Determination of hydraulic characteristics of an aquifer capacity from pumping test: A case study of Konshisha Area, central Nigeria
Constant rate, single well pumping tests were conducted using boreholes located in four communities in the study area with the aim of determining the aquifer hydraulic properties using the Cooper Jacob method. Fractured shales yielded groundwater into the wells whose depths ranged from 26 to 35m while the static water level varied from 5.81 to 8.76 m. During the test, the maximum drawdown observed was between 11.89 and 21.34 m. The hydraulic conductivity values fell between 6.1 x 10-2 and 6.45 x 10-1 m3/day while transmissivity ranged from 0.49 to 4.52m2/day and specific capacity from 18.41 to 117.92 m2/day. The specific yield varied between 78.62 and 87.26 m3/day. Classification based on transmissivity values shows a very low to low yield aquifer. This correlates well with the litholog which showed fractured shales as the groundwater bearing unit supplying water into the wells. Good correlation (correlation coefficient, R2) of 0.8753 was obtained between transmissivity and specific capacity. The hydraulic coefficient and transmissivity indicate that for sustainable aquifer productivity, boreholes in the area should be installed with low horse power pump size for domestic use.
Key words: Pumping test, Aquifer, Hydraulic conductivity, Transmissivity, Specific capacity