Optimal design of pumping networks in coastal aquifers using sharp interface models

Abstract

A method for optimal design of pumping networks in coastal aquifers based on genetic algorithms and numerical solution of the governing differential equations of freshwater flow, is developed. The objective is to optimize the well locations subject to constraints that protect the aquifer from saltwater intrusion. Two are developed. The first is based on simultaneous optimization of well locations and pumping rates using genetic algorithms (GA). The second method follows two stages where the first stage concerns optimization of well locations and the second stage concerns optimization of pumping rates. The last method uses GA for searching the well positions and at each generation of GA, a simpler optimization with respect to the pumping rates is performed using nonlinear programming. The formulation of the constraints is based on numerical simulation of freshwater flow equations obtained from the sharp interface and the Ghyben–Herzberg approximations and the single potential formulation of Strack. The optimization methodologies are applied effectively for determining the optimal design of a pumping network and assessment of pumping rates in an island coastal aquifer.