Simulated changes in potentiometric levels resulting from groundwater development for phosphate mines, west-central Florida

• Published in: Journal of hydrology (Amsterdam) Vol. 43; no. 1; pp. 491 - 515
• Main Authors: Wilson, William E., Gerhart, James M.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.1979
• Subjects: Florida, United States
• ISSN: 0022-1694; 1879-2707
• DOI: 10.1016/0022-1694(79)90189-6

A digital model of two-dimensional groundwater flow was used to predict changes in the potentiometric surface of the Floridan aquifer resulting from groundwater development for proposed and existing phosphate mines during 1976–2000. The modeled area covers 15,379 km 2 in west-central Florida. In 1975, groundwater withdrawn from the Floridan aquifer for irrigation, phosphate mines, other industries and municipal supplies averaged about 28,500 l/s. Withdrawals for phosphate mines are expected to shift from Polk County to adjacent counties to the south and west, and to decline from about 7,620 l/s in 1975 to about 7,060 l/s in 2000. The model was calibrated under steady-state and transient conditions. Input parameters included aquifer transmissivity and storage coefficient; thickness, vertical hydraulic conductivity, and storage coefficient of the upper confining bed; altitudes of the water table and potentiometric surface; and groundwater withdrawals. Simulation of November 1976 to October 2000, using projected combined pumping rates for existing and proposed phosphate mines, resulted in a rise in the potentiometric surface of about 6 m in Polk County, and a decline of about 4 m in parts of Manatee and Hardee counties.