PERFORMANCE EVALUATION OF WONJI-SHOA IRRIGATION SCHEMES (CASE STUDY OF ULAGA IRRIGATION PROJECT)

Abstract

Irrigation schemes are usually designed and implemented on the basis of assumed efficiencies in water application, water conveyance, and water distribution. However, over time, physical changes in the schemes such as poor maintenance of structures, soil property changes and deterioration of equipment may alter these efficiencies. It is therefore imperative that the efficiencies are periodically evaluated as a way of monitoring and evaluating the irrigation scheme. The study was conducted to assess the performance of the two wonji -Shoa expansion irrigation schemes using various indicators such as output per unit cropped area and water consumed, related to production with land and water. Relative water supply (RWS), irrigation supply (RIS) and water delivery capacity (WDC), related to water supply from the system with crop water demand. The irrigation schemes were Ulaga zone100 and Ulaga zone200. In this study, the performance indicators in Ulaga zone100 and Ulaga zone200 Irrigation Scheme were determined for year 2013/14; the results were discussed and evaluated. Moreover, the research assesses the main problems in the major component of dragline sprinkler systems, and suggest the possible solution. The necessary primary and secondary data to calculate the eight indicators were collected. Primary data collection included daily field observation related to the conveyance systems, measurement of the actual dimensions of the conveyance systems, measurement of the actual dimensions of the structure, measurement of pressure at inlet of each field, Interview of technical experts and assistances, geographical coordinates (Longitudes & latitudes) of the scheme. The secondary data were collected from Ethiopian Sugar Development Agency Research Center and from Water Works Design and Supervision Enterprise, which included topographic map of specific site, meteorological and Hydrological data, and design document of a scheme, total yields and investment costs.