On‐farm performance evaluation of small‐scale irrigation schemes in the Ethiopian Rift Valley: Internal and external performance process approach

Abstract

This study evaluated the on‐farm performance of two small‐scale irrigation schemes, Furfuro and Bedene Alemtena (hereafter referred to as Bedene), in the Ethiopian Rift Valley. Two sets of performance indicator parameters were used. The first group was internal performance indicators, which included conveyance, water application and application uniformity. The water flow velocity through canals was monitored using the floating method. The amount of irrigation water applied to the fields was measured using a cutthroat flume. The second group was external performance indicators, including agricultural performance, water use performance and physical sustainability indicators. The results indicated that Furfuro had average conveyance, application and uniformity efficiencies of 84%, 59% and 50%, respectively, while that of Bedene were 79%, 63% and 55%, respectively. The overall efficiencies for both schemes were about 49%, which is lower than the minimum permissible values. The outputs per irrigation supply and consumed water for Furfuro were 0.14 and 0.16 US$/m³, respectively, and they were 0.11 US$/m³ for Bedene. The relative irrigation and total water supply of Furfuro were 1.21 and 1.20, respectively, indicating the presence of excess water in the command area during the study season. The relative irrigation and water supply of Bedene was 0.81, which indicated that the scheme was water deficient. Irrigation water management practices need improvement in the two schemes.