consist of Pliocene to Pleistocene hornblend andesitc. The rock is gray, dense and hard. It is generally porphyritic with hornblend and plagioclase feldspar phonocrysts. D acitic phases occur as lava flows. Agglomerate and ash flows occur. 443.0 5.0 QVP Pliocene to This consists of andesite, basalt, lava, Recent and agglomerate flows, tuff and vol Pyroclastics canic ash. It is subaqueous and sub aerial. 719.0 9.0 UC Paleocene Consists of serpentinized peridotite of saxonite, dunite. Pyroxenite varie ties in Davao, and gabbro. 137.0 2.0 Kpg Cretaceous to This unit is intercalated with the Paleogene Cretaceous to Paleogene lava flows. It consists of dense, relatively imper vious tuffaceous mudstone and gray wacke that have been partly meta morphosed. It is intruded by Paleo cene peridotite, diorite and dolerite. It is exposed in the rugged western and eastern Davao forested mountain ranges. 1,558.0 20.0 Pliocene to Fossiliferous mudstones, marl, im Pleistocene pure limestone, sandstone, conglo merate with younger poorly conso lidated, calcareous silts tone and con glomerate. 1,814.0 23.0 TOTAL 7 ,901.0 100.0 44 B .4 Soils and Capabilities B .4.1 .soil classification Classification of the given area into different soil categories is essential for the proper evaluation of such area to determine the lands agricultural adap tability. The soil groupings are primarily based on the profile, parent rocks, texture, relief and drainage characteristics of the soil. The table below shows the characteristics and distribution of the different soil classifications. Areal extent is presented in Figure V-B-3.
Table V-B-3 MAJOR GROUPS OF SOILS, CHARACTERISTICS AND AREA COVERAGE Tagum-Libuganon Basins
Area Percentage Classes Description (Sq. Km) (%) A The soils under this class were developed from recent alluvial deposits. They have medium to coarse texture from A down to the C horizon. The relief is generally level to nearly so. Drainage is good to partly excessive. Permeab ii ity is very rapid to moderately rapid. 1,241.0 16.0
B Under this class are soils of upland areas developed from hard igneous rocks, such as andesites and basalts. The soils, thus, developed are deeply weathered, fairly friable, reddish brown, dark brown to red. Internal drainage is good. Permeab ii ity is moderate. 964.0 12.0 c Soils under this class are soils of upland areas developed from shales. The relief is rolling to hilly. The soil is very sticky and plastic when wet and hardens upon drying. Permeability is very slow. 2,607.0 33.0
D The soils under this class are of older ter races or uplands developed from the weathering of limestone of calcareous shale and sandstone. The relief is from un dulating to steeply rolling. 324.0 4.0 E The soils under this class include soils found in mountainous, rugged terrain. They have not been classified because of terrain restrictions. 2,765.0 35.0
TOTAL 7 ,901.0 100.0%
45 B .4.2 land capabilities The land capability classes are represented by letter symbols. They indicate the extent and limitations of crop productivity of each class progressively. Rice here is given priority as the major crop, followed by secondary crops and other vegetation of agricultural value. Table V-B-4 presents the area distributions and percentage of each class. Figure V-B-4 shows areal coverage.
Table V-B-4 LAND CAPABILITY CLASSES, CHARACTERISTICS AND AREA COVERAGE Tagum-Libuganon Basins
Classes Description Area Percentage {Sq. Km) {%)
A Good cropland. It is highly suited to paddy rice production which requires simple but good farm management prac tices. The soils in this class are aadapted to almost any crop common in the area. 724.0 9.0
B Moderately good cropland. Soil in this class is suited for cultivation of diversified crops. It has some slight limitations which may include effects of gentle slopes, moderate susceptibility to erosion and slight salinity. 996.0 13.0
c Fairly good cropland. Soils in this class have moderate restrictions that limit the choice of crops. It is best recommended for tree farms. However, when used for cultivation of crops, it requires careful management and complex conservation practices. 897.0 11.0
D This type of land has severe limitations which include, among others, steep slopes, severe susceptibility to erosion and shal low soils that limit its use largely to pasture. 2,198.0 28.0
E Very steep land, excessively eroded, shal low, rough, and dry for cultivation· hence, it is best suited for forest. ' 3,086.0 39.0
TOTAL 7,901.0 100.00% 46 B .5 Soil Erosion Susceptibility Soil erosion, one of the most restraining factors of soil fertility, needs to be identified, too, in order to check the various degrees of losses accordingly. Shown in table below are the area and percentage of each group to the total basins' area. Figure V-8-5 shows areal extent.
Table V-B-5 SOIL EROSION SUSCEPTIBILITY AND AREA COVERAGE Tagum-Libuganon Basins
Classes Description Area Percentage (Sq. Km) (%)
1 Not susceptible to erosion 3,895.0 49.0 2 Moderately susceptible to erosion 0.0 0.0 3 Susceptible to erosion 4,006.0 51.0 4 Very susceptible to erosion 0.0 0.0
TOTAL 7,901.0 100.0%
B .6 Existing Land Use A notably mountainous region, the western section is consistently covered by forests, which is almost 50 per cent of the basins entire area. The adjacent uplands are utilized as pasture grounds, the next dominant land use cover. Coco nut and other permanent crops fill the moderately sloping terrain, including the coastal plains along the Davao Gulf and the whole Samal and Talikud Islands. Level areas constitute an advantageous 48.3 per cent, but these are not fully cultivated to rice since soil characteristics in some areas do not allow for produc tive rice culture. However, rice dominates the centralmost portion while the northern expanse is devoted to diversified crops. All in all they make up for a total of 1,088 sq. km. or roughly 13.8 per cent of the total area.
Table V-B-6 EXISTING LAND USE PATTERN AND AREA COVERAGE Tagum-Libuganon Basins Area Percentage General Land Use Pattern (Sq. Km.) (%)
Rice 335.0 4.0 Diversified Cropland 733.0 9.0 Tree Farms 1,000.0 13.0 Grassland/Shrubland 2,040.0 26.0 Forest 3,773.0 48.0
TOTAL 7,901.0 100.0%
47 B .6.1 special land use
B .6.1 .1 national parks/archaeological/ recreational sites Davao City itself is a major tourist attraction in thP. South. The presence of a highly rated hotel makes it a more ideal vacationing spot for foreign and local tourists alike, who want to get away from it all. Several beach resorts are already in business and others arc just awaiting further development. As for national parks, none has yet been declared within the Tagum-Libu ganon region. B .6.1 .2 forest reserves Only one forest reserve is located within the Tagum-L ib uganon territory. This is the Mt. Kimongol Forest Reserve covering some 20,432.00.
B .6.2 proposed land use Land capability analysis has shown that the basins have a potential agricul tural area of approximateiy 4,815 square kilometers comprising some 61 per cent of the basins' total land area. Of these agricultural potentials, about 2,617 square kilometers or half exhibit potentials for general cropland use. However, land use information shows that the basins' approximate agricul tural land is 4, 128.0 square kilometers or about 52.2 per cent of its total land area where the basins' croplands are roughly placed at 2,000 square kilometers or some 52.2 per cent of the present agricultural aggregate area. Comparing. the soil's .Jdaptability to crops with the basins' actual use of land will indicate that its agricultural land will increase by 16 per cent. Noticeable in crease will be observed in the basins' rice areas and somewhat minimal with the other crops. Further development of rice culture in general and the basin's other primary crops will employ multiple use of its prime agricultural lands and eventually a shift in its present land use specially in areas that are classified as potentially cultivable.
48 Table V-B-7 AREA REQUIREMENT/LIMITATIONS ON LAND USE Tagum-Ubuganon Basins
Land Use Land Capability Land Use Requirement (Sq. Km.) {Sq. Km.) {Sq. Km.)
Irrigated 144.0 248.0 Non-Irrigated 211.0 265.0 Total Riceland 335.0 389.0 230.0 Diversified Cropland 733.0 263.0 393.0 ------Total Cultivated Land 1,088.0 1,720.0 623.0 Tree Farms 1,000.0 897.0 371.0 Grassland/Shrubland -2tQ_4-Q~_ 1_J~~Q ~Q_~_i)_ Total Agricultural Land 4,128.0 4,815.0 3,067.0 Forest 3,773.0 3,086.0 ------TOTAL 7,901.0 7 ,901.0
49 126"00' RI a1011 11
LOCATION MAI'
7•4&'
7•30' 7•30•
LEGE NO:
~RECENT (R)
~ PLIOCENE TO PLEISTOCEN l"•e' RECENT !N +0 LI ~AND 3 1 1 IN -t-0 Sl ~ ~t i'1~~~~ET,?E 3 1 EEEE PLIOCENE TO RECENT (QVP) llifJKj ~~igc~~OECE~~2TSO) em ~A~7Dg~~G~75~fNE( N1Ll ~ PLIOCENE TO PLEISTOCENE ltmtWl AND RECENT I QV) 1•00' !HHm MIDDLE MIOCENE (NI) 7 -oO ~ PALEOCENE TO ~ OIORITIC !Pg ll ~ PAL!OCENE (U Cl ~ CRETACEOUS TO ~PALEOGENE (Kpg) ~PLIOCENE TO ~PLEISTOCENE IN~I
Figure V-B-2 GEOLOGIC FORMATION TAGUM-LIBUGANON BASINS SCALE 1k lfU..OM(T[M F~i I~ I - I 71 ':. 10 '' 20 l':. 30 •MS
12~·30• 126•00' 126"•:1'
50 125°15' 126"00'
9"15'
11•00'
LOCATION llAI'
7•4&'
7•30' 7' 0 30'
mmM ~Ctivff:''bW~if~OM RECENT lllIIllIDIIl1 ~~~~ ~~Ruri'To'\NEDO~Eif~c~~VELOPED
1·00· ~ ~~~ ~_k'L"ELfND AREAS DEVELOPED mmJ ~~~ ~E~f~tR~~oARJAL~M~~~ur~~ CALCAREOUS SHALE AND SANDSTONE ~ ~~l}~EbN~~~~AINOUS •••- REGIONAL BOUNDARY -··- MAJOR BASIN BOUNDARY -·- MINOR BASIN BOUNDARY PROVINCIAL BOUNDARY ~ RIVER, CREEK @ PROVINCIAL CAPITAL &•4&' e CHARTERED CITY o MUNICIPALITY
MAJOR GROUPS OF SOILS TAG UM-LI BUG ANON BASINS SCALl •N KILOMETER I I I +===; 0 5 10 15 25 30 KMS Figure V-B-3 e•30' 126°00' 126°15' 6•30' 125•15' 125°30'
51 -----1 14'.b•()O'
"I a10M 11
LOC.&TIOll '""'°
7•45'
7•30'
7°15°
---- REGIONAL BOUNDARY MAJOR 8:.0SIN ea.mot.RY MINOR BASIN OOUtWARY PROVINCIAL 80\HWARY @ PROVltJCIAL CAPITAL CITY o MUNICIPtJ...ITY
~ GOOD CROPLAND
1•00' ~ MOOERATElY GOOO CROPLAND 7"'0C1
- FAIRLY GOOD CROPLAND
Im AREAS SUIT~ FOR -PASTURE
- AREAS SUITABLE FOR AQUA-OJLTURE
~ AREAS THAT SHOULD BE PERt.~AtENTLY ~ COVERED WITH FOREST 9"45' -
LAND CAPABILITY TAGUM-LIBUGANON BASINS Scale in Kilometer
10 ,, lO "' lO .... , Figure V-8-4 &•JO' 125°15' 125° 30' ·~·40' 12t1•00'
52 125"1'3' 12!!0 45' 12e'°OO'
11(.1011 11
11"15'
LOCATION MAI'
LEGEND: --- REGIONAL BOUNDARY -··-MAJOR BASIN BOUNDARY -·---MINOR BASIN BOJNDARY 1•00' - ·-- PROVINCIAL BOUNDARY ~;:: RIVER,CREEI< • PROVINCIAL CAPITAL/CHARTERED Ci(Y 0 MUNICIPALITY ~ ~E~foE:TiBLE
~ r:go::t~i~ SUSCEPTIBLE
~ SJSCEPTIBLE TO EROSION 8"45' m.iiJ ¥5~~g~1 ~EPTIBLE
SOIL EROSION SUSCEPTIBILITY TAGUM-LI BUGANON BASINS SCALE IN KILOMETER FW"4 I I I 1779 5 0 5 10 15 20 ..?5 30 KMS. Figure V-8-5
12!5°4!1'. 126°15'. 125°15' 125°30'
53 12D"49' •• ••Oii ..
1•00'
,
7~·
1~·
7•19' 1•18'
- RICELAND lml DIVERSIFIED CROPS
~ COCONUT AND OTHER FRUIT TREES
- GRASSLAND I SHRUBL~D roo ~FOREST
It~ SWAMPS, MANGROVES, MARSHES
REGIONAL BOUNDARY MAJOR BASIN BOUNDARY MINOR BASIN BOUNDARY PROVINCIAL BOUNDARY @ PROVINCIAL CAPITAL ··49• 0 MUNICIPALITY
Figure V-8-6 EXISTING LAND USE TAGUM-LIBUGANON BASINS SC....l '" ""°""' T(• f- r-l I - 1 ' oo 11 10 n JO• ...
••'Jtl 125•30• •·Ja
54 1•15' 7°1!1'
BOUNDARY REGIONAL BOUNDARY -- -- PROVINCIAL BOUNDARY --- MAJOR BASIN OUNDARY -·•= MINOR BASIN B -· CREEK ~ RIVER, CAPITAL PROVINCIAL @ CHARTERED CITY ~ MUNICIPALITY • FOREST RESERVE
Figure V-B-7AME REFUGE ERVES, G y FORE~TN ~E:I RD ~~~ SCALE IN Kll..OMETER 30 KMS. 10 l!I 12&•15• 55 CHAPTER VI PRESENT AND FUTURE DEVELOPMENT RESOURCE NEEDS A. Social Environment A.1 Demographic Charc.cteristics A.1 .1 population The Tagum-Libuganon Basins comprising 17 municipalities had a to~al population of 1 ,012,931 in 1975. This reflected a 27 per cent increase from the 1970 total or an annual growth rate of 5 per cent. Table Vl-A-1 summarizes the basins' population characteristics while Tables E-1 and E-2 show its popula tion distribution. Table Vl-A-1 ACTUAL AND PROJECTED POPULATION, DENSITY AND STRUCTURE-1-/ Tagum -Libuganon Basins Actual Projected 1970 1975 1980 1990 2000 Population 796,100 1 ,012,900 1 188 3oo±-/ 1,914,200 2,763,400 ' ' Density 88 112 132 212 306 Distribution Urban 268,200 286,400 343,700 578,800 872,800 ( 34) ( 28) (289) ( 30) (32) Rural 527,900 726,500 844,600 1,335 ,400 1 ,890.700 ( 66) ( 72) (71) (70) ( 68) J}Refer to Appendix E for the breakdown of figures. Figures in parenthesis refer to% share . .1/ Based on NCSO Preliminary Release. A.1.2 population density Population density in the area was placed at 112 persons per square kilo meter. Of the 17 municipalities, 8 municipalities had population densities higher than the basin average, with the most densely populated ones being Tagum (328), Panabo {274), Sabak (261), Davao City (219), Samal (197) and Kaputian (164). Low population densities were noted in the towns of kapalong (16), Mabini (43), Pantukan (45) and Asuncion (57). A.1 .3 urban and rural population structure The 1975 census statistics showed that the basin was predominantly rural where 72 percent of the basin population resided. Of the 17 municipalities, 2 were totally rural. Only 28 percent of the basin population resided in urban areas. 57 A.1 .4 age-sex structure and dependency ratio The population aged 1-14 years comprised 44 percent of the total popula tion. The working age group (ages 15-64) accounted for 54 percent or 541,918 of the total while the older group ( 65 years and over) represented only 2 percent. The dependency ratio in the basins area was placed at 0.86. The basin sex-structure showed a 52 percent-48 percent male-female distribution. A.1 .5 household/family size The total number of households reached 169 ,386 while the number of families was higher with 173 ,700. The average household and family sizes were both 6. By the year 2000, the projected number of households and families will reach about 462, 100 and 4 73 ,800 respectively. A. l .6 demographic projections Using the population projections (medium assumption) of the NCSO, the computed annual growth rate of the basin was placed at 4 percent for the period 1975-2000. In absolute terms the population is expected to increase from 1,012,931 in 1975 to some 2,760,000 in 25 years. The urban population would reach some 872,700 while the rural population about 1,890,000. The population density will likewise increase from 112 persons per square kilometer in 1975 to 306 persons per square kilometer in the year 2000. A.2 Income A.2.1 income levels Based on the 1975 NCSO preliminary hand tabulations, the estimated total family income of Tagum-Libuganon Basins was i>l ,291 million, 26 percent of which was accounted for by the ruban sector. (Table Vl-A-2) Table Vl-A-2 ESTIMATED TOTAL INCOME AND PER CAPITA INCOME CLASSIFIED INTO URBAN AND RURAL, 1975 Basin 1 I Total Family Income ('PM) 1,291 Urban 335 Rural 956 Per Capita Income ('P) 1,275 Urban 1,170 Rural 1,416 11 NCSO Preliminary Tabulations, 1975 58 A.2.2 per capita income The average family income in the basin was estimated at 'P7 ,893 reflecting the basin per capita income of'Pl ,275. The urban sector of the basin, per capita income reached ::Pl ,170 compared to the rural figure of Pl ,416. Table Vl-A-3 INCOME PROFILE BASIN Tagum-Libuganon Basins Bas i n if Percent of Families % Share of Total Urban Rural Total Income Under ?2,000 28 17 31 4 'P2,000 - 'P'4,000 42 48 40 21 1>6,000 - ?-10 ,000 15 19 14 15 'Pl 0 ,000 - Over 15 16 15 60 J/ Estimates Based on data from the NCSO Household Surveys Division (Provincial tabulations) Table Vl-A-4 DISTRIBUTION OF FAMILIES BY INCOME CLASSES Tagum-Libuganon Basins 1965 1971 1975 Under ?2 ,000 23.7 25.2 27.6 :P2 ,000 - :P6,000 42.6 43.4 42.4 P6,000 - 'P'l0,000 17.4 15.9 15.2 -Pl 0,000 - over 163 15.5 14.8 Percent Below mean 40.3 70.4 73.1 Family Income Source: NCSO 59 A.2.3 income profile The income distribution pattern in the basin showed that 28 percent of all fam ii ies belonged to the income stratum with annual income below 'P2 ,000. Alto gether these families contributed 4 percent to the basin total income. The middle income group (those receiving between =r2 ,000-PlO ,000) comprised 57 percent and contributed 36 percent to the total income; while the high income group accounted for approximately 15 percent of all families dnd earned 60 percent of the total income (Tables Vl-A-3 to Vl-A-5). Table Vl-A-5 SELECTED INCOME MEASURES 1961, 1965, 1971 AND 1975 Tagum-Libuganon Basins 1961 1965 19TI 1975 ---~------GINI RATIO Basin .3811 .3906 .3984 .3997 Urban .3988 .3981 .4036 .4056 Rural .4010 .4092 .4903 .4937 Mean Family Incomes (In Pesos) 4,738 5,037 6,281 7 ,893 Index of Intra-Basin .4172 .4190 .4287 .4296 Inequality ------·--·------A.2.4 farm income In 1971, there were 46,444 farms in the planning area which produced crops valued at P218 million. The average income reached some P4,699 (Table Vl-A-6). Table Vl-A-6 FARM INCOME STATISTICS, 1971 Tagum-Libuganon Basins Basin Farms 46,444 Value of Crops ('PM) p 218 Average Income/Farm (:P:) p 4,699 Source: Census on Agriculture, 1971 A.3 Labor Force and Employment Structure A.3 .1 labor force . The working age population ( 15-64 years) in the basin was placed at 541 900 which was placed at 54 percent of the total basin population. The econ~mic 60 active population accounted for 5 6 percent or 303 ,000 persons of the total work ing age population while 44 per cent were economically inactive. Of the economi cally active 96 per cent were employed (Table Vl-A-7) Table Vl-A-7 LABOR FORCE PROJECTIONS Tagum-Libuganon Basins Potential Economically Active Economically YEAR Labor Inactive Force Number % Employed % Unemployed % Number % 1975 541,900 303,000 56 291,000 96 12,000 4 239,000 44 1980 634,800 357 ,900 56 347,200 97 10,700 3 277,800 44 1990 1,024,100 585,800 57 574,100 98 11,700 2 438,300 43 2000 1,478,400 860,500 58 843,200 98 17 ,200 2 618,000 42 Based on data from the NCSO Integrated Census of the Population and its Economic Activities Report. A.3.2 employment Of the total employed force in the basin 68 percent were in agriculture, 8 percent were in industry and 24 percent were in tertiary sector. Agricutural workers totalled 197 ,900, while industrial and tertiary workers totalled 24,600 and 68,600 respectively (Table Vl-A-8). Table Vl-A-8 EMPLOYMENT DISTRIBUTION BY INDUSTRY GROUP Employment 1975 % 2000 % Agriculture 197 ,900 68 279,100 33 Industry 24,600 8 185 ,500 22 Mining 684 * 4,800 * Manufacturing 18,000 6 105,000 13 Electricity 470 * 2,000 * Construction 5,500 2 73 ,600 9 Services 68,600 24Yi 378,600 45 Commerce 20,700 7 9,800 1 Transportation 10,800 4 8,700 1 Service & Others 37,000 13 360,100 43 TOTAL 291,000 100.0 843,200 100.0 Based on data from the NCSO 1975 Integrated Census of the Population and its Economic Activities report. * Less than one. 61 A.3.3 employment projections . The basin potential labor force ( 15-64 years) was derived by applying the 1975 working age population proportion to the respective population projec tions. The results are shown in Table VI -A-7. If development programs proposed for the area will be implemer.ted within the next 25 years, the increase in employment levels due to this development will be reflected by an upward adjustment of labor force participation rates and employment ratios. The projected labor force participation rates and their corres ponding absolute figures are also shown in Table Vl-A-7. Assuming an increase of 1 percent in the employment ratio every five years, the employed population would reach 843 ,200 in the year 2000. U nemploy ment levels correspondingly will be reduced from 4 percent to 2 percent in the year 2000. A.4. Domestic and Municipal Water Use In this study, the 1975 average per capita water use of 0.115 cubic meters and 0.025 cubic meters were used for urban and rural domestic consumption respec tively. By the year 2000, per capita requirements arc projected to reach up to 0.190 cubic meters for the urban users and 0.040 cubic meters in the rural sectors. The basin domestic requirements are estimated to reach some 66,455 CMD in 1980, 129, 784 CMD in 1990 and 241,451 CMD in the year 2000. The shares of urban sector were 66, 69 and 70 percent respectively (Table Vl-A-9). Table Vl-A-9 PROJECTED WATER WITHDRAWALS FOR DOMESTIC USE (CUBIC METERS PER DAY) Tagum-Libuganon Basins ------~------1980 1990 2000 ------~----- Urban 43,650 89 ,714 165 ,824 Run.I 22,805 40,070 75 ,627 TOTAL 66,455 129,784 241,451 of Urban Intake % 66 69 70 A.5 Water Supply Facilities Sources . In 1970, rainwater was the main source of water for 48 per cent of the total basin households. The next major source of water were springs. The remaining household ~ere distributed as follows: open wells ( 14 per cent), pump (9 per cent), artesian wells {8 per cent), piped water (6 per cent) and lakes and streams (2 per cent). (Table Vl-A-10 and Table E-3 for breakdown). 62 Table Vl-A-10 NUMBER OF HOUSEHOLDS BY SOURCE OF WATER 1970 Source Number % Served Piped Water 7,179 5 Artesian Well 10,001 8 Pump 11,112 8 Open Well 18,216 14 Spring 19,719 15 Rain 62,358 48 Lakes & Streams 2,413 2 Total Number of Households 130,998 100 Source: NCSO 1970 Census of Population and Housing (Refer to Appendix E for breakdown of figures) A.5 .1 water supply infrastructure The Rural Waterworks Development Corporation ( R\VD C) has recognized three levels of services, namely: Level I, II and Ill. Among the three levels of services, Level I is the most basic. Essentially, water comes from point sources such as open wells, artesian wells and springs without a system of distribution. It is intended for rural centers where houses are clustered densely enough to jus tify a simple common piped distribution system. This system serves an average of 100 households. Level 111 services refer to a pipe system with individual house connections. Unlike Levels I and 11, it caters for densely populated urban centers. Based on the 1980 Survey conducted by the Ministry of Public Works and Highways (MPWH), the municipalities belonging to the Tagum-Libuganon Basins depend highly on existing public wells (Level I) as means of providing for its domestic water needs. There are 132 operational wells that serve an estimated population of 164,850 and 137 non-operational wells. At this point, the existence of Level 11 facilities cannot be determined yet si nee MPWH has no available data. So not exact number of Level 11 facilities is re- quired. Within the Tagum-Libuganon Basins, there are two (2) existing water di~ tricts2/Davao Metropolitan Waterworks and Tagum Water System. The for'.11er is attending to the needs of Davao City Proper and portions o: twelve ( 12) ad~acent barrios. It has a maximum capacity of 2.96 MCM/year and 1s generally serving. an estimated population of 40,000. On the other hand, the latter serves a population of about 31,000. ~ NWRC Survey, 1978. 63 With the population rapidly increasing, additional water supply facilities. will have to be installed to meet the water needs of the basins. On Table Vl-A-11 1s an inventory of water supply facilities (based on avail~ble data} along with the .re- quired additional facilities for the year 2000. Assuming an average ho~schold size of 6.0, some 5,637 units for Level I, 732 units for Level 11 and 16 units for Level 111, should be added to meet the demands of the basins. Table Vl-A-11 INVENTORY OF WATER SUPPLY FACILITIES Tagum-Libuganon Basins Province Estimated Projected Additional Popula- Required Addi- Municipalities Population Population tion to be Served nal Facilities Served ( 1980) (2000) {2000) Level Rural Urban Rural Urban Rural Urban II 111 ------~- -- -· ---- -·-- DAVAO DEL SUR 1. Sta. Cruz 3,845 44,784 41,892 40,939 136 40 2. Davao City 72,205 40,000* 843,053 558,566 770,848 518,566 2,569 190 DAV AO DEL. NORTE 1. Kapalong 2,800 74,335 12,219 71,535 238 43 2. Kaputian 3,850 58,879 55,029 183 26 3. Panabo 11,550 119,902 28,801 108,352 361 39 4. Sam al 7,350 45,053 10,473 37,703 126 17 5. Sto. Tomas 4,900 41,677 28,801 36,777 123 29 6. Asuncion 8,750 124,171 115,421 385 93 7. Mabini 3,850 42,264 20,946 38,414 128 30 8. Maco 2,800 90, 104 12,219 87,304 291 39 9. Nabunturan 1,750 77,032 22,692 75,282 251 26 10. Corella 2,450 53,250 11,346 50,800 169 31 11. Pantukan 11,800 58,640 15,710 46,840 156 29 12. Tagum 3,850 31,000* 87,150 75,930 83,300 44,930 278 57 13. Babak 11,200 36,296 13,964 25,096 84 17 14. Carmen 11,900 59,590 7,854 47,690 159 26 TOTAL 164,850 71,000 1,856, 180 861,413 1,691,330 563,496 5,637 732 16 National Water Resources Council (NWRC) Survey. 