Effect of Head Build-Up and Seepage on the Water Table Fluctuation in a Semi-Confined Aquifer

Abstract

In semi-confined leaky aquifers, occurrence of vertical seepage from the confining layer is common. Due to which water table rises in the overlying unconfined aquifer and creates water logging problem. The problem aggravates when recharge from rainfall, irrigation return flow and recharge from uplands also occurs. Thus, in the present study, an analytical solution has been presented to study the water table fluctuation in a semi-confined aquifer subjected to upward seepage and constant recharge from the land surface. The analytical solution will be helpful in controlling the rise of water table due to flow convergence and to avoid the water logging. The validity of the proposed analytical solution has been established by comparing with already existing mathematical solution. The results of the proposed solution have been presented to show the effect of piezometric head, resistance of the confining layer, drainable porosity and head build up above the drains due to convergence of flow on the water table rise. A rise of 0.30 m head above the drains causes 0.21 m corresponding rise in the water table and a minimum water level of 0.30 m is maintained above the centre of drains.