Saltwater Upconing in Unconfined Aquifers

Abstract

The need for skimming of fresh groundwater above a saline water body without producing an unacceptable contamination in the pumped water calls for the investigations carried out in this research work. Two axisymmetric models, namely the steady state and the transient upconing models, are developed with the assumption of an abrupt interface. Finite element method with an iterative scheme is employed in solving the steady state model whereas a method of finite element in space and finite differences in time is used with iterative schemes for the transient model. The models are calibrated with the analytical solutions for the case of radial flow to a fully penetrating well in an unconfined aquifer. A method of superimposing the effects of hydrodynamic dispersion on the upconing is discussed. The simulation results of both models, together with the technique of dimensional analysis, provide information for establishing design criteria for optimal pumping or choice of well depth or both.