A Simple Geostatistical Approach in Geoelectrical Estimation of Aquifer Hydraulic Parameters: A Case Study of Benin Hydrogeological Province in Umuahia Area, Southern Nigeria

Abstract

Knowledge of aquifer parameters is essential for the assessment, management and protection strategy of groundwater resources. The values of these parameters are best estimated through pumping tests but are costly and time consuming. Data from Electrical resistivity survey carried out at the vicinity of a borehole where pumping tests have been acquired together with pumping test data provides a cost-effective and efficient alternative to estimate aquifer parameters in sites where pumping tests are not available using the surface geophysical methods. In this Paper a simplified geo-statistical integrated approach to derive aquifer parameters from pumping tests data and surface resistivity soundings (VES) is presented. This method was explored by using pumping tests analysis data especially hydraulic conductivity to calculate the transmissivity (T) of the same boreholes from data (thickness) acquired through surface resistivity soundings (VES). A graphical linear relationship was established from a set of data and subsequently used in places where pumping test is not available for the determination (estimation) of aquifer hydraulic parameters. When the method was compared with existing data, the compared result was further used in deriving transmissivity factor and subsequently used in the determination (estimation) of other aquifer hydraulic parameters. It was concluded that hydraulic conductivity can be accurately predicted using this approach. The main advantage of the estimation method presented here is its simplicity and accuracy.