Combining genetic algorithms and boundary elements to optimize coastal aquifers’ management

A common problem in coastal aquifers’ management is maximization of groundwater extraction rate without saltwater intrusion. To this end, i.e., to optimize layout of a number of wells and distribution of total flow rate to them, a computational procedure has been developed, combining an optimization and a flow simulation tool. The optimization code is based on genetic algorithms. The respective evaluation function includes numerical simulation of an “equivalent” depth-integrated groundwater flow, by means of a boundary element code. Observance of the main constraint, i.e., zero water inflow through the coast, is checked using the sign of flow rate values at the coastal boundary elements. Validity of this approach is checked with the help of an analytical solution and the balance between accuracy and simplification is discussed. Applications of the proposed method to a coastal aquifer with two zones of different transmissivities, investigating the role of form and magnitude of the penalty function in the optimization process and demonstrating the efficiency of the proposed computational procedure, conclude the paper.