A triangulation approach for groundwater potential evaluation using geospatial technology and multi-criteria decision analysis (MCDA) in Edo State, Nigeria

Abstract

The quality and availability of groundwater resources are under extreme pressure as a result of growing urbanisation and population. The creation of lithological, structural, and geomorphological maps is made easier by satellite-based remote sensing data, notably at a regional level. This study uses the analytical hierarchical process (AHP) and geoinformatics-based approaches to facilitate and analyse different layers of geographically influencing data to define groundwater potential zones (GWPZ) in Edo State, Nigeria. The generated GWPZ map was created by selecting and weighting eleven precisely defined variables (including rainfall, lineament density, geomorphology, slopes, drainage density, soil type, landuse/landcover, proximity to surface water bodies, geology, a digital elevation model, and land surface temperature) based on their effect on groundwater availability. The zones of groundwater potential were developed using a GIS that incorporated the regulating variables. Depending on the degree of groundwater accessibility within each, this was grouped into four classifications (high, moderate, low, and very low). Low to moderate levels were seen across the study area, with high GWPZ representing 18% (3135.0294 km2) of the total area but only found in the Edo-central and isolated portions of the Edo-south. However, a very small fraction (3%) of very low GWPZ was found in the study's northern region. The exactitude of the established GWPZ map was determined to be 81.25% utilising well yield data (m3/d) from sixteen strategically selected boreholes in the study location, which were used to validate the GWPZ map. The research has shown that the criteria that have been observed are what govern the asymmetric distribution of these groundwater potential zones. The study will aid in the creation and governance of groundwater sources by improving recharge techniques, particularly in very low and low groundwater potential zones.