Assessment of irrigation performance trends using selected comparative indicators over consecutive periods: A case study of the Koga Irrigation Scheme in the Amhara region, Ethiopia

The Koga Irrigation Scheme is a modern irrigation scheme in Ethiopia, and furrow irrigation is a common water application method. The main purpose of this study is to show in which year it performed well and what the problems were and to identify the best alternatives that may be essential for managing the scheme effectively and efficiently. The performance trends of the Koga Irrigation Scheme were evaluated using four selected performance indicators, namely, physical, agricultural, water use and economic performance indicators. Primary and secondary data, including geographic locations, water supply, harvested yield, market prices, irrigated crops, actual irrigated area, planned irrigable area, total management and operation cost, water fees and historical climate data, were collected. Land use performance analysis indicates that the scheme operates below its potential. The maximum irrigated area was 6,327.7 ha less than the designed 7,000 ha in 2015 and 3,619.9 ha in 2016. Water consumption peaked in 2015 and decreased in 2016. The dominant crops were wheat (55%), potato (19%), barley (7.6%), onion (7.4%), maize (5.6%) and other crops (5.4%). This suggests a preference for low-value, water-intensive crops. Water use by crops is lower than reservoir release, indicating significant water loss. Economic water productivity is low, primarily due to the dominance of low-value, water-intensive crops. To enhance scheme performance, the study recommends adjusting cropping patterns, estimating actual water demand for the respective crops and irrigation scheduling, adopting efficient water application methods and strengthening the market chain.