1978 No data for Existing Level 11 service *** Mawab has no data for estimated population served, thus computation is not included. A.6 Sewerage and Waste Disposal The basin had no existing centralized sewerage and waste disposal facilities. As per 1970 census report, much of the basin households had self-supplied systems. The survey s~owed that 30 per cent used the closed pit system, 28 per cent used the open pit, 16 per cent used flush/water sealed facilities and 2 per cent used public toilets. Approximately 24 per cent of the total households had no access to sani tary toilets. 64 B. Economic Sectors B .1 General Economic Structure B .1 .1 gross domestic product and employment The gross domestic product estimate of the Tagum-Libuganon Basins to talled to =?4,979 M in 1975. Agriculture gave the largest contribution with 43 per cent, closely followed by services with 42 percent and the least contribution of 15 per cent by Industry. In terms of employment, the basin absorbed a total of 290,982 workers in the same year. Of this total, 68 per cent were engaged in the primary industries, 24 per cent were absorbed by the tertiary industries and 5 per cent by the secondary industries. In the absence of data on labor productivity rates on basin level, the com puted labor productivity rates for the region were used to arrive at sectoral value added of basin GDP. In 1975, the highest average labor productivity rate was registered by Services at :P30 ,577 and followed by Industry at =f3=30,515. Agriculture has the lowest rate at only:P10,782. On the assumption that the labor productivity growth rates computed for the whole region are equally applicable to all component basins, a long-range projection of output/labor ratios were made up to year 2000. The annual growth rates used were 6 per cent for Agriculture, 15 percent for Industry and 9 per cent for Services. (See Appendix C). The resulting values were multiplied with the sectoral employment figures to compute for the projected sectoral GV A's of the basin. Analysis of the projection shows that if employment will increase· by 290 per cent over 25 years or 4 per cent annually, there will be a corresponding increase of 890 per cent in GDP within the same period or 9 per cent annually. A considerable shift will occur in both employment and GV A from Agriculture to Industry at the same time the increase in Services would pick up from the expan- sion in Industry. Employment in Agriculture shali be reduced to 33 per cent of the basins' total while that of the secondary and tertiary sectors shall increase to 12 per cent and 45 per cent respectively. Development in the plan period is expected to be led by the industrial sector's expansion with an annual growth rate of 15 per cent fol lowed by Services with a lower growth rate of 6 per cent. Agriculture, which con- tributed for the highest share of GDP, will have the least growth rate of only 5 per cent annually. In absolute terms, output in the primary sector shall have in creased by about 3 times, in the secondary sector by 36 times and in tertiary sector by almost 4 times. With the total basin population growing yearly at an average rate of 4 per cent during the 25 year plan period, per capita GDP (at 1977 p~ices) stood at :P4916in1975 and will reach alevelof:P15,052byyear2000.Th1srepresentsan annual' growth rate of 5 per cent. The level of per capita GDP in year 2000 will be about 3 times that of the 1975 level. Refer to Table Vl-B-1 and Figure Vl-8-1 for statistics on employment and output. 65 Figure Vl-B-1 GVA-EMPLOYMENT DISTRIBUTION BY MAJOR SECTOR TAGUM-LIBUGANON BASINS GVA ('PM) EMPLOYMENT {'000) 1975 AGRICULTURE 2000 ~ -·- -· F=v1 1975 I INDUSTRY 2000 \II I!\ 1975 'I SERVICES II II\ 2000 ti.. I I I I I I I I I ' ' I ' I I 28000 26000 10000 8000 6000 4000 2000 0 0 60 120 200 280 320 360 400 Table Vl-B-1 GROSS DOMESTIC PRODUCT AND GROSS VALUE-ADDED BY INDUSTRY GROUP, 1975 & 2000 {lnff.1at1977 Prices) Tagum-Libuganon Basins 1975 2000 Agiculture 2,133 6,280 Industry 750 27,059 Mining * 299 Manufacturing 636 19, 157 Construction 100 7,031 Electricity 14 572 Services 2,096 8,257 Commerce 1,803 1,366 Transportation 113 305 Services 180 6,586 GROSS DOMESTIC PRODUCT 4,979 41,595 Source; •Less than 1 million. B.1.2 sectoral highlights A brief perspective on sectoral performances and industrial characteristics relevant for economic analysis will be the main feature of the succeeding dis cussions. B .1.2.1 agriculture, fishery and forestry The primary sector in the basin is aimed to have an average growth rate of 4 per cent per year in the plan period. From its dominance as an output contri butor in 1975, it is projected to decline as other sectors, particularly Industry begins to grow at much higher rates. Hence, in 1975, gross value-added in this sector will drop from a share of 43 per cent to 15 per cent in year 2000. Moreover, its labor utilization capacity is seen to decrease from 68 per cent in 1975 to 33 per cent of the total employment of the basin in the next 25 years. In terms of crop production, palay, corn, and rootcrops accounted for almost 99 per cent of the temporary crops produced in the basin in 1971 with a combined value of =?62 million, while coconut and fruits for the permanent crops accounted for 84 per cent with a total value of =?38 million. B .1.2.2 industry In 1975, the Industrial sector's contribution to the Gross Domestic Product amounted the least at only 15 pr cent and only 8 per cent of the basins' total employment was utilized. For the next 25 years, the sector is expected to show a remarkable change. With the highest growth rate of 15 per cent annually, the 67 Figure Vl-B-2 AGRICULTURAL AREA DISTRIBUTION TAGUM-LIBUGANON BASINS PERCENT DISTRIBUTION AGRICULTURAL LAND USE AREA IN THOUSAND HECTARES PERMANENTMEADOWS4% ----- PLANTED TO TEMPORARY CROPS ALL OTHER LANDS ------ LYING IDLE TEMPORARY CROPS 39% PLANTED TO PERMANENT CROPS PERMANENT MEADOWS AND PASTURES PERMANENT CROPS 36% COVERED WITH FOREST GROWTH FOREST GROWTH 8% ALL OTHER LANDS Source: 1971 CENSUS OF AGRICULTURE 20 40 60 80 100 120 industrial GVA contribution will change from a mere 15 per cent in 1975 to as high as 65 per cent in year 2000. The total industrial output is being dominated by the manufacturing and construction sectors at 85 per cent and 13 per cent respectively in 1975. These are expected to hold the same positions for the next 25 years in view of extensive programs in preparation for the implementation of the region's industrial stra tegy. B .1.2.3 services In line with the development of both the primary and secondary industries, the Services sector contributed 42 per cent of GDP in 1975, and has an employ ment of 68,557 which is almost 3 times that of the Industrial sector's employ~ ment. Commercial activities accounted for 86 per cent of the sector's output while utilizing 30 per cent of the total service employment in the basin. From a share of 86 per cent in 1975, it decreased to only 17 per cent in year 2000. The results 9f the 1974 Annual Survey of Establishments in the Tagum Libuganon Basins showed a total of 35 ,612 firms engaged in tertiary activities. Of this total, 85 per cent or 30, 146 firms were engaged in commercial services; 9 per cent or 3,342 firms in Services and the least at 6 per cent were in the Trans portation, Communications and Storage sector. In terms or average annual employment, these industries absorbed a total of 36,754 persons for the same year. Among the service industries, Commerce absorbed a slightly bigger share than Services with 41 per cent and 39 per cent, respectively. Transportation had the least with 20 per cent or 7 ,406 persons. Gross output and book value of fixed assets for the whole sector registered at '?382 ,806 and :P254,226, respectively with gross output per employee highest in the Commerce sector (¥13 ,000), followed by Services (:P-9 ,000) and Transpor tation (=?8,000). (Table Vl-B-2). Table Vl-B-2 SUMMARY STATISTICS FOR SELECTED INDUSTRIES Tagum-Libuganon Basins (1974) No.of Employment Gross Book Value Estab Average for Output of Fixed lishments the Year ~ M) Assets (P'M) Mining 3 52 * 31 Commerce 30,146 14,839 192 102 Electricity, Gas and Water 6 351 53 63 Transportation, Communication and Storage 2,124 7,406 63 51 Construction 9 645 14 4 Services 3,342 14,509 127 101 *Less than a million Source; 69 B .2. Agriculture B .2.1 general The agricultural production pattern of the Tagum-Libuganon Basins was derived from the aggregate performances of the municipalities within its influence area. These include 6 municipalities in Davao del Sur and 15 municipalities in Davao del Norte. All these comprise a total area of 790,100 hectares. B .2 .2. agricultural area distribution The agricultural area of the basins comprised about 280,388 hectares in 1971 ( NCSO Census of Agriculture, 1971). This was further distributed into the following: 108,799 hectares or 39 per cent were planted to temporary crops; 100,022 hectares or 36 per cent to permanent crops; 31,013 hectares or 11 per cent were lying id le; 23 ,467 hectares or 8 per cent for forest growth; 11,310 hec tares or 4 per cent to permanent meadows and 5 ,778 hectares or 2 per cent classi- fied as al I other lands. B.2.3 farm features The Tagum-Libuganon Basins had a total of 46,444 farms. Of the total number of farms, 90 per cent were less than 5 hectares with the rest having 5 hectares and over. From the total number of farm operators, 71 per cent were full-owners, 26 per cent were tenants, 23 per cent were part-owners and 0. 7 per cent were of other forms of tenure. B.2.4. land ownership and distribution The land ownership and distribution pattern for all crops found in the basin followed a trend similar to that of income measures. The size of land distribution in the basin reflects its fragmented character with the majority of households (90 per cent) owning the smaller parcels of land ( 1.0 to 4.9 hectares), comprising about 34 per cent of the total farm area and almost 1 per cent of families owning the bigger land parcels (25.0 hectares and above) (Table Vl-8-3) Table Vl-B-3 VARIOUS MEASURES ON LAND OWNERSHIP AND DISTRIBUTION BY FARM SIZE, ALL CROPS, 1971 Tagum-Libuganon Basins Mean Area % Distribution Ratio of % Distri- Farm Size Per HH of Farm Farm HH bution of (Mas.) (Has.) Area to Area Farm HH Under 1.0 .0579 .52 7.2660 6.73 1.0 - 3.0 .2741 12.65 3.6486 34.86 3.0 - 5.0 .5507 20.82 1.8158 28.56 5.0- 10.0 .9233 23.31 1 .0831 19.08 10.0 - 25.0 1.8821 24.70 .5313 9.91 25.0- 50.0 4.1403 3.25 .2415 .59 50.0 & over 42.5362 14.76 .0235 .26 Basins .7555 1.3236 70 At present, increases in land productivity in the basin are highly dependent on the actual size of land area being farmed by the household. A principal reason for this is the level of technology and manner of cultivation. Thus, much of the anticipated changes in cultivation intensity will largely be brought about by im proved water control and management and the provision of water for rice and lowlands. However, current trends in land ownership and distribution for the basin indicate smaller farm areas per household within the lower farm size brackets (Table V l-B-3 ). The concentration of land ownership distribution is also evidenced by the Lorenz Curve for the basin (Figure Vl-B-3) indicating a ratio of 0.4901. A pre-condition for income-transfer in the rural areas of the basin will still, therefore, be highly dependent on land transfer, particularly in the food-pro ducing areas. Direct government investments especially for social overhead capital in water-resources related /infrastructure project will not, in themselves, guaran tee significant effects in reducing income inequalities caused by unequal land ownership distribution patterns. Since much of the productivity increases are pre dicted on agricultural land development and improved farm technological usage, one important policy implication is the adjustment of water resource projects to benefit those presently without the physical preconditions. B .2 .5 cropland distribution The total cropland of the basin planted to permanent and temporary crops reached 208 ,820 hectares or 75 per cent of the total agricultural lands. However, permanent crops utilized a smaller farm area thari the temporary crops. The crop area planted to temporary crops such as palay, corn, rootcrops was approximated at 108,799 hectares or 52 per cent of the total cropland. Of these, corn occupied a total of 71,103 hectares representing 34 per cent; palay areas with 35 ,473 hectares or 17 per cent : sugarcane, tobacco, rootcrops and vege tables with 2,223 hectares or 1 per cent. Major permanent crops namely coconut and fruits occupied 48 per cent of the total cropland area or 100,022 hectares. Table Vl-B-4 shows cropland distribution volume and value of produc- ti on. B .2.6 production During the 1971 crop year, the basin contributed about =?=115 million in terms of crop production value. Of the principal crops, palay was the major earner with a total production value of =?'34,362 million or 30 per cent of the total agri cultural receipts. Corn ranked second with total production of f127 million or 24 per cent. Sugarcane, tobacco, rootcrops and vegetables amounted to =F.2 million or 2 per cent. Other permanent crops like coconut, coffee and fruits contributed 43 per cent or about =F51 million. B .2.6.1 temporary crops The temporary crops namely: palay, corn, sugarcane, tobacco, vegetables and rootcrops are planted to a total of 108 ,798 hectares or 52 per cent of the total cropland area. These crops had a total output of "P'63 million which was 55 per cent of the basins' total value of production. 71 Figure Vl-B-3 LORENZ CURVE FOR LAND OWNERSHIP DISTRIBUTION IN TAGUM-LIBUGANON BASINS ALL CROPS, 1971 100 I/ 90 j 80 1/ VI 70 I/ I <( I UJ -· oc <( ~ I 0:: 60 v I < u.. v u.. 0 I t- I z 50 I w.J v u a:: UJ 0.. UJ ~ v > 40 v ~ ....J :::> ~ 30 I~ ~~) :::> u // / v 20 .J/ v , 10 / / ~ !/ ___,. ~ 10 20 30 40 50 60 70 80 90 100 CUMULATIVE PERCENT OF FAMILIES 72 Table Vl-B-4 CROP DISTRIBUTION Tagum-Libuganon Basins Crop Area Production Physical Effective Volume Value % (Has.) (Has.) (M.T.) (¥'000} Share TEMPORARY CROPS Palay 35,473 57,055 66,524 34,362 54 With Irrigation 14,392 27,633 40,896 20, 710 Without Irrigation 21,081 29,422 25,628 13 ,652 Corn 71, 103 109,658 72,002 27,014 43 Sugarcane 65 87 1,396 104 * Tobacco 66 122 28 50 * Rootcrops 1,343 2,162 4,369 1,015 2 Vegetables 749 1,680 1,008 916 SUB-TOTAL 108,799 150,846 146,327 63,461 100% PERMANENT CROPS Coconut 69,672 69,672 27 27,696 54 Fruits 13,865 13,865 30,881 10,727 21 Coffee 13,312 13,312 3,964 11,960 23 Ab a ca 3,173 3,173 624 772 2 SUB-TOTAL 100,022 100,022 35,496 51,155 100% GRAND TOTAL 208,820 270,726 181,823 114,616 Source; NCSO Census of Agriculture, 1971 * Less than one Pa I a y The basin is extensively cultivated to palay, occupying 35 ,473 hectares re presenting 17 per cent of the total cropland area. Total production reached 66,524 metric tons valued at fi4 million or 30 per cent of the area's total agri cultural receipts in 1971. With an effective area planted to palay at 57 ,055 hectares, cropping intensity was averaged at 1.61. Average productivity was recorded at 1.16 metric tons or 26.4 cavans per hectare.~ Irrigated areas of about 14,392 hectares or 41 per cent of total palay area had an average productivity of 34 cavans per hectare; while non-irrigated areas yielded an average productivity of 19 ca vans per hectare. ~One cavan of palay in 1971 = 44 kgs.; 1975 and 2000, = 50 kgs. 73 Using the NIA palay irrigated areas of 14,392 hectares and non-irrigated areas of 21, 081 hectares, NCS0 1s cropping intensity for irrigated and non-irri gated lands of 2.8 and 1.4, respectively and NIA Productivity of 3.45 MT /has. for irrigated and 2.2 for non-irrigated, the total palay production was placed at 203,456 MT or ar. equivalent of 122,374 MT of rice, using a recovery rate of 60 per cent. Total rice demand for 1975 was placed at 96,836 MT, thus the realized surplus was 25,538 MT. Demand for rice is expected to increase by 4 per cent annually over the next 25 years. Thus in year 2000, the rice requirement of 2,763,442 persons in the basin is expected to reach some 228,841 MT (For details on computations of food requirements, see Appendix C}. Providing an allowance of 25 per cent for seeds, buffer stocks and wastage, total demand will be 286,051 MT of rice. Several factors, such as land constraints, farm technology, productivity level, as well as, urban development on the basin area were used as bases for palay pro jection. The production target for the basin is focused on the optimization of palay cultivation in the areas classified as suitable for rice. With lowland irrigated palay estimated at 65, 160 hectares, as determined by the land suitability factors (net area for urban settlements), output projection was determined with the assumed changes in farm technology, irrigation facilities, cropping intensity and milling recovery (Table Vl-8-5). Table Vl-B-5 RICE PRODUCTION SUFFICIENCY ANALYSIS YEAR 2000 Tagum-Libuganon Basins NIA Programmed NIA Potential Lowland Self Area Irrigated Area Sufficiency rr 1 rn Area (in has.} OJ 1 1UV 32,783 Palay Productionll (MT) 488,528 812,219 408,644 Rice SupplyLJ (MT) 341,969 568,553 286,051 (or 6.8 million cavans) (or 6.1 million cavans) (or5.7M ca vans) Rice Demand (MT) 286,051 286,051 286,051 (or 5.7 million cavans) (or 5.7 million cavans) (or5.7 M ca vans) Rice Surplus 55,918 282,502 (Deficit) (or 1.1 million cavans) (or 5.6 million cavans) !LPalay Production = (Area) (Cl) (P) Where; Cl = cropping intensity = 2. 77 p = productivity = 4.5 m.t./ha. 'MRice Supply = (palay production) (recovery rate, 70%) Unit = 1 cavan = 50 kgs. 74 For year 2000, using the potential lowland irrigable area of 65 ,160 hectares, cropping intensity of 277 and the NIA average productivity of 4.5 MT /ha., palay output could reach a total of 812 ,219 metric tons or 568,553 metric tons of rice (using recovery rate of 70 per cent). The basin can realize a surplus of 282,502 metric tons of rice. At l 00 per cent self-sufficiency in rice, only 32,783 hectares are required for cultivation in the basin. Corn As of 1971, the Tagum-Libuganon Basins had a total of 71,103 hectares of cornlands. It yielded a total output of 72,002 MT at a productivity level of 0.66 MT /hectare or 12 cavans/hectare. In 1975, assuming that the corn area remained constant at 1971 level, and cropping intensity and yield per hectare increased to 3.56 and 1.30 respectively, total corn supply was placed at 329 ,060 MT. The total corn demand for that same period grossed at 43 ,521 MT. This com prised the demand for food of about 39,000 MT, the consumption of corn for feeds at 3,160 MT (See Table Vl-8-6) and an allowance of 1 per cent or 431 MT ·for seeds, wastage, etc. Comparing supply and consumption figures, a surplus of 285 ,539 was presumably realized that year. Table Vl-8-6 FEEDGRAIN REQUIREMENTS Tagum-Libuganon Basins 1975 20ooti Anima11..l Feedgrain Corn Animal F eedgrain Corn Population Requirement Requirement Population Requirement Requirement Hogs 40,622 8,531 2,559 960,057 20,161 6,048 Chicken 800,794 2,002 601 27,288,888 68,222 20,467 TOTAL 3,160 26,515 1fAct.ual, 1971 YAppendix for Methodology, In projecting future demand for corn, two important variables namely, population and income, were considered. The consumption pattern for corn varies inversely with income; thus, as income rises by 5 per cent annually, per capita intake will decrease from 39.42 kg/year in 1975 to 23.10 kg/year in year 2000. The projected human consumption for year 2000 is placed at about 64,000 MT. Included to this is the estimated requirement for feeds in year 2000 placed at about 27 000 MT. This amount is substantial in the production of 88,000 MT of ' ... feeds needed to support 960,057 hogs and 27M heads of chicken (Table Vl-8-7). Summing up, total food and feed demand for corn and one per cent allowance will reach 91,255 MT. 75 Based on land capability studies, cornlands in the basin was estimated at 77 ,613 hectares. With a cropping intensity of 3 .66 and productivity of 2.565 MT I ha.41 , corn supply in the basin will reach 728,623 MT. Total cor.n demand. for year 2000 was placed at 91,255 MT, thus resulting in a big surplus in production. To be able to meet such corn demand, only 9,720 hectares should be utilized. The remaining 67 ,893 hectares could be utilized to supply deficient crops in the basin. Table Vl-B-7 shows the present and potential demand and supply in the basin. Table Vl-B-7 SUMMARY OF CORN DEMAND AND SUPPLY 1975 2000 Human Consumption.!l 39,930 63,836 Animal Corn requirements 3,160 26,515 Seeds, Wastage, etc.?:J 431 904 TOTAL DEMAND 43,521 91,255 728 623 ~ TOTAL SUPPLY 329,063 ' CORN SURPLUS 285 ,542 637,368 (Deficit) 1fsee Appendix for methodology. ~1 % allowance. 1fsased on projected cornland expansion and Masaganang Maisan productivity levels. Sugarcane In 1971, sugarcane in the basin occupied only 64 hectares. Gross ouput was recorded at 1,383 MT with a productivity level of 16.01 MT /ha. and cropping intensity of 1.35. In 1975 assuming no changes in the physical area, with a crop ping intensity of 1.34 and an increase in productivity to 26.31 MT./Ha., produc tion reached 2,274, MT. At the cane-to-processed-sugar conversion rate of 1 :0.045 MT~, this is roughly equivalent to 103 MT of processed sugar. Compared to the total demand of 21,596 MT, the basin presumably incurred a deficit of 21,493 MT or almost 100 per cent of its sugar requirements in that year. This sugar production is seen to continue throughout the plan period on the basis of land constraints. Estimated area for sugar cane production in year 2000 based on land capability factors (using the 1971 cropland distribution in the basin) total to only 75.7 hectares. With a cropping intensity of 1.45 and using the projected yield/hectare of 46.9 MT~, total sugarcane production could reach 11 Masaganang Maisan Estimate of 45 cavans/hectares. §.]National Sugar Trading Corp. (NASUTRACO) standards, 1980. Jli MAAGAP Estimates, "Data Base and Technology Set of MAAGAP; The ADAM National Models," journal of Agricul ture and Economic Development, Vol. VIII No. 3, November, 1978. 76 some 5, 148 MT or 232 MT of processed sugar. This sugar supply level is almost negligible compared to the basin population's demand of 61,238 MT in the year 2000. In order to meet the goal of self-sufficiency in sugar and area requirements for sugarcane, production will have to be expanded to some 20,011 hectares or 11 per cent of total diversified croplands. Tobacco Tagum-Libuganon Basins had some 66 hectares of land utilized for tobacco production. Output reached 28 MT valued at 'P0.5 M. Production targets for tobacco will be oriented towards exports. Vegetables The 1971 vegetable production in the basin was placed at 1,008 mt at a pro ductivity level of 0.60 MT /ha. and at a cropping intensity of 2.24. Its total value of production grossed P0.92 M, contributing 0.8 per cent to the total agricultural receipts. In 1975, assuming that productivity and cropping intensity increased to 3.4 7 MT /ha. and 4.11 MT /ha. respectively and with area planted remaining constant at 1971 level (749.6 hectares), total production reached 10,691 MT. Comparing this to basin population's demand of 48,013 MT, a deficit of 37 ,322 MT was ap parently incurred, indicating that about 78 per cent of vegetable consumption in 1975 was imported from neighboring basin areas. Using the MAAGAPll , vegetable productivity target of 9 .2 MT /ha. for year 2000, a cropping intensity of 4.21 and vegetable areas reaching 757 .2 hectares (land capability estimates), total production could reach 29 ,328 MT. Even at this high level of productivity in the basin, there will still be a shortage of 148,444 MT or 20 per cent of the projected food demand of 177 ,772 MT. Area requirement of 4,590 hectares will have to be utilized to meet the vegetable demand effectively in year 2000. Rootcrops Various rootcrops such as camote, cassava, gabi, etc., were planted to 1,343 hectares in 1971. With total effective area of 2, 162 hectares, cropping intensity was estimated at 1.61. Its volume of production grossed 4,369 MT, valued at M .0 M with a productivity of 2.02 MT /hectare. In 1975, assuming that productivity and cropping intensity increased to 3.18 MT/ha. and 2.39 respectively, and physical area remained constant at 1971 level, total production reached 10,206 MT. With the basins' demand for root crops at 25,941 MT, there was a production deficit of 15,735 MT or 61 per cent of the 1975 demand. zl Model Analysis for Agricultural Adjustments in the Philippines. 