GIS Based Surface Irrigation Suitability Assessment and Development of Map for the Low Land Gilo Sub-Basin of Gambella, Ethiopia

Abstract

Ethiopia has an important opportunity in water-led development, but it needs to address critical challenges in the planning, design, delivery, and maintenance of its irrigation systems. Gambella has an abundant water and land resources, but due to lack of information related to cultivable and irrigation suitability of the land, its agricultural system does not yet fully productive. This study was initiated to assess the land resources potential of the low land Gilo sub-basin for irrigation and providing geo-referenced map of these resources using Geographic Information System (GIS). By delineating the boundary of the study area, irrigation suitability of each physical land parameters was classified based on the FAO guideline for land evaluation in to S1, S2, S3 and N suitability classes independently, where the final existing and potentially irrigable land was identified by weighting the factors of suitability. The main suitability factors using to identify the existing and potential irrigable land were slope, soil texture, depth, drainage characteristics, soil type and land use/cover. The suitability analysis of the parameters indicates that 89.7% slope, 87.2% soil, 92.9% land use/cover of the study area were classified as potentially suitable for irrigation development in the study area. By weighting analysis of all parameters 9.1% of the study area was found to be existed suitable whereas about 1.3% was restricted for irrigation developments.

Keywords: GIS, land suitability, irrigation, Gilo sub basin, weighted overlay,