Quantitative and Qualitative Appraisals of Aquifer Properties in Kachia Area of Kaduna State, Nigeria

Abstract

Kachia Local Government Area (LGA) is located at the southern part of Kaduna State, Nigeria. Quantitative and qualitative appraisals were carried out in order to have proper understanding of the aquifer system and ensure sustainable development by using geophysical, geological and pumping test data obtained from 32 producing boreholes across the entire LGA. Hydraulic conductivity, transmissivity and storativity values were computed, piezometric surface map and the basement relief map were prepared, geoelectric layer characteristics were delineated and two geological profile sections were constructed. The hydraulic conductivity values were found to range from 0.021 m/day at Walijo to 1.391 m/day at Iddah-Hanya with an average of 0.42 m/day. The transmissivity values ranged between 0.90 m²/day at Walijo to 25.37m²/day at Iddah-Hanya, with average value of 6.31 m²/day. Storativity values were lowest at Walijo with a value of 89.42 and highest at Iddah-Hanya having a value of 2877 with an average of 929.82. The lowest values of these three aquifer constants were observed to converge at Walijo at the extreme eastern part and they all peaked at Iddah Hanya on the western border of the study area. The piezometric surface contour map showed that static water level is generally deeper around the central part of the study area than at the southern and western parts. The basement relief map revealed that the depth to Basement rock is generally deeper at the central part than at the eastern, western and southern boundaries of the study area. Three-layer geoelectric horizons delineated agreed with the drilled sections. The two profile sections 1 and 2 suggested that the weathered layer constituted the major aquiferous unit, and it occurred within a depth of 1 m to as much as 35 m, except Kurmin-Sara with 80 m thickness. Groundwater prospecting can therefore be targeted to an approximately uniform regolith thickness across the entire study area.