Management of seawater intrusion in unconfined coastal aquifers

Abstract

This work presents a new methodology to control seawater intrusion in coastal aquifers using artificial surface recharge. The proposed method is based on a combination of abstraction of saline water near shoreline and recharge of aquifer using surface ponds. The efficiency of this method is investigated in terms of quality and cost by comparing its results with another different scenario of groundwater management using continuous abstraction only in the hypothetical aquifer. The variable density flow and solute transport model, SUTRA, is used to simulate this aquifer system in both 2D and 3D under steady state conditions. A Simple Genetic Algorithm as optimization tool is integrated with simulation model to search for optimal solution of each scenarios of seawater intrusion control. The main objectives of these models are to minimize the total cost of management process and the total salt concentration in the aquifer. The total cost is defined as the sum of capital and operational costs of the abstraction and recharge wells. The results show that the proposed system performs significantly better than using abstraction alone as it gives the least cost and least salinity in the aquifer.