Sensitivity analysis in aquifer studies

A method is presented for determining in which areas detailed knowledge of aquifer characteristics and conditions is most critical to the success of a management plan. These questions are answered by using sensitivity analysis to determine how variations in parameters and input data affect the optimal solution of a linear programing management model. The model uses either finite element or finite difference approximations of the groundwater equations as constraints. The optimal locations and discharge rates of wells were determined for dewatering a rectangular area to a specified level while minimizing steady state total pumping rate. The area is in a small aquifer having constant head boundaries. Sensitivity analysis showed that the optimal steady state solution is most sensitive to hydraulic conductivity at and near the aquifer boundaries parallel to the length of the dewatered area. Thus field exploration and testing should be concentrated on determination of hydraulic conductivity in those areas.