Sensitivity analysis of flow in multilayered leaky aquifer systems

The sensitivity of drawdown prediction to the uncertainty in estimating the hydraulic properties of multiple leaky aquifer systems is studied by first-order sensitivity analysis. A new set of dimensionless parameters is suggested to reduce the amount of sensitivity coefficient calculations. The procedure is illustrated for three aquifer configurations pumped by one well: one aquifer with impermeable boundaries (Theis case), one aquifer with two aquitards, and two aquifers with one aquitard. The results allow one to assess the relative contribution of uncertainty of each hydraulic property on the accuracy of predicting drawdown and to reduce the number of parameters that influence uncertainty. The methodology and results may be employed when margins of confidence of the predicted drawdown are needed.