Geospatial signature of augmented groundwater accessibility around streams

Routine application and widely accepted thought on the use of drainage density thematic layer to groundwater potential modelling (GPM) using remote sensing and geographical information system has assumed that the higher the drainage density, the lower the groundwater potential. Spatial distribution of hand pump boreholes in Dengi area points to the contrary as more than 80% of hand pump boreholes located by this study occur in areas of higher drainage density. About 23.8% of these hand pump boreholes were located less than to 50 m of the nearest stream; 19% were between 50–250 m; 42.9% were between 250–500 m; while only 14.3% were located at distances greater than 500 m from the closest stream. Spatial observation of the influence of geology, crystalline rock–sedimentary rock contact, lineament, elevation, slope, and soil on the location of groundwater abstraction structures suggest slight relationship, while the influence of lineament density is found to be minimal. The effect of streams is most consistent even as the thickness of aquifers obtained closer to streams hint at increased groundwater availability. This is in opposition to widely accepted belief. Thus, the need for a review of the traditional thought on the application of drainage density thematic layer to GPM is advocated.