77 Project ADAM~ researches indicate that the rootcrop production could possibly reach the 5.5 MT/ha. productivity levels~ by year 2000 provided that intensified use of land resources and cropping techniques would be maximized. Even if this could be realized in the basin, a deficit of 4 7 ,213 MT would still be in curred even as earmarked rootcrops areas will increase to 1,514 hectares (based on land capability studies) with cropping intensity of 2.49. An area of about 4,962 hectares will be required to attain self-sufficiency in rootcrops. 8 .2.6.2 permanent crops About 48 per cent or 100,022 hectares was contributed by permanent crops in the total cropland of the basin. The major permanent crops were coconut, fruits, coffee and abaca. Total production of permanent crops was 35 ,496 MT with a value of-¥51 M. Coconut Coconut was planted to 69 ,672 hectares or 70 per cent of total permanent cropland area. Production accounted for 27 MT valued at=F28 M or 24 per cent of the basins' total agricultural receipts. Fruits Various types of fruit-bearing trees were grown in an area of 13 ,865 hec tares. Fruit crops produced a total of 30,881 MT valued at~ 1 M. With total effective area placed at 13 ,865 hectares average productivity was estimated at 2.23 MT/ha. Allowing yields to increase to 3.15 MT /ha. in 1975, a production volume of about 43,673 MT was presumably harvested in that year, incurring a shortage of 8,219 MT or 16 per cent of the basin population's fruit demand of 51,892 MT. Based on Project AD AM studies for year 2000, fruit tree yields could reach about 5 MT /ha. As fruit tree areas expand to 15, 144 hectares as constrained by the basins' land capability map, and using a cropping intensity of 1, fruit pro duction could reach some 75,720 MT. In year 2000, a deficit of 109,983 MT could still be incurred if total fruit demand will stand at 185, 703 MT. Some 37, 141 hectares of fruit tree lands will be required to sufficiently meet the basins' total fruit demand. Coffee In 1971, coffee was planted to 13 ,312 hectares. Production amounted to 3,964 MT, valued at ¥12 M or 23 per cent of total permanent crops' receipts. Ab a ca Based on th~ 1971 NCSO Census of Agriculture, abaca was planted to some 3,173 hectares with total production amounting to 624 MT valued at ~0.8 M. ~Agricultural Diversification and Markets. g JAED, ibid. 78 B .2.7 irrigation The 1975 inventory of NIA irrigated palay area showed that the basin had a total irrigated area of 14,392 hectares. With the proposed irrigation projects of NIA, additional areas proposed will be some 24,800 hectares. Hence, by year 2000, the total irrigated areas will reach 39,192 hectares. The total irrigated areas suitable for palay cultivation was established to be about 72,400 hectares. Netting 10 per cent of the area for settlement purposes, the available area for development will be about 65,160 hectares. The analysis of the demand and sup ply for irrigated palay area is presented in Figure Vl-B-5. See also Tables Vl-B-8 and Vl-8-9. Table Vl-B-8 EXISTING IRRIGATION SYSTEMS Tagum-Libuganon Basins (Hectares) I. National Systems None 11. Communal System Davao del Norte 9,900 Davao del Sur 2,387 Sub-Total 12,297 111. Private Systems Davao del Norte 2,032 Davao del Sur 73 Sub-Total 2,105 TOTAL 14,392 Table Vl-B-9 PROPOSED IRRIGATION PROJECTS Tagum-Libuganon Basins (Hectares) I. National Projects Davao del Sur 0 Davao del Norte 18,000 Sub-Total 18,000 11. Communal Projects Davo del Sur 150 Davao del Norte 6,650 Sub-Total 6,800 111. Private Projects 0 Total 24,800 79 B .2.8 livestock and poultry B.2.8.1 population In 1971 the Tagum-Libuganon Basins raised and tended some 923,752 heads of livestock and poultry. Livestock population registered 115 ,387 heads valued at ¥30 M and poultry stood at 808,365 heads with production value of ¥2 M. (Table Vl-8-10) Table Vl-B-10 LIVESTOCK AND POUL TRY INVENTORY Tagum-Libuganon Basins 1971 Volume Value (No. of Heads) ~ ·ooo) Livestock: Carabaos 43,437 17 ,738 Catties 9,550 4,072 Hogs 40,622 7,662 Others 21,778 977 Sub-Total 115,387 30,449 Poultry: Chickens 800,794 2,477 Ducks 5,886 21 Others 1,685 1 Sub-Total 808,365 2,499 GRAND TOTAL 923,752 32,948 Of the total livestock population, carabaos and hogs were the most common animals raised, totalling 84,059 heads or 73 per cent of the total livestock popu lation. There were only 31,328 heads of cattle and other livestock or 27 per cent of the total livestock population. Chicken, on the other hand, dominated the poultry population with 800,794 heads or 87 per cent of the total animal population.Ducks ranked next at 5 ,886 heads or 0.7 per cent of the total poultry population. B .2.8.2 demand In 1975, the meat requirements of the basin were estimated at 7, 172 MT of pork; 3,971 MT of beef/carabeef; and 4,7 50 MT of poultry meat. With extraction rate assumed at 60 per cent for hogs and poultry and 30 per cent for cattle, the estimated meat supply reached 2,384 MT of beef/carabeef; 2, 172 MT of pork and 582 MT of poultry meat (See Appendix C). On the whole, the meat supply in the basin incurred a deficit of 5 ,000 MT of pork; 1,587 MT of beef/carabeef and 4, 168 MT of poultry meat. 80 Using the projected population and increase in income as bases, the food demand will reach 33,410 MT of pork; 18,653 MT of beef/carabeef and 19,648 MT of poultry meat. Preliminary estimates show that the basin may be able to meet the require ments of the basin in the future. The Tagum-Libuganon Basins is expected to have some 219,800 h\'!ctares of pasture lands by the next 25 years. At a stocking rate of 2 heads per hectare, the area could hold some 439,600 heads of cattle equivalent to a beef supply of · 19, 782 MT. A surplus of 1, 129 MT of beef supply could be realized in the basin. To meet the basin population's beef demand of 18,653 MT in year 2000, an area of 207,256 hectares could be utilized. It is estimated that some 960,057 heads of hogs and 27 million heads of poultry will be required to sufficiently meet the 1 basin requirements for pork and poultry meat for the same year. ' B .2.9 agricultural water requirements Agricultural water requirements for the basin were derived for major crops, livestock and poultry. The total agricultural water requirements in 1975 were esti mated at 1,637 MCM. About 200.05 MCM or 12 per cent was attributed to the irrigation of palay and 1,436 MCM or 87 per cent was assigned for other crops such as corn, sugarcane, tobacco, rootcrops and vegetables. Livestock and poultry required only 0.91 MCM or less than one per cent of the total agricultural water. Projection of agricultural water use in the basin proper for the year 2000 was established based on land constraints as reflected in the land capability maps of the basin. By year 2000, agricultural water demand is expected to reach 2,529.84 MCM. Irrigating palay will require about 905.72 MCM, while 11.58 MCM will be required by livestock and poultry. (Table Vl-8-11 ). Table Vl-B-11 AGRICULTURAL WATER REQUIREMENTS (MCM/YR.) Tagum-Libuganon Basins 1975 2000 Crops Palay 200.05 905.72 Corn 1,394.72 1,565.19 Sugarcane 1.48 1.86 Tobacco 11.50 13.27 Vegetables 12.92 13.37 Rootcrops 16.04 18.85 Sub-Total 1,636.71 2,518.26 Livestock and Pou Itry Cattle and Carabao .40 3.12 Swine and Other Livestocks .47 7.20 Chicken and Other Poultry .04 1.26 Sub-Totai .91 1 i.58 Grand TOTAL 1,637.62 2,529.84 81 B .3 Fisheries In 1979, Tagum-Libuganon Basins fish production totalled to 17 ,328 MT valued at 1925 M. Davao del Norte contributed 2,144 MT or 12 per cent at an estimated value of :P-16 M while Davao del Sur contributed 15, 184 MT or 88 per cent valued at =fl 09 M (Tabie V!-8-12). Table Vl-B-12 FISH PRODUCTION, 1979 Tagum-Ubuganon Basins Province:; Davao del Norte Davao def Sur Volume Value Area Volume Value Area (MT) {?'000) (Ha.) {MT) (r'OOO) (Ha.) Commercial 42 294 8,363 58,625 IVhmidpa.! 1,644 11,771 6,021 43'110 Fishpond 458 4,122 1,018 800 7,200 1,777 TOTf\l 2,144 16,187 15'184 108,935 ----···--- Source: BFAR The basins' fishponds in operation covered an approximate area of 2,795 hectares. Among the three sources of fish production in the basin, commercial fishing ranks first with 49 per cent or 8,405 MT, followed by municipal fishing with 44 per cent or 7 ,665 MT and lastly, by fishpond operations with 7 per cent or 1,258 MT. The fish requirements of the basin, using the standard NF AC per capita consumption of 38.63 kgs. in 197 5 and 52.49 kgs. for year 2000, are 39, 130 MT and 145,053 MT, respectively. B .4 Industry Analysis of the industrial sector's performance by basin utilized a methodo logy which depends on employment and labor productivity per employed person to derive a value of production by industrial subsector and by industry group and on census reports at the municipal level. The projected shares of manufac turing employment and output for the various industries were patterned from the RDS-NEDA paper, "The Role of Industry in Regional Development." Establish ments' data were from the 1967 and 1972 Census and the Annual Survey for 1974 and the water coefficients were from the NEDA "Input and OutputTables.'1 In 1975, the whole Industry sector generated r?50 M or about 15 per cent of the GDP of r4,979 M. 8 y year 2000, it is projected to boost its selective sig nificance by a substantial increase in share of 65 per cent to an output level of -f'27 ,058 growing almost 36 times in 25 years at an annual growth rate of 15 per cent. 82 8 .4.1 mining Based on the 1975 Census of Population, the mining sector in the basin employed a total of 684 workers representing 0.2 per cent of the basins' total work force. Gross value added for the sector was estimated at"'P0.2 M. The 1978 Annual Reports of the Bureau of Mines showed that there were gold and copper ore reserves in the basin. The estimated ore reserves in the basin totalled to 140.9 million MT while copper reached 39.6 million MT. For non metallic ore reserves, limestone and marble registered reserves of 181.8 million MT located in Davao City and Kapalong (Table Vl-B-13). Table Vl-B-13 MINERAL RESERVES Tagum-Libuganon Basins Mineral Province Location Estimated Status Reserves /Remark i. Metallic Gold Ore Davao del Norte Maco 12,874,286 Producing Mabini 128,000,000 Under Explora- tion & Develop- ment '78 Copper Maco 39,600,000 No production '78/Under Ex- ploration and development Mabini 172,230,400 Under Explora- ti on 11. Non-Metallic Limestone Davao del Norte Davao City 153,848,000 No production Mineral Reserves Marble Kapalong Kap along 128,000,000 Under develop ment '78 Source: Bureau of Mines, 1978 Data on mineral production in 1978 were derived from 55 repoitlng estab~ lishments/licenses (Bureau of Mines, 1978) with a combined production of T26.2 million as compared to the 1977 mineral production value off""'20.6 miliion. Among the non-metallic minerals, sand and grave! had the greatest decrease in production, from 103, en 6 f\:ff in 1977 to 64,310 MT in 1978. The others didn't show remarkable changes in their production (Table Vl-B-14). 13.4.2 manufacturing The manufacturing sector in the basin has been closely linked with that of agriculture. Total manufacturing employment represented some 6 per cent of the basins' total number of workers while output took about 13 per cent of GDP. The primary industries of food; beverages, tobacco, textiles and wood products 83 Table Vl-B-14 MiNERAL PRODUCTION CY 1978 vs. CY 1977 Tagum-Libuganon Basins No of Permittees/ CY ·1978 CY 1977 Mineral/ L icensees/Estab. Unit Quantity Value ('F) Mineral Product Reporting Quantity Value ('P) METALLICS: 17,560,905 Gold kg. 538 24,483,560 518 132,757 Silver kg. 327 330,647 275 Copper {Metal) MT. 26 293,682 Copper (Con- centrate) DMT. 103 NON-METALLICS: 54 Sand and Gravel Cu.m. 64,310 6,339,600 103,016 2,485,012 Guano Cu.m. 24 63,300 25 6,289 Limestone for Agri- cultural Use MT. 4 675 1,417 129,353 Soil Cu.m. 40 550 69 690 Pebbles Cu.m. 52 7,200 Source: Bureau of Mines, 1978. manufacturing contributed the biggest portion of manufacturing output with 44 per cent, followed by the capital goods industries with 35 per cent. The inter mediate goods industries namely paper products, chemical and petroleum pro ducts shared the least with 21 per cent. According to the 1972 Census of Establishments, manufacturing operations in Davao del Norte and Davao del Sur were largely carried out by small-scale operators. These establishments absorbed 74 per cent of the sector's working force while contributing 68 per cent of the sector's output. For the period 1967- 1972, the employment creation rate of these small scale establishments expanded by 51 per cent annually, while output was observed to have increased at an annual rate of 131 per cent. The increases were a result of the entry of new establishments and overall improvement of existing industries. Note that while average employment size for the two censal years under consideration increased to about 13,000, average employment size decreased from 3.2 to 2.3, while out put per employee increased from 'fi,500 to f21 ,000. Large-scale industries, on the other hand, registered a slight decrease in average employment from 103 to 102 and so with the labor productivity which decreased from ¥30,400 to ns,ooo per employee. On the whole, the performance of the industries for the five-year period has been impressive. The rise in production costs was lesser than realized returns, thereby, increasing the net profit margin from 76 per cent to 119 per cent. The rate of return also increased from 176 to 219. Industrial statistics are presented in Tables Vl-B-15 and Vl-8-16. The primary manufactures of food, textiles and wood industries in the basin will realize a long term annual growth rate of 13 per cent from =?'278M in 1975 to 84 Table Vl-B-15 SUMMARY STATISTICS FOR LARGE-SCALE MANUFACTURING ESTABLISHMENT IN T AGUM-LIBUGANON BASINS Annual 1967 1972 Growth Rate(%) Total Estab I ishments 102 121 3.5 Total Engaged 10,555 12,296 3.1 Wages and Salaries {'P'OOO) 24,969 42,436 11.2 Total Receipts (P'OOO) 325,515 344,107 1.1 Total Costs (?'000) 185 ,057 232,416 4.7 Census Value Added (¥'000) 130,345 149,458 2.8 Gross Fixed Capital Formation {¥'000) 39,105 Source: NCSO Census of Establishments, 1967 and 1972 Table Vl-B-16 SUMMARY STATISTICS FOR SMALL-SCALE MANUFACTURING ESTABLISHMENTS IN TAGUM-LIBUGANON BASINS Annual 1967 1972 Growth Rate(%) Total Establishments 1,402 15,116 60.9 Total Engaged 4,477 35 ,410 51.2 Wages and Salaries {:p'OOO) 1,902 9,715 38.6 Total Receipts {¥'000) 11,256 744,654 131.3 Total Costs (P'OOO) 6,227 265,020 111.7 Census Value Added {?'000) 6,269 479,634 138.1 Gross Fixed Capital Formation (¥'000) Source: NCSO Census of Establishments, 1967 and 1972 :ps ,766 M in year 2000. However, it is observed that their share to gross manufac turing output will show a downward trend from a share of 44 per cent in 1975 to 30 per cent in year 2000. This is an outcome of the shift of industry emphasis from consumer goods to intermediate and capital goods manufactures and the modern ization of the small unorganized sector. The intermediate sector is expected to have a significant increase from :P-133 M in 1975 to ¥4,617 M in the next 25 years. The contribution to gross output will slightly increase from 21 per cent to 24 per cent. The capital goods industries will represent an annual growth rate of 16 per cent or a shift from '?245 Min 1975 to'PB,774 Min year 2000. This pro portion to gross value added increased from 35 per cent to 46 per cent. 85 Refer to Table Vl-B-17 for further details. Table Vl-B-17 GROSS VALUE ADDED iN rv1ANUFACTURING BY INDUSTRY GROUP 197 5 and 2000 (In PM at 1977 Prices) Tagum-Libuganon Basins 1975 2000 1- and Beverages 108 2,759 Tcbacco 8 134 Footwear and Apparel 50 977 2;nd Wood Products 112 1,896 Paper Products 38 1,743 ~nd Chemical Products 95 2,778 '..':Ulri r:rod ucts 1 96 !ic Min. Products 30 2,433 Ba.sic ;s,1 eta! and Meta! Products 130 4,425 Electrical iv1achincry 63 268 Others 1 1,647 Total Manufacturing 636 19,156 B .4.3 cons~ru ::Uon and electricity The construction and electricity, g:!s and water had a combined output of ¥114 M representing 2 per cent c.i GDF v1hik employing about 2 per cent of the basins' total number of workers. The annual survey of est~~b!ishrnents reported a total of 15 establishments engaged in utilities sector ln 1974. The utilities sector absorbru an output per employee ratio of V-67, 141. Its book value of fixed 2.sscts rcgistc rt::d at PO. 06 :,,\. BAA industrial water require1nents Based on the projections of industrial output and mix of ind u~~ i·i cs, the quantification of industrial water needs of the study area w2s rnc.dc po:::;ib!c. Industrial water requirements of Tagum-Libuganon B 2sirt'.J are c:- 86 Tables Vl-8-18 and Vl-B-19 show a sectoral breakdown and the industrial water requirements. Table Vl-B-18 INDUSTRIAL WATER REQUfRHAENT B''l INDUSTRY GROUP (IN MCM/YR.) Tagum-Libugar.nn Basins 1975 2000 Food and Beverages .0273 .6954 Tobacco .0006 .0095 Textiles, Footwear, and Apparel .0090 .1762 Wood and Wood Products .0174 .2955 Paper and Paper Products .0094 .4343 Chemical and Chemical Products .0152 .4444 Petroleum Products .0003 .0230 Non-Metallic Mineral Products .0015 .1185 Basic Metal And Metal Products .0434 1.4895 Electrical Machinery .0096 .0407 Others .0003 .4407 Total Manufacturing .1340 4.1677 Table Vl-8-19 INDUSTRIAL WATER REQUIREMENTS (In MCM/Year) Tagum-Libuganon Basins 1975 2000 Manufacturing.!l .1340 4.1677 Mining ~ .0083 Construction .0078 .5506 Electricity .0065 .2690 Total industrial Water Requirements .1483 4.9956 -21 Less than .0001 MCM. B .5 Transportation B .5 .1 highways and road transport. As of 1980, the total road kilorneterage of Tagum-Libuganon Basins is 4,406.822 kilometers. Of this total, barangay roads ranked first with a total of 1,816.915 kms. or 41 per cent, followed, by provincial roads at 1,236.223 kms. or 28 per cent. National roads registered a total of 630,462 or 14 per cent while municipal and city roads totalled to 459,070 krns. ( 10 per cent) and 264.152 kms. ( 6 per cent), respectively (Table Vl-8-20). 87 Table Vl-B-20 ROAD INVENTORIES AS OF 1980 Tagum-Libuganon Basins Type of Road (kms.) Total By Administration Concrete Asphalt Gravel Earth Length 1. National 212.033 24.916 290.506 103.007 630.462 2. Provincial 3.944 87.195 1,039.114 105.970 1,236.223 3. Municipal .360 12.135 415.835 30.740 459.070 4. City 3.794 76.444 148.314 35.600 264.152 5. Barangay 7.000 1,141.385 668.530 1,816.915 TOTAL 220.131 207.690 3,035.154 943.847 4,406.822 Soun:*3: MPH - Minbtry of Public Higl'wmys. As to the types of road surface, the basin is mostly constituted of the gravel type v1ith 3,035.154 kms., then by the earth type v1ith 943.84 7 kms., followed by the concrete type with 220.131 kms., ancl lastly, by the asphalts roads at 267 .690 kms. !n terms of motor vehicles, the basin registered a total of 28,565 units. Cars contributed "12,'i units or 43 per cent folio\vcd by trucks with 9,439 units or per cent, motorcycles with 6,666 units or 23 per cent and trailers with 263 units or per cent. Using vehic!es-per-1000 population ratio, the basin indexed ·1 :15 v Table V~-B-21 VARJOUS ~!'-JDICES FOR ROAD TRANSPORT Tagurn-Ubuganon Basins 790,100 ( 1980) 1,914,242 Kilometerage 4,406.822 Motor Vehicles 28,565 of Road/1,000 has. 5.58 of Roads/1,000 Population 2.302 ~··lo. of Vehicles/1,000 has 36 No. of Vehicles/1,000 Population 15 No. of Vehicles/km. of Road 7 Sources: BLT, NCSO, MP'llVH, BS, 1930. B .5 .2 water transport As per 1978 PPA Annual Statistical Report, the basin had only one port w~ich is the Port of Davao. The total number of vessels in the said port was 303 with total cargo tonnage handled at 135,771 tons. Of this total cargo, the inward cargo accounted for 81,881 tons while outward cargo totalled 53,890 tons. 88 The Port of Davao also engaged in foreign shipping activities using 177 vessels. Its cargo tonnage handled totalled to 483,652 tons; 17 ,898 tons of which were imports, and much of it ( 465 ,754 tons) were exports (See Table Vl-8-22}. Table Vl-B-22 PORT OF DAV AO 1978 Tagum-Libuganon Basins A. Domestic Shipping 1. Number of Vessels 303 2. Gross Registered Tonnage 193,317 3. Net Registered Tonnage 131,668 4. Cargo Tonnage Handled 135,771 4.1 Inward 81,881 4.2 Outward 53,890 8. Foreign Shipping 1. Number of Vessels 177 2. Gross Registered Tonnage 945,556 3. Net Registered Tonnage 608,401 4. Cargo Tonnage Handled 483,652 4.1 Import 17,898 4.2 Export 465,754 Source: PPA Annual Statistical Report, 1978. 8 .5 .3 air transport As of 1979, there is only one airport found in the basin and this is located at Sasa, Davao City. It is classified as an alternate international airport. The total aircraft operation was registered at 12,012 and the total passenger traffic was 299 ,351. The airport occupied an area of 60 hectares. Detailed descriptions of the airport are given in Table Vl-8-23. Table Vl-B-23 AIRPORT STATISTICS Tagum-Libuganon Basins DAVAO DEL SUR 1. Location Sasa, Davao City 2. Classification Alternate International (A) 3. Aircraft Operation 12,012 4. Passenger Traffic 299,351 5. Runway (Meters) 2,154x36 6. Stopway (Meters) 100/100 MAC/cone. 7. Clearway (Meters) 120/150 8. Apron (Meters) 2.65 x 21 9. Taxiway (Meters) 200 x 100 10. Land Area (Has.) 60.20 Source: Bureau of Air Transportation, 1979 89 B .6 Power B .6.1 power generation and consumption The power generation for the entire island of Mindanao involves the deve lopment of a system through full exploitation of hydroelectric, geothermal and coal energy sources. Hydro power is presently being developed as a cheap indigenous source of power in the island. Initial development included the Lake Lanao-Agus River complex with a potential capacity of 944 mw in seven (7) sites along the Agus River Complex to lligan Bay. This was followed by the development of Pulangi River capable of supplying a potential of 873 mw. The rapid industrial development in the island has increased demand for power ai such a rate that hydroelectirc projects may not be able to meet expected future loads. For this reason, it has become necessary for the National Power Corporation ( N PC) and the National Electrification Ad ministration ( N EA) to consider the early introduction of diesel and thermal plants to boost energy supply to support load growth within the area and for the development of new load centers. Presently, however, in Davao area is separated from the Mindanao grid due to the prevailing problem encountered in the construction of the B ubong-Kibawe portion of the Agus-Davao 138 kv transmission lines. Thus, with the limited operation and capability of the Davao Light and Power Company to supply power load growth within the region will become stunted. As an interim measure the third power barge will be moored in Davao City until power from Agus be comes available by 1983. It is also planned that a thermal plant with a capacity of 150 mw be installed in Davao to stabilize operations and to provide additional capacity within the grid. The plant will be operational by 1984. It is planned that Agus 111 with a capacity of 225 mw be developed and be ready for operation by 1984 to be followed by Pulangi IV with the first 2 units scheduled by 1985. By 1985, the second thermal plant located in Nasipit, Agusan del Norte with a capacity of 150 mw is scheduled to come into stream early January followed by Pulangi 111 with a capacity of 136 mw at the start of the following year. Pulangi V with a capacity of 348 mw is scheduled to be operational at the require ment of 26.5 mw DLPCO diesel plants in 1987. In the year 1988 Cagayan I with a capacity of 100 mw and a thermal plant 111 shall be on stream. ' The total generated power for the Mindanao grid by 1980 totalled to 314 mw. F?r the same year, the projected power consumption within Tagum-Libu ganon 1s forecasted at 67.682 mw representing 21.55 per cent of the total generat ed power for Mindanao grid. It will provide adequate power service at approxi mately 98,782 consumers with an average consumption of 35 KWH/month/ consumer. The sytem installed capacity by 1990 will be 2,724 mw. The load forecast for the basin by 1990 is 124.87 mw or 5 per cent of the total load will provide to 229 ,709 consumers an average consumption of 58 KWH/month/ consumer. In the year 2000, the system peak demand will be 202.02 mw or 6.4 per cent at 3,154 mw of the system's installed capacity with a reliable service to 90 428,019 consumers and an average consumption of 80 KWH/month/consumer. 8 .6.2 power generating facilities The total generating capacity of the existing Mindanao grid is 212.6 mw which is composed of 201.6 mw of hydro and 11 mw of diesel. The present isolaied operation in the Davao area will be maintained until 1983 when it will then be integrated into the grid. Agus River No. 11 ( 180 mw), under a crash construction program, was scheduled to be on the stream last May 1979. Start-up of the initial unit was as early as February 1979. Constructed were three (3) diesel units of 18.65 mw each at Aplaya, two of which were commissioned last August 1979 and the 3rd unit coming in by Febru ary 1980. The General Santos Diesel Plant consisting of 3 x 7.3 mw units was expected to be energized in mid 1979. This plant operated as in isolated system and will be connected to the grid in July 1983 when the Cotabato Electrifica tion Project is completed. To increase the base load capability of the system, three (3) additional diesel units of 18.65 mw each were commissioned in June 1980, bringing the total installed capacity of the Apia ya Diesel Plant to 133.8 mw. To meet the requirements of the suppressed load forecast and serve the ever expanding load requirements of existing customers and the opportunity given by the financier, one Power Barge of 32 mw consisting of 4 units of 8 rnw each is planned in Davao City by 1981. This Barge will be maintained in Davao City until the integration of Davao area into the grid by 1983. Four ( 4) hydro plants namely, Agus VII (54 mw), Agus I ( 80 mw), Agus IV (150 mw) and Agus V (57 mw) are in the pre-construction stage. Scheduled com pletion dates are: (a) AgusVll May and August 1981 (b) Agus I November 1981 and January 1982 (c) AgusV April and j uly 1982 ( d) Agus IV March, April and j uly 1983 To meet the systems' requirements, especially energy, with the least expec ted suppression of load growth, three ( 3) coal-fired thermal plants of 150 mw each are programmed, one coming in January 1983, the second in January 1984 and the third in 1988. These units will be located in Davao City, Nasipit, B utuan City and probably Surigao City since endline generating stations are imperative to achieve supply reliability and voltage stability. Several hydro plants are already identified as programmed for construction and completion towards the latter part of the study period. These are: (a) Agus 111 with an .installed capacity of 225 mw for commissioning by April 1984. This project is presently being appraised by A.D .B. (b) Pulangi IV (Marumag) with an installed capacity of 225 mw with the initial two units scheduled to be on stream by January 1985. Contract documents were expected to be ready by the third quarter of 1979. ( c) Pulangi 111, with an in.stalled capacity of 136 mw, is programmed for 91 comm1ss1oning in 1986. This will be followed by Pulangi V ( 348 mw) by 1981. The pre-feasibility study of the Pulangi River Basin has been completed. The definite design including an interim report on feasibi lity is proposed to be taken up immediately. {d) Cagayan I ( 100 mw) is also programmed for commissioning in 1983. The pre-feasibility study of the Cagayan River Basin along with that of the Tagoloan River Basin is funded by A.D .B. By the end of 1988, the Mindanao Grid will be capable of generating 2,447 mw of power with the retirement of 26.5 mw D LPCO diesel plants. The genera tion mix by this time will be 72 per cent hydro, 26 per cent coal-fired and 2 per cent diesel based on system energy requirements of 10,467 GWH. 72,400 LAND SUITABILl7Y3/ 65,160 Vi' UJ 0::: <( 1-u UJ :r: Cl z <( Vl ::::> 0 :r: 1- z <( UJ 0::: <( Cl UJ I <( ~ ~ 0 19~7;5~--~~719~8~0:--~----~1~98~5:----~~-1~9-90~~~---1-919-5 ______12000 IRRIGATED PALAY AREA DEMAND vs. SUPPLY T AGU M-LI BU GAN ON BASINS (1) N.l.A. 25 YEAR IRRIGATION PROGRAM (2) BASED ON MINDANAO I RRIGA fED AREA STUDIES (3) EXCLUSIVE FOR LOWLAND IRRIGABLE RICE AREA BASED ON LAND SUITABILITY FACTORS (NET RESIDENTIAL LANO) Figure Vl-B-4 92 TUGANAY RIP 3,000 Hos. IP NATIONAL tROPOSED TAGUM-L~:~~~T~gN PROJECTS SCALE IN KILOMETER N BJ\SI NS 5 IO - 15 ---- ~ FigureVl-B-~ 25 30KMs. 12!1"1!5' 93 7•40' 7"30' 1~·- 7•10' 1•18' Ls -7•00' LEGEND: @ BASE METAL Au. G~ ;Cu· Copper A. OTHER lPtOUSTR •- M. Marble ;LI -~~m~~!~AL -·= ~EGIONAL BOUNDARY -·- M~ BASIN BOUNDARY --- BASIN 90Ult'.lARY ~ =NCIA.t.. BOJNOARY 6"40' 0 . ~ED< e PROo'INOAL CAP1T4. o CHMTER!l) OTY ~ICIPAUTY 5 10 I~ ;>() 25;;~ 30 .... Figure Vl-B-G 94 TAGUM - LIBUGANON BASINS DEMAND CURVES Figure Vl-B-7 80 ~ - , / " / / / ~ / " 70 700 , / / " 200 / #~' \$~ 60 600 (\y.. / ~o~"-' 1(\1 ~ ~~ / / !50 , a: 500~ 8 1!50 / w / :Ji 9 / ::J '1> / (/) 0:: ~ / z / 8 ~ ~ / :::> w / ~ 0 / 40~' 4008 I- .. / ~ / " :E ~ ~ 0:: 9 ,' :x:' ltf ~ ~~.~~ ~ ~ :::> 100 z ~· 30 300 /•·~~ / .. 20 200 !50 ~·· ~- 10 100 1980 1990 2000 YEAR OF PROJECTION INCREASE IN 10TAL SYSTEM KILONATT DEMAND RELATIVE 10 INCREASE IN NUMBER OF CONSUMERS AND AVERAG:. CONSUMPTION 95 TAGUM - UBUGANON BASINS DEMAND CURVES Figure Vl-B-8 !500 400 400 ~o _J w > w _J z Q 0:: .... u w w ID z ::E z ~ 200 IOO 8 200 100 100 l980 1990 2000 YEAR OF PROJECTION INCREASE IN HOUSE CONNECTION LEVEL AND NUMBER OF CONSUt.ERS FROM l9eo TO 2000 YEARS 96 CHAPTER VII WATER RESOURCES DEVELOPMENT FRAMEWORK A. Sectoral Indicators of Development A.1 Water Resources A.1.1 water requirements Water requirements for the agricultural, industrial and domestic sectors for the year 1980 was estimated at 1,729 million cubic meters ( MCM} and is pro jected to increase to 2,062 MCM by the year 2000. Breakdown of these require ments is shown on the table below. Table Vll-A-1 WATER DEMAND IN MCM/YEAR 1980 & 2000 1980 2000 Agricultural i ,703.86 1,968.84 Industrial 1.12 4.99 Domestic .24.26 88.13 TOTAL 1,729.24 2,061.96 A.1.2 water availability Water resources consist mainly of rainfall, surface runoff and groundwater storage. For the Tagum-Libuganon Basins, average annual runoff is approximately 10,862 MCM. Eighty ( 80) per cent dependability is about 15 MCM per day. On the other hand, groundwater storage is estimated to be 5 ,812 MCM, with an inflow to the groundwater reservoir system of 859 MCM/year. Meanwhile, rain fall, the source of both surface and groundwater is roughly 2,476 mm/year (Table VI l-A-2 and Figure VI l-A-1 ). Table Vll-A-2 ESTIMATED WATER RESOURCES Surface Runoff 10,862 MCM/year Groundwater Safe Yield 859 MCM/year11 Rainfall 2,476 mm/year JI Based on groundwater recharge rate which includes water that discharge as surface runoff. 97 Figure VI 1-A-1 WATER PICTURE TAGUM-LIBUGANON BASINS 35 301..-,__,,,_,__ ~~;..;..;;...;..:;;.;;._ AVERAGE SURFACE ______RUNOFF~~--~~--~~~--1 25 ><( 0 -~ u ~ z ~ 20 z UJ ~ UJ ~ :J 0 LL.I 80% DEPENDABLE SURFACE RUNOFF ~ 15 ~ LL.I I- <( ;: 10 98 A.2 Land Resources Results of the 1975 Census of Agriculture indicate that cultivated lands in the basins constitute some 14 per cent of its total aggregate area, spread over 4, 128.0 sq. km. of agricultural lands. Permanent crops cover 1,000 sq. km., while more than twice this size, is left to grass and shrublands. Land capability analysis indicates that the total cultivable lands can still be increased by 58 per cent i.e., an additional 56 per cent for rice and 38 per cent for diversified cropland. Aside from these recommended increases, pasturelands have a negligible increase area of only 8 per cent. Future additions to these cultivable areas may be derived from fairly rated lands which can be upgraded through careful farm management and complex soil conservation practices and from lands which are presently covered with tree farms and forests. Total cultivable lands are underutilized, most significantly the rice areas. However, the disparity between the existing and the recommended modifications in land uses is only moderate. Total agricultural areas can be expanded or in creased by 687 sq. kms., or 17 per cent wherein ricelands have the biggest share of increase (Table VI l-A-3). Table VI 1-A-3 LEVEL OF LAND RESOURCE UTILIZATION Tagum-Libuganon Basins INDEX LAND USE (1971) LAND CAPABILITY Agricultural Land/Total Basins' Area 0.52 0.61 Cultivated Land/Total Basins' Area 0.14 0.22 Cultivated Land/ Agricultural Land 0.26 0.35 Irrigated Land/Cultivated Land 0.13 0.14 Irrigated Land/Non-Irrigated Land 0.68 0.52 A.3 Agricultural Self-Sufficiency The present level of basin development can be determined through the pro duction of crops, livestock and poultry and the level of food self-sufficiency. As indications of potential resource availabilities, these provide basic guidelines in the formulation of plans and programs for future development, especially those relat ing to land utilization for crop and livestock production unit in the basic eco nomy. In 1975, as shown in Table Vll-A-4, it can be seen that the Tagum-Libuga non Basins was a surplus producer of rice and corn but incurred large deficits in all other food items. Based on demand, food items like sugar, rootcrops and vege tables incurred shortages of about 62 per cent while pork, and poultry meat suf ferred supply shortages of more or less 50 per cent. The sugar supply is noted to be almost 100 AJCr cent deficient. 99 In year 2000, the trend of production level is seen to extend with more than 700 per cent in corn and more than 30 per cent deficits in sugar, rootcrops, vegetables and fruits. To arrive at the various production/supply levels, it is how ever, emphasized that area estimates used were based in the 1971 cropland distri bution in the basin. The future direction. of the basin development, with regards to the priority crops to be produced, ·will have to consider changes in the existing land utilization pattern as well as meeting the targetted productivity levels used in this report. With improved farm management and cropping techniques, such pro ductivity estimates have been accepted as realistic at the national level. Moreover, preliminary base year indices indicate that such targets could be realized by year 2000, having the production variables of yield lesser in magni tude of importance than the problem of land constraints in the basin. Table Vll-A-4 FOOD SELF-SUFFICIENCY {In Metric Tons) Tagum-Libuganon Basins 1975 2000 Self- Self- Food Item Demand Supply Sufficiency Demand Supply Sufficiency Rice 96,83()!/ 122,374 153 % 286 ,051 !l 568,553 198% Corn 43,521-Y 329 ,060 756% 91 255~ 728,623 798% ' Sugar 21,596 103 .5% 61,238 232 .4% Rootcrops 25,941 10,206 39% 67,953 20,740 31% Vegetables 48,013 10,691 22% 177 ,772 29,328 17% Fruits 51,892 43,673 84% 185,703 75 ,720 41% Pork 7,172 2,172 30% 33,410 33,41~ 100% B eef/Carab eef 3,971 2,384 60% 18,653 19 78211 106% ' Poultry Meat 4,750 582 12% 19,648 19,64~ 100% 1f 1ncludes 25% allowance for buffer stock, wastage; etc. ti Human Corisumption, feed requirements and 1% allowance for seeds and wastage. ~Target levels to meet d·~mand. ~Based on earnmarked p~stures land. NOTE: Level of Self-Sufficiency= Supply/Demand A.4 Social Indicators A.4.1 health Based on th~ ~975 and 1977 provincial data on morbidity and mortality rates from the Mm1stry. of He~lth (MOH) Disease Intelligence Center, the most ~revalent water-borne d l'..;ease m the two provinces (Davao del Norte and Davao def Sur) covering the Tagum-Libuganon Basins was gastro-enteritis (Tables Vll-A- 5 to Vll-A-6). 100 SCIENCE AND TBCl·Ir 1 r.i ~s'l lNFOR~ ..1 :\TION INSTITUTE DEPARTMENT Oi' ~A~lENCL 1\1-JD Tt;CHNOLOGY LIBRARY Table Vll-A-5 MORBIDITY AND MORTALITY RATES OF WATER-BORNE DISEASES (Rate Per 100,000 Population) 1975 and 1977 Tagum-Libuganon Basins Province: DAVAO DEL SUR 1975 1977* WATER BORNE DISEASE CASES DEATH CASES DEATH NO. RATE NO. RATE NO. RATE NO. RATE CHOLERA EL TOR 95 18.5 12 2.4 59 10.4 10 1.8 TYPHOID & PARATYPHOID FEVER 300 58.3 22 4.3 349 61.1 11 1.9 DYSENTERY ALL FORMS 2,229 438.2 51 10.1 1,989 353.1 116 20.7 GAST RO ENTERITIS 3,319 1,093.1 219 43.2 3,356 595.7 325 58 ACUTE POLIOMYELITIS 20 3.9 6 1.2 25 4.4 25 4.4 ACUTE INFECTIOUS ENCEPHALITIS 47 2.7 14 2.7 15 2.6 8 1.4 INFECTIOUS HEPATITIS 149 29.1 13 2.6 134 23.8 17 3.1 MALARIA 1,041 203.7 37 7.3 593 106.4 40 7.2 1 SCHISTOSOMIASIS 136 26.8 17 3.4 56 10.0 22 3.9 FILARIASIS 0 0 0 0 Source: Philippine Health Statistic Disease Intelligence Center, Ministry of Health *Latest data available. Table VI 1-A-6 MORBIDITY AND MORTALiTY RATES OF WATER-BORNE DISEASES (Rate Per 100,000 Population) 1975 and 1977 Tagum-Libuganon Basins Province: DAVAO DEL NORTE 1975 1977* WATER BORNE DISEASE CASES DEATH CASES DEATH NO. RATE NO. RATE NO. RATE NO. RATE CHOLERA EL TOR 0 0 5 0.8 5 0.8 TYPHOID & PARATYPHOID FEVER 2 0.3 2 0.3 3 0.5 3 0.5 DYSENTERY ALL FORMS 1,344 235.0 20 3.5 1,056 167.4 60 9.5 GASTROENTERITIS 2,653 464.0 120 21.0 2,221 352.0 187 29.6 ACUTE POLIOMYELITIS 5 0.9 5 0.9 15 2.4 4 0.6 ACUTE INFECTIOUS ENCEPHALITIS 5 0.9 5 0.9 1 0.2 0 INFECTIOUS HEPATITIS 99 17.3 9 1.6 264 41.8 15 2.4 MALARIA 841 147.1 41 7.2 548 86.9 50 7.9 SCHISTOSOM IASIS 578 101.1 32 5.6 437 69.3 22 3.5 F!LARIASIS 8 1.4 1 0.2 0 0 Source: Philippine Health Statistic Disease Intelligence Center, Ministry of Health *Latest data available. 101 Information from the MOH Malaria Eradication Service Office showed that, of the 17 municipalities covering the basin, 11 municipalities had positive cases of malaria. Mortality and morbidity due to malaria decreased in number and rates in the two provinces. Eleven of the 17 municipalities comprising the Tagum-Libuganon Basins were indicated as endemic for schistosomiasis. The estimated number of cases represent 16 per cent of the 1975 total population of these municipalities (Table Vll-A-7). Table VI l-A-7 POPULATION (1975) AND ESTIMATED NUMBER OF SCHISTOSOMIASIS CASES BY MUNICIPALITY INCLUDING ESTIMATED SNAIL AREAS AS OF DEC. 1980 Tagum-Libuganon Basins Province/ Municipality Po~ulation Estimated Number Estimated Snail of Cases Area (Has.) DAVAO DEL NORTE New Corella 26,809 3,589 143.36 Carmen 23, 163 2,636 468.65 Napalong 33,362 6,235 34.05 Panabo 53,250 9,585 2.00 Sta. Tomas 31,584 2,691 40.66 Asuncion 66, 102 14,042 36.89 Mabini 26, 194 4,895 90.00 Maco 32,562 6,085 51.10 Mawab 17,085 2,398 143.34 Tagum 64,225 6,691 1.98 Nabuntaran 30,883 5,923 13.70 TOTAL 405,219 64,770 1,025. 73 Source: National Schistosomiasis Control Commission Ministry of Health A.4.2 education The basins, literacy rate for 1970 was 82.0 (No literacy data available for 1975). In 1975, about 56 per cent of the basins' population of six years old and over either reached elementary level or completed their elementary education. Some 20 per cent reached high school or completed their high school education. About 6 per cent reached college level while only 4 per cent completed college. Approximately 13 per cent had no schooling (Table VI l-A-8). 102 Table VI 1-A-8 EDUCATIONAL ATTAINMENT, 1975 Tagum-Libuganon Basins Number Percentage No Grade Completed 108,365 13.3 Elementary 459,565 56.4 High School 1 62,3.11 20.0 College (No Degree} 44,847 5.5 Academic Degree Holder 29,045 3.6 Not Stated 10,391 1.3 TOTAL 814,524 100.0 Source: NCSO Census of the Population and its Economic Activities report ( 1975) A.4.3 income The basins' average family income increased by 'P3,155 over 14 years start ing from 1961. In 1961, the average family income was ¥4,738 and by 1975, it rose to '?7,893. The Gini ratios within the period, as well as for its urban and rural sectors depicted marked increments. The basins' Gini ratio increased from 0.38l, in 1961 to 0.3997 in 1975. The urban ratio increased 0.3988 in 1961 to 0.4056 in 1975 while the rural ratio also increased from 0.4010 to 0.4937 also for the same period. The index of intra-basin inequality -increased from 0.4172 in 1961 to 0.4296 in 1975 illustrating a worsening income distribution. B. Project Profiles B .1 Potential Multi-Purpose Projects The potential of Tagum-Libuganon Basins for water impounding projects has not been fully utilized. Although the area has several potential sites for multi purpose reservoirs, only one existing damsite can be found within the basin which is situated in Mi ntal, Davao d el Sur. According to the inventory by NWRC in 1978, there are eight (8) identified potential sites within the basins.Table Vll-8-1 lists the existing and potential dam sites along with their coo rd in ates, drainage area, dam heights and functions, while Figure VI 1-8-1 shows their approximate locations. Area-capacity curves of the potential sites are provided in Figures VI l-B-2 to Vll-B-7. Langitang Reservoir of Magtuga and Kapalong Reservoir at Jaguimitan have an impounding capacity of 2,750 MCM and 2,260 MCM, respectively at an elevation of 200 meters. · The reservoirs can be made to function for irrigation, flood control, power generation, and other uses if their potentials can be fully tapped. 103 Table VI l-B-1 WATER IMPOUNDING RESERVOIR PROJECTS PLANNING AREA 2 - REGION XI Tagum-Libuganon Basins ESTIMATED CODE COOR DI NA TES D.A. D.H. FUNCTIONS SITE RIVER PROVINCE MEAN ANNUAL BASIS NO. (Sq.Km.) (M) RESERVOIR STATION N. LAT. l E. LONG. I \ P \Fe\ ~ jetc. INFLOW (MCM) S112003 Sto. Niiio New Corella Unnamed CR. Davao Norte 1.50 x x x Ml 13005 Lingdan Hijo Davao Norte 7°25'00" 125°57'56" 299.58 100 x x x x Ml 13006 Matan tao Simona Davao Norte 7°40'32" 125°35'45" 110.41 90 x x x x Ml 13007 Andelanto Libugaon Davao Norte 7°43'02" 125°38'42" 24.16 70 x x x x Ml 13008 Jaguimitan Kapalong Davao Norte 7°51 'l O" 125°37'20" 162.5 120 x x x x Ml 13009 Mactuna Langi tang Davao Norte 7°53'27" 125°32'27 73.01 130 x x x x I 11101 o Mintal Talomo Davao Sur 7°05'30" 125°30'12" 218.75 x M113014 Cali nan Davao Davao Sur 7°16'00" 125°23'50" 1,603.61 90 x x x x 0 .p.. Ml 13016 Cali nan Su wan an Davao Sur 7°16'35" 125°18'50" 157.5 160 x x x x LEGEND: =IRRIGATION CODING SYSTEM CATEGORY STATUS p =POWER CATEGORY ~- REGION NO. M =MAJOR 1 ·EXISTING FC "' FLOOD CONTROL STATUS I =INTERMEDIATE 2 ·PROPOSED S =SMALL 3 ·POTENTIAL M&I = MlJNl:IPAL & INDUSTRIAL PROJECT NO. 4-UNDER SUPPLY CONSTRUCTION 125°30' 125•45• 12e°OO' ------6_ CALINAN NO. 2 DAM ------6. CALI NA NO. 1 DAM £Ml~HAL DAM - 6_ MA3TUGA DAM 6, MAGBANTAO DAM I ~--.ir- LOCATIOll MA~ 6, UNGOAN DAM 7•30' 1•15' 1•00' 1~d LEGEND: A NPC PROJECT ~ POTENTIAL OAMSITE EXISTING OAMSITE -----• WATER RESOURCE REGION BOUNDARY ~ RIVER, CREEK 18"45' 6"4!1' WATER IMPOUNDING RESERVOIR PROJECTS TAGUM-LIBUGANON BASINS SCALE IN KILOMETER =i! 10 15 20 25 30 KMS. Figure VI 1-B-1 1s• s•!d s•30' 125°15' 125°30' 125•4e' 12&"00' 12a• 105 VOLUME (MCM) 400 300 200 100 0 300 ~ / - ...... / --.. v....- !"- 4VOLUME ELEVATION CURVE· 280 '""""' .... \[> v ~ / AREA-CAPCITY CURVE v HIJO DAM E 260 ~ " ...... LINGDAN, DAVAO DEL NORTE L (TAGUM-LIBUGANON BASINS) E v" '-. v ,.v A 240 ~' ...... T ,;v ~ I ~ 0 220 r: ~"' ' N ~AREA ELEVATION CURVE I (M) v- I\ 200 / "\ ,I \ 180 I \ v \ [/I 160 .J~.~ 0 10 Figure Vll-B-2 VOLUME {MCM) 300 200 100 180 160 I 140 --... ,,,,,...... ~ ...... _.. ~VOLUME ELEVATION CURVE E / L \lJ'" v ... ~ """"-. ,,/" E 120 v AREA-CAPACITY CURVE D ~ SI MONG DAM A v MABANTAO, DAVAO DEL NORTE T 100 / (TAGUM-LIBUGANON BASINS) I / " ... 0 rt:::>- N /'f-4AREA ELEVATION CURVE "' (M) 80 / ' ", / .Al' \ v I/ 60 I\ 40 0 4 Figure VI 1-B-3 106 VOLUME (MCM) 2 000 1 500 1 000 5 00 200 I --r-- r----...... _ / v ~r--..,. !-41v'OLUME ELEVATION CURVE v r---... "'-- / 180 I I/ \D-- r----. r-.. / v :--...... f' ... ,J v E 160 ...... ~ L ,..,,,. / ...... E ...... ~ ' v 140 ... v ~ A / I'.. T / ~ ~ v "!"-. 0 120 ..... N NAREA ELEVATION CURVE (M) / I'\ // ' 1r fl \ ~ AREA-CAPACITY CURVE / KAPALONG DAM \ JAGUIMITAN,DAVAO DEL NORTE. 1 (TAGUM-LI BU GA NON BASINS) 80 ~v I 60 I 10 15 20 25 30 35 40 45' .Figure Vll-B-4 VOLUME (MCM) 700 600 500 .400 300 200 100 E 300 / L r----. I VOLUME ELEVATION CURVE --- r-... i--.. v E r...... i..--""'" - v '1--J'" r...... i...... - A 280 r-..... v -- AREA-CAPACllY CURVE ! T t:>< ""-. DAVAO DAM ,___ ,,, CALINAN,DAVAO DEL SUR I ~ _...V :".... (TAG UM-LI BUGANON BASINS) 0 260 , N ~- / I'".... (M) I ~REA ELEVATION CURVE " "~ 240 v / v ~ 220 v" v 200 4 6 10 11 12 13 14 15 16 17 18 Figure Vll-B-5 107 VOLUME (MCM) 300 200 100 500 V" r-.. r--... l/ - ~ VOLUME ELEVArioN cuRVE v r'' _,. I/ 480 \. ~ f'...... / v ..,V ~ I 460 v ' / ~ I ~ AREA-CAPACITY CURVE _...,: SIWAWAN DAM [ 440 / ~ CALINAN, DAVAO DEL SUR (TAGUM-LIBUGANON BASINS) l ~AREA ELEVATION CURVE E "' v 420 v \ A T ,/ I\ ) 0 400 \ N I (M) I 380 ' 360 ~ ' I I I 340 I 0 Figure Vll-B-6 -VOLUME (MCM) 2500 ~000 1500 1000 500 200 ~ ....--- r-r-r--, _ L--"" ~ t.,...--"'- r-~ /1NOLUME ELEVATION CURVE -- ~ I 180 l..-- \.:::::: r-- ~ r-- r-- 1--"" I""'--- i.---- [:>< -- L 160 ~ r--.... I !/" I...... _ v ~ ~ A ... T v -r---.... I 140 V' r---..._ 0 ,,,, ,f.y .. r-... -- (Ill) V' _/ f-41 REA ELEVATION CURVE 12 0 "' ""'- ~v I / 10 0 " ""' Alt!A- CAPACITY CURV[ ~v LAlllQITAllG DAM ~ v llATUOA. DAVAO Df:L llOllTt: \ 0 ~ ITAOUM·LlllUOAllOll 8AS1NS) " v I 0 I 10 15 20 25 35 40 45 50 55 Figure Vll.S-7 108 B.2 Irrigation Projects Several irrigation projects can be found within the basins. These irrigation projects are classified into national, communal and private irrigation systems. Actually existing in the area are some 24 communal and 275 private systems, which serve approximately 14,392 hectares. The National Irrigation Administration (NIA) has identified and proposed 24,800 hectares for irrigation purposes. The national irrigation system will en compass 72.58 percent of the proposed irrigable area, while, communal irrigation system, 27.42 per cent. Table Vl-8-9 lists the inventory of proposed irrigation projects. B .3 Water Supply Projects B .3 .1 agency proposals and activities Government agencies are compelled to exert efforts in coping with the exist ing and future water supply needs of the basin. The Rural Waterworks Develop ment Corporation ( R 'NOC), created out of the NWRC Task Force on Rural Water Supply, assists in· the construction of shallow and deep wells. In line with this, several programs are being undertaken to improve water service. An example is the B agong Lipunan Communal Water Program which aims to construct and re habilitate shallow wells in the area. Likewise, the Local Water Utilities Adminis tration, operating through its water districts, utilizes groundwater for provincial urpan areas. It also reestablishes water supply systems whose components con form to the formation of water districts. Within the basin, there are two (2) exist ing water districts, Tag um Water System and Davao Metropolitan Waterworks. Tagum Water System serves a total population of 31, 100. This population is rapidly increasing and expected to reach 54,800 by year 1983. Consequently, new wells in the poblacion may be drilled to meet the demands of the service area. Davao Metropolitan Waterworks is currently attending to the needs of Davao City Proper and portions of 12 adjacent barrios. 1.Q.L About 2,000 hectares of land avail the services of the said water districts. By year 1990 and 2000, the service area is expected to increase to approximately 5 ,000 hectares and 7 ,500 hectares, respectively. Improvements proposed in the area consist of collector wells, pump ing equipment, electric power supplies, chlorination facilities, distribution mains, customer services and meter and fire hydrants. B.3.2 study proposals To provide potable water supply to the projected population. Some 5 ,637 units of level I, 732 units of level II and 16 units of level 111 will be required by year 2000. Table Yl-A-11 shows the municipal distribution of estimated level I, 11 and 111 facilities required . .l!J./ Report cf Feasibility Improvement and Expansion of Urban Water System Davao Ci-.y, 1973. 