Groundwater chemistry, storage and dynamics in parts of Jigawa Central, Northwestern Nigeria

Abstract

The Sedimentary (Chad formation) and Basement complex rocks in parts of Jigawa State were investigated for groundwater suitability for drinking, efficiency in water transmission and storage using aquifer properties derived from pumping test data using the Cooper and Jacob straight line method for single well tests. The mean values of transmissivity, hydraulic conductivity and Specific capacity recorded for the area are 4.06×10^-2m²/s, 4.52×10^-3 m/s and 1.30×10^-1m² s/m, respectively. Boreholes yield ranges between 0.20 to 1.5 l/s with an average of 0.9 l/s, while drawdown ranges from 3.39 to 22.90 m. The low values computed for these aquifer properties indicates the inefficiency and poor performance of the aquifer in the area as far as groundwater potentials and transmission are concern. This can also be attributed to the poor porosity and permeability of the parent rock from which the aquifer material were derived especially for the basement complex aquifers (weathered/fractured rocks), and the shallowness of the wells which terminate in Clayey sand or Silty aquifers with low yield. Other possible reasons include poor borehole design and the use of feldsphatic materials as gravel pack which weathers into clay over time. However, the yields can support handpump equipped wells. The water analysis revealed water of low dissolved salt and hardness that are within the recommended limit set by WHO and NIS for drinking.

Keywords: Aquifer performance, Efficiency, Hydraulic properties, Water quality, Chad formation