Hydrogeological and hydrogeochemical evaluation of the groundwater potentials of Kaduna area, Central Nigeria

Abstract

An assessment of the groundwater potentials of Kaduna area, Central Nigeria has been carried out using hydrogeological and hydrogeochemical characteristics. The investigations had led to a fairly good appraisal of the hydrogeological characteristics of the area of the basement complex terrain in Nigeria. The basement complex as studied in the area has two main aquifer systems: the weathered overburden and the fractured crystalline rocks which are interconnected. Groundwater contour map showed the flow direction to be southwards toward River Kaduna. Analysis of the relationship between static water levels and depth of dug wells in the area gave a correlation of 0.89 with a regression coefficient of 0,79. While a correlation coefficient calculated for the variation of static water level with elevation of wells was -0.0479. The mean depth to water table was 4.03m with a standard deviation of 1.49 and a coefficient of variability of 37. The mean elevation of wells is 603.75m with a standard deviation of 27.54 and a coefficient of variability of 37. The mean elevation of wells is 603.75m with a standard deviation of 27.54 and a coefficient of variability of only 4.5. Borehole yields in the area range from 30.24 to 207.3m3/day with an average of 90.65m3/day. Transmissivity values range from 0.38 to 47.4m3/d with an average of 6.96m2/d and specific capacity values range from 0.43 to 31.85m3/day with an average of 13m3day/m. The depth to water level ranges from 1.1 to 16.63m with an average 6.51m while the overburden thickness ranges from 8.5 to 42.0m with an average of 23.4m. Analysis of hydrogeological parameters from boreholes in the area revealed a correlation coefficient calculated for the variation of the overburden thickness with the transmissivity, specific capacity and yield as 0.083, -0.249, and 0.18 respectively with a regression coefficient of 0.0069, 0.062, and 0.032 respectively. The correlation coefficient calculated for the relationship between the transmissivity and the specific capacity was 0.78 and the regression coefficient 0.61. Chemical analysis of major ions for groundwater in the area indicates sodium, potassium and bicarbonate ions were the dominant ions and hence the groundwater of the area is classified as Na-K and Bicarbonate water type.