14-Modelling of a Scavenger Well System.

Abstract

A scavenger well system, essentially a skimming well system designed to pump fresh water from a fresh-saline aquifer, consists of two pumping wells located side by side. One of the wells taps the freshwater zone and the other taps the deeper salinewater zone. These wells pump fresh and saline waters from the same site simultaneously without mixing, through two separate discharge systems. The rise of interface (upconing) due to pumping of freshwater well is countered by the pumping of salinewater well. This leads to a reduction in the upconing of the interface. A finite-difference model is developed to study the upconing below a scavenger well system. The model accounting for both advective and dispersive components of saltwater transport is based upon numerical solutions of the coupled differential equations governing two dimensional axis symmetric flow and salt transport. Results of a few numerical experiments performed on the model are presented herein.