109 B .4 Data Collection System B .4.1 water resources data The management of water resources within the basin depends highly on the adequacy and accuracy of relevant hydrologic and other water and land related data. Thus, the implementation of an efficient data collection is crucial in the development and effective use of the area's resources. B .4.1.1 rainfall data Rainfall data aside from other considerations, is important in the analysis and interpretation' of surface and groundwater records. As such, a comprehensive rainfall station network is needed in the basin to provide the necessary informa tion. At present, there are four ( 4) existing stations established by PAGASA, all situated on flat plains. Based on the NWRC recommended standards, 111 the required number of stations for the Tagum-Libuganon Basins for flat plain areas and mountainous/rolling areas are twelve ( 12), and fourteen ( 14) stations, respec tively. Thus, the basin is in need of an additional eight (8) stations for flat plains and fourteen (14) stations for mountainous/rolling areas in order to arrive at a more accurate picture of the spatial distribution of rainfall within the basin. B .4.1 .2 streamflow data Stream discharge measurements are the only direct means of quantifying the amounts of water relevant to the utilization and prevention aspects of water re sources development. As such, the installation, operation and proper maintenance of the instruments for flow measurement are priority considerations in water re sources planning. There are four ( 4) existing gaging stations, three of which are situated on flat plain areas. For the entire influence area of the basins, the total number of required stations as recommended by NWRCW is nine (9) stations for flat plain areas and fourteen ( 14) for the mountainous areas. At least six ( 6) more additional gaging stations on the plains and thirteen ( 13) on the. mountains should be installed to monitor the streamflows of the major rivers and their tributaries. B .4.1.3 evaporation and other climatic data Evaporation and other related data, such as temperature and humidity, are important for water balance and agrometeorological studies of a basin. Studies performed on the Philippines have shown that evaporation rates do not vary sig nificantly with respect to location.12' In th is view ,the N WRC recommends a station density of one station per 20,000 square kilometers. Within Water Resource Region XI, covering a total influence area of 23,858 square kilometers, no station collects evaporation data. Therefore, it is necessary to install at least one evaporation station in any of three basins - Tagum-Libuga non, Davao-Oriental or South Cotabato.. 111 NWRC, Manual for Water Data Standards, Vol. 2, 1979. m NWRC, Manual of Water Data Standards, Vol. I, 1979. m M.M. Obradovich" A Climatic Map of the Philippines" Technical Series No. 15, WMO/UNDP Project, Feb.1973. 110 B .4.1.4 groundwater data Involved with the groundwater development and management are eight ( 8) government agencies, namely: National Water Resources Council, Bureau of Water Supply (Ministry of Public Works and Highways), Bureau of Mines, Natio nal Irrigation Administration, Metropolitan Waterworks and Sewerage System, Local Water Utilities Administration, Army Corporation of Engineers and Rural Waterworks Development Corporation. These agencies facilitate the collection of of groundwater data essential for domestic, agricultural and industrial water supply. Just recently, NWRC has been entrusted with the responsibility of coordinat ing water resources exploration and exploitation, defining some standards for groundwater development and data collection, undertaking special activities in surface-resistivity and assembling and synthesizing information necessary for the analysis of the complex groundwater situation. The area has still inadequate data on groundwater. This could be attributed to the non-existence of uniform standards and systems of data collection. In view of this, NWRC has developed a Manual on Data Standards. Furthermore, NWRC has initiated the listing of.all water resources developments and their correspond ing data of the country. This requires the submission of data from well drillers and well owners. Likewise, the registration of water users has been operational, but then, the response of the private sector has not been enough to have an as sessment of groundwater exploitation. Therefore, there is a need to improve the manner by which information could be effectively disseminated in order to acquire an accurate and sufficient data essential for groundwater quantification. To install groundwater station network, several factors should be taken into consideration. Among them are the subsurface geologic conditions which influ ence the occurence and distribution of groyndwater resources in the area and the presence of other nearby wells or adjacent bodies of water. Since no specific in stallation requirements are prescribed, precautionary measures must be contem plated. This will ensure efficient development and utilization of groundwater resources. B.4.2 !and resources data The source of basic land resources data is the Bureau of Soils. Except for the existing land use, information on soil types, erosion susceptibility, etc. are generated from the Provincial Soil Survey Charts and Maps. B .4.2.1 land capability Land capability classification, a critical factor in determining the agricultural potentials of an area is done in a gene-rat manner. B .4.2.2 soil fertility Information on the different levels of fertility is not provided. C. Development Impact Evaluation C.1 Socio-Economic Im-pact Evaluation 111 C.1 .1 general The framework of development for Tagum-Libuganon, on one hand, is predi cated on the complementary and interrelated strategies of proper and rational land utilization and on the other hand, on water resource development and man , agement. Significant among the derivative strategies for development for Tagum- Libuganon are the following: the allocation of land resources to optimum use based on the national criteria of maximizing productivity, environment protection and re source conservation; the provision of water for agricultural, domestic, municipal, industrial, and other sectoral requirements. These strategies will expectedly contribute to sustained increase in the in comes of the majority of the area's population, in the self-sufficiency in their food requirements, in the minimization of unemployment and in the improve ment in the level of social services. C.1.2 effects in basin incomes Intercensal changes in mean family incomes have, as a whole improved for Tagum-Libuganon over a 14-year period. With the bulk of economic activities highly dependent on agriculture and land development, any attempt to increase population incomes will have to be based on present income sources of the popu lation, notably farming and land-based activities. The package of projects found feasible at the basin level will have quantifi able and direct income increase effects for the target beneficiaries due to im proved water management, higher levels of cropping and land cultivation inten sity, and water control. Based on figures derived from similar areas proximate to the basin some 5 to 7 per cent increase over present productivity levels is observed due to irrigation of rainfed lands. C.1.3 possible effects on income inequality The distribution of family income shares for the Tagum-Libuganon River Basin has generally been worsening for the past ten years. Percentage shares of families earning below T-2,000 have generally increased while those earning above fk'J0,000 have also become smaller (Table Vl-4). This trend is equally borne out by the relatively increasing concentration ratios for the basins as a whole, and for its urban and rural components. Inequality among families and in the distribu tion of income has not been altered. In fact, using the index of intra-basin in equality of differences in income inequality due to occupational variations, the profile which emerges is fairly consistent with the derived income concentration ratios (Table Vl-5). C.1.4 spin-off impact on land reform development Correlating the income measures with the land ownership distribution for all crops provides a similar pattern. The distribution of land in the basins reflects its fragmented character with majority of households owning 90 per cent of small p~rcels (under 1.0 to 4.9 hectares). The pattern is, however, altered drastically with the concentration of one per cent of families owning bigger land parcels 112 (25.0 hectares and above) which comprise 18 per cent of total croplands (Table Vl-B-3). At present, increases in land productivity in the basins will be highly depen dent on the actual size of land being farmed by the household. A principal reason for this is the level of technology and manner of cultivation. Thus, much of the anticipated changes in cultivation intensity will largely be brought about by im proved water control and management and the provision of irrigation for rice and cornlands. For the present, however, it appears that there is no definite direction in this aspect. Various measures in land ownership and distribution of the basins indicate smaller farm areas per household within the lower farm-size brackets (from 0.0579 to 0.5507) and the greater number of households per hectare in this lower farm-size brackets (Table Vl-B-3). The concentration of land-ownership distribution is also evidenced by the Lorenz Curve for the basin (Figure Vl-B-3), indicating a ratio of 0.4901. A precondition for income transfers in the rural areas of the basins will still, therefore, be highly dependent on land transfers, particularly in the food pro ducing areas. Direct government investments especially for social overhead capital in water resource related infrastructure projects will not in themselves guarantee significant effects in reducing income inequalities caused by unequal land owner ship distribution patterns. Since much of the productivity increases are attribut ed to agricultural land development and improved farm technological usage, one important policy implication is the adjustment of water resource projects to be nefit those presently without the physical preconditions. The effects, therefore, of the package of projects for water resource develop ment on income redistribution and land inequalities will largely be prepositioned on the development of the institutional factors such as patterns of land owner ship and the rate of land transfer in the basin. Full irrigation development of systems identified in the basins can.generally provide the material conditions whereby land reform can be accelerated. Con versely, the institution of a reform coverage in the basin areas can substantially hasten the water resource development. C.1.5 effects on employment generation in the agricultural sector Development activities for Tagum-Libuganon consists of irrigation deveiop ment, provision of water supply for various sectors, flood control and drainage, hydro-power, land development and other land improvement schemes. Employ ment generation for these activities will largely consist of ( 1) those pertaining to direct public expenditures; (2} those related to land expansion and improve ment schemes; and ( 3) those associated with spin-effects due to increased activi ties in the above investments. C.2 Environmental Impact Evaluation In any national development, it is necessary to seek a balance between eco nomic progress and environmental aesthetics. Implementation of resource deve lopment projects may produce long term environmental effects on the natural resources in the basin area. However, at this stage, only potential sites have been 113 identified which need advanced investigations and detailed studies for possible water resource development. When studies.are justified to be feasible for proposed hydropower, irrigation, flood control and reservoir development, they may even tually enhance the economic and social development of the country. At present, only a general description of the environment and probable deductions in river basin planning have been made requiring still further research and evaluation. The proposed water resource development may create potential environ mental effects yielding suitable results, such as: decreased soil erosion, improved watershed and forest management, expansion of fisheries, reduced stream and reservoir sedimentation, increased dependable water supply and groundwater resources, improved scenic attractiveness, improved health and standard of Iiving and income. C.2.1 natural vegetation and wildlife The basin area is dam inantly covered by forest growth in the mountainous areas followed by sections of coconut land, rice paddies and other lowland crops. Mt. Kimongol Forest Reserve (20,432.00 has.) is the only designated forest reserve in the area. It may not be affected by any potential water related projects, which have yet to be subjected to investigations and detailed studies in order to determine the feasibility of the area to undergo water resource development. Forest growth in the mountainous areas are considerably under dipterocarp, secondary, and primary forest growth. Some important trees found under primary forest growth are akle (Albizzia acle), ipil (/ntsia biyuga), narra (Pterocarpus sp.), molave (Vitex parvif!ora), yakal (Shorea gisok), tindalo (Pahudia rhomboidea), banaba (Lagerstroemia speciosa) and guijo (Shorea guiso). Other common trees found also under secondary growth species are tibig (Ficus nota), binunga (Maca ranga tanarius), dita (Alstomia scholaris), anobiong (Trema orienta/is), anonang (Cordia dichotoma), arang (Artocorpus odortissima) and alim (Me/ano/epsis multi g!andulosa). Grass species are also equally abundant such as cogon (/mperata cylindrica). The forest grounds also support diverse species of wildlife. Rare species such as the Monkey-eating Eagle (Pithecophaga jefferyi) and the Rofous Horn fill (Bucenos hydrocorax) are also sighted in the ranges of Mt. Apo. When the area has been found feasible for proposed water impounding projects, environmental changes caused by construction activities may adversely affect vegetation, wildlife and habitat. Water impounding may reduce the area of wildlife habitat through fencing, affecting feeding ranges that are incorporated with the mainstreams and/or its tributaries, considering that almost all forms of wildlife exist along river banks. Elimination of trees and shrubs by burning and cutting may have adverse effects on the existence of some animals. For instan~e, forest t~ees. are primarily nesting spots of birds and manipulation may result m a reduction m their numbers. Noise caused by construction activities can cause animals to leave or avoid a particular area. Other habitats that are elimi nated by co~struction are nests and burrows containing eggs and young which are alm~st certainly destroyed. These adverse effects may eventually force animal species to move out to other niches in the surrounding territorie-s. 114 Vegetation is also greatly affected by such physical disturbances. Reservoir construction and operation along various surface run-off control projects may affect large areas of natural vegetation. Natural vegetation such as trees and shrubs are likely affected by resulting erosion and may, therefore, restrain its re establishment. Measures must then be implemented to preserve the existence and diversity of vegetation and wildlife. When endangered species exist in the vicinity of an impoundment, steps must be taken to establish a shelter for their preservation. If construction activities are confined to an area where possible habitats are affected, such disturbances must be minimal. Land clearing must also be limited to an absolute minimum. Therefore, planning should ensure the minimization of expected adverse effects. In addition, further preimpoundment studies must also be undertaken to properly assess the impact the new reservoir will have on the environment. C.2.2 fisheries and water quality No fisheries development and water quality surveys were conducted by the Bureau of Fisheries and Aquatic Resources (B FAR) and the National Pollution Control Commission ( N PCC), respectively for this basi!l. C.2.3 soils The soil types in this area are basically a combination of clayey and loamy soil. The area is dominantly covered by primary, secondary and dipterocarp forests. Farm management practices must be appropriately applied to avoid erosion in higher areas. Since external and internal drainage is good, ~owland rice is suitable especially where rivers and streams are available for irrfgation. The slopes in the area vary from level to almost imperceptible. Further investigations must be undertaken to test its suitability for water im pounding reservoirs. When the area is found to be promising for project sites, pre ventive measures must be set to preserve the productive value of top soils, as we!! as, subsoils from any physical disturbances. Some areas must be strictly under forest growth, since they are not suitable for agricultural purposes due to their unfavorable topography. Forests form more stable ecological communities and may, therefore, be more effective in protecting unstable catchments of soils. In areas of unstable soil, where flash flood occurs, streambanks are a major source of erosion. Most of the sediments carried into the reservoirs are the products of soil erosion from the catchment area or from the upstreams. Erosion also from rural and urban areas also contribute to sedimentation of streams and reservoirs. Preservation, such as control of indiscriminate cutting of forest and afforestation, can provide success ful stabilization measures. The planning and execution of soil conservation measures may be direct and effective means of controlling reservoir sedimenta tion, improving the infiltration capacity of the soil and slowing down the run off of excess water to reduce flood peaks. The areas with coconut are usually kept under grass with occassional trimming since grass helps in the control of erosion. Other measures that may be applied are contour plowing and farming, utilization of drainage channels, grass waterways terraces and diversion and strip 115 cropping. Planting of ipil-ipil (Leucaena glauca) which serves as a cover crop should be sufficient. C.2.4 mineral resources The major mineral ore reserves (Metallic) found in the basin area are deposits of gold ore in Mabini and Maco, Oavao del Norte and copper deposits also in Maco, Oavao del Norte. Non-metallic ore reserves, such as deposits of limestone and marble are found in Davao City and Kapalong in Davao del Norte. Water supply intake facilities for transmission to mineral operations is neces sary in any mining activity, thus affecting the water quality as well as the land resources of the basin. Waste water containing decomposed organic compounds and suspended rock materials may produce undesirable water quality changes. High levels of turbidity in water and siltation of the downstream portions of rivers may take effect as a resu It of the discharge of industrial effluents. At the same time, growth of algae which is the basic food substance of water organisms is most Iikely endangered. Furthermore, heated water discharge could have serious effects on the local wildlife and fishing habitat by increasing the temperature to intolerable limits, consequently affecting species diversity and abundance. When the area is found to be feasible for water resource development no pro posed reservoir is affected, nevertheless, waste material may extend to other areas through water currents of small tributaries and streams that are drawn to the pro posed impounding projects. Diversion or elimination of sewage and industrial wastes is es~cntial for rea sons of health as well as water appearance. Other mitigation measures for control of effluents of these mining operations must be undertaken to prevent any possible alterations or changes on agricultural production or on fishery resources. C.2.5 historical and archaeological sites There are no archaeological sites found in this basin as reported by the National Museum. However, there is a possibility that sites may be encountered if further excavations are done in this area as a result of the proposed projects. Therefore, proper planning and management of the facilities which would be associated with these water impoundings is necessary. It is also imperative that any earthworks to be done in the basin, must have prior consultation with the concerned agency. C.2.6 vectors and public health Aside from the common human diseases ( enteric, metabolic and respira tory), water borne diseases such as cholera, typhoid and El Tor are very common in the area. Schistosomiasis is also known to occur. Of the waterborne causes of morbidity and mortality over the periods of 1975 and 1977, reported cases of gastroenteritis ranks first based on rates per 100,000 population, followed by dysentery with malaria and schistosomiasis ran king third and fourth respectively in Davao del No'."te and Davao del Sur. One of the significant results that may follow in any water resource develop me~t is the production of more breeding grounds of vectors (mosquitoes, flies, snails, etc.) therefore, increasing the prevalence of the disease. The physical struc- 116 tu re of reservoirs directly influences the distribution of breeding populations; production is low where the shoreline is steep but high where it slopes gradually. When the area is found to be feasible for water resource development, cons truction and operation activities may result in the propagation of serious human diseases. For example, schistosomiasis is essentially a "water-base" disease, being dependent on an aquatic intermediate host, namely, the snail (Oncomelania quadrasi). The host is adapted to a wide range of environmental conditions. They breed in different sites in the presence of water, solid surfaces (for deposi tion of eggs) and some food supply. Snails do not only thrive in the presence of human excrement but also in unpolluted water as long as there is enough food supply (weeds, algae and other micro organisms). The most common parasitic worm (schistosome) which is confined in the Philippines is the Schistoma japo nicum. Upon completion of water impounding projects, prevalence of the disease may increase since surface area is widened. Plant growth consequently colonizes the shorelines, thus, doubling the probability of development and incidence of the schistosome-carrying snail. Mats of weeds and other floating vegetation infested with the snail host, may be transported downstream spreading the disease to other areas where none existed before. The disease is often associated with defective drainage of irrigation systems, forming stagnant pools, we areas and seepages which are favorable conditions for breeding. Outbreaks of malaria may also occur upon impounding. Plasmodium vivax and P/asmodium flaciparum are the most prevalent malarial drugs. No program of malaria control can succeed as long as female anopheles mosquitoes are per mitted to breed. Mosquitoes pass through four (4) stages of devel0pment: the egg, larva, pupa and the fully developed insect, of which first three (3) stages take place in water. The transmission of arbovirus disease such as malaria is associated mainly with irrigation areas linked to dams. Other habitats that are also favorable for mosquito production in the reservoir include depressions in the zones of water fluctuation that trap water, burrow pits and sloughs. Although mass human treatment may be the easiest and most promising method for treatment of such water-borne diseases, it may also be proven, in adequate for the following reasons: defective and untidy irrigation schemes in adequate facilities for excreta disposal, lack of health education and unsanitary practices of inhabitants. To carry out environmental control, there must be cooperation between public health services, government agencies and the local inhabitants. Improvement and control of environmental changes caused by water deve lopment schemes is possible provided that health measure~ are applied from the earliest phases of planning and control meas.ures are ~s~oclated th~oughout each stage of water development. These measures include: siting of h_ou~mg away fr?m canals; providing of adequate and safe wat~r supply ~nd san~tat~on protect1_on for bathing water recreation and laundering; shoreline san1tat1on; educating population ~o improve its habits in disposing wastes and excreta; providing of foot bridges; controlling astray animals and improving the monitoring system. 117 These must be developed to assure early detection of any adverse effects. C.2.7 socio-cultural aspects The cultural minority groups within the basin are the Samals, B agobos, Saranganis and the Sama/A'A Samas in Davao del Sur and the Karagas, Mansahas and Manobos in Davao d el Norte. The initiation of environmental changes caused by water resource deve lopment oftentimes affects local residents particularly farmers, fisherman and and traders. Displacement of people occur in areas to be inundated thu~, such drastic change may, therefore, be mitigated depending on the system of planning. Previous reservoir development often gave rise to serious issues concerning evacuation and relocation of communities. The Pantabangan Dam in Nueva Ecija, which was constructed in 1971, has readily satisfied its economic demands by fostering increased rice production and providing hydroelectric power. i'kvcr theless, unforseen physiological, physical administrative and economic conflicts have emerged. Housing for settlers and designated lots were located on haphazard areas. Conflict arose between settlers and cultural minority groups inhabiting the specified resettlement areas hence, causing irregularities and disorder in the re settlement program. The Chico Dam, though has not yet been completed, is considered to be a controversial dam in the Northern highlands. Four ( 4) multi-purpose dams called Chico I , 11, 111 and IV would have been the biggest in Asia relieving the country's wavering oil import bill. Though the project is scheduled for completion by 1982, it has been temporarily shelved. Opposing forces from people who are affected by the project, specially the Bontoc and the Kalingas have made construction impossible. Although the government is set on finishing the project, unyielding tribesmen WP,re similarly firm and determined due to psychological religious and economic factors which have been aroused, affecting their political system as well. The people have strong links with their dead believing that their lands have been assigned to them by their gods and are expected to care for these. Such a project would submerge hectares of land including the world famous rice terraces, villages, orchards, and finally displacing almost 15 ,000 fam i! ies. The efficiency and success of a relocation program depends on two (2) factors mainly: 1) time and 2) resettiement sites chosen. The environmental change rouses a crisis of individual and cultural identity. Preparation can eliminate the shock of being physically uprooted, so that relocation authorities must pro pose adequate and appropriate provisions to promote the settler's identity as a community thus, leading to a systematic and comprehensive strategy for growth through careful location of community facilities. Agricultural lands set aside for cultivation, should be arable to compensate for the loss of agricultural crops. Re s~ttlers mu~t be provided with substitute and continuing employment opportuni ties. Essential resources should be operative such as housing adequate and safe water supply, sanitary facilities, equipment or domestic stock' and medical servi ces. The introduction of social and institutional reforms and measures from ex perienced advisers supported by government policies to motivate settlers to assume responsibility for the development of their communities is also critical to the resettlement program. 118 D. Institutions The network of institutional relationship in water resource management of the river basin or water resource sub-station level includes national, regional and local bodies. The national agencies work through their field offices, special projects or task forces. Their range of activities covers policy formulation, coordination, planning and project development, construction and operation of projects, monitoring, training, research and data management, regulatory and adjudicatory functions and enforce ment of legal measures. A brief description of the organizational structure, functions and activities of these agencies at water resource area level are presented in the succeeding paragraphs. D .1 National Organizations D .1 .1 The National Economic and Development Authority (NED A) The NEDA is the highest planning and coordinating body in the country. It lays down the overall policy guidelines for the long-range development of water resources and related sectors as vital components of the Five, Ten and Twenty Five Year National Development Plan. The main control mechanism available to NEDA in effectively pursuing its coordinative functions and imposing its policies is its review and approval of pro jects for inclusion in the annual national budget. Technical review is exercised by the appropriate staffs under NED A through inter-agency committees that are organized from time to time to handle special review functions. The policy, plan coordination and technical functions of NED A are decentralized at the regional level through its Regional Offices. The Five-and Ten-Year Regional Development Plan for Region XI was completed by the NEDA in 1977. D .1.2 The National Water Resources Council ( NWRC) The NWRC was created by virtue of Presidential Decree No. 424 to coor dinate and integrate all activities related to water resource development and to exercise regulatory and adjudicatory functions relative to water rights and other provisions of the Water Code of the Philippines. In add it ion to its regular functions, the NWRC has a special interim respon sibility of organizing, through a task force, water associations and cooperatives in rural areas of non-PADAP provinces. It also provides technical, institutional and financial assistance to the same until such time that a permanent institutional arrangement has been forged. In line with its planning and research functions, the: NWRC undertakes the preparation of integrated regional water resource development frameworks using the river basin as the unit of data generation and analysis, project identification, evaluation and planning. Part of this exercise is the framework plan for the Tagum-Libuganon Basins and the regional development framework plan for Water Resource Region XI. 119 126900' REGION II LOCATION MAP 1•30'- 7•30' 7°i!S' 7•1!!' FOREST SUSCEPTIBLE TO EROSION - 7•00' ?"0{1- SCHISTOSOMIASIS AREAS (ESTl~,•ATlD CULTURAL MINORITIES Ml NERAL RESERVES FOREST RESERVES POTENTIAL DAMSITE EXISTING DAMSITE PROPOSED IRRIGATION SYS TE,_. MAJOR AREAS OF SIGNIFICANT ECCLOGICAL INTEREST TAG UM-LI BU GA NON BASINS 'iC.ALf •"f WLL ')Mc- lrP ~,___.,--~--~----.~--~--~--~~ l/)lr'W' Figure VI l-C-1 12!S" 30' 1~·45• 126" l!S' _J_ 120 D .1.3 The National Irrigation Administration (NI A) The NIA is a corporate body having the responsibility for the planning, cons truction, operation and maintenance of all national irrigation systems, as well as, government-funded communal and pump irrigation systems. It is also empowered to implement multi-purpose water resource projects and supportive activities like road construction, reforestation and extension services. The latest inventory of on-going and proposed irrigation projects shows that approximately 18,000 hectares are to be served by national systems and 6,800 hectares by communals. NIA works with the Ministry of Public Works and Highways (MPWH) in designing and constructing drainage facilities and protective works in the agricul tural areas served by the NIA projects. With regard to hydroelectric power deve lopm~nt, NIA works in coordination with the National Power Corporation. The NIA also establishes and operates climatologic and hydrographic sta- tions. D .1.4 The Ministry of Public Works and Highways ( MPWH) The MPWH undertakes the planning and implementation of infrastructure projects in the following categories: flood control, reclamation and drainage, water-works systems, artesian wells and springs and other public works. It also maintains stream gaging stations in strategic points in major rivers all over the country. At the basin level, these functions are exercised by the Ministry's engi neering district offices. The MPWH maintains gaging stations with the basin. It also has a continuous development program for waterworks systems for major settlements, as well as, the construction of wells and springs. The latter is carried out in cooperation with the local governm.ent units of the area. Flood control structures maintained by the Ministry in the flood-prone areas include dikes/levees, revetments, cut-off channels/ diversion channels and spur dikes. It also undertakes the construction, repair, maintenance and development of roads, bridges and other infrastructures. D.1.5 The National Power Corporation ( NPC) The NPC undetakes the development of electric power generation facilities including hydroelectric power, construction and operation of dams, reservoirs and diversion facilities required for this purpose. The agency is authorized in coordina tion with NIA and MPWH, to assume the lead where the hydroelectric purpose is of primary importance in multi-purpose projects. The Davao area is presently separated from the Mindanao Grid but will eventually be integrated into the grid by 1983. Because of this, three (3) thermal plants will be constructed in Davao and Nasipit, Agusan del Norte from 1984- 1986. To increase the base load cap ab ii ity of the three ( 3) diesel plants in Aplaya, three (3) more plants of 18.65 MW each are to be built. One power barge consist ing of 4 units of 8 MW each is planned for Davao City until its integration into the Mindanao Grid. At present, there are 4 hydro plants with a total of 339 MW are 121 on the pre-construction stage. Also, three ( 3) coal-fired thermal plants of 150 MW each are programmed to meet system requirements. D .1.6 The Bureau of Forest Development (B FD) The B FD has authority over the protection, development and management of all forest lands, grazing lands and forecast reservations including watershed reservations. In the basin, there is only one forest reserve which total 20,432 hectares. This is the Mt. Kinongol Forest Reserve. D .1.7 The Bureau of Soils (BS} The 8 ureau of Soils is responsible for the assessment, development and con servation of soil resources. In 1956, it conducted a nationwide classification of soils and has been undertaking various reconnaissance soil surveys in both the sub-regional and regional levels. It also conducts specific area surveys upon request and, where specific pro jects require, updated and detailed soil data. D.1.8 The Ministry of Local Government and Community Development ( MLGCD) The MLGCD provides advice and assistance to local governments and com munities to improve and support their operations through training, education, co operatives, technical and financial assistance through its regional, provincial and municipal offices. Part of the Ministry's program is the "B arangay Water Supply Project" in 25 provinces nationwide to provide potable water supply to rural communities with populations ranging from 500 to 5 ,000. Likewise, the "Barangay Road Program" of the Ministry is undertaken in cooperation with the Ministry of Public Works and Highways. D.1.9 The Farm Systems Development Corporation ( FSDC) The FSDC was created to aid in organizing farmer irrigator associations and to provide technical and financial assistance in the establishment of irrigation faci lities in areas outside the NIA development program. In addition, it extends pro duction, processing, diversification and marketing support to farmers. FSDC's present efforts are concentrated in compact farmlands of less than 1,000 hectares that have been or are to be transferred to farmer-owners under the Operation Land Transfer of the Ministry of Agrarian Reform. D .1.10 The Local Water Utilities Administration ( LWUA) The LWUA is a national agency which provides technical, financial and man agement services to local water districts to assist them in the development and operation of water utilities.Because of the small size of the urban settlements and t~e l~w population density in Tagum-Libuganon, there are two (2) existing water districts namely the Tagum-Libuganon Water System and the Davao Metropolitan Waterworks. ·122 D .1 .11 The National Electrification Administration (NEA) The N EA is the national agency that takes charge of transmission and distri bution of NPC-supplied power. The NEA organizes and assists electric coopera tives, manages operations, maintains facilities and collects electric fees. D .1.12 The Philippine Atmospheric, Geophysical and Astronomical Services Administration (PA GAS A) The PAG ASA was created to operate a system for weather forecasting, for collecting and disseminating climatological data and for studying seismic disturb ances. It operates and maintains a network of 4 rainfall stations within the basin. D .2 Regional Organizations D .2.1 The Regional Development Council ( RDC) The RDC serves as the regional policy and coordinating body whose mem bership consits of the regional directors of NED A and national line agencies, the governors of the member provinces and, where there are chartered cities within the region, the mayors of such cities. Because of its comprehensive membership, the RD C has the capability to integrate programs of agencies having water-related activities with the develop ment strategies of the region. D .2.2 Regional sectoral agencies Sectoral agencies are decentralized at the regional and provincial level in varying degrees and in some cases, the planning, decision-making and program ming of development projects may be done autonomously by the regional agency. One of the most decentralized agencies is the Ministry of Health's regional office which can undertake programs in cooperation with provincial and local governments and related agencies for such objectives as the improvement of health services, water supply and community health facilities. D .3 Local Governments D .3.1 Provincial government Under the decentralized local government system, the provincial government has powers to generate developments funds and work in partnership with national line agencies and other entities to improve social conditions and develop related infrastructure. Particular areas of involvement include irrigation, roads, electric power and water supply. D .3.2 Municipal and barangay governments The local population, who are generally the target beneficiaries of water resource development projects, should be given more importance than the local governments and participative groups involved in t~e .said ~rojects. Howeve~, since the financial costs of most projects are hardly within the investment capab1-: 123 lity of those local units, their participation centers mostly in the non-monetary aspects of projects like cooperative labor and, at times, free voluntary operation of completed projects. Counterpart funds are sometimes required but often the amount involved is minimal, with the national or other organizations taking the larger share of the financial burde!l. Examples of the projects where local government participation is of prime significance, are barangay water supply, local waterworks and other social im provements. 124 APPENDICES APPENDIX A Water Resources APPENDIX B Power APPENDIX C Economics Sector APPENDIX D Land Resources APPENDIX E Social Environment APPENDIX A WATER RESOURCES • Classification of Climate • Minimum, Mean, Maximum Monthly Temperature and Relative Humidity Data Davao City Figure A-1 Temperature Table A-1 Monthly Minimum Temperature Table A-2 Monthly Maximum Temperature Table A-3 Monthly Mean Temperature Figure A-2 Relative Humidity Table A-4 Mean Relative Humidity • Statistical Parameters of Monthly Rainfall Table A-5 Davao City, Davao del Sur· Table A-6 Bago Oshiro, Davao del Sur Table A-7 Tagum, Davao del Norte Table A-8 Tagnanan, Mabini, Davao del Norte • Table A-9 Rainfall Depth Duration Frequency Analysis • Statistical Parameters of Monthly Runoff Table A-10 Hija River: Tipaz, Tagum, Davao del Norte Table A-11 Tagum River: Pagsabangan, Tagum, Davao del Norte Table A-12 Matina River: Pangi, Matina, Davao del Sur Table A-13 Sibulan River: Sibulan, Sta. Cruz, Davao del Sur • Table A-14 Annual Peak Discharge of Rivers • Table A-15 Annual Minimum Flows of River • Table A-16 Existing Flood Damage Protection Measures • Groundwater Mining Picture Figure A-3 Tagum-Libuganon River Basin {Major 8 asin) Figure A-4 Tagum-Libuganon Basins (Sub-basins & Watersheds) Figure A-5 Matibo River Basin Figure A-6 Tagulaya River Basin Figure A-7 Hija River Basin Figure A-8 Tuganay River Basin Figure A-9 Davao River Basin Figure A-10 Lasang River Basin Figure A-11 Li pad as River Basin Figure A-12 Talamo River Basin 127 CLASSIFICATION OF CLIMATE I. CORONAS CLASS I Fl CATION 1st Type: Two pronounced seasons; dry from November to April; wet during the rest of the year. 2nd Type: No dry season with a very pronounced maximum rainfall from November to January. 3rd Type: Seasons not very pronounced, relatively dry from November to April and wet during the rest of the year. 4th Type: Rainfall more or less evenly distributed throughout the year. 11. HERNANDEZ CLASSIFICATION Type A: (Wet) Rainy throughout the year with at most 1 1 /2 dry months, Q less than 0.143. Type B: (Humid) Rain, well or evenly distributed throughout the year with at most 3 dry months; Q equals 0.14 or more but less than 0.33. Type C: (Moist) Rain sufficiently distributed with at most 4.5 dry months; Q equals 0.33 or more but less than 0.60. Type D: (Dry) Rain not sufficiently distributed with at most 6 dry months; Q equals 0.60 or more but less than 1.00. Type E: (Arid} There are more dry than wet months; at most there are 4 1/2 wet months; Q equals 1.00 or more but less than 1.67. Type F: (Barren) 0 eficient rainfall with less than 3 wet montbs; Q equals 1.670 or more Where: Q = Number of dry Months Number of wet Months 111. KOPPEN CLASSIFICATION AF Climate Tropical Wet Climate Temperature of coolest month above 18°C; rainfall of the driest month is at least 60 mm. Within this climate, there is a minimum of seasonal variation in temperature and precipitation. Both remain high during the year. AW Climate Tropical Wet and Dry Climate Temperature of the coolest month above 18°C, distinct dry season in low sun period or winter; characterized by a marked seasonal rhythm of rainfall; at least one month must have less than 60 mm. of rainfall. AM Climate Tropical Monsoon Climate Temperature of the coolest month above 18°C, short dry season but with total rainfall so great that the ground remains sufficiently wet throughout the 128 year to support rain forests; rainfall of the driest month is below 60 mm. It is intermediate between AF and AW, resembling AF in amount of rainfall and AW is seasonal distribution. CF Climate Warm Temperature Rainy Climate Average temperature of coldest month below 1s 0 c but above 3°c, average temperature of warmest month over 10°c, no distinct dry season, the driest month of summer receives more than 30 mm. of rainfall. CW Climate Warm Temperature Rain Climate Average temperature of coldest month below 18°C but above 3°c, average temperature of warmest month over 1o 0 c, winter dry; at least ten times as much rain in the wettest month of summer as in the driest month of winter. Table A-1 MONTHLY MINIMUM TEMPERATURE, oc Tagum-Libuganon Basins STATION DAVAO CITY LAT. 07°18'00" LONG. 125°35'00" YEAR JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 1949 21.5 22.0 22.2 22.8 23.2 23.0 22.5 22.3 22.6 22.7 22.5 23.7 50 22.0 21.5 22.4 22.9 23.2 22.8 22.4 22.4 22.7 22.3 22.4 21.5 51 21.9 22.3 22.2 23.1 23.1 22.9 22.6 22.5 22.9 22.9 22.5 52 21.9 22.4 22.1 22.8 23.6 23.0 22.8 22.6 22.6 22.8 22.5 22.5 53 22.0 21.8 22.1 23.1 23.3 23.3 22.6 22.9 22.7 23.0 22.8 22.6 54 22.0 22.0 22.9 22.7 23.3 23.0 22.4 22.3 22.3 22.2 22.6 22.1 55 21.6 21.9 22.7 22.3 23.0 22.5 22.0 22.1 22.3 22.5 22.9 22.1 56 21.8 22.1 22.3 23.0 23.0 22.6 22.3 22.6 22.5 22.8 22.6 22.3 57 22.3 22.2 22.5 23.0 23.4 23.1 22.9 23.1 23.2 22.8 22.6 22.4 58 22.4 22.1 22.1 23.4 23.7 23.5 23.0 23.0 23.0 23.5 23.1 22.8 59 21.9 21.5 23.1 23.3 23.3 23.3 22.9 22.8 22.6 22.7 22.9 22.3 60 22.1 22.3 22.3 23.4 23.3 22.9 22.6 22.9 22.2 22.0 22.0 21.7 61 21.2 22.1 22.1 22.8 22.9 22.1 21.6 22.0 22.3 22.4 22.3 22.5 62 22.2 22.0 22.2 22.8 23.2 22.7 22.9 22.8 22.6 23.1 22.7 22.7 63 22.1 21.8 22.4 22.8 23.2 23.1 22.7 22.9 23.2 22.8 22.1 7.2.2 64 22.2 22.1 21.9 22.8 23.3 22.9 22.3 22.6 22.7 22.7 22.6 22.4 65 21.9 22.1 22.5 22.6 23.0 22.8 22.6 22.7 22.9 22.6 22.3 2i.9 66 21.0 21.3 22.6 23.2 23.5 22.9 23.0 23.1 23.2 23.0 22.9 22.7 67 22.5 22.2 22.5 22.9 23.2 23.5 23.2 23.2 23.3 22.8 22.8 22.2 68 22.2 22.1 22.2 23.0 22.9 23.0 22.9 23.2 22.8 22.8 22.6 22.4 69 21.3 21.8 22.0 22.6 23.8 23.3 22.3 22.5 22.6 22.5 22.4 22.2 70 21.7 24.2 21.9 22.4 22.9 22.7 21.9 21.6 21.7 21.8 21.4 21.7 71 21.9 22.5 23.0 23.1 23.2 22.9 23.0 22.5 22.5 22.7 22.1 22.0 72 21.2 21.5 21.6 22.1 22.4 22.1 22.2 21.8 22.1 22.1 22.1 21.5 73 21.2 20.9 22.1 22.3 22.3 22.2 21.9 21.4 22.5 23.3 22.8 21.0 74 21.9 22.0 22.6 23.0 23.4 23.0 24.8 23.2 23.2 23.2 23.1 22.7 75 22.1 22.0 22.7 22.1 23.1 22.1 22.8 22.9 22.9 23.1 22.1 21.6 2-i.9 76 21.4 21.1 21.8 22.3 23.0 22.7 23.1 22.7 22.6 22.5 22.1 77 21.2 21.0 21.5 22.5 22.7 22.5 22.5 22.8 22.3 22.7 23.0 22.4 78 22.6 22.9 22.9 24.1 23.7 23.8 23.4 22.9 79 22.6 22.9 22.9 24.1 23.7 23.8 23.4 23.8 23.8 '23.6 22.7 22.6 22.3 MEAN 21.9 22.0 22.3 22.9 23.2 23.0 22.7 22.6 22.7 129 MINIMUM, MEAN, MAXIMUM MONTHLY TEMPERATURE ( 0 C) (TAG UM LI BUGANON BASIN) i 35 ....---. /" ·~. ..---· i""-.. ,___ ... ~ .. · r---.. ~·· .. """ -· _../ 30 __I ~ - ~ u ~ .__""" ~ ~ - ::::: I ...... r: 25 '1.l Cl.. E ~· '1.l ~ !- "-· ~- ·- -·i------· --· --·-- 20 10 F M A M A s 0 N D LEGEND: Maximum-···- Mean Minimum-~ STATION: DAVAO CITY LAT. 7°18' LONG. 125°35' PERIOD OF RECORD: 1949 -1979 Figure A-1 130 Table A-2 MONTHLY MAXIMUM TEMPERATURE, 0 c Tagum-Libuganon Basins STATION DAV AO CITY LAT. 07-18-00 LONG. 125-35-00 YEAR JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 1949 30.0 30.4 31.2 32.3 31.7 31.6 30.8 31.0 30.8 31.9 31.4 29.8 1950 30.7 31.2 31.7 32.4 31.9 31.2 31.2 31.3 31.1 31.9 30.9 30,0 1951 29.9 31.0 31.7 31.9 32.2 31.6 31.0 31.2 31.3 - 31.7 31.0 1952 31.3 30.9 37.5 33.1 32.1 31.2 30.6 31.6 31.0 31.5 31.7 31.0 1953 30.6 30.0 32.9 33.7 32.0 31.2 31.2 31.4 31.3 31.9' 31.7 31.1 1954 32.6 32.0 32.4 33.3 32.6 31.1 30.7 31.2 31.1 31.7 31.6 30.7 1955 29.6 31.3 32.7 32.8 31.7 30.4 30.8 30.8 31.4 31.4 31.2 30.9 1956 29.8 31.3 32.5 31.4 31.1 31.6 31.1 30.7 30.9 31.7 31.8 30.2 1957 31.4 31.4 31.9 32.4 32.4 31.7 31.1 31.1 31.8 32.2 32.6 31.6 1958 31.9 32.6 33.5 34.3 33.0 31.6 31.6 31.5 31.5 32.0 31.8 31.8 1959 30.6 32.5 32.9 32.6 32.1 31.5 31.0 30.7 31.3 31.8 31.7 32.1 1960 31.6 31.4 32.4 32.5 32.8 31.4 31.5 31.5 31.6 32.0 31.3 30.8 1961 30.1 31.1 32.7 32.6 31.9 31.4 31.1 31.6 31.8 32.0 32.7 31.5 1962 29.6 29.4 31.3 32.5 32.1 31.7 30.9 31.6 31.2 32.6 31.7 31.1 1963 29.0 29.2 31.2 33.1 33.2 31.9 31.3 31.2 32.0 32.2 32.3 32.3 1964 31.8 30.2 32.0 32.l 32.2 31.4 31.7 31.7 31.6 32.0 31.8 31.7 1965 30.4 30.6 31.5 32.4 32.4 31.4 30.7 31.4 31.6 32.3 32.4 31.1 1966 30.6 31.8 33.5 33.3 31.9 31.9 31.1 31.4 32.4 32.0 32.3 31.7 1967 31.1 31.5 32.2 33.7 32.8 32.8 32.6 32.5 32.6 32.2 32.3 32.3 1968 30.5 31.2 33.0 34.0 33.1 32.4 32.1 '31.9 32.6 32.5 32.8 29.7 1969 30.4 31.3 32.4 33.7 33.7 32.0 31.6 31.8 31.8 32.9 31.9 32.1 1970 31.4 31.6 31.9 33.1 33.0 32.2 31.9 31.8 32.9 32.2 32.1 30.9 1971 31.0 30.9 32.7 33.7 33.0 31.6 31.6 32.3 32.7 31.7 32.6 31.8 1972 31.9 31.7 31.5 33.5 33.0 32.2 32.9 32.4 32.0 33.2 32.6 32.5 1973 33.2 33.4 33.3 32.5 33.0 32.7 32.6 32.6 32.3 32.9 31.2 31.9 1974 29.8 29.7 31.4 31.8 32.3 31.5 31.4 31.8 32.2 31.1 31.7 30.8 1975 31.0 31.3 31.5 32.0 32.4 31.5 31.7 32.5 32.2 32.2 32.7 31.6 1976 31.2 31.2 31.9 33.3 33.1 32.1 31.8 32.1 31.6 32.6 32.6 32.8 1977 31.6 31.5 31.9 33.7 33.6 31.6 31.6 31.1 31.0 32.6 32.8 32.3 1978 32.0 33.1 32.1 33.9 32.2 32.6 31.6 31.8 32.8 32.9 31.3 1979 32.0 33.1 32.1 33.9 33.2 32.6 31.6 31.8 32.8 32.9 31.3 MEAN 30.9 31.2 32.2 33.0 32.5 31.7 31.5 31.6 31.7 32.2 32.0 31.3 131 Table A-3 MONTHLY MEAN TEMPERATURE, 0 c Tagum-Libuganon Basins STATION DAVAO CITY LAT.: 07-18-00 LONG.: 125-35-00 YEAR JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 1949 25.8 26.2 26.7 27.6 27.4 27.3 26.7 26.7 26.7 27.3 27.0 26.8 1950 26.3 26.3 27.1 27.7 27.6 27.0 26.8 26.9 26.9 27.1 26.7 25.8 1951 25.9 26.9 26.9 27.5 27.3 27.2 26.8 26.9 27.l 27.3 26.8 1952 26.6 26.7 27.3 28.0 27.9 27 .1 26.7 27.0 26.8 27.2 27 .1 26.7 1953 26.3 25.9 27.5 28.4 27.7 27.2 26.9 27.2 27.0 27.4 27.2 26.8 1954 27.3 27.0 27.7 28.0 27.9 27 .1 26.6 26.7 26.7 26.9 27.1 26.4 1955 25.6 26.6 27.4 27.6 27.3 26.4 26.4 26.7 26.9 26.9 27 .1 26.6 1956 25.8 26.7 27.4 27.2 27.0 27 .1 26.7 26.6 26.7 27.2 27.2 26.2 1957 26.8 26.8 27.2 27.7 27.9 27.4 27.0 27.1 27.5 27.5 27.6 27.0 1958 27.2 27.4 27.8 28.8 28.4 27.6 27.3 27.2 27.2 27.8 27.4 27.3 1959 26.2 27.0 28.0 28.0 27.7 27.4 27.0 26.8 27.0 27.2 27.3 27.2 1960 26.8 26.0 27.4 28.0 28.1 27.2 27.1 27.2 26.9 27 .1 26.7 26.3 1961 25.7 26.6 27.4 27.7 27.4 26.8 26.4 26.8 27.1 27.2 27.5 27.0 1962 25.8 25.7 26.8 27.7 27.7 27.2 26.9 27.2 27.0 27.9 27.2 26.9 1963 26.7 25.5 26.9 28.0 28.2 27.5 27.0 27.1 27.6 27.5 27.6 27.3 1964 27.0 26.2 27.0 27.5 27.8 27.2 27.0 27.2 27.2 27.4 27.2 27.1 1965 26.2 26.4 27.1 27.5 27.7 27.1 26.7 27.1 27.3 27.5 27.4 26.5 1966 25.8 26.6 28.1 28.3 27.7 27.4 27.1 27.3 27.0 27.5 27.6 27.2 1967 26.8 26.9 27.4 28.3 28.4 27.9 27.9 27.9 28.0 27.5 27.6 27.3 1968 26.4 26.6 27.6 28.5 27.8 27.7 27.5 27.6 27.7 27.6 27.7 26.0 1969 25.9 26.6 27.2 28.2 28.3 27.7 27.0 27.2 27.2 27.7 27.2 27.2 1970 26.6 26.7 26.9 27.8 28.0 27.5 26.9 26.7 27.3 27.0 26.8 26.3 1971 26.5 26.7 27.9 28.7 28.1 27.3 27.3 27.4 27.6 27.2 27.4 26.9 1972 26.6 26.6 26.6 27.8 27.7 27.2 27.6 27.1 27.1 27.7 27.4 27.0 1973 27.2 27 .1 27.7 27.4 27.7 27.5 27.3 27.0 27.4 28.1 27.0 27.3 1974 25.9 25.9 27.0 27.4 27.9 27.3 27.2 27.5 27.7 27.2 27.4 26.8 1975 26.6 26.6 27.0 27.1 27.8 26.8 27.3 27.8 27.6 27.5 27.4 26.1 1976 26.3 26.2 26.9 27.8 33.1 27.4 27.5 27.9 27.1 27.6 27.5 27.2 1977 26.4 26.3 26.7 28.1 28.2 27.1 27.1 26.9 26.8 27.7 27.9 27.4 1978 27.0 28.0 28.0 29.0 28.2 28.0 1979 27.0 28.0 28.0 29.0 28.2 28.0 27.5 27.8 - 28.2 28.2 27.1 MEAN 26.4 26.6 27.3 27.9 28.0 27.3 27.0 27.2 27.2 27.4 27.3 26.8 132 Table A-4 MEAN RELATIVE HUMIDITY, % Tagum - Libuganon Basins STATION: DAVAOCITY LAT.: 07-18-00 LONG.: 125-35-00 YEAR JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 1949 84 78 78 84 86 73 81 89 81 83 86 1950 84 80 86 80 81 84 84 83 82 81 84 82 1951 85 81 78 81 81 84 84 82 84 82 83 1952 79 81 72 76 84 85 84 81 82 81 82 83 1953 82 84 77 75 82 86 84 83 84 82 84 82 1954 75 78 79 77 81 83 84 82 81 80 81 82 1955 1956 81 79 77 84 82 81 81 83 82 81 81 85 1957 80 76 80 80 81 83 84 83 81 81 78 79 1958 78 73 72 72 80 82 80 81 82 80 81 79 1959 79 75 74 76 80 82 83 82 81 82 81 78 1960 78 79 75 76 79 83 82 81 82 81 83 84 1961 82 84 76 80 82 83 83 83 81 80 78 82 1962 86 88 83 79 82 82 84 84 83 78 81 82 1963 83 84 80 76 79 79 82 82 80 80 81 79 1964 79 81 77 81 83 82 81 78 81 81 81 80 1965 81 81 80 80 80 84 82 81 81 82 81 83 1966 81 78 76 78 83 82 84 83 79 81 80 82 1967 84 82 80 76 80 80 79 79 78 79 79 80 1968 82 80 80 75 79 77 79 78 77 80 78 82 1969 82 77 76 74 79 83 83 83 81 83 1970 83 81 81 79 80 84 81 81 79 83 83 1971 82 83 79 78 82 83 81 79 80 82 81 81 1972 79 81 77 80 81 80 79 80 78 80 79 1973 77 80 77 82 78 80 80 80 82 80 83 81 1974 82 86 83 83 82 83 83 81 80 85 81 84 1975 82 83 83 77 84 82 83 84 76 86 1976 85 83 82 79 80 81 81 80 79 81 82 83 83 1977 84 84 82 77 80 83 83 84 82 83 84 1978 81 78 1979 78 77 78 75 82 82 82 79 78 81 82 1980 83 80 72 76 79 84 84 82 80 82 1981 83 77 81 82 77 81 81 81 82 MEAN 81 81 78 78 81 82 82 81 133 MEAN RELATIVE HUMIDITY(%) (TAGUM-LIBUGANON BASINS) 25 u «-..- .f' .E"'O ::l I 20 10...___ ..._ __ _._ __ ...&...__,....a.. __ _._ __ _.... __ __. __ ___..______.....______ F M A M A s 0 N D STATION: DAVAO CITY LAT. 7°18' LONG. 125°35' PERIOD OF RECORD: 1949-1981 Figure A-2 134 Table A-5 STATISTICAL PARAMETERS OF MONTHLY RAINFALL AT KOl DAVAO CITY, DAVAO DEL.SUR 1961-76 79-81 JAN FEB MARCH APRIL MAY JUNE JULY AUGUST SEPT. OCT. NOV. DEC. ANNUAL MEAN 120.53 119.97 87.24 162.72 199.29 191.58 152.12 181.49 189.78 155. 73 136.44 105.41 1,809. STD. DEV. 63.08 77.89 58.78 90.73 110.27 121.07 83.76 94.20 85.33 40.28 56.81 56.89 32. CO. VAR. 0.52 0.65 0.67 0.56 0.55 0.63 0.55 0.52 0.45 0.26 0.42 0.54 0 SKEW 0.16 0.40 0.41 0.32 1.14 1.05 1.44 0.19 0.38 -0.09 0.74 1.22 0 MAX. 248.90 274.30 199.80 325.60 462.30 519.00 388.60 347.60 329.10 228.10 247.40 231.80 MIN. 4.30 19.90 3.10 29.20 46.60 20.30 33.70 37.90 61.40 73.60 40.10 29.00 Table A-6 STATISTICAL PARAMETERS OF MONTHLY RAINFALL AT K02 BAGO OSHIRO, DAVAO DEL SUR 1976-80 JAN FEB MARCH APRIL MAY JUNE JULY AUGUST SEPT. OCT. NOV. DEC. ANNUAL w V'l MEAN 91.50 69.10 92.05 83.88 176.25 289.15 306.18 270.07 211.08 213.68 172.68 176.95 2, 185. STD. DEV. 78.03 22.41 60.S7 18.20 99.85 92.30 70.66 124.26 118.22 63.85 77.29 46.50 249. CO. VAR. 0.85 0.32 0.66 0.22 0.57 0.32 0.23 0.46 0.56 0.30 0.45 0.26 0. SKEW 1.41 -0.83 0.36 0.23 -0.20 1.63 -0.79 -1.00 1.73 0.86 -1.00 -1.36 0. MAX. 202.70 92.80 166.30 110.00 277.60 423.00 364.70 17.10 384.00 303.70 251.30 216.30 MIN. 21.20 38.90 27.20 59.50 62.70 217.80 215.00 33.80 133.60 164.50 66.70 111.40 Table A-7 STATISTICAL PARAMETERS OF MONTHLY RAINFALL AT K09 TAGUM, DAVAO DEL NORTE 1966-76 JAN FEB MARCH APRIL MAY JUNE JULY AUGUST SEPT. OCT. NOV. DEC. ANNUAL MEAN 191.52 174.66 123.70 178.40 231.12 232.98 145.20 193.78 177.10 198.06 248.61 164.70 2258. STD. DEV. 107.39 107.55 108.85 168.74 92.31 65.73 69.01 68.30 59.15 72.23 150.16 58.96 218. CO. VAR. 0.56 0.62 0.88 0.95 0.40 0.28 0.48 0.35 0.33 0.37 0.60 0.36 SKEW 0.44 0.66 2.29 2.58 0.82 -0.30 0.21 0.25 -1.12 0.19 0.85 0 0. MAX. 401.90 373.70 404.70 651.90 427.20 329.20 279.50 320.50 238.50 319.20 533.20 249.30 MIN. 9.40 42.20 32.50 61.20 88.80 115.30 18.10 95.60 49.40 106.60 55.20 77.50 Table A-8 STATISTICAL PARAMETERS OF MONTHLY RAINFALL AT KlO TAGNANAN, MABINI, DAVAO DEL NORTE 1966-79 JAN FEB MARCH APRIL MAY JUNE JULY AUGUST SEPT. OCT. NOV. DEC. ANNUAL MEAN 158.58 111.09 106.62 160.19 199.65 245.60 160.77 234.68 153.28 210.63 157.06 121.67 1903 STD.DEV. 98.87 63.78 67.22 131.67 91.04 208.80 61.04 117.50 121.74 109.29 74.70 63.84 415 CO. VAR. 0.62 0.57 0.63 0.82 0.46 0.85 0.38 0.50 0.79 0.52 0.48 0.53 SKEW 0.34 0.70 1.29 0.54 0.96 2.83 0.40 0.64 1.11 1.02 0.46 0.94 1. MAX. 337.30 243.20 268.40 413.50 414.50 872.00 267.20 421.50 384.30 420.60 299.40 272.50 MIN. 1.60 20.30 27.00 15.80 63.60 88.40 50.80 82.00 21.80 77.60 26.70 53.80 Table A-9 RAINFALL DEPTH-DURATION FREQUENCY ANALYSES DAVAO CITY {INTENSITY IN MM/HR.) Tagum-Libuganon Basins Return Period (Years) 2 5 10 15 20 25 50 10') Duration 5 mins. 146.4 179.8 201.1 213.4 222.0 228.6 249.1 269.4 10 mins. 130.1 163.1 184.9 197 .1 205.8 212.4 232.8 253.1 15 mins. 118.3 146.8 165. 7 176.3 183.8 189.5 207.2 224.8 30 mins. 93.7 118.4 134.7 143.9 150.3 155.3 170.6 185.7 1 hour 67.1 82.9 93.3 99.2 104.2 106.6 116.4 126.1 2 hours 37.8 46.4 52.1 55.3 57.5 59.3 64.6 69.9 3 hours 26.2 32.1 35.9 38.1 39.6 40.8 44.4 48.0 6 hours 13.8 18.6 21.7 23.4 24.7 25.6 28.6 31.5 12 hours 7.0 9.5 11.2 12.1 12.7 13.2 14.8 16.8 24 hours 4.0 5.4 6.3 6.8 7.2 7.5 8.3 9.2 Table A-10 STATISTICAL PARAMETERS OF MONTHLY FLOW AT 1107 HIJO RIVER AT TIPAZ, TAGUM, DAVAO DEL NORTE 1963-64, 66-70 JAN FEB MARCH APRIL MAY JUNE JULY AUGUST SEPT. OCT. NOV. DEC. ANNUAL MEAN 61.58 48.65 47.69 49.78 57.68 57.63 54.17 43.35 44.78 55.30 48.69 46.64 517. STD. DEV. 8.37 7.23 6.06 16.80 21.52 8.64 8.84 8.89 10.53 20.05 17.88 12.07 30. CO.VAR. 0.14 0.15 0.13 0.34 0.37 0.15 0.16 0.20 0.24 0.36 0.37 0.26 0. SKEW -0.12 -1.70 -1.46 1.73 1.15 1.49 0.95 -0.09 1.33 0.80 0.58 -0.15 0. MAX. 70.55 53.30 52.28 69.18 81.56 67.44 68.19 53.46 63.82 89.97 80.12 60.61 MIN . 52.10 40.32 40.82 39.97 39.77 51.19 43.63 32.60 33.57 35.54 26.52 31.26 .... w -....J ··-"·· Table A-11 STATISTICAL PARAMETERS OF MONTHLY FLOW AT 1108 TAGUM RIVER AT PAGSABANGAN, TAGUM, DAVAO DEL NORTE 1949-69 JAN FEB MARCH APRIL MAY JUNE JULY AUGUST SEPT. OCT. NOV. DEC. ANNUAL MEAN 443.08 304.50 230.98 177.95 326.85 420.74 346.06 282.19 347.56 320.23 256.43 321.14 3,945.0 STD. DEV. 289.26 161. 79 123.52 121.26 223.87 178.35 52.92 67.35 136.12 102.52 114.99 189.82 897.8 CO. VAR. 0.65 0.53 0.54 0.68 0.69 0.42 0.15 0.24 0.39 0.32 0.45 0.59 0.2 SKEW 1.29 0.56 1.13 1.75 2.33 0.87 -0.32 0.65 -0.68 1.48 0.80 0.83 0.5 MAX. 1,029.09 570.67 525.31 486.52 937.49 800.82 444.27 404.15 504.90 571. 76 444.68 701.02 MIN. 165.58 142.01 83.22 60.96 140.56 24'1 .39 239.29 168.45 134.24 205.59 138.67 114.81 Table A-12 STATISTICAL PARAMETERS OF MONTHLY FLOW AT 1109 MATINA RIVER AT PANGI, MATINA, DAVAO DEL SUR 1959-64, FEB MARCH APRIL MAY JUNE JULY AUGUST SEPT. OCT. NOV. DEC. ANNUAL 66-70 JAN MEAN 4.36 2.·14 2.12 2.38 2.44 2.76 2.61 2.98 2.51 2.47 1.54 1.41 29. STD. DEV. 5.15 1.65 1.51 2.62 1.97 1.46 1.34 2.14 1.50 1.51 0.64 0.48 16. CO. VAR. 1.18 0.77 0.71 1.10 0.81 0.53 0.51 0.72 0.60 0.61 0.42 0.34 0. SKEW 1.59 1.88 1.82 2.74 1.93 1.31 1.07 1.36 1.47 1.66 0.99 0.60 2. MAX. 14.52 6.07 5.68 9.20 7.10 5.86 5.33 7.42 5.83 5.92 2.80 2.28 MIN. 0.62 0.55 0.67 0.60 0.59 1.40 0.99 0.91 0.88 0.96 0.88 0.80 w 00 Table A-13 STATISTICAL PARAMETERS OF MONTHLY FLOW AT 1110 SIBULAN RIVER AT SIBULAN, ST A. CRUZ, DAVAO DEL SUR 1955-54, MARCH MAY JULY AUGUST DEC. ANNUAL 66-70 JAN FEB APRIL JUNE SEPT. OCT. NOV. MEAN 16.27 15.79 14.90 14.08 16.04 15.93 17.15 16.66 15.85 16.92 17.17 17.57 192. STD. DEV. 4.33 5.42 4.90 5.18 5.24 3.90 6.26 5.08 4.92 4.51 6.23 5.96 51. CO. VAR. 0.27 0.34 0.33 0.37 0.33 0.25 0.37 0.31 0.31 0.27 0.36 0.34 0 SKEW 0.77 0.09 0.62 0.92 0.37 0.46 0.99 0.73 0.34 -0.87 0.52 0.15 0 MAX. 25.07 24.28 24.83 25.19 25.47 23.69 31.39 27.72 25.79 22.04 28.20 27 .11 MIN. 11.28. 7.69 7.18 6.79 8.41 9.69 8.76 8.73 7.70 8.36 7.57 7.58 Table A-14 ANNUAL PEAK DISCHARGE OF RIVERS (Discharge in CMS) Tagum-Libuganon Basins YEAR HIJO RIVER TAGUM RIVER MATiNA RIVER SIBULAN RIVER 1950 226. 71 1951 345.48 1952 255.3 1953 235.89 1954 151.93 1955 384.22 1956 261.73 8.19 1957 308.96 6.02 1958 152.76 6.18 1959 174.26 4.21 1960 171.91 2.77 8.07 1961 205.39 1.12 9.51 1962 476.92 4.5 8.63 1963 38 331.46 1.18 9.27 1964 47.99 279.64 .99 10.88 1965 1966 25.6 1967 26.34 456.13 1.56 1968 24.75 255.89 5.42 9.14 1969 26.13 165.87 1.43 11.72 1970 24.46 74 D. A. (Sq. Km.) 617 2326 48 128 No. of Years 7 18 9 11 Mean-Log 1.47 2.40 0.24 0.90 Std. Dev.-Log 0.11 0.16 0.30 0.13 Skewness 2.70 0.26 1.18 1.64 139 Table A-15 ANNUAL MINIMUM FLOWS OF RIVER IN THE T AGUM-LiBUGANON (Discharge in CMS) SI BULAN YEAR HIJO TAGUM MATINA 1950 69.94 1951 69.14 1952 95.06 1953 23 ..52 1954 27.95 1955 49.27 1956 69.07 6.36 1957 51.79 4.04 1958 35.38 3.55 1959 31.07 2.62 1960 44.90 0.33 49 1961 60.51 0.54 6.90 1962 77.87 0.76 5.44 1963 21.34 49.18 0.45 5.63 1964 13.27 35.96 0.43 5.92 1965 1966 18.15 1967 11.53 38.29 0.23 1968 10.23 25.97 0.22 4.26 1969 17.94 28.53 0.67 3.96 1970 15.56 0.35 NO. OF YEARS 7 18 9 11 MEAN 15.43 49.08 0.44 4.83 STD.DEV. 3.99 20.57 0.19 1.31 SKEW. COEFF. 1.12 0.67 0.55 0.002 D.A. (SQ. KM.) 6.17 2326 48 128 140 Table A-16 INVENTORY OF EXISTING FLOOD DAMAGE PROTECTION MEASURES Tagum-Libuganon Basins Revet- (C-0-C/ Control ment/ Diver- Timber Gates PROJ. Name of Location of Dikes/ Bank sion Dredging Spur Pile Gravity River Closing Drainage No. Project Levees Protec Channel Cl Dikes Hurdles Walls Walls/ Dikes Main {Km) (Km) (Km) (Km) (m) (m) (Units) (Km) (m) (m) DAVAO DEL SUR ~ ..i:::.. 1. Davao RC, Davao City 1.342 2. Pilan RC., Sta. Cruz 0.040 0.210 3. Tuban & Coronan RC, Sta. Cruz 0.850 DAVAO DEL NORTE 4. Manat RC, Nabunturan 6 units 5. Panabo RC, Tagum & Panabo 1.407 6. Tagum-lsing RC 1.650 TOTAL 0.040 1.342 4.117 6 units GROUNDWATER MINING PICTURE TAGUM-LIBUGANON BASINS 700 l I I I I l I I I TAGUM-LIGUGANON RIVER BASIN (Major Basin) TAGUM-LIBUGANON BASINS (Sub-Basins and Watersheds) 60 0 \ 1200 ~ ~ >- >- l i' 50 0 -g 1000 u \ ~ ~ ESTIMATED GW STORAGE = 2254 MCM z ESTIMATED GW STORAGE =3559 MCM z ESTIMATED SAFE YIELD = 333MCM/YR. ESTIMATED SAFE YIELD = 526 MCM/YR. \ = 373 MCM/YR. CY ESTIMATED 50-YR GWM YIELD = 597 MCM/YR. 0 ' ESTIMATED 50-YR GWM YIELD ....I~ ESTIMATED 50-YR GWM _j ~Tl MATED 50-YR GWM 2 2 "' 0.12 MCM/KM <( WELL DENSITY .. 0.2 MCM/KM <( WELL DENSITY :: 40 0 <( 800 :: ~ \ <( 0:: oc ~ 0 0 :::r: ~ :::r: I- \ ~ I- tV ~ ~ l!) ~ l!) 300 z 600 - z z z o.1..22.L+ 333 - t ~ ~ ~Qcr } 5 ~ 9 +526 200 400 200 100 0 0 0 20 40 60 80 100 0 20 40 60 80 100 PERIOD OF EXHAUSTION PERIOD OF EXHAUSTION Tin years T in years Figure A-3 Figure A-4 GROUNDWATER MINING PICTURE TAG UM-LI BU GAN ON BASINS I I I I MATIBO RIVER BASIN AGULAYA-SIBULAN RIVER BASINS 40• cz2 ~ ...__>- ...__>- ~ ~ u u ~ 50 I ~ z ESTIMATED GW STORAGE 116 MCM ESTIMATED GW STORAGE = 127 MCM = ~ ESTIMATED SAFE YIELD ESTIMATED SAFE YIELD = 19 MCM/YR. 0 = 17MCM/YR. 0 ESTIMATED 50-YR GWM YIELD 20 MCM/YR. ESTIMATED 50·.YR GWM YIELD = 21 MCM/YR. = .....I~ .3 ESTIMATED 50-YR GWM ESTIMATED SQ.YR GWM <( 2 <( 2 WELL DENSITY = 0.12 MCMiKM WELL DENSITY = 0.12 MCM/KM 3 3 <( 30 oc 40 ~ Cl Cl ::r: ::r: I- ~ I- t 19 Q:,.--+17116 .J::>. 3 Vi 3 w (.!) l? ~ z z 30 z z ~ :E '< ~ 20 20 10 0 100 0 20 40 60 80 100 0 20 40 60 80 PERIOD OF EXHAUSTION PERIOD OF EXHAUSTION Tin years T in years Figure A-5 Figure A-6 GROUNDWATER MINING PICTURE TAGUM-LIBUGANON BASINS I I I I I I I I HIJO RIVER BASIN TUGANAY RIVER BASIN o2 ?: >-°' ~ u ~ 20 0 u 200 ~ ~ z ESTIMATED GW STORAGE = 515 MCM z ESTIMATED GW STORAGE =490 MCM ESTIMATED SAFE YIELD = 76 MCM/YR. ESTIMATED SAFE YIELD = 72 MCM/YR. 0 0 _J- ESTIMATED 50 YR GWM YIELD = 86 MCM/YR. ESTIMATED 50·YR GWM YIELD = 82 MCM/YR. _J- 40 40 I 0 0 I 0 20 40 60 80 100 0 20 40 60 80 100 PERIOD OF EXHAUSTION PERIOD OF EXHAUSTION Tin years Tin years Figure A-7 Figure A-8 GROUNDWATER MINING PICTURE TAG UM-LI BUGANON BASINS 90 J I I I I I I I DAVAO RIVER BASIN LASANG RIVER BASIN 1 ., 300 80 ~ ci - >- ~ ~ >- u \ ~ 70 ~ u \ z \ ESTIMATED GW SlORAGE "'1194 MCM ~ ~ESTIMATED GVISTORAGE = 344 MCM 0 ~ESTIMATED SAFE YI ELD = 177 MCM/YR. z ESTIMATED SAFE YIELD = 51 MCM/YR. 200 MCM/YR. ESTIMATED 50-YR GWM YIELD = 58 MCM/YR. _j' ESTIMATED 50-YR GWM YIELD = ESTIMATED 50-YR GWM 0 ' ESTIMATED 50.YR GWM <( 2 WELL DENSITY = 0.12 MCM/YR/KM ...S WELL DENSITY = 0.12 MCM/KM2 3 . """"""'-- <( 200 <( 60 ...... _. - ct: :: Cl <( ::c ct: ...- I------0 ~ ~ ~ ::c Q:il.11_ +51 Vl ~ I- t (..!) z 3 50 (..!) z z ~ .... no~ 11 ;4 +177 z ~ 100 40 30 0 20 0 20 40 60 80 100 0 20 60 40 80 100 PERIOD OF EXHAUSTION PERIOD OF EXHAUSTION Tin years Tin years Figure A-9 Figure A-10 GROUNDWATER MINING PICTURE TAG UM-LI BUGANON BASINS I I I I I I I I 1 LIPADAS RIVER BASIN T AL OMO RI VER BASIN ci cd >- ~. ~ 2u u 50 2 100 ~ z ESTIMATED GWSTORAGE = 96 MCM z ESTIMATED GW STORAGE = 180 MCM ESTIMATED SAFE YI ELD = 15 MCM/YR 0 ESTIMATED SAFE YIELD = 27 MCM/YR ESTIMATED 50-YR GWM YIELD 0 ESTIMATED 50-YR GWM YI ELD = 17 MCM/YR _J~ = 30 MCM/YR _J~ ESTIMATED 50-YR GWM ESTIMATED 50-YR GWM 2 10 20 0 0 20 40 60 80 100 0 20 40 60 80 100 0 PERIOD OF EXHAUSTION PERIOD OF EXHAUSTION Tin years Tin years Figure A-11 Figure A-12 APPENDIX B POWER GLOSSARY Load Factor the ratio of the average load over a designated period of time to the peak load occurring in that period. average load maximum demand Connected load sum of continuous load Maximum demand the greatest of ail demands which have occurred during a specified period of time. Geothermal relating to the heat of the earth's interior Grid interconnected network of power stations and transformation facilities Hydroelectric of, relating to, or employed in the production of electricity by water power. Nuclear of, or relating to atomic energy. Power energy capable of being transformed into 'Nork Substation consists of one or more transformers mechanically and electrically connected and coordinated in design and construction" Voltage the greatest root mean square difference of potential between any two conductors of the circuit connected Watt absolute MKS unit of power equal to 1 joule per second or 1/746 horsepower. Note: l megawatt (MW) - 1,000,000 watts Watt-Hour unit of work or energy equivalent to the power of one watt operating for one hour and equal to about. 2,655 foot pounds. Average Kilowatt per consumer per-month simulation of load behavior of each type Hour (KWH) of load for a given 24-hour period. The average KWH per con sumer per month based on NEA and assumptions. Total KWH per total number of consumers x average kwh/month /consumer month System Loss transmission losses from the generation outlet ta the transfer point to service areas of 24 per cent were assumed. Summary of Forecast Assumptions Based on statistics and practices here in the Philippines, the commercial levels and usage of the potentials consumers in the data were computed for the 1st ( 1980), 15th (1990), and 25th (2000) years taking into consideration the percentage connection level and population growth rates. Other considerations which were taken into account were as fol lows: the Engineering Feasibility Report by the National Electrification Administration; the actual housecount, the field investigation and the load feasibility and engineering studies by 147 NEA engineering consultants. The load levels and usage (KWH/month/consumer) were pro jected up to year 2000. The percentage connection in 1980 was assumed to be 49.88%; for 1990, 72% and for year 2000, 93%. The low percentage connection in 1980 was due to the initial connection covered by poblacion areas and minimal connections along the feeder route. The percentage increase in the number of potential consumers for poblaciones and barrios were based on the annual growth per area covered by the basin. Consumption in kilowatt hour per type of consumer was based on the consumption rates prepared by the NEA engineering consultant. From the average consumption in KWH/ month/consumer and estimated number of consumers, the maximum demand was deter mined for every city and municipality covered by the basin. The number of consumers and corresponding kilowatt demand in the data were pro jected up to year 2000 to determine the overall system demand within the Tagum-Libuga non Basins. LOAD FORCAST Tagum-Libuganon Basins Planning Year Description 1975 1980 1990 2000 1. Population 1,012,931 1,188,327 1,914,242 2,763,442 2. Number of Households 169 ,386 198,055 319,040 460,236 3. Number of consumers 98,782 229,709 428,019 4. Projected increase on number of households based on 1975-80 figures(%) 16.93 88.35 171.71 5. Average KWH/month/consumer 35 58 80 6. Total KWH/year x 103 3,457 13,323 34,242 7. Total KWH/year x 103 41,488 159,877 410,899 8. Other loads (KWH/year x 1o3) 86,182 200,373 373,685 9. Sub-total (KWH/year x 103) 127,670 360,250 784,580 10. System loss ( %) 24 24 24 11. KWH/year (Purchase/generate) 167,990 474,014 1,032,347 12. Load factor (Annual system) 34 52 70 13. KW Peak/month (Average) 56,402 104,060 168,354 14. Peak factor 1.2 1.2 1.2 15. KW Demand (Annual) 67,682 124,871 202,025 In the other load computations, the following were assumed: 1. Population growth rate 1980 - 1990 = 1.048834 1980 - 2000 = 1.0430994 148 2. Connection level and assumption rates 1980 = 49.88% at 35 KWH/month/consumer 1990 = 72% at 58 KWH/month/consumer 2000 = 93% at 80 KWH/month/consumer 3. Population increases 1980 = 1.175 1990 = 1.901 2000 = 2.751 From the above assumption, the following multipliers were dervied from the other load computations: C = other load in 1980 =86,182 x 103 KWH/year 1 10th year other load (1990) = ( 1.048834) O 72 C = 2.325 C 49.88 2 20th year other load ( 2000) = ( 1.0430994 ) 093 C = 4.336 C 49.88 149 Mindanao Power LEGEND: Projects GENERATING PLANTS Hydroelectric ~ Coal Thermal APLAYA DIESEL _ 112MW (1981) ~Diesel /:I.PLAY A DIESEL SU SST AT! ONS ll MW (1977) 0 Main Substation AGUSAN HE ~Load End Substation 1.6 MW (1957) TRANSMISSION LINES Existing Under Const · I propose d Implementation Vl 0 lebnlt PULANGUI 11 HE / 70 MW (1989) _/ / PULANGUI 111 HE 136 MW (1988) PULANGUI IV HE 255 MW (1980) MINDANt() GRID INSTALLED CAflelTY AND SYSlf:.M DEMAND OF li\GUM - LIBUGANOO BASINS Figure B-2 ,,,,,..,,,,,.. .,,,,. ,,,,,.. ---- ,..,,,,,...... - ,, ,,--' ---- _,"',, ~ / ~ / ,/ / I +--i MINDANAO GRID TOTAL INSTALLED CAPAOTY I 2000 I I I I I I I I I I I I I I 1000 I I I I I I I I I I I ~Tt>GUM - L\BUGANON BASINS 1980 1990 2000 YEAR OF PROJECTION 151 APPENDIX C ECONOMIC SECTOR ECONOMIC METHODOLOGY 1.0 Industrial Output 1.1 Gross Domestic Product GDP= GVA (Agriculture+ Industry+ Services) 1.2 Gross Value-Added GVA = N x LP Where: GVA =estimated output by major sector N =sectoral employment in the river basin (NCSO) Lp = NED A Regional productivity rates, re based to 1980 prices 2.0 Labor Productivity 2.1 General Sectors Labor productivity rates for the various industries in 197 5 were derived from the NEDA Five-Ye_ar Development Plan, Region XI (Table 2.1 ). Gross value-added per industry at constant prices in this region are rebased to 1980 prices by the factor 3.023 (Consumer Price Index, Region XI). These are divided by total employment per industry in the political region to arrive at labor productivities by industry for 1975. For year 2000, the projected 1987 GVA of the same source was used by multiplying the projected annual growth rate for the various sectors (agriculture 5.8%, industry 15.1 % and services 8.5%) up to the year 2000, after which an infla tion factor of 3.023 was applied. Thus: GVA 2000 = projected GVA 1987 x an nual growth rate x 3.023. Table C-1 REGION XI LABOR PRODUCTIVITIES (P /employee) 1975 2000 Agriculture, Fishery and Forestry 10,780 22,500 Mining 280 61,920 Manufacturing 35,410 182,440 Electricity 29,660 280,200 Construction 18,270 95,470 Transport 10,450 35, 100 Commerce 86,990 138, 730 Services 4,870 18,290 153 2.2 Manufacturing Industries For Lp's of the various manufacturing industries, annual growth rate of GVA's {taken from Table 10 of the Industry Sector, RDS) for_ 197~-85 were projected to derive 1975 and then rebased to 1980 prices by t!1~ rnfla tr on factor 3.023 (Consumer Price Index, 1980). These in turn, were d1v1dcd by the res pective employment levels to arrive at Lp's for 1975. Lp's for year 2000 were derived residually as the quotient of projected GV A's over projected employment. Table C-2 MANUFACTURING LABOR PRODCTIVITIES (P /employee) 1975 2000 Food and Beverages 28,900 182,440 Tobacco 61,110 182,450 Textiles, Footwear and Apparel 10,500 182,440 Wood and Wood Products 24,490 182,440 Paper and Paper Products 105,300 182,490 Chemical & Chemical Products 214,740 182,440 Petroleum Products 22, 124 182,440 Non-Metallic Mineral Products 106,280 182,440 Basic Metal& Metal Products 291, 740 182,440 Electrical Machinery 30,340 182,320 Others 1,020 182,440 3.0 Employment The total basin employment figure for year 2000 (588,086) was taken from NCSO using medium projection assumptions. Breakdown into the major industries (agriculture, industry, services} was based on the 25-year regional trend of NEDA which is (Regional Planning Studies Series, Number One, 1978, Table 27) as follows: (a) the share of Agricultural employment to the total will decrease by 34.9 per cent (b) the share of Industry will increase by 13.6 per cent and (c) that of Services will increase by 21.3 per cent. Further breakdown of Industry and Services employment into their component sub-sectors was patterned from projected NEDA figures (Southern Mindanao Region Five-Year Development Plan, 1978-82, Table 2.5). The 1987 levels were projected to year 2000 using the 1977-87 growth rates for each industry. Then, the resulting year 2000 employment distributions under Industry ard Services were applied to the totals for the river basin. 154 Table C-3 INDUSTRY AND SERVICES EMPLOYMENT DISTRIBUTION INDUSTRY 100.00% SERVICES 100.00% Mining 2.6 Transportation 2.3 Manufacturing 56.6 Commerce 2.6 Construction 39.7 Services 95.1 Utilities 1.1 Source: NEDA NRO XI 5-Year Development Plan. 4.0 Manufacturing Industries 4.1 Employment Distribution Employment distribution of the various manufacturing'ind~ustries in the river basin in 1975 was derived from the actual NCSO (provincial) figures for the same year. Initially, the river basins, percentage share in terms of area coverage per pro vince was multiplied by the total employment per industry in the respective provinces. These were then added up to approximate the employment levels in manufacturing in the basin. For year 200_0, the same basis for distributing manufacturing output ( GV A) was utilized for employment. 4.2 Output ( GV A) Distribution With the projected total output (GVA) in manufacturing as a constraint, distribution to the industries was based on the NEDA·RDS projection ratios (NEDA-RDS, The Role of Industry in Regional Development, August 1976, In dustry Table I, Region XI). (Table C-4). Table C-4 PERCENTAGE SHARE OF GVA IN MANUFACTURING 2000 Food and Beverages 14.4 Tobacco .7 Textile and Footwear 5.1 Wood and Wood Products 9.9 Paper and Paper Product 9.1 Chemical and Chemical Products 14.5 .5 Petroleum Products 23.1 Basic Metal and Metal Products Non Metallics 12.7 Electrical Machinery 1.4 Others 8.6 TOTAL 100.0 Source: NEDA, RDS 155 5.0 Industrial Water Requirements IWR = Qutp~ijGV_&~~~~~c_.£>~!!~~~ water rate Where: I WR =industrial water requirement, by industry Water coefficients= proportion of cost of water to total industrial cost fro~ .N E_D A 1974 Inter-Industry (Input-Output) Accounts of the Phrl1pp1nes (Appendix Table C-5) Water rates = rates commodity by water district (LWUA) ?2.40/cu.m. for Tagum-Libuganon River Basin, 1980 prices. Table C-5 WATER TECHNICAL COEFFICIENT Food and Beverages .000605 Tobacco .000171 Textiles .000433 Wood .000374 Paper .000598 Chemical .000384 Petroleum .000576 Basic Metal and Metal Products .000808 Electrical Machinery .000364 Non-Metallic .000117 Mining .000067 Electricity, Gas and Water .001129 Construction .000118 Others .000642 Source: NE DA Input-Output Tables, 1974. 6.0 Palay Projection 6.1 197 5 Palay Area Indices derive palay production from irrigated areas in the basin (NIA estimates). Irrigated areas (21,758) were multiplied by the average cropping in tensity (2.77) and yield per hectare (3.45). Production from non-irrigated areas, on the other hand,. was derived from various parameters. First, irrigated areas were deducted from total ricelands in the basin to arrive at non-irrigated area estimates. Second, corresponding non-irrigated area yield per hectare ( NCSO = 1.0} and average cropping intensity of ( NCSO = 1.40) were applied to these areas. . Total palay production was estimated as the sum of irrigated and non-irriga ted palay yields. 156 Conversion from palay to rice production used a standard recovery rate of 60 per cent for 1971 and 1975 and 70 per cent for year 2000. 6.2 Year 2000 Palay Projection Palay projection was based on several factors such as land constraints farm technology, productivity levels as well as urban development in the basin' area. Year 2000 production levels were estimated using the land capability esti mates against NCSO cropping intensity and Mindanao Irrigation Studies pro ductivity. 7 .0 Corn Production/Demand Corn production in 1975 was estimated by allowing yield per hectare to increase from the 1971 level of 0.20 to 1.255 MT while holding constant cropping intensity and corn area. For year 2000, the Masaganang Maisan productivity es ti mate of 2.5 65 MT /ha. ( 45 cavans) was used as well as total land earmarked for corn production based on land capability studies for the basin with cropping intensity at 1975 levels. Projections of corn demand, on the other hand, were estimated considering the two important variables of population and income growth. The consumption pattern of corn varies inversely with income as reflected by the negative income elasticity for corn resulting in a shift to other food items as income rises. Total demand for corn was then converted to area requirements and in turn compared with land capability corn areas to get the level of self-sufficiency of corn production in the river basin. 8.0 Sugarcane Production/Demand Based on National Sugar Trading Corp. (NASUTRACO) coversion rates, one MT of canned sugar is roughly equivalent to 0.045 MT of processed sugar. This was adopted in the study to approximate the supply of processed sugar in the planning area which is comparable to demand. Sugarcane area requirements and targeted production levels to sufficiently meet total demand were, likewise, tallied with existing capacities of adjacent sugar centrals to process the projected sugarcane production levels. 9.0 Other Crops For other crops, projections were established based mainly on Project AD AM productivity estimates for year 2000 (Journal of Agriculture and Economic Develop ment, Vol. VI 11, No. 3 Nov. 197 8). Assuming minimal changes in cropping intensities for vegetables, rootcrops and fruits, land capability area estimates were used with productivity levels at 9.2 MT/ha. for vegetables, 5.5 MT/ha. for rootcrops and 5.0 MT/ha. for fruits. With the objective of assessing the level of self-sufficiency of er.op production in the river basin, area requirements based on demand were compared with potential crop-lands based on land capability factors from which future land utilization guidelines for basin development could be deduced 157 10.0 Livestock and Poultry Projections 10.1 Population Requirements Livestock and poultry population requirements were estimated based on food demand computations using the formula: Required Animal Population= Food Demand 2000 (Carcass Weights) (Extraction Rate) Where: Unit Carcass Weight= 58 kg. (hogs) 150 kgs. (cattle) 1.2 kgs. (chicken) Extraction Rate= 30% (cattle) 60% (hogs and chicken) 10.2 Feedgrain Requirements Livestock and poultry feedgrain requirements were determined by the formula: Total Animal Feeds = (Animal Population) (Feed Requirements per head/year) Where: Unit feed requirement =210 kgs. (for hogs) 2.5 kgs. (for chicken) 30% of total animal feeds were assumed to be corn components. 11.0 Agricultural Water Demand Agricultural water demand in the basin was derived for palay and other major crops and livestock and poultry. Water demand for palay in 1975 was determined using NIA existing irrigated areas, while for the other major crops, the 1971 distri bution of physical area cultivated to each crop was considered. Agricultural water demand for year 2000 was derived from the land capability of the basin. 11.1 Crops The mathematical computation and working equation for the diversion requirement for crops are given as follows: a) TOR rice= uwr x .01 x PA Where: TD R = total diversion requirement for rice (in MCM/year) uwr = unit water requirement per annum based on NI A rainfall and evapotranspiration studies at selected sites (in/m/year). For Tagum-Libuganon Basins it is 1.390 MCM/Year PA = physical area (in hectares) 158 b) TWR other crops= wr x Cl x PA x No of days/growing season 106 Where: wr =water requirement for other crops (In cu.m./ha./day) Cl = cropping intensity PA = physical area Table C-6 PHYSICAL AREA (In Has.) AND CROPPING INTENSITY Tagum Libuganon Basins Crops PA 1975 PA 2000 Cl 19751 20002/ Palay Irrigated 14,392.0 65, 160 2.77 2.77 Non-Irrigated 21,081.1 1.40 Corn 71, 102.6 77,613 3.56 3.66 Sugarcane 64.5 75.7 1.35 1.45 Tobacco 66.0 75.7 15.12 15.22 Rootcrops l,342.8 1,514.4 2.39 2.49 Vegetables 749.6 757.2 4.11 4.22 Fruits 13,864.6 15, 144.0 1.0 1.0 Source: NIA, NCSO, Land Capability Map 1/ Actual 2/ Conservative Estimates Table C-7 WATER REQUIREMENT AND NUMBER OF DAYS PER GROWING SEASON Water Requirements Number of Days/ Crops (m3 /ha./day) Growing Season Corn 58 95 Sugarcane 43.5 390 Tobacco 48 240 Vegetables 49.1 85.4 Rootcrops 51. 7 96.7 Source: NEDA, 1975. 11.2 Livestock and Poultry Livestock and poultry water demand· was determined by multiplying the actual (for 1975) and required (for year 2000) livestock and poultry population {based on food demand) by the water consumption per head (Table C-8). 159 Table C-8 UNIT WATER REQUIREMENTS Livestock and Poultry Livestock and Poultry Water Consumption/Head/year Cattle 7.5 cu. m. Swine 7.5 cu. m. Chicken 0.046 cu. m. Source: BAI Cattle water demand was determined by using the actual population (in 1971) and ihe potential population based on grazing area. For year 2000, the number of cattle heads was based on the maximum population that the earmarked pasture lands could hold at a stocking rate of 2 heads per hectare. Table C-9 ANIMAL POPULATION (in thousands} 1975 2000 Cattle and Carabao 53.0 415.5 Swine and Others 62.4 960.1 Poultry 808.4 27 ,288.9 12.0 Future Food Demand The food pattern in the basin area was deduced from the general consumption characteristics of Region XI. The aggregate consumption levels of selected items were calculated considering population growth, income changes and dietary traditions or nutritional requirements. The method used was the compound growth rate formula. Dt = P x C (1 + Ye)n Where: Dt = demand for nth year p = population in nth year c = per capita consumption y = real income growth rate e = income elasticity of demand Tables C-10 and C-11 show Per Capita Consumption of major foods and income elasticities of demand for Region VI, respectively. 160 Table C-10 PER CAPITA CONSUMPTION OF MAJOR FOODS {In Kg./ Year) Commodity 1975 2000 Rice 76.48 82.81 Corn 39.42 23.10 Sugar 21.32 22.16 Fruits 51.23 67.20 Vegetables 47.40 64.33 Rootcrops 25.61 24.59 Pork 7.08 12.09 Beef/Cara beef 3.92 6.75 Poultry Meat 4.69 7.11 Source: NEDA Table C-11 INCOME ELASTICITY OF DEMAND FOR - - . SELECTED COMMODITIES First Ten Years Next 15 Years Rice 0.10 0.05 Corn 0.24 - 0.53 Sugar 0.54 0.27 Fruits 0.26 0.21 Vegetables 0.26 0.24 Rootcrops 0.02 - 0.04 Pork 0.60 0.30 Beef/Cara beef 0.76 0.30 Poultry Meat 0.66 0.30 Fish 0.35 0.21 Source: NEDA 13.0 Area Requirements to Meet Demand 12.1 For Crops Estimation of area requirements based on demand in the river basin in 1975 and year 2000 utilized the following formula: Area Requirement = Total Demand Cl x Yield Per Hectare 161 Rice demand was first converted to palay production by the rice/palJy conversion factor of 60 per cent for 1975 and 70 per cent for year 2000, while sugar was converted back to cane utilizing the NASUTRA cane-to-processed sugar conversion rate ofl :0.045 M.T. Table C-12 TOTAL DEMAND Tagum-Libuganon Basins 1975 2000 1 Rice 96,8361 I 286,051 / 2 Corn 43 521 2/ 91,255 / ' Sugar 21,596 61,238 Fruits 51,892 185, 703 Vegetables 48,013 177,772 Rootcrops 25,941 67,953 Pork 7' 172 33,410 Beef/Carabeef 3,971 18,653 Poultry Meat 4,750 19,648 Fish 39, 130 145,053 11 Human consumption and 25% for buffer stock, wastage, etc. 21 H uman consump t"ion, f ee d gram . requirements . and 1 % allowance for seeds, wastage, etc .. Table C-13 YIELD PER HECTARE {MT /Hectares) Tagum-Libuganon Basins 19751/ 2000 Rice Irrigated 3.45 4.5 21 Non-Irrigated 1.0 Corn 1.255 2.5653/ Sugarcane 30.33 46.94/ Fruits 3.74 5.o51 Vegetables 3.74 9.26/ Rootcrops 2.85 5.5 7/ 1 / Adjusted from 1971 actual figures. 2/ Mindanao Irrigation Studies 3/ MASAGANANG MAISAN target of 45 cavans/ha. 4/ MAAGAP (Project ADAM) estimates. 5/ Ibid 6/ Ibid 7/ Ibid 162 13.2 For Pasture Lands Pasture land requirements based on demand considered the standard NCSO stocking rate of 2 heads per hectare. Required animal population as discussed in section 10.1 and shown in animal population as discussed in section 10.1 and shown in APPENDIX TAB LE C-9 was divided by 2 to approximate area requirements for pasture lands to hold the projected cattle production. 163 APPENDIX D LAND RESOURCES Methodology for General Land Use Study for Water Resource Region XI 1.0 The evaluation process requires a thorough interpretation, analyses of the physical environment of land like water, topography, vegetation, climate, and the various properties of soil and its characteristics, all of which influence the capability and/or suitability of land to certain use it is best recommended to. The process starts with the assessment of the performance of land with its present uses, then carefully analyses the physical factors like terrain, drainage, climate type and erosion conditions. However, the determinants do not limit to the above but also include the ecological and cultural factors. Based on the overall evaluation process, the study shall make general suggestions on the recommended type of land use. 2.0 Diagnostic Criteria 2.1 Existing Land Use A general land use is undertaken by the Bureau of Soils with the use of aerial photographs. Field checks were undertaken in April 1978. Land Use maps in Water Resource Regions were done in 1 :250,000. 2.2 Land Capability Under the land capability analyses, three major factors are considered, namely, the slope of the land, soil type and degree of soil erosion. Analyses and classification is made with reference to present land use, soil conservation measures and farm management practices. 2.2.1 slope Slope classes are determined and mapped out to determine the suitability of land for agricultural production. Each slope category determines the extent of the recommended agricultural use. 2.2.2 soils Soils in the area are classified in order to determine the soil types that could be utilized for crop production. 2.2.3 soil erosion susceptibility Extent of soil erosion in the area is classified and mapped out in order to determine areas which could be utilized for intensive agricultural diversification, and the farming practices to follow also determine areas which should be under forest cover. 2.3 Sectoral Demand/Requirement on Land 2.3.1 agriculture 2.3.2 pasture/livestock 165 2.3.3 forest 2.3.4 fishpond 2.4 Ecological Balance 2.5 Land Use Regulatory Measures Some policies and laws concerning land use in the Philippines arc as follows: 1. P.D. 815 - Restrict the conversion of prime agricultural lands for other uses. 2. P.D. 705 _The Forestry Reform Code of the Philippines was promulgated by the Republic of the Philippines on 19 May 1975. This code defines the functions and responsibilities of the 8 ureau of Forest D cvclopment. It an swers all views of forest resources management, utilization, demarcation, protection, enforcement and rehabilitation. This code have several instruc tions concerning forest policies and the following policies been adopted: The multiple uses of forests land shall be oriented to the develop ment and progress requirements of the country, the advancement of science and technology and the public welfare: Land classification and survey shall be systematized and hastened: The establishment of wood-processing plants shall be encouraged and rationalized, and the protection, development and rehabilitation of forest lands shall be emphasized so as to ensure their continuity in pro ductive condition. Section 54. No forest lands 50% in slope or over may be utilized for pasture purposes. 3. P.D. 331 - The document stipulated that all public forest be developed, managed and utilized on a sustained yield basis with the assistance of tech nically, trained and Registered Foresters. As emphasized, it seeks the help of technical personnel to carry out logging practices as well as silvicultural aspects. It seeks to harmonize the productivity and stab ii ity of the nation's forest ecosystems. Implementing guidelines, rules and regulations on forest occupancy serve the purpose of requiring concerning terms of reference in forest occu pancy. Strict compliance of the rules are written in the whole context of the agreement. 4. P.O. 953 - This decree requires every person who owns land adjoining a river or creek, to plant trees extending at least 5 meters on his land adjoin ing the edge of the bank of the river or creeks, except when such land, due to its permanent improvement, can not be planted with trees. Likewise, every holder of a license agreement, lease, license or permit from the govern n:1ent, involving oc~upancy and utilization of forest or grazing land with a river or creek therein shall plant trees extending at least 20 meters from each edge of the bank of river or creek. 5. L.0.1. 423 - This letter of instruction brought a new massive approach towards forest ecosystem management. It directed the creation of a Presiden tial Council for Forest Ecosystem Management (PRO FEM) to "formulate 166 programs, rules, guidelines, regulations and policies that will maintain and enhance the country's forest ecosystem management, which involves refores tation, afforestation, Agroforestation, establishment of communal forests, family orchards and recreational parks and areas. 6. LO.I. 145. - Directed the Presidential Committee on Wood Industries D eve lopment to work out and submit a program at promoting the development of industrial forest plantation and tree farms in the Republic of the Philip pines. This move has the primary objectives of introducing agro-forestry program and the production of raw materials for wood based industries in cluding the rehabilitation of critical watershed that are resettled. 7. LO.I. 409 - Was issued to the officials of the Department of Natural Re sources and Bureau of Forest Development to determine the performance of forest concessionaries and their adherence of forest regulations and poli ci~s. 8. LO.I. 525 - Was issued to expedite the implementation of the government agro-forestry development pilot project under Proclamation No. 1632. The Ministry of Natural Resources is authorized to use funds from the Depart ment to compensate the value of improvements of the various ranchers and small settlers within the agro-forestry development pilot project. It exempts displaced settlers and ranchers from the payment of application fees, regis tration of their land patents or pasture application. 167 Table D-1 GENERAL LAND USE ANALYSIS MATRIX Recommended Land Capability Class Slope Soil Erosion Existing Land Use Land Use 1. Rice Good cropland. It is highly suited to paddy rice pro- 0-3 Clayey 1 - 2 Ricelands, diversified duction which requires simple but good farm manage- 3-8 Clay loam crops, grassland ment practices. Soils in this class is adopted to almost Sandy clay loam any crop common in the area. 2. Diversified Moderately good cropland. Soils in this class is suited 8-15 Suited to almost 2-3 Diversified crops Crops for cultivation of diversified crops. It has some slight all soil type grassland limitations which may include effects of gentle slopes, moderate susceptibility to erosion and slight salinity. 3. Tree Farms Fairly good cropland. Soils in this class have moderate 15-25 Suited to almost 3 Diversified crops, fruit O"I restrictions that limits the choice of crops. It is best all soil type trees, grasslands 00 recommended for tree farms. However, when used for cultivation of crops, it requires careful management and complex conservation practices. 4. Pasture/ This type of land have severe limitations {when used 15-25 Suited to almost 3 Grass and Shrublands Rangeland for cultivation of crops) that limits its use largely to all soil types pasture. 5. Forest Steeply sloping to hilly and mountainous excessively 25 and Mountain soils 4 Forest, grass and eroded, shallow, rough or dry for cultivation, hence above shrublands it is best suited for forest. 6. Recreation/ This type of land is too steep, rocky, rugged and barren. 25 and Rugged mountain 4 Forest, grass and Wildlife It is only suited to wildlife preservation and recreation. above soils shrublands 7. Fishponds, This type of land is wet most of the time. It cannot be 0-1 Hydrosol Fishponds, swamps !twamps, economically drained. It is best suited to fishponds, marshes, mangrove mangrove and wildlife preservation. APPENDIX E SOCIAL ENVIRONMENT Table E-1 POPULATION, DENSITY AND POPULATION DISTRIBUTION IN THE BASIN Tagum-Libuganon 8asins Population Density Population Municipality Persons/Km2 Distribution (%) 1975 1970 1975 1970 1975 Urban Rural I I I I *Bunawan *Cali nan Davao City 392,475 484,678 177 219 38 62 Sta. Cruz 34,762 41,834 124 150 33 67 *Toril *Tugbok Babak 17 ,649 19'149 240 261 24 76 Carmen 20,385 23,163 72 82 11 89 Kapalong 20,225 33,362 "10 16 12 88 Kaputian 17 ,086 19 ,319 145 164 100 Panabo 42,920 53 ,015 222 274 18 82 Sam al 16,113 17 ,676 180 197 20 80 Sto. Tomas 21,241 31,584 96 142 30 70 Asuncion 36,033 66,102 31 57 100 Mabini 18,343 26, 194 30 43 26 74 Maco 29,693 32,562 98 107 13 87 Mawab 13 ,537 17 ,085 100 126 22 78 Nabunturan 27,689 30,883 98 110 24 76 New Corella 18,745 26,809 92 132 14 86 Pantukan 21,890 25,291 39 45 21 79 Tagum 47,324 64,225 242 328 39 61 TOTAL 796, 101 1,012,931 88 112 28 72 *All are districts of Davao City. 169 Table E-2 POPULATION PROJECTIONS BY MUNICIPALITY 1975 - 2000 {Medium Assumption) Tagum-Libuganon Basins 1975 1980 Municipality Actual Actual 1990 2000 * Bunawan * Calinan Davao City 484,678 611 ,311 966,117 1,401,619 * Sta. Cruz 41,834 48,272 66,309 86,612 * Toril * Tugbok Bobok 19'149 21,370 36,798 50,260 Carmen 23, 163 26,869 47,285 67,444 Kapa!ong 33,362 40,034 56,318 86,554 Kaputian 19 ,319 22,207 40,764 58,879 Panabo 53 ,015 63,618 102,398 147 ,903 Sam al 17,676 18 ,841 38,442 55 ,526 Sto. Tomas 31,584 37,901 49 ,371 70,478 Asuncion 66, 102 42,589 85 ,967 124,171 Mabini 26,194 16,306 43,762 63,210 Maco 32,562 40,945 70,841 102,323 Mawab 17 ,085 20,970 32,297 46,649 Nabunturan 30,883 36,046 68,216 99,724 New Corella 26,809 24,637 44,722 64,596 Pantukan 25,225 30,397 51,731 74,350 Tagum 64,225 86, 114 112,904 163,080 TOTAL 1,012,931 1,188,327 1,914,242 2,763 ,442 *All are city disttricts of Davao City. 170 Table E-3 NUMBER OF HOUSEHOLDS BY SOURCE OF WATER, 1970 Tagum-Libuganon Basins Municipality Total No. of Piped Artesian Pumps Open Springs Rain Lakes & Households Water Wells Wells Water Stream *B unawan *Calinan Davao City 64,395 3,788 5,232 3,345 4,437 7,341 29 ,320 932 Sta. Cruz 5,671 1,377 160 562 376 2,297 740 159 *Tori! *Tugbok Babak 2,910 21 634 65 26 237 1,897 30 Carmen 3,440 67 192 ·1,280 278 1,605 18 Kapa long 3,411 65 86 479 1,097 288 1,036 360 Kaputian 2,907 164 176 87 129 937 1,397 17 Panabo 6,821 108 546 906 1,856 673 2,720 12 Sam al 2,666 62 56 20 168 387 1,938 35 Sta. Tomas 3,494 73 106 869 1,451 343 652 Asuncion 6,050 233 37 310 1,839 1,530 1,740 361 Mabini 2,964 29 103 335 684 1,197 486 130 Maco 4,895 481 319 822 904 1,056 1,244 69 Maw ab 2,308 48· 696 366 408 514 252 24 Nabunturan 4,516 376 221 466 1,395 725 1,321 12 New Corella 3,231 93 21 35 855 486 1,651 90 Pantukan 3,720 133 855 530 574 971 556 101 Tagum 7,599 128 686 1,723 737 459 3,803 63 TOTAL 130,998 7,179 10,001 11,112 8,21619,719 62,358 2,413 Source: 1970 Census of Population and Housing. * All are city districts of Davao City 171 REFERENCES Books Frevert, R.K., et. al 1971 Soil and Water Conservation Engineering, Second Edition. Liongson, L.Q. 1978 A User's Guide to a Subprogram Library for Applications in Stochastic Hydrology, Quezon City. Maass, Arthur, et. al. 1962 Design of Water Resource System. Harvard Univ.ersity Press,· Cambridge, Massachusettes. Martin, Charles 1976 Project Oriented Orgardzation in Project Management, How to Make it Work. Obradovich, M.M. 1973 A Climatic Map of the Philippines. Processed. Ven Te Chow 1963 Handbook on Applied Hydrology. McGraw-Hill, New York. Reprinted Articles Boie, Eugene C. Interdisciplinary Teamwork in Watershed Planning. Processed. Coutu, Arthur Jr. Estimation of Income and Hydrologic Effects of Alternative Watershed Programs. Journal Paper No. 1057, North Carolina Agricultural Experi ment Station. Processed. Ellis, Harold H. Relationship Between Water and Other Property Rights and Small Watershed Development in the Eastern States. Processed. Ford, Edwin C., et. al. The Benefits from Watershed Development, Journal Paper No. 1145, North Carolina Agricultural Experiment Station. Processed. Reagan, Mark M. Economically Desirable Institutional Arrangement and Cost Sharing Requirements. Processed. Riggs, Fretcher E. The Watershed as an Entity for Planning. Processed. Scot, William Henry 1958 A Preliminary Report on Upland Rice in Northern Luzon. Vol. 14. Processed. Young, Gladwin E. Where Does Watershed Development Fit into the Total Picture of Resource Development. Processed. 173 GOVERNMENT REPORTS AND PUBLICATIONS (Republic of the Philippines) BUREAU OF FOREST DEVELOPMENT 1977 Philippine Forestry Statistics. ManilJ. BUR EAU OF MINES 1976 Metallic Ore Reserves. Processed. Man ilJ. DEPARTMENT OF TOURISM 1975 Regional Tourism Situation Report. Manila. HUMAN SETTLEMENTS COMMISSION 1977 National Multi-Year Human Settlements Plan. Manila. NATIONAL ELECTRIFICATION ADMINISTRATION 1976 National Directory of Electric Cooperatives. Manila. NATIONAL ECONOMIC AND DEVELOPMENT PLAN, 1978-1982, Manila. 1977 Five-Year D eve lo pment Plan, 1978-1982. Manila. 1978 Regional Development: Issues and Strategics Philippine Development Planning Studies, Regional Planning Studies, Series No. One. 1976 The Role of Industry in Regional Development. UNDP/18 RD Regional Planning Project. Processed. NATIONAL CENSUS AND STATISTICS OFFICE 1975 Integrated Census of the Population and its Economic Activities. Manila. 1975 Population Projections of Cities and Municipalities in the Philippines: 1970-2000. Manila. 1974 Listing of Cities, Municipalities and Municipal 0 istricts. Manila. 1975 Population, Land Area and Density, 1948, 1960 and 1970. Manila. 1971 Census of Agriculture. Manila. 1977 Labor Force Projections by Age and Sex for the Philippines by Region and Province: 1970-2000. Monograph No. 10. 1976 Geographical Patterns of Internal Migration in the Philippines 1960- 1970. Monograph No. 5. Manila. 1975 Total Income and Per Capita Income. Preliminary Tabulation. Manila. 1970 Census of Population and Housing. Manila. NATIONAL POWER CORPORATION 1979 Power Expansion Program. Manila. NATIONAL WATER RESOURCES COUNCIL 1977 Survey Inventory of Water Impounding Reservoir, 1978. Quezon City. 1976 Philippine Water Resources.Quezon City. 1977 Manual of Water Data Standards, Vols. 1-15. Quezon City. 174 PHILIPPINE ATMOSPHERIC GEOPHYSICAL AND ASTRONOMICAL SERVICES ADMINISTRATION . 1975 Tropical-Cyclones. Processed. Quezon City. 1960 Climatic Observation. Processed. Quezon City. Climate of the Philippines. Processed. Quezon City. PHILIPPINE COUNCIL FOR AGRICULTURE AND RESOURCES RESEARCH 1977 Philippine Recommends for Soil Conservation. Laguna. 1978 Philippine Recommends for Coconut. Laguna. PHILIPPINE WEATHER BUREAU Annual Climatological Review, 1952, 54, 60-70.Quezon City. INTERNATIONAL PUBLICATIONS 1974 Approaches to Water Development Planning in Developed and Deve loping Economics. Food and Agriculture Organizations. Processed. Rome. . 1976 A Framework for Land Evaluation. Food and Agriculture Organization. Processed. Rome 1974 Methods for Projection of Urban and Rural Population. United Nations Manual V 111. Processed. New York. MAP BUREAU OF COAST AND GEODETIC SURVEY 1976 Topo Maps. Scale 1 :250,000. Manila. 175