Assessment of groundwater potential zones using GIS and remote sensing techniques: a case study of Rwamwanja refugee settlement, Kamwenge district

Abstract

Analysis of groundwater potential zones is a prerequisite to achieving optimum utilization of the available land resources. The aim of this study was to identify and delineate suitable areas for groundwater exploration and exploitation based on physical and environmental factors of production using a Multi-Criteria Decision Analysis (MCDA) & GIS approach. The study was carried out in Rwamwanja Refugee settlement, Kamwenge district in Uganda. Biophysical variables of soil, and rainfall were considered for suitability analysis. The study area is water stressed with less or no water during the dry season. This leaves the population with a choice of travelling distances to access water for domestic use and this is usually done by women and children especially girls. There was therefore a need therefore to identify and delineate suitable areas for groundwater exploitation and exploration to achieve maximum potential yield. The deterministic factors such as Geomorphology, Lithology, Lineament Density, Lithology, Drainage Density, Slope, Soil and Rainfall were evaluated based on experts opinions. All data were stored in ArcGIS 10.3 environment and the factor maps were generated. For MCDA, Pair wise Comparison Matrix was applied and the suitable areas for groundwater exploration and exploitation were generated and graduated. AHP with the integration of GIS-based multi-criterion decision making, an approach using DEM was utilized to evaluate suitability for Groundwater exploration in the study area. Various ‘expert opinions’ were used to assign importance of the selected parameters and pair wise comparison matrix was used to establish the weights. Finally, the land use land cover map was overlaid with the suitability map to identify variances between the present and potential land use of the study area. The results of this research revealed that, 22.28 % area is classified as highly suitable, 25% as moderate, 22.72 % as suitable, and 30 % as unsuitable for the exploration of groundwater. The techniques, methodology and results of the study can be effective to assess the groundwater potential zones in Rwamwanja refugee settlement, Kamwenge district.