Habila Alfred Zingchang
National Water Resources Institute, Mando Road Kaduna, Nigeria
The objective of this research is to determine the aquifer characteristics, groundwater quality and geology/groundwater potential maps of study area. The methodology involved four phases covering three months namely; desk study/secondary data collection for boreholes, geological field mapping on a scale of 1:12,500, water sampling mapping and analysis of field results and data. Constant rate well pumping test results for twenty-five (25) boreholes within Langtang Area (study area) were collated and analysed to assess the Groundwater potentials of the study area while also analyzing twenty-five (25) groundwater samples taken from various sources within the study area. Geological field mapping on a scale of 1:12,500 revealed that the area is made up of four (4) major rock types; Pan African older Granites, Migmatite-gneiss, Alluvium and Agwu Formation. Cooper-Jacob’s non-uniform flow equation was used to determine the transmissivity (T), Storativity (S), hydraulic conductivity (K), and specific capacity (Sc), of the aquifers of the study area.
Geographical Information System (GIS) tool was used to generate color coded maps of the determined hydraulic characteristics of the aquifers. Static Water Level (SWL) ranged from 2 to 15.42 m. Hydraulic Conductivity values falls between 0.3 and 4.83 m/day. Specific capacity values ranged from 4.86 to 79.3 m2/day. Transmissivity values ranged from 0.89 to 14.5 m2/day. Storativity values ranged from 0.02 to 4.94. Hydraulic parameters analyzed, classified the Crystalline Basement of study area into five (5) Groundwater Potential Zones; very low, low, moderate, high and very high. Analysis of water samples show that major cations; Ca2+ had value range of 1.053 to 60.346 mg/L, Mg2+ with values of 1.424 to 60.346 mg/L, Na+ had values of 0.212 to 2.66, and K+ with value range of 2.13 to 27.22 mg/L. While the Anions; NO3 - ranged from 0.56 to 87.52 mg/L, SO4 - with values of 0.00 to 3.2 mg/L, HCO3 - with values of 0.00 to 4.7 mg/L, and F- ranged from 0.35 to 3.47 mg/L.
The pH value averaged at 6.4, Temperature 26.5° C, and EC 681.96 μS/cm. The Piper Trilinear Plot, Stiff and Durov plots classified the water of the study area into three major types; Ca-Mg-HCO3, Na-HCO3 and Ca-Mg-
SO4. The computed hydraulic characteristics of the study area can form a reference for ground water prospecting and development, and the water quality of the area show that Fluoride is leached from biotite granite into
the ground water (through weathering processes) thereby raising level above acceptable limits 1.5 mg/L.