PERFORMANCE EVALUATION OF SANKO SMALL SCALE IRRIGATION SCHEME AT BASKETO SPECIAL WOREDA IN SNNPR, ETHIOPIA

Abstract

This study was conducted to evaluate the performance of Sanko small scale irrigation scheme at Basketo Special Woreda, South Nation Nationalities Peoples Regional states. The irrigation scheme includes command area of 120 ha and 600 beneficiaries. To achieve the objective of the study; primary and secondary data were collected. The irrigation scheme was evaluated using minimum sets of internal and external comparative performance indicators which include agricultural, water use, physical and economic performance indicators. In order to evaluate the irrigation water use efficiency of farmers at field level, nine farmer fields were selected from the irrigation scheme in relation to their location (from the head, middle and tail end water users).The internal performance indicators which include conveyance, application, storage, deep percolation ratio and overall irrigation efficiency were used to check the performance of the irrigation scheme. From the analyses of the internal performance indicators, the conveyance efficiencies was found to be 69.3% and application efficiencies were found to be 61.6%, 63.4% and 46.5% at head, middle and tail end part of the irrigation scheme respectively. Average field application efficiency through out of the Sanko irrigation scheme was 57.2%. A deep percolation ratio in the same order of the scheme was found to be 42.8% and Storage efficiencies of 78.5%. Generally overall scheme efficiency of Sanko irrigation scheme was 39.6%. From the evaluation of external comparative indicators, the outputs per cropped area were found as 84,706 Birr ha-1 , 220,690 Birr ha-1 and 69,686.4 Birr ha-1 at head, middle and tail end part of irrigation scheme respectively and the value of the outputs per command area of scheme was 15,003,276 Birr per command area. The output per unit irrigation supply of irrigation scheme was 13.5 Birr m-3 , 33.95 Birr m-3 and 22.12 Birr m-3 at head, middle and tail end part of the scheme respectively. The water use performance of the scheme, like relative water supply and relative irrigation supply were found as 1.28 which was the same since there was no rainfall during study period. The irrigation ratio of the Sanko irrigation scheme was found to be 1.00 which means 100% of command area was under irrigation and additional 25ha was on the construction during study period. Water delivery performance indicator which includes adequacy, efficiency, dependability, and equity from these measures only adequacy was fair and good at head and middle part of irrigation scheme according to standard values but all of other measures were poor according to standard values. In general, based on the evaluation carried out; Sanko irrigation scheme at middle part was performed better than upper head and lower part of the scheme. But there is still a room for improvement of the performance at all of the system level. Therefore to reduce over and under irrigate farmers should get awareness how to use, when to use and how much water used on their fields.