This research concerns with optimal utilization of unconfined coastal aquifers under different constraints. This problem is a complicated, nonlinear, and constrained one. Therefore, the Genetic Algorithm nonlinear optimization method was selected to handle the present problem. Analytical solution was applied for the groundwater flow equation under assumption of steady sharp interface in homogenous aquifer. Image theory and the superposition principle were the main tools used through the analytical procedure. A Fortran program was written to apply the mathematical concepts of the problem. The method was applied to aquifer system underlain the City of Miami Beach at north of Spain.