Hydraulic and operational performance of irrigation schemes in view of water saving and sustainability : sugar estates and community managed schemes In Ethiopia

Abstract

ABSTRACT The rate of global expansion of irrigated lands has been declining since the 1970s due to the fact that most of the potential for large and medium-scale irrigation schemes has been developed. This rate of decline is also expected to continue in the next decades. As such significant proportion of the expected increase in production would have to be supplied from the existing irrigated and /or cultivated lands. This in turn could be achieved by improving land and water productivity in the existing schemes through ensuring better performance and optimal operation and maintenance. With less than 15% of over 5 million ha irrigation potential developed, irrigated agriculture in Ethiopia remained low. The largest proportion of the developed irrigation in the country belongs to small-scale irrigation by smallholder farmers. While accelerated development of new irrigation, particularly of large and medium-scale schemes is relevant in Ethiopia, performance and sustainability of existing schemes is equally important. The existing irrigation schemes in Ethiopia are generally characterized by overall performance and technical sustainability levels below expectation. The research presented in this thesis evaluates the performance of two large-scale and two small-scale community-managed irrigation schemes located in the Awash River Basin of Ethiopia. The research focussed on hydraulic/water delivery performance in the large-scale schemes and on comparative performance assessment and internal irrigation service utility evaluation in the community-managed schemes. It was found that hydraulic, operational and institutional aspects play a significant role in the overall performance of the irrigation schemes. Major performance challenges were addressed and operational/water management options for improvement were proposed for each case. &nbsp