Ground Water Potential And Land Suitability Mapping For Surface Irregation Using Geospatial Technology: The Case Of Katar Watershed, Rift Valley Basin, Ethiopia

Abstract

In Ethiopia, surface water is the primary source of agricultural production while groundwater is mainly used for domestic water use. Many irrigation systems that use surface water for irrigation get their water from river diversions, which only helps farmers that own the land along the river. But as rivers dry up due to climate change and increased irrigation use, there will be less water available, which will lead to new societal issues. Utilizing ground water potential is more crucial in order to increase irrigation potential and the possibility of acquiring reliable water resources for irrigation in the area that is far from the river because it is more reliable, less sensitive to droughts, and easily accessible for individual users. To overcome these challenges the aim of this study was to delineate Ground Water Potential and Land suitability for surface irrigation using Geospatial Technology in Katar Watershed, Rift Valley Basin, Ethiopia. The methodology under taken was considering nine parameters (lithology, geomorphology, slope, lineament density, land cover, rainfall, drainage density, Elevation and soil) that affect groundwater potential while soil, slope, GWPZ, equidistance to road, and land use/cover were taken into consideration for the potential land suitability zone (PLSZ). The weights of each thematic layer were assigned (weighted), normalized and ranked based on their Suitability to groundwater occurrence and land suitability for irrigation by AHP method through Pairwise Comparison Matrix (PCM). All reclassified thematic maps were integrated into the weighted overly analysis tool to create the GWPZ and PLSZ. The findings shows that the area could be divided into four classes: very low potential 39.92km2 (1.12%), low potential 1382.68km2 (40.73%), moderate potential 1852.28km2 (54.56%), and high potential 121.75km2(3.59%) for GWPZ, and not suitable 1.30km2 (0.04%), low suitable 437.06km2 (12.90%), moderate suitable 2143.59km2 (63.29%), and high suitable 805.05km for PLSZ. This shows that, relative to its overall area coverage, the study area has better groundwater potential and land suitable for irrigation. The delineated GWPZ was verified using the existing water yield point data and 86% of the total were matched with their respective zones. Thus, the identified Results are reliable. The study offers helpful information for upcoming irrigation projects that are intended to be foreseen, and it serves as a tool for policymakers' higher-level cognitive processes about irrigation development projects within the watershed.