GIS‐based surface irrigation potential assessment of Gololcha River Watershed, Awash Basin, Ethiopia

Abstract The Gololcha River Watershed is lacking comprehensive assessment of land suitability for surface irrigation, available water potential, and prioritized irrigable areas. This study aims to evaluate the potential of land and water resources for surface irrigation in the Gololcha River Watershed. The study employed a multi‐criteria analysis approach using the analytical hierarchy process (AHP) and ArcGIS to assess land suitability, considering factors like slope, land use/cover, soil characteristics, and proximity to water sources. The observed mean monthly water flow potential for each sub‐watershed was statistically evaluated, and the area ratio approach was used to transfer discharges from gauged sites to the site of interest. Irrigation water requirements for three major crops in the study area were calculated using the CROPWAT8.0 model. The findings revealed an average water availability for irrigation of 2.70 m 3 /s/month, 1.10 m 3 /s/month, and 1.03 m 3 /s/month for the Kurkura, Midagdu, and Wefi sub‐watersheds, respectively, with a total annual river flow of 161 m 3 /s. Based on the suitability analysis, 2508 ha (7.27%) of the watershed area was classified as highly suitable for surface irrigation, 16,420 ha (47.565%) as moderately suitable, 1502 ha (4.35%) as marginally suitable, and 14,029 ha (40.71%) as unsuitable. The overall surface irrigation potential, aligned with available water, was estimated at 4872.58 ha. However, due to water limitations, only 14.15% of the total suitable land can be irrigated using existing flows. The study highlights the significant potential for expanding surface irrigation in the Gololcha River Watershed, particularly during the rainy seasons when substantial water flows are available. The findings provide valuable insights for developing sustainable irrigation strategies, enhancing agricultural productivity, and contributing to food security in the region.