Assessment of suitable land for surface irrigation using spatial information systems: Case of Bilate River Basin in the Rift Valley Lakes Basin, Ethiopia

Abstract

Identifying the limited available resource, use of improved irrigation technology and better water resources management have been suggested as mechanisms for increased production. To optimize the agricultural production, knowing the available land for irrigation is mandatory. This study aimed to assess the suitable land for surface irrigation using different spatial parameters (normalized difference vegetation index, soil, slope, proximity, rainfall deficit, and land use). Land suitability was assessed by considering the individual parameters and then by overlaying. The overlay suitability analysis was performed by using weighted overlay tool within spatial analyst tool in ArcGIS. After excluding the irrigation constraints suitable land for surface irrigation was identified. Based on the individual parameters analysis the normalized difference vegetation index gives the largest land size which is 95 % of the total land as suitable. While the slope factor gives the lowest figure which is 57 % of the total land is suitable for irrigation. The weighted overlay analysis, gives only 28.46 % of the total land in the basin was suitable for surface irrigation. More than 93 % of this suitable land is grouped in to small scale while only about 7 % is used for medium to large scale irrigation.