Analysis of groundwater-surface water interaction in horizontal unconfined aquifer bounded by a stream and groundwater divide using a non-linear numerical model

Abstract

In this study, a non-linear numerical model was developed to analyse the interaction between the drainage water moving from an unconfined aquifer and a surface water body. This interaction can occur during or after a rainfall event, which can cause the groundwater table to change. At first, a laboratory-scale aquifer model with stream and groundwater divide boundaries was established to examine horizontal unconfined aquifer condition. Both steady-state and transient experiments were performed by setting the water table at a steady-state using a constant recharge rate, and then allowing the aquifer to drain. The transient water table data showed highly non-linear variations. Then the experimental data were recreated using a non-linear numerical model, which used non-linear one dimensional Boussinesq equation and Picard iteration for solving non-linear term of the Boussinesq equation. The numerical model was able to predict the observed groundwater table data. The proposed numerical model is a useful and cost effective tool for managing groundwater-surface water management problems.