Evaluating the Performance of Small-Scale Irrigation Schemes in Sub Humid Ethiopian Highlands; a case study in Mugie and Fesas

Abstract

Background This study was conducted to evaluate the performance of two small-scale irrigation (SSI) schemes in the sub-humid Ethiopian highlands. Water application at the farm level was monitored using partial flume and the average flow velocity along the main canal was measured using the current meter. The infiltration measurement was conducted at the head, middle, and tail of the scheme within the command area using a double-ring infiltrometer. Soil samples were collected using an auger up to 60cm depth. Climatic and agronomic data were collected from the nearby meteorological station and woreda agricultural office, respectively. CROPWAT was used to determine the water requirement of crops. Results The result showed that the average conveyance efficiency for the lined main canal was 90% and 92% for Mugie and Fesas SSI, respectively. The conveyance efficiency for the unlined main canal was in the order of 86% and 87% for Mugie and Fesas SSI. On the other hand, the average application efficiency and overall efficiency were found to be 56% and 51%, respectively, with storage efficiency of 50% for Mugie irrigation scheme. Similarly, the overall, application and storage efficiencies were found 50%, 54%, and 56%, respectively, for Fesas irrigation scheme. The relative irrigation and water supplies were 1.23 and 3.17, respectively, for Mugie SSI, while the supplies were 0.94 and 2.45, respectively, for Fesas SSI. Conclusions Conveyance efficiency for both Mugie and Fesas schemes was found below standard (95%) and overall efficacy was low as well (~50%). Failure of operating gates in the main canal, overtopping of water from the main canal due to canal siltation, and leakage through the main canals were the main causes for poor performance. Improvement measures are needed for both Mugie and Fesas irrigation schemes and institutional support is vital to improve and maintain the failure of infrastructures for better performance.

Assessment of Irrigation Water Management Performance Indicators and Mitigation Measure in Arba Minch Irrigation Scheme, Ethiopia

“…The average relative water and irrigation supply in the scheme were 1.7 and 3.3, respectively (Table 2) which were greater than the average recommended relative water and irrigation of 1 [19]. The average relative water and irrigation supply in Quashine and Dodicha small scale irrigation were 5 and 6 and 3.3 and 2.9 [16], respectively. All this conducted research shows that most irrigation project in Ethiopa faced under water management problem.…”

“…This poor scheme condition resulted from shortcomings in infrastructure design, construction, operation and maintenance [13], and the absence of strictly controlled water management practices [14]. Additionally, irrigation schemes will fail due to insufficient technical skills to manage available irrigation water [15] and sedimentation of the weir and canal structure [16]. Improving irrigation efficiencies along the distribution system and at the farm level is an important water management goal to reduce the wastage of water [17].…”

“…Effectiveness of infrastructure measure status of functional and nonfunctional infrastructure in the scheme whereas water surface elevation ratios also evaluate change of canal bed due to siltation and weeding problem [24]. Water supply indicators (such as relative water and irrigation supply) are used to describe how supply and irrigation demands are matched [16]. Irrigation water loss along the canal system can be minimized by providing lined canals using various materials like concrete, asphaltic concrete, flexible membranes [25], compacted earth, and soil cement mixture [26].…”