The Water Channel
Video and Multimedia
The Changing Everglades
Learn how the quest for farmland and a dependable water supply and flood protection forever changed the Everglades.
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Lake Okeechobee and Phosphorous
Learn why Lake Okeechobee is polluted by contaminants in stormwater runoff that flows into the lake.
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Everglades Stormwater Treatment Areas
Learn how phosphorous and other pollutants are removed from the water through a natural process utilizing aquatic plants in the Everglades Stormwater Treatment Areas.
Learn About Your Watershed
Everglades Watershed
Watershed and River Basin Stats
Size of Basin: Historically, the Everglades covered about 2,560,000 acres or about 4,000 square miles from the south shore of Lake Okeechobee to the mangrove estuaries of Florida Bay. Today's Everglades Protection Area comprises 863,200 acres in Water Conservation Areas 1, 2A, 2B, 3A, and 3B, 64,000 acres in the Holey Land and Rotenberger Wildlife Management Areas and more than 1.5 million acres in Everglades National Park, which includes most of Florida Bay.
Major Towns: Belle Glade, Pahokee, Flamingo, and Chokoloskee
Counties: Palm Beach, Hendry, Broward, Dade, Monroe, and Collier
Major Water Features: Water Conservation Area 1, also known as the Arthur R. Marshall Loxahatchee National Wildlife Refuge; Water Conservation Areas 2A, 2B, 3A, and 3B; West Palm Beach, Hillsboro, North New River, and Miami Canals; and Everglades National Park including Taylor Slough, Shark River Slough, and Florida Bay
Overview
The Everglades, also known as the Everglades Protection Area, is a unique national resource. Historically extending from Lake Okeechobee to Florida Bay, it is the largest and most important freshwater, subtropical peat wetland in North America. The Everglades consists of sawgrass prairies, mangrove and cypress swamps, pinelands, and hardwood hammocks, as well as marine and estuarine environments. The varying water depths, diverse habitat types, and abundant food across the Everglades attract large populations of wading birds and threatened and endangered species, including wood storks, snail kites, bald eagles, Florida panthers, and American crocodiles.
The Everglades ecosystem evolved in response to low concentrations of nutrients, particularly phosphorus, and seasonal fluctuations of water levels. The primary source of nitrogen and phosphorus was rainfall. Natural disturbances, such as fire, drought, and infrequent frosts, also shaped the Everglades' ecosystem structure.
To meet the growing water needs of agriculture and people, the Everglades Drainage District established three water conservation areas (WCAs 1, 2, and 3) in 1945. Bounded by levees and connected by a series of canals, the WCAs were placed under the jurisdiction of the South Florida Water Management District (SFWMD). These large tracts of land under public ownership provide multiple benefits, including flood protection, water supply storage, and environmental resource protection. Present flow patterns in the Everglades are controlled by managing the WCAs, pumping agricultural and urban areas, and using drainage canals in urban areas to the north and east.
The Everglades is the largest and most important freshwater wetland in North America.
WCA-1, a 143,200-acre area owned by the state and managed by the U.S. Fish and Wildlife Service, encompasses most of the Arthur R. Marshall Loxahatchee National Wildlife Refuge. The refuge is located west and southwest of West Palm Beach. Additional lands in the Loxahatchee Refuge, but outside WCA-1, include the 1,604-acre Strazzulla Marsh to the east and about 2,550 acres to the east and west.
Covering 134,400 acres, WCA-2 is the smallest of the WCAs. Situated directly south of WCA-1, it stretches over parts of southern Palm Beach and northern Broward Counties. Historically, this area was part of the overland flow system that extended from Lake Okeechobee to Florida Bay.
WCA-3 is over twice the size of WCA-1 and WCA-2 combined. Covering 585,600 acres in western Broward and Dade Counties, it is located west and southwest of WCA-2 and extends approximately 40 miles from north to south and 25 miles from east to west. Currently, it is the only WCA not entirely enclosed by levees. The L-28 Gap, a seven-mile stretch left open in the midwestern perimeter, permits overland flows to enter the area from the Big Cypress National Preserve and other drainage basins to the west.
Historically, WCA-3 was hydrologically linked to the other WCAs and ENP, as part of the overland flow system that extended from Lake Okeechobee to Florida Bay. During this time, it received most of its water from local rainfall and overland surface flow from the northern portions of the Everglades and the Big Cypress Basin to the west.
Everglades National Park (ENP), created in 1947, forms the southernmost portion of the greater Everglades system. The park's original boundaries contained 460,000 acres; however, subsequent expansions have increased its size to the current 1,509,000 acres, including most of Florida Bay. Historically, the primary sources of water to this area were overland flow from the northern Everglades and Big Cypress marshes to the west and from rainfall. The WCAs and ENP were designated as Outstanding Florida Waters in 1978.
The Everglades Agricultural Area (EAA), comprising about 741,120 acres, is situated just northwest of WCA-1. This important regional economic resource includes sugarcane farms, winter vegetable and sod farms, and cattle ranches.
Human Impacts
Only about 50 percent of the original, historical Everglades ecosystem currently remains. Human activity and land use changes have altered water flow throughout the Everglades. Significant modifications to the movement and storage of water in the region occurred between the late 1800s and 1975, when Florida adopted nutrient water quality standards for state surface waters, including the Everglades. In the late 19th and early 20th centuries, local and state drainage districts drained large portions of the Everglades and converted them to agricultural and urban uses.
Authorized by the Flood Control Act of 1948 and modified by subsequent acts, the massive Central and Southern Florida (C&SF) Project was designed to improve flood control and drainage and to serve other purposes for both central and southern Florida. As part of the project, the federal government constructed a comprehensive infrastructure of levees, canals, and water control structures, and exotic tree species such as melaleuca were introduced to help drain the region. These modifications significantly altered natural water quantity and the distribution and timing of flows. Water that reached the Everglades became increasingly loaded with nutrients and contaminants with concentrated discharge points, and excessive amounts of fresh water were lost to tide.
In WCA-1 (Loxahatchee National Wildlife Refuge), constructing and operating the C&SF Project has significantly affected the area's hydrology, vegetation, and wildlife. In WCA-2, levee construction beginning in the early 1960s eliminated the natural sheetflow pattern that created the unique Everglades system. Levees now entirely enclose WCA-2.
In the late 19th and early 20th centuries, large portions of the Everglades were drained and converted to agricultural and urban areas. Only about 50 percent of the original Everglades remains.
The construction of levees encircling WCA-3 began in the 1950s and was completed in 1962. Hydrologic alterations to WCA-3 have resulted from several interior canal systems, which further compartmentalize the area. These include the Miami Canal, which traverses WCA-3 from the northwest (Lake Okeechobee) to the southeast (Miami); the L-67A levee, which runs southwestward from the eastern boundary toward ENP, forming the boundary between WCA-3A and WCA-3B; and the Alligator Alley borrow canal, which crosses the northern half from east to west.
Due to the use of fertilizers by local farmers and soil subsidence, the EAA is a large source of phosphorus to the Everglades. The land east of WCA-1 is predominantly urban, except for the agricultural lands in the East Coast Buffer area.
Overall, these changes in land use and hydropattern, a growing demand for water, and the introduction of excess nutrients to the Everglades have resulted in ecological changes over extensive areas of the Everglades marsh. The impacts have been observed in several trophic levels, including microbial, macrophyte, and vertebrate communities. Wildlife changes have resulted from numerous factors, including direct hunting and specimen collecting, vehicle road kills, direct loss of habitat (e.g., land development, introduced species), and large changes in the character of the habitat.
In recognition of these impacts, DEP, the SFWMD, U.S. Army Corps of Engineers (USACOE), and local governmental, scientific, educational, and citizen organizations are working to develop strategies for protecting and restoring water quality and quantity in the Everglades watershed.
Interesting Facts:
- The Everglades is the largest and most important freshwater, subtropical peat wetland in North America.
- The original area of almost 8.9 million acres, extending from the lakes and marshes of central Florida southward to Florida Bay, was composed of interconnected wetlands. Four million of those acres were known as the Everglades.
- The Kissimmee watershed, in central Florida, forms the headwaters of the Kissimmee-Okeechobee-Everglades system.
- Florida Bay, which lies between the southern edge of the Everglades and the Florida Keys, is a large, shallow, subtropical estuary covering about 850 square miles. It is the largest estuary in Florida and the largest waterbody within Everglades National Park.
- At least 22 commercially or recreationally important aquatic species are known to use Florida Bay as a nursery ground.
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Copyright 2009 Florida Department of Environmental Protection