Investigation of Aquifer Characteristics and Borehole Performance in Adamawa State

Borehole water supply systems serve as the primary safe water source for urban and semi-urban communities in Adamawa State, North East Nigeria, yet aquifer characterisation to guide reliable borehole siting and design is poorly documented for many areas. This study investigates aquifer characteristics and borehole performance in seven borehole installations in Yola North, Gombi, and Mayo-Belwa LGAs of Adamawa State. Pumping test data from extended step-drawdown and constant-rate pumping tests were analysed to derive transmissivity, storativity, and specific capacity for each borehole. Aquifer type and hydraulic boundary conditions were interpreted from time-drawdown and distance-drawdown analysis. Water level recovery records were assessed for aquifer recharge characteristics. Available driller's logs were compiled to correlate hydrogeological units. Results indicate that transmissivity values range from 24 to 186 m2/day, reflecting variable aquifer productivity across the study area. Three boreholes show evidence of storage depletion during extended pumping, indicating limited aquifer extent in weathered basement aquifers. Specific capacity values of 0.4 to 4.2 m3/h/m suggest moderate yield potential. The most productive aquifers are associated with fractured basement zones aligned with structural lineaments visible in satellite imagery. The study recommends that future borehole siting in Adamawa State incorporate remote sensing lineament analysis and a minimum 8-hour step-drawdown test to verify sustainable yield before community handover.

Keywords: aquifer characterisation, borehole performance, pumping test, Adamawa State, groundwater