Characterization of aquifer parameter in basaltic hard rock region through pumping test methods: a case study of Man River basin in Akola and Buldhana Districts Maharashtra India

Abstract

Aquifer parameters transmissivity ‘T’ and storage coefficient ‘S’ are very important parameters to assess the groundwater potential either through mathematical modeling or any conventional methods. In early days, these parameters are estimated either by means of in situ test or performing test on aquifer samples brought in the laboratory. In recent times, the pumping test has become an important method to estimate these parameters. This is the only method that provides simultaneous information on the hydraulic behavior of the well (borehole), the reservoir and the reservoir boundaries, which are essential for efficient aquifer and well field management. The applicability of the result from the laboratory test has limitations while in situ tests give representative aquifer parameters. The most common in situ test is pumping test performed on wells, which involves the measurement of the fall and rise of water level with respect to time. Theis (American Geophysics Union Transcripts, 16th annual meeting, part 2, pp 519–524, 1935) was first to propose method to evaluate aquifer parameters from the pumping test on a bore well in a confined aquifer. Since then, several methods have been developed to analyze the pumping test data (time-drawdown) under different conditions. For the characterization of the aquifer parameters in Man River basin area, it is essential to know the Transmissivity (T = Kb where, b is the aquifer thickness: pumping flow rate, Q = TW (dh/dl) flow through an aquifer) and Storativity (confined aquifer, S = bSs, unconfined, S = Sy) so as to predict the rate of drawdown of the water table/potentiometric surface during the pumping of an aquifer. The determination of aquifer’s parameters is an important basis for groundwater resources evaluation, numerical simulation, development and protection as well as scientific management. Pumping test is a main method for determining aquifer’s parameters. A study area shows that this method has rapid speed and high accuracy. The results of parameter’s determination are optimized so that it has important practical value for scientific research and engineering practice.