A quasi three-dimensional model was constructed to simulate the response of the Piney Point and Cheswold aquifers underlying Kent County, Delaware to ground-water withdrawals. The model included the Magothy, Piney Point, Cheswold, and unconfined aquifers, and was calibrated using historical pumpage and water-level data. Model calibration was accomplished through the use of both steady-state and transient-state simulations.

Water-level records from 13 observation wells in Delaware for the period July, 1966 - December, 1977 provide the bases for the analyses of water-level fluctuations. Water levels in shallow water-table wells generally rise from November to March, when recharge exceeds discharge, and decline during the warm growing season from May through September. Although water-levels in individual wells changed by as much as 11.17 feet during the 11.5 year period studied, the water-table system remained in a state of dynamic equilibrium and exhibited no permanent changes in aquifer storage.

A two-dimensional digital model was developed to simulate the effects of increased pumping on the Piney Point aquifer in Kent County, Delaware. The calibrated digital model was used to predict water-level declines as the aquifer responded to both changes in the distribution and increases in the quantity of pumping to the year 2000.

The hydraulic properties of the Piney Point (Eocene) aquifer and overlying basal silt of the Chesapeake Group (Miocene) were determined by a 23-day aquifer test conducted at the Danner Farm Well Field of the City of Dover, Delaware. During the test, head changes were monitored continuously in the Piney Point aquifer, overlying Cheswold (Miocene) aquifer, and the intervening confining bed.