This plateau dissolves slowly in the acidic groundwater, so that over time a network of solution cavities, conduits, and sinkholes has developed. Submarine springs occur with enormous frequency around the edges of the peninsula where ground water exits the coastline. Within the peninsula, sinkholes and freshwater springs appear as surface expressions of limestone dissolution in acidic groundwater. More than 8,000 lakes can be found from Pensacola to Miami, Florida. This submarine discharge is on the order of a small river, such as the Narragansett River, Rhode Island, or Pearl River, Mississippi.
Several factors contribute to the rate of groundwater discharge along a coastline.
Hydraulic head can be defined in general terms as the change in elevation of a water body along a given distance. Transmissivity usually controls horizontal flow and is based on the relationship between soil and rock hydraulic conductivity and the saturated thickness of the aquifer. Another factor affecting groundwater flow is the vertical intrinsic permeability of overlying soils and sediments, which directly influences the magnitude of groundwater recharge. Discharge measurements, obtained as subsurface fluids exit the sediments along a shoreline, represent the effective flow rate across the sediment- water interface. Groundwater discharge and associated pollutants could be particularly important to Florida estuaries because of widespread urban development, the occurrence of large and productive aquifer systems, a long coastline, extensive precipitation, and high permeability of the karst terrain that underlies the Florida platform.