Yilma, Sileshi (PhD)Yeshi, Andualem2019-01-172023-11-112019-01-172023-11-112018-11http://etd.aau.edu.et/handle/12345678/15854Water delivery performance is the degree to which whether the system delivers water at the required rate at the right place and time so, water delivery performance evaluation of irrigation system plays a dynamic role in identifying the gaps and applying mitigation measures. Koga irrigation scheme was designed to irrigate around 7000ha but, it does not meet the proposed objective, hence the objective of the study was evaluating the water delivery performance of Koga irrigation scheme. This study was carried out for three month on a single irrigation season from February to April; 2018. Water delivery performance of the scheme was evaluated by comparing irrigation water demand with actual irrigation water supply by using 7 indicators classified under water delivery and water use or water supply indicators. As per the result, deficit of supply has been progressive in March and April; because actual irrigation water supply in March and April was less than the crop demand. However, supply was exceeding the demand during February. The average, irrigation water supply was observed in shortage of the requirement at the head middle and tail reach of the main canal. The overall relative water supply, relative irrigation supply and deficiency of the scheme were 0.65, 0.75 and 0.28 respectively. As shown from the result water delivery performance indicators; adequacy, dependability, equity and efficiency were found to be 0.68, 0.29, 0.08 and 0.95 respectively. According to these values, performance of water delivery of the main canal was rated as poor in terms of adequacy and dependability; however it was good in relation to efficiency and equity. These values indicate that, actual water level as well as command area was reduced from initially designed. The results from this study are very clear to that of, non-proportionality of irrigation water demand with supply, poor temporal water delivery system, absence of frequent management aspect have been strongly affected the water delivery performance of the schemes. Therefore, it is suggested that, effective water management, supplying irrigation water based on crop demand , optimal crop plan, and apply a strong water delivery plan are required to mitigate these problems.en-USwater delivery performanceirrigation water demand and supplywater delivery and supply or use indicatorsKoga irrigation schemeThesis