Performance Evaluation of Yayo-Baka Small-Scale Irrigation Scheme Water Distribution Systems; (A Case Study of Bako-Tibe District, West Showa Zone of Oromia Regional State).

Abstract

The rational utilization of irrigation water is a fundamental aspect for achieving sustainable agriculture for food security and poverty alleviation. To achieve the objective of sustainable agriculture many factors are involved, and irrigation water delivery is one of the most important. Consequently, its evaluation as well as the search for feasible solutions to problems detected during the evaluation could be of special interest. This study analyzed the water management performance of small-scale irrigation system in Bako-Tibe. International Institute for Land Reclamation and Improvement / International Water Management Institute (ILRI/IWMI) water balance and maintenance indicators used to test Yayo-Baka irrigation scheme as a base for the performance evaluation. Necessary data were collected from Oromia Water Works Design and Supervision Enterprise (OWWDSE) the company that made the feasibility study and the design of the system and from Bako-Tibe Meteorological Station. In the field, certain parameters including: type of crop, irrigation water discharge in channel, and field size were measured and/or observed before, during and after an irrigation event while farmers were conducting their normal irrigation practice. Survey related to water availability also conducted among the farmers. Finally, crop pattern of the study area was organized in CROPWAT 8.0 model along with necessary data such as climate, soil, and crop, cropping pattern. The results showed that the source is delivering 40.15 L/s while the water requirement is 385.6 L/s. The delivery is only 10.41% of the water requirement. The insufficiency of irrigation water, the type of irrigation system in use, the poor maintenance of irrigation structures and the farmer’s unawareness of irrigation practices were the main problems identified in the management and operations of the scheme. Some corrective measures have been recommended to improve the system.