Performance Evaluation of Small-Scale Irrigation Scheme: Case Study of Selamko Irrigation Scheme, Upper Blue Nile, Ethiopia

The study was conducted to evaluate the performance of the Selamko small-scale irrigation scheme using internal and external performance indicators. The irrigation scheme command area was 63 ha and during the study season, the irrigated area was 42 ha. Overall activities in the primary data collected included: field observation, discharge measurements in the canals, soil moisture before irrigation and after irrigation, depth of water applied at the field, and interviewing beneficiary farmers. Secondary data was collected from secondary sources that were the South Gondar Small Scale Irrigation coordination office, SGBoWR, and WUA of the scheme. In order to evaluate the irrigation water and use efficiency of the scheme, nine farmer fields were selected from the scheme concerning their location: at the head, middle, and tail end water users. The internal process indicators which include conveyance efficiency and application efficiency were used to evaluate the performance of the scheme. From the analyses of internal performance indicators, the conveyance efficiencies were found to be 9% in the main canal, 57.09 at secondary canal 1, and 54.55% at secondary canal 2. The canals supply less water than the demand of the delivery points. And the application efficiencies were estimated to be 56.994%. The overall efficiency was 35.268%. The output per command area has to be calculated as 60,198.14 Birr/ha and 89,738.1 Birr/ha during the 2017 and 2016 irrigation seasons, respectively. The output per cropped area was estimated as 90,297.62 Birr/ha and 99,621.1 Birr/ha in the 2017 and 2016 irrigation seasons, respectively. The output per water consumed has to be determined as 17.66 Birr/m3 and 20.14 Birr/m3 in the 2017 and 2016 irrigation seasons, respectively. The water supply and irrigation supply were found as 1.71 and 1.47, respectively. From the analysis of the physical performance of the scheme, during the study period, the irrigation ratio of the scheme was 66.67%, and the sustainability of the scheme was 62.69% but in the 2016 irrigation season, the irrigation ratio was 84.7% and sustainability of the scheme was 90.08%. During the study period, the total effectiveness of the scheme infrastructure was 20.69%. It displayed that high system maintenance is required. Generally, the performance of the irrigation scheme is poor. Therefore, scheme monitoring, capacity building of the users and the water user associations, providing the flow control measurement structures, and adequate operation and maintenance of the system are required to improve the irrigation scheme performance.