A Simplified Analytical Solution for Predicting Water Table Fluctuation subjected to Variable Recharge and Variable ET in a Sloping Aquifer

Abstract

In the present study, an analytical solution has been developed by solving the Boussinesq equation for a sloping aquifer subjected to transient recharge and depth-dependent evapotranspiration. A unique transformation approach is suggested to transform the Boussinesq equation in a very simple heat flow equation for obtaining the analytical solution. The proposed analytical solution is very versatile and sound enough to predict the water table for any combination of recharge and ET. The validity of the proposed analytical solution has been established by comparing the special cases of the proposed solution with the experimental data and already existing solutions. The results of the proposed solution have been presented to show the effect of recharge and ET on the water table variation. Since consideration of constant or depth-dependent ET results in a faster decline of water table as compared to the case of no ET, the drainage design will result in wider drain spacing and will be economical. As this study accounts for both variable recharge and variable ET close to the actual field cases, the outcome of the study will also be close to the practical values.