Groundwater exploration in a landscape with heterogeneous geology: An application of geospatial and analytical hierarchical process (AHP) techniques in the Edo north region, in Nigeria

Abstract

One of the most critical challenges affecting emerging nations is the inaccessibility to potable water, particularly in regions where people compete for domestic water with irrigation, heavy industry, and sewage disposal. Therefore, in order to efficiently explore for this resource, it is necessary to establish an efficient, dependable, and lasting method or methods of identifying zones of groundwater occurrence and distribution with high precision. The groundwater potential zones (GWPZ) in the Edo North region of Nigeria were mapped using integrative techniques for sustainability in this study. The objectives were accomplished by developing six separate theme layers that determine groundwater potential, namely Geomorphology (G), Slope (S), Drainage Density (DD), Lineament Density (LD), Landuse/Landcover (LU/LC), and Geology (GE). Thematic maps were weighted, normalised, and compared pair-wise using Saaty's Analytical Hierarchical Process (AHP) model before being integrated and queried in the ArcGIS environment to categorise groundwater zones. Hence, the groundwater potentiality map created in a GIS environment classified recharge capacities into four zones: very low 561 Km2 (17%); low 1989.9 Km2 (60.3%); moderate 627 Km2 (19%); and high 122.1 Km2 (3.7%). The GIS model and RS findings suggest that the eastern and northern sections of the study area have moderate to high recharge and storage potential. These findings for water resource development are in areas with considerable groundwater potential.