1. ASSESSING IRRIGATION CONVEYANCE LOSSES: CASE STUDIES OF AHERO & BURA IRRIGATION SCHEMES A COLLABORATIVE RESEARCH PROJECT BETWEEN NIB AND UON By Gichuki F., Maina D., S. M. Muturi and Wanjogu R. K. Date: 13 th JUNE 2013 Ahero, Bura and Mwea Irrigation Schemes case studies 1

2. P RESENTATION OUTLINE Introduction Objectives Methodology Research results Acknowledgements 2 AIS & BIS water loss study-NIB & UON

3. I NTRODUCTION Irrigation in Kenya faces serious challenges which have negatively affected the productivity, profitability and sustainability of most irrigation schemes. The following is a partial listing of the main challenges High pumping costs; High levels of siltation; unpredictable flooding & drought High conveyance and application losses; High mismatch between water demand and supply; Inadequate drainage of excess water and removal of excess salts; and Inequity in water delivery in different irrigation blocks and irrigated fields. Inadequate irrigation skills among farmers and other stakeholders Source: NIB Strategic Plan 2008-2012 3 AIS & BIS water loss study-NIB & UON

4. NIB S S TRATEGIC D ECISIONS NIB has prioritized research on irrigation water loss and has consequently included it as a global PC target FY 2012/13. This is a logical step in any water management improvement initiative Cognizant of these challenges, NIB + UON – College of Architecture and Engineering have developed a comprehensive research program to improve performance of irrigated agriculture through better irrigation water management. Phase I of the research will focus on water conveyance losses 4 AIS & BIS water loss study-NIB & UON

5. G OALS OF NIB-UON RESEARCH COLLABORATION Specific goalRationale Reduced water loss Reducing water loss will secure water for expansion of irrigated area, enhancing equitable distribution, reduce operation and maintenance costs and avail water for downstream users Enhance equitable water distribution Enhancing equitable water distribution will reduce water use conflicts and enhance payment of operation and maintenance fees Reduce operation and maintenance costs Reducing costs will enhance recovery of operation and maintenance fees Enhance production and profitability Enhanced production and profitability will enhance poverty reduction outcomes of irrigated agriculture Reduce environmental degradation Enhance sustainability through reduced in-scheme land and water degradation and by securing water for downstream ecosystems. 5 AIS & BIS water loss study-NIB & UON

6. RATIONALE FOR CONVEYANCE SYSTEM RESEARCH: Low efficiency (30-70%) of conveyance and distribution system with major implications on: Scheme water intake sub-system Operation and maintenance of conveyance sub-system On-farm sub-system 6 AIS & BIS water loss study-NIB & UON

7. O BJECTIVES Overall goal : To generate and enhance utilization of data, information and knowledge on irrigation water management in ways that promote innovation and effective and efficient utilization of the resources. Specific objectives To quantify conveyance and distribution water losses in Ahero, Bura and Mwea Irrigation Schemes Formulate strategies and plans for performance improvements 7 AIS & BIS water loss study-NIB & UON

8. K EY ISSUES THAT WILL ADDRESSED 1. Assess performance and opportunities and constraints for improving performance; 2. Identify innovative solutions that will enhance the performance of the water delivery and water application sub-systems; 3. Evaluate technical performance of the innovative solutions; 4. Evaluate costs and benefits of performance improvements; 5. Formulate strategies and plans for performance improvements; 6. Identify investment priorities; and 7. Propose financing/ options. 8 AIS & BIS water loss study-NIB & UON

9. M ETHODOLOGY : SYSTEM CHARACTERIZATION Task 1: Digitizing the network 9 AIS & BIS water loss study-NIB & UON

10. M ETHODOLOGY : SYSTEM CHARACTERIZATION Task 1: Digitizing the network 10 AIS & BIS water loss study-NIB & UON

11. M ETHODOLOGY : SYSTEM CHARACTERIZATION Task 1: Digitizing the network 11 AIS & BIS water loss study-NIB & UON

12. M ETHODOLOGY : SYSTEM CHARACTERIZATION Task 1: Digitizing the network 12 AIS & BIS water loss study-NIB & UON

13. K EY OUTPUTS : SYSTEM CHARACTERIZATION 13 AIS & BIS water loss study-NIB & UON

14. K EY OUTPUTS : SYSTEM CHARACTERIZATION 14 AIS & BIS water loss study-NIB & UON UCALength(km)Area(ha)Canal density m/ha U16.76136.4849.56 U25.25110.1847.64 U36.73134.1650.16 U44.63105.0744.10 U55.14126.6540.58 U63.3059.9455.01 U75.69107.7352.80 U85.23120.9443.24 U93.6570.1052.04 U103.1661.1851.60 U112.4944.4156.03 GrandTotal64.481,076.8559.88

15. K EY OUTPUTS : SYSTEM CHARACTERIZATION 15 AIS & BIS water loss study-NIB & UON

16. K EY OUTPUTS : SYSTEM CHARACTERIZATION 16 AIS & BIS water loss study-NIB & UON UCALength (km)Area (ha)Canal density m/ha MainCanal 69.012,641.5526.12 U1 27.54196.32140.27 U2 29.04550.7452.72 U3 33.19433.0976.63 U4 53.801,044.0151.53 U5 16.74361.6446.29 U6 6.4055.73114.83 Total 166.712,641.5563.11

17. K EY OUTPUTS : SYSTEM CHARACTERIZATION 17 AIS & BIS water loss study-NIB & UON

18. K EY OUTPUTS : SYSTEM CHARACTERIZATION 18 AIS & BIS water loss study-NIB & UON UCALength(km)Area(ha)Canallengthm/ha MIAD 7.7790.0086.34 M10 3.5133.00106.27 M9 5.9251.00116.04 M11 2.9848.0061.99 M17 8.92139.0064.14 M12 5.0677.0065.66 M13 4.1968.0061.58 M14 8.11106.0076.48 M15 4.8447.00103.03 M16 10.88132.0082.43 H18 8.99115.0078.19 H20 6.96115.0060.49 H19 8.17111.0073.65 M5 6.6475.0088.57 M6 7.1664.00111.88 M7 3.2949.0067.24 M8 2.2025.0087.98 M1 9.0580.00113.16 M2 3.2441.0079.01 M3 4.6753.0088.17 M4 10.47132.0079.28 H1 4.4473.0060.77 H6 13.13111.00118.28 H7 7.7983.0093.86 H8 7.9796.0083.06 H2 7.3092.0079.32 H3 8.20108.0075.96 H4 6.0290.0066.92 H5 17.23156.00110.47 W7 6.6460.00110.69 W1 12.40130.0095.39 W2 14.44195.0074.05 W3 11.37173.0065.71 W7 6.5261.00106.94 W4 14.40132.00109.06 W5 10.94163.0067.09 W6 22.04206.00106.97 K1 21.24208.00102.10 K2 13.86165.0084.01 K3 15.70132.00118.96 K4 12.63145.0087.08 K5 16.54148.00111.73 K6 10.97111.0098.87 K7 9.05131.0069.08 K8 3.3230.00110.70

19. M ETHODOLOGY : L OSS ASSESSMENT 19 AIS & BIS water loss study-NIB & UON Canal loss mainly comprise of seepage, evapotranspiration (EVT) & leakages The water balance (inflow/outflow) method will be used for quantifying canal loss-this will not interrupt irrigation program Seepage rates will be measured using inflow/outflow, ponding and seepage meter methods Calibration and possibly repair of all measuring/regulating canal structures will be necessary to facilitate flow measurements-critical in this study

20. M ETHODOLOGY : L OSS ASSESSMENT 20 AIS & BIS water loss study-NIB & UON

21. M ETHODOLOGY : L OSS ASSESSMENT 21 AIS & BIS water loss study-NIB & UON Ponding method To eliminate the effect of wind, the rate of drop should be measured at each end of the pool and averaged. Staff or hook gauges attached to existing structures or stakes driven into the canal bed should be used as shown in the figure below.

22. P RELIMINARY RESULTS : L OSS ASSESSMENT 22 AIS & BIS water loss study-NIB & UON Distance from point [m] Dept h [m] Widt h [m] Area [m^2] Velocity 1 [cm/s] Veloci ty 2 [cm/s ] Veloci ty 3 [cm/s ] Avera ge Veloci ty at Point [cm/s ] Discharge [m^3/s] 2.30 00000.000.000 2.10.250.20.0523.524.120.222.600.011 1.80.420.30.12651.950.449.550.600.064 1.50.470.30.14144.240.339.541.330.058 1.20.430.30.12927.72828.528.070.036 0.90.350.30.10522.1 21.621.930.023 0.60.20.30.064.13.923.330.002 0.400.200000.000.000 Total Discharge [m^3/s] 0.195

23. P RELIMINARY RESULTS : L OSS ASSESSMENT 23 AIS & BIS water loss study-NIB & UON Site Offtak e Gross loss m/day Efficien cy % loss to closed offtakes Gross loss due to INFILTRATION and EVAPO. mm/day % Site 1 Site 2 0.0940.980.7028.05 Site 3 0.3580.890.8071.53 Site 4 Site 5 0.4700.880.8570.48 Site 6 Site 7 0.7070.510.9070.73 Site 8 Site 9 0.1770.850.5088.33

24. M ETHODOLOGY : W ATER BALANCE MODELING Thiba system linkages 24 AIS & BIS water loss study-NIB & UON

25. M ETHODOLOGY : W ATER BALANCE MODELING Elements of the water balance model 25 AIS & BIS water loss study-NIB & UON

26. P RELIMINARY RESULTS : W ATER BALANCE MODEL 26 AIS & BIS water loss study-NIB & UON UnitIWR m3/daySL m3/dayEL m3/day Main Canals - 179.56 359.11 U1 11,792.28 32.47 64.94 U2 9,519.29 24.94 49.89 U3 11,591.65 33.99 67.99 U4 9,078.19 22.41 44.82 U5 10,942.63 25.11 50.23 U6 5,178.76 18.20 36.39 U7 9,308.14 27.12 54.24 U8 10,449.02 24.95 49.89 U9 6,056.82 16.48 32.97 U10 5,285.65 14.72 29.44 U11 3,837.36 12.04 24.08 Grand Total 93,040 432 864

27. P RELIMINARY RESULTS : W ATER BALANCE MODEL 27 AIS & BIS water loss study-NIB & UON

28. P RELIMINARY RESULTS : W ATER BALANCE MODEL 28 AIS & BIS water loss study-NIB & UON

29. O N - GOING SIMULATION STUDIES Design, operation and maintenance issues for example what is the effect of changes on cropping calendar and system layout 29 AIS & BIS water loss study-NIB & UON

30. A CKNOWLEDGEMENT The implementing team comprising of Dr. F. Gichuki, R. Wanjogu, A. Owilla, D. Maina and S. Muturi wish to thank the General Manager, NIB for funding this project Thank you 30 AIS & BIS water loss study-NIB & UON