ASSESSING IRRIGATION CONVEYANCE LOSSES: CASE STUDIES of AHERO & BURA IRRIGATION SCHEMES

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

Presentation outline • Introduction • Objectives • Methodology • Research results • Acknowledgements AIS & BIS water loss study-NIB & UON

Introduction • 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 AIS & BIS water loss study-NIB & UON

NIBs Strategic Decisions • 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 AIS & BIS water loss study-NIB & UON

Goals of NIB-UON research collaboration AIS & BIS water loss study-NIB & UON

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 AIS & BIS water loss study-NIB & UON

Objectives 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 MweaIrrigation Schemes • Formulate strategies and plans for performance improvements AIS & BIS water loss study-NIB & UON

Key issues that will addressed • Assess performance and opportunities and constraints for improving performance; • Identify innovative solutions that will enhance the performance of the water delivery and water application sub-systems; • Evaluate technical performance of the innovative solutions; • Evaluate costs and benefits of performance improvements; • Formulate strategies and plans for performance improvements; • Identify investment priorities; and • Propose financing/ options. AIS & BIS water loss study-NIB & UON

Methodology: system characterization Task 1: Digitizing the network AIS & BIS water loss study-NIB & UON

Key outputs: system characterization AIS & BIS water loss study-NIB & UON

Methodology: Loss assessment • 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 AIS & BIS water loss study-NIB & UON

Methodology: Loss assessment AIS & BIS water loss study-NIB & UON

Methodology: Loss assessment 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. AIS & BIS water loss study-NIB & UON

Preliminary results: Loss assessment AIS & BIS water loss study-NIB & UON

Methodology: Water balance modeling Thiba system linkages AIS & BIS water loss study-NIB & UON

Methodology: Water balance modeling Elements of the water balance model AIS & BIS water loss study-NIB & UON

Preliminary results: Water balance model AIS & BIS water loss study-NIB & UON

On-going simulation studies Design, operation and maintenance issues for example what is the effect of changes on cropping calendar and system layout AIS & BIS water loss study-NIB & UON

Acknowledgement • 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 AIS & BIS water loss study-NIB & UON

ASSESSING IRRIGATION CONVEYANCE LOSSES: CASE STUDIES of AHERO & BURA IRRIGATION SCHEMES