GIS-based surface irrigation suitability analysis: A case study of Walga sub-basin, Oromia Region, Ethiopia

摘要

Irrigation development could improve agricultural productivity and enhance socioeconomic development of the community. Though agriculture is the leading economic development sector of Ethiopia, most of the country’s cultivated land is under rain-fed farming. Assessment of GIS-based irrigation suitability analysis with regard to the prevailing slope, soil, land use/land cover and surface water resources has been carried out. Geo-referenced irrigation suitability map of the watershed area for the intended irrigation method was produced using ArcGIS weighted overlay model. Results of the suitability analysis revealed that about 45.72% (135,519.2 ha) of the watershed area is categorised in the range of highly suitable to marginally suitable for surface irrigation development as a result of combined effect of slope, soil and land use land cover suitability. Potentially suitable sites for surface irrigation development were evaluated for the selected dominant crops (maize, soybean and sesame) in the sub-watershed. Accordingly, Amanya, Rebu, Kulit, Nano, Walga and Darge river catchments have a total potentially irrigable area of 41.32% (122,488.2 ha). The analysis results from the present study might be providing a useful information for decision makers.