Groundwater Circulation Well for Controlling Saltwater Intrusion in Coastal aquifers: Numerical study with Experimental Validation

Abstract

Saltwater intrusion into coastal aquifers has become a prominent environmental concern worldwide. As such, there is a need to prepare and implement proper remediation techniques with careful planning of freshwater withdrawal systems for controlling saltwater intrusion in coastal marine and estuarine environments. This paper investigates the performance of groundwater circulation well (GCW) in controlling saltwater intrusion problems in unconfined coastal aquifers. The GCWs have been established as a promising in-situ remedial technique of contaminated groundwater. The GCW system creates vertical circulation flow by extracting groundwater from an aquifer through a screen in a single well and injecting back into the aquifer through another screen. The circulation flow induced by GCW force water in a circular pattern between abstraction and recharge screens and can be as a hydraulic barrier for controlling saltwater intrusion problem in coastal aquifers. In this study, an effort has been made to investigate the behavior of saltwater intrusion dynamics under a GCW. An experiment has been conducted in a laboratory-scale flow tank model under constant water head boundary conditions, and the variable-density flow and transport model FEMWATER is used to simulate the flow and transport processes for the experimental setup. The evaluation of the results indicates that there is no further movement of saltwater intrusion wedge towards the inland side upon implementation of GCW, and the GCW acts as a hydraulic barrier in controlling saltwater intrusion in coastal aquifers. The present study reveals the GCWs system can effectively mitigate the saltwater intrusion problem in coastal regions and could be considered as one of the most efficient management strategies for controlling the problem.