WRRCTMR No.66 Formation of Transition Zone in a Basal Aquifer Under Pumping Stresses

Abstract

Formation of a freshwater-sea water transition zone in a basal aquifer under pumping stresses was studied by sand-box experiments and by comparing experimental data with results from other theoretical and field investigations. Upconing height for different pumping rates and well penetration depths were measured in the laboratory. These experimental data were then compared with theoretical values computed with or without the sharp interface assumption. Dispersivity of laboratory sand was determined by matching the observed thickness of the transition zone with the theoretical value. The thickness of the transition zone was found to increase as the pumping rate and/or the partial well penetration depth increased. The results of the laboratory experiments were compatible with the values predicted by theoretical equations.