A digital-computer model for estimating drawdowns in the sandstone aquifer in Dane County, Wisconsin

A digital-computer program was developed to compute nonsteady and steady-state hydrologic changes caused by pumping from a confined aquifer. The program computes head changes in the confined aquifer and the rate and volume of water withdrawn from aquifer boundaries.

The program was used to model the sandstone aquifer underlying Dane County, Wisconsin. The aquifer was modeled as a confined aquifer recharged by leakage from the overlying upper aquifer. The physical properties of the aquifer system needed for the model were approximated using aquifer-test data and by matching drawdowns resulting from aquifer development through 1970 with draw-downs computed by the model.

The sandstone aquifer should be able to supply the water needs of Dane County well beyond 1990. Maximum regional drawdowns of approximately 40 feet (12 m) between 1970 and 1990 were computed by the model. This amount of additional drawdown would not seriously deplete the ground-water supply.