PERFORMANCE EVALUATION OF UPPER MILLE IRRIGATION SCHEME IN NORTHERN ETHIOPIA

Abstract

Upper Mile Irrigation Scheme is found in Amhara National Regional State, specifically in Ambasel woreda. Though the scheme has short service years after construction, many complains were reported by the farmers regarding the operational and management aspects of the scheme. However, no any assessment was made since its implementation to know the present status of the scheme. The objective of this study was evaluating the performance of Upper Mille Irrigation Scheme using the water delivery and water use performance indicators. Primary and secondary data were collected using standard procedures. Laboratory analysis, CROPWAT-8 Model, GIS and Excel sheet were the major data analysis tools employed. The result of the study revealed that, the average conveyance efficiency of the main, tertiary and field canal system were 88.89%, 69.09% and 51.33%, respectively. The relative water supply and relative irrigation supply values in the study months were found to be 1.89 and 1.69, respectively. The average application efficiency, storage efficiency and overall efficiency of the scheme were also 67.12%, 79.56% and 45.14%, respectively. The deep percolation loses have an average value of 32.88%. This implies that, the value of most of these water delivery and water use indicators were below the attainable value suggested by many researchers. The survey result also shows that, there was no water user association in the scheme but the water user committee was formed by the users at the village level to manage the scheme. 53.57 % of the farmers agreed that, the main factor of the water loss in the scheme was due to the conveyance system. 71.43% were also responded that there was unfair water distribution to the users. Poor canal alignment, damage of the controlling gates, unavailability of enough tertiary and field canals, canal breaching by the illegal users, seepage and illegal diversion were among the causes of water lose and unfair distribution of water to the users. In case of the irrigation scheduling criteria; 42.86% have used the symptom of crop leaf welting, 39.29% have used checking of soil moisture near crop roots, and (17.86%) used both techniques. Based on the result of this study, the overall efficiency of the scheme was obtained as 45.14% which was nearly equal with the value considered at the design stage. But, it was the lowest value suggested by Rai et al. (2017) and it needs some improvement for a better performance.