Position of the saltwater-freshwater interface in the upper part of the Floridan Aquifer, southwest Florida, 1979

Ground-water withdrawals in southwest Florida are increasing because of urban growth, industrial expansion and increased agricultural irrigation. As a result, the potentiometric surface of the Floridian aquifer has been lowered in some areas, allowing seawater to encroach into the aquifer and threaten the freshwater resources of the area. Effective management of groundwater is needed to control the encroachment and protect the freshwater aquifer.