Georgia-Florida Coastal Plain Study Unit Description
The Georgia-Florida Coastal Plain study unit includes five major river basins draining into the Atlantic Ocean and the Gulf of Mexico, and covers an area about 61,000 square miles. The population of the study unit was nearly 11 million in 2000. Population growth has been rapid—the populations of several major cities in the study unit increased from 10 to 30 percent between 1990 and 1999. Large quantities of water are used in the study unit to meet the demands for agricultural and public water supplies. Approximately 3 billion gallons per day (BGD) of groundwater were withdrawn in the study unit in 2000. More than 90 percent of the groundwater withdrawals came from the highly productive Floridan aquifer system, which is composed of a thick sequence of carbonate rocks that underlies 87 percent of the study unit.
The majority of the urban areas in the study unit are located in central and northern Florida, including the three largest cities, Tampa, Orlando, and Jacksonville. All three of these cities rely on the Floridan aquifer system for drinking water, as do most of the people living in the study unit. Although there is much water-quality data available for the Floridan aquifer system (especially in Florida), the suite of constituents studied has not been large and generally does not include trace elements, pesticides or VOCs. In addition, past sampling efforts have been targeted toward monitoring wells and not the types of wells from which most people get their drinking water. The GAFL study unit is participating in several NAWQA studies to address groundwater quality issues for drinking water, including "Source water-quality assessments" of community supply wells and the topical study "Transport of contaminants to supply wells."
Mercury bioaccumulation is an important topic throughout the study unit because of the numerous fish consumption advisories issued by Georgia and Florida authorities based on mercury concentrations. The GAFL study unit is participating in the NAWQA topical study "Bioaccumulation of mercury in aquatic ecosystems" to address this issue.
The land uses of significance within the study area include forest, agriculture (citrus and row crops), wetlands, urban, and rangeland. Forest areas, much of which are in silviculture, cover approximately 48 percent of the study area. Much of the forest lands are softwood pines used to manufacture paper products (facial tissue, toilet paper, hand towels, bags, and boxes). Agricultural areas account for nearly 28 percent of the study area, are concentrated in several areas, and include growing of field crops, fruits (including citrus), vegetables and cattle, dairy and poultry operations.