Optimal management of a theoretical coastal aquifer with combined pollution and salinization problems, using genetic algorithms

Abstract

The paper discusses optimal management of a theoretical coastal aquifer, providing water for drinking and/or irrigation purposes, which is threatened by seawater intrusion from the coast and by non-conservative pollutant plumes from the inland. A new computational tool, able to address the combined pollution-salinization problem, is used. It optimizes the classic Pump-And-Treat and Hydraulic Control techniques without compromising aquifer's sustainability. Οptimization entails minimization of pumping, pipe network construction and pumped polluted water's remediation costs. Practically, the goal is: find the best distribution of total required flow rate to existing wells and the best locations and flowrates of additional abstraction wells, in order to protect the aquifer with minimal management costs. The respective objective function includes a complex penalty function. The optimization technique used is a binary genetic algorithm including elitism. In order to maintain a reasonable balance between computational volume and accuracy, a simplified equivalent 2D groundwater flow field is simulated by a boundary element method, while advective mass transport (pollution spread and seawater intrusion) is simulated by a particle tracking code.