GROUNDWATER RESOURCES EVALUATION OF THE UPPER BIMA SANDSTONE AQUIFER IN KALTUNGO AREA AND ENVIRONS, NORTHEASTERN NIGERIA.

Hamidu, H.*, Abubakar, U., Abdulganiyu, Y., Usman, M.B. and Ibrahim, F.G.

The Groundwater resources of the Upper Bima sandstone in the Kaltungo area and its surroundings have been investigated. A borehole yield range of 0.13 to 6.60 l/s with an average of 1.34 l/s were recorded for the area, while the Transmissivity and Specific capacity computed for the area ranges between 9.46 x10^-3 to 14.23x10 (m²/s) with an average of 3.85x10^-1 (m²/s) and 7.75x10^-3 to 11.70 x10 m²/s/m with average of 3.98x10^-1 (m²/s/m) respectively. This shows the area to be of low or poor groundwater resources potentials with low reserve. Lithological borehole logs interpretation reveals aquifer materials that compose of fine to medium Sandstone, Sand and Silty materials with shale and clay intercalations. Petrographic study and grain size analysis conducted on the Upper Bima Sandstone member by previous workers have revealed the sandstone of the upper Bima formation to be poorly sorted, immature with reduced porosity and of crystalline origin. These factors are most probably responsible for the poor hydrogeological condition of the Upper Bima Sandstone member, which have similar hydrogeological situations with those obtained for basement complex terrain elsewhere, hence confirming a crystalline origin for the Bima sandstone aquifers with low groundwater potentials.

Key words: Upper Bima Sandstone, Porosity, Cement materials, Borehole specific capacity, Poor hydrogeological unit, Kaltungo..