Development of semi-analytical solution for recharging through multiple well points system under constant head conditions

Abstract

Under natural geographical settings, there are numerous regions where freshwater floats in layers on the native brackish groundwater. Skimming of these floating freshwater layers for fulfilling water needs using lesser capacity wells is a proven technology and is popularly known as multiple well points system (MWPS). Excessive exploitation of water is thinning these freshwater layers. Therefore, for reducing stress on existing freshwater layers due to pumping and/or retaining the fresh–brackish water interface at desired depth, it is mandatory to maintain adequate recuperation rate. For this purpose, the most convenient way is to use the existing MWPSs for recharging these aquifers when quality potable water is available in excess during the monsoon season. However, prior information regarding the performance of MWPSs during recharging operation is of much significance while planning of any recharging project. Therefore, by incorporating the principle of superposition and Darcy–Weisbach relation-based newly developed position-oriented opportunistic proportion equation, a semi-analytical solution for evaluating hydraulic head distribution and recharge rate in a single leaky aquifer while recharging the freshwater under constant head conditions through MWPS has been developed. A close conformity of the computed results with the field observations describes the potential of the developed solution.