COMPARATIVE PERFORMANCE EVALUATION OF TWO SMALL SCALE IRRIGATION SCHEMES IN EAST SHOA ZONE, ETHIOPIA

Abstract

Comparative performance evaluation of irrigation schemes is a tool to establish benchmarks for both land and water productivity, and to identify performance gaps and improvement options. Therefore, the aim of this study was to evaluate and compare the performance of Koftu and Fultino community managed small-scale irrigation schemes using comparative performance indicators. For this purpose, relevant data were collected from the schemes from February to April 2017. The primary data were collected by observations, household survey, discussion and flow measurements, whereas the secondary data were collected from secondary sources. After the data were collected, CROPWAT 8.0 computer model was used to calculate the crop water and irrigation requirements. Then, the schemes were evaluated using four groups of comparative indicators such as water supply, physical, outputs and financial indicators. The results obtained showed that the values of relative water supply and irrigation supply were 2.64 and 2.72 for Koftu scheme, whereas 3.32 and 3.52 for the Fultino scheme, respectively. These values showed that both schemes withdraw more water than demanded. In addition, the water delivery performance ratio values for both schemes were found to be high. Physical indicators such as irrigation ratio and sustainability of the irrigated area showed that 0.9 and 1.5 for Koftu Scheme, 0.61 and 0.8 for Fultino scheme, respectively. Likewise, the values of the output per unit command area were 5,765.57 and 3,925.42 US$/ha, similarly the output per unit harvested area was 3,714.93 and 3,545.81 US$/ha for Koftu and Fultino scheme, respectively. The output per unit water consumed and unit water supply were 0.77 and 0.72 US$/m3 , and 0.23 and 0.1 US$/m3 for Koftu and Fultino scheme, respectively. The financial self-sufficiency of the both schemes were higher due to small values spent on operation and maintenance works. According to these results, it can be concluded that by both land and water productivity the performance of Koftu scheme was better. While the poor water productivity at Fultino scheme is due to excess water supplied at the head. At the end, the following ideas were recommended: the water available at the head of the system could be used to irrigate more land if enough technical supports and training on distribution and irrigation scheduling should be applied and all canals should be maintained on a regular basis.