Delineation Of Groundwater Potential Zone Using Remote Sensing And Geographical Information System: A Case Of Kaffa Zone,South Regional State, South Western Ethiopia

Abstract

Groundwater is considered as the first most source of pure water and represents 30% of the world’s fresh water contained in aquifers, a geological formation or part of the earth consisting of permeable material capable to store/yield in the layers beneath the surface. at very high depths, helps protecting it from contamination and preserve its quality and with significant quantities of water. However, with increasing of anthropogenic activities and geological formations coupled with climate change, its quality and quantity is deteriorating at alarming rate. Hence, closely monitoring the potential of groundwater intended to be used for domestic purposes is very important. Accordingly, the objective of current study focused on the delineation of Ground water Potential and recharge area of Kaffa Zone using remote sensing and ArcGIS 10.4 software analysis techniques. Different data from all over the world and Ethiopia were used to identify groundwater potential and recharge zone influencing factors. Eight main factors influencing groundwater potential zone were identified in this study; these were rainfall, slope, geology, lineament density, geomorphology, drainage density, Landuse/land-cover and soil texture. Likewise, six main influencing factors (rainfall, slope, land use/cover, lineaments, and drainage density and lithology) are selected for groundwater recharge zone mapping. Thematic maps were scanned; geo-referenced and classified as per suitable for groundwater using ArcGIS 10.4. The methods to assess the potential zone was using weight overlay analysis and Analytical Hierarchy Process (AHP) algorithm. The result depicted the groundwater potential and recharge zones into four categories, those are; very good, good, and moderate and low that can be used for better planning and management of groundwater resources. Accordingly, low, Moderate, High and Very High groundwater potentials area cover 1664.1 km2 ,7682.9 km2 , 958.27km2 and 192.78 km2 respectively. The prediction accuracy was checked based on borehole yield observed and predicted data of respective location. The prediction accuracy obtained (68.42%) reflects that the method applied for present study produced significantly reliable and precise results.