Abstract

The study area lies within the Upper Benue Trough South of Gombe town. Field study was carried out by methods of compass traversing and traversing along stream courses. Gombe formation, exposing 3 sandstone lithofacies comprising the upper, middle and lower members, in this part of the Trough, has a thickness of about 63 m. 2 aquiferous zones occur in the formation. The upper aquifer is found towards the bottom of the upper member of the formation and sometimes at the top of the middle member where sandstone beds interbed with impervious layers of ironstone. The middle member of the formation is essentially an aquitard and overlies the lower member which is an aquifer. Both aquifers are low water yielding. Analysis of grain size of the lower aquifer shows that the sandstones are very fine-grained to fine- to medium-grained, poorly sorted to moderately sorted, and they are river or beach sediments. The intrinsic permeability of the sediments (aquifers) determined from the grain size varies from 1.215 × 10^-4 to 3.840 × 10^-4cm/s. The aquifers can be developed for rural water supplies.

Key words: Groundwater, aquifer, Upper Benue trough, Gombe formation, Nigeria.