Cape May County, New Jersey, is on a natural peninsula that is virtually surrounded by saltwater. A calibrated quasi-three-dimensional sharp-interface model was used to simulate ground-water flow in the shallow aquifer system under two water-supply-development alternatives for a 30-year planning period. The alternatives involve modest increases in withdrawals in combination with desalination of brackish ground water or inland relocation of wells. Simulation results indicate that projected withdrawals for the two alternatives can be sustained without significant additional saltwater encroachment over the planning period.