Exploration of Groundwater Potential using GIS and Remote sensing in Embu County, Kenya

Abstract

Integration of Remote Sensing (RS) and the Geographical Information System (GIS) uses in groundwater resources is a major development. The RS and GIS geospatial techniques enhances the assessment, monitoring and conservation of groundwater resources. In this study, RS and GIS geospatial approaches were applied with the aim of identifying groundwater potential zones in Embu County, Kenya, based on selected multi-influencing factors. The multi- influencing factors include Drainage density, Slope, Lithology, Soil, Lineament density, Land use/ Land cover and Rainfall. Embu County, in Kenya mainly depends on groundwater for domestic use. Sadly, occurrence of conflict among the communities is frequent due to water shortages in the County. Therefore, a detailed investigation of groundwater potential is necessary for efficient and sustainable management of this scarce natural resource Lineament layer was obtained by processing Landsat 8 ETM+ image using Principal Component Analysis (PCA) in ENVI 4.7 and automatic extraction from Principal Component Image (PCI) using the LINE module in Geomatica software. All thematic layers were transformed to raster format before applying weighted overlay analysis in GIS, for mapping of potential groundwater zones in Embu County. The groundwater potential map produced showed that about 78% of the total area fell under ‘high’ to ‘very high’ zones indicating that over three quarters of the study area falls under good groundwater potential zone. About 20% showed moderate potential while only 2% fell under the low potential zone. The proposed study approach can be used as a way of modelling geospatial data for mapping of groundwater potential zones. The groundwater potential map produced along with the other thematic maps serve as resource information database which can be updated from time to time by adding new information. The study findings are useful to first-hand information planners and local authorities for assessment, planning, management and administration of groundwater water resources in Embu County and the same procedure can further be replicated in other counties