ASSESSMENT OF LAND SUITABILITY AND IRRIGATION POTENTIALOF GOCE WATERSHED, OMO GIBE RIVER BASIN, ETHIOPIA

Abstract

Assessing available land and irrigation potential is important for planning their use. The main objective of this study was assessing surface irrigation potential in Goce watershed for irrigation development and generating suitable map of these resources by using Geographic Information System. Watershed delineation, identification of potential irrigable land, and estimation of irrigation water requirement were the steps that are followed to assess the irrigation potential of the study area. To identify potential irrigable land, irrigation suitability factors such as soil type, land cover/use, and distance from water supply (sources) were taken into account. To develop crops on these recognized irrigable areas, three crops Potato, Tomato, and onion were selected and the gross water requirement was computed by using close by climatic stations. The crop water requirement of major growing crops of the study area were identified based on some agro climatic condition of the study area. Crop water demand was estimated by implementing CROPWAT.8 model as an input of climatic data. The particular discharges at ungauged sites were transferred from gauged sites by using area ratio method and outcome was obtained on a monthly basis. The result of the weighted overlay analysis revealed that 99210 ha (98. 04%) of soil highly to marginally suited and 1990 ha (1. 96 %) not suitable, 52926 ha (67. 3%) of slope highly to marginally suitable, and 47993 ha (47. 6 %) not suitable, 97205. 3 ha (95. 3 %) distance highly to slightly suitable and 3937. 8 ha (10%) unsuitable and 9720.04 ha (96.1 %) of distance to river highly to relatively suitable and 20500 ha (20. 25%) not suitable. The discovered surface irrigation prospective assists policymakers in the development of irrigation projects. This kind of study considered only slope, land use land cover, and soil physical properties but other appropriateness factors like, socioeconomic, environmental issues, soil chemical characteristics, and irrigation method should be studied.