Site Suitability Analysis for Surface Irrigation using GIS, Remote Sensing, and Analytical Hierarchy Process (AHP) Integration in Wama Watershed, Western Ethiopia

The study integrates GIS, Remote Sensing and Analytical Hierarchy Process (AHP) to evaluate suitable sites for surface irrigation by taking eight parameters into account, including slope, elevation, distance to water source, land use, soil texture, soil type, soil depth, and soil drainage in Wama watershed. A numeric range was created by standardizing each parameter to a single measurement scale, with higher values denoting more suitable and lower values denoting less suitable one. The final site suitability map was prepared in GIS environment by using the weighted overlay method. Distance to streams (44%), slope (18%), elevation (13%), LULC (13%), and soil drainage (5%) scored highly in the pairwise comparison matrix. Additionally, they are the most crucial elements in evaluating eligible lands for surface irrigation, followed by soil depth (4%), soil type (3%), and soil texture (2%). The final suitability map, which will aid in supporting rain-fed agriculture by surface irrigation, was developed with four classifications highly suitable (16%), moderately suitable (49%), marginally suitable (34%), and not suitable (1%). Therefore, this study demonstrates a robust method of using GIS and remote sensing techniques, which is efficient and useful in mapping potential site suitability for surface irrigation and an important guideline for planners, and decision-makers to give the fast decision for irrigation management.