Computer simulation of the steady-state flow system of the Tertiary limestone (Floridan) aquifer system in east-central Florida

The predevelopment steady-state ground-water flow system for 13 ,700 square miles of the Tertiary limestone aquifer system (known as the Florida aquifer in Florida) in east-central Florida is simulated by means of a digital computer model. The model results indicate that about 1,900 cubic feet per second recharges the aquifer as downward leakage from the surficial aquifer. The average recharge rate where recharge actually occurs (approximately 6,550 square miles) is about 4 inches per year. The maximum recharge rate is about 14 inches per year. An additional 21 cubic feet per second is recharged to the modeled area of the aquifer by means of lateral boundary inflow along the northeast boundary. The Floridan aquifer system, as simulated, discharges 1,300 cubic feet per second as springflow, 540 cubic feet per second as diffuse upward leakage to the surficial aquifer in an area of approximately 7,150 square miles and 81 cubic feet per second as lateral boundary outflow to the southwest and to the east. The average transmissivity of the upper unit of the aquifer, as simulated, is about 120,000 square feet per day while that for the lower unit is about 60,000 square feet per day. (USGS)