PUMP-AND-TREAT OPTIMIZATION USING WELL LOCATIONS AND PUMPING RATES ASDECISION VARIABLES

A new optimization formulation for dynamic groundwater remediation man agement is developed by simultaneously using well locations and the co rresponding pumping rates as the decision variables. The genetic algor ithm is applied to search for optimal pumping rates and the discrete s pace of well locations. The optimization model is applied to hypotheti cal, three-dimensional, contaminated aquifer systems with homogeneous and heterogeneous porous media properties. Optimal well locations and pumping rates obtained with the moving-well model are less expensive t han solutions obtained with a comparable fixed-well. model. Optimizati on with a linear objective function formulation identifies some of the optimal well locations obtained with a nonlinear formulation but resu lts in higher pumping rates than the nonlinear formulation and ignores the higher drawdowns produced in low-permeability areas. Optimal well locations are found along the mass centerline of the contaminant plum es and in high-permeability areas in the heterogeneous system. Dynamic pumping rates and well locations produce more cost-effective solution s relative to a static model. The well location search path and conver gence behavior indicate that the genetic algorithm is an effective alt ernative solution scheme and that well location optimization is more i mportant than pumping rate optimization.