SENSITIVITY ANALYSIS OF FLOW IN MULTILAYERED LEAKY AQUIFER SYSTEMS

The sensitivity of drawdown prediction to the uncertainty in estimatin g the hydraulic properties of multiple leaky aquifer systems is studie d by first-order sensitivity analysis. A new set of dimensionless para meters is suggested to reduce the amount of sensitivity coefficient ca lculations. The procedure is illustrated for three aquifer configurati ons pumped by one well: one aquifer with impermeable boundaries (Theis case), one aquifer with two aquitards, and two aquifers with one aqui tard. The results allow one to assess the relative contribution of unc ertainty of each hydraulic property on the accuracy of predicting draw down and to reduce the number of parameters that influence uncertainty . The methodology and results may be employed when margins of confiden ce of the predicted drawdown are needed.