Guide to user modification of a three-dimensional digital ground-water model for Salt Lake Valley, Utah

A digital-computer model was calibrated to simulate, in three dimensions, the ground-water flow in the principal and shallow-unconfined aquifers in Salt Lake Valley, Utah. The model can be used to predict water-level and waterbudget changes that would be caused by changes in well recharge or discharge. This report shows how a user can revise the input data so that recharging or discharging wells may be simulated and how stress-period intervals can be varied to simulate different periods of recharge or discharge.