Computer modeling of the groundwater flow system underlying the Beach Point barrier beach was conducted to evaluate the potential for groundwater to flow toward, and discharge to, the East Harbor Lagoon under both existing conditions and with increased tidal flow to the lagoon. The elevation of the water table in the barrier beach fluctuates in response to tides in Cape Cod Bay. At high tide, water from the bay infiltrates into the barrier beach, causing the water table to rise. At low tide, groundwater drains from the barrier beach to the bay, lowering the water table. The amplitude of tidal fluctuation of the water table decreases with increasing distance from the bay.