Predictive Mapping for Groundwater within Sokoto Basin, North Western Nigeria

Abstract

Scarcity of water within and around Northern Nigeria is no longer a wieldy issue. There is an over reliance on groundwater, and this has led to an increase in the number of bore-holes drilled in order to augment the water needs within the study area. Unfortunately the failure of many installed bore-holes has been rampant in this area. This is due to absence of or improper groundwater investigation and interpretation of site suitability. In this study, a remote sensing approach was employed to delineate and classify groundwater potentials of the Sokoto basin. GIS-based groundwater potential map of Sokoto Basin was modelled by producing and subsequently combining thematic maps. The data set includes; drainage, lineament, soil, lithology, elevation, slope and rainfall. Thematic maps of each data set were produced as distinct layers first before combining them together. For each layer, weighting for different classes was performed. The ground water potential map was then reclassified into five classes; very good, good, moderate to good, moderate and poor class. Results from the maps produced show that areas mapped indicating zones of very-good groundwater potential covers approximately 2.2% (1432.66 km2); zones mapped indicating good groundwater potential covers approximately 7.79% (5071.5237 km2); zones mapped indicating moderate to good groundwater potential covers approximately 27.5% (17577.8 Km2); zones mapped indicating moderate groundwater potential covers approximate 49.2% (32030.676 km2) and zones mapped indicating poor groundwater potential covers approximately 13.1% (8528.493 Km2) of the study area. The study further revealed that the southern part of the study area has a better water potential than the northern part of the study area. There is a close agreement between the groundwater potential map produced and field pump test data obtained previously within the Sokoto Basin according by previous authors.