Transformation Technique for the Water Table Prediction Influenced by Recharge and ET

Abstract

An analytical solution has been developed by solving the linearized form of the Boussinesq equation to predict the water table fluctuation between drains in presence of evapotranspiration (ET) and recharge from the land surface. The variable ET rate has been considered to decrease linearly with increase in depth to the water table below the land surface and the recharge has been taken to occur at a constant rate. Specific cases of the proposed analytical solution converge to the already existing analytical solutions and numerically a close match of the water table height has been observed. The variation of water table and performance of the solution has been highlighted with the aid of a numerical example for which the drainage parameters have been taken from an actually operating drainage system. Application of the solution results in wider drain spacings and suggests a 7 to 12% economy in the drainage design for the given example.