publications > circular > Circular 1134 > the natural system > watersheds and coastal waters > big cypress watershed U.S. Department of the Interior U.S. Geological Survey Circular 1134 Environmental Setting-- The Natural System Watersheds and Coastal Waters Big Cypress Watershed The Big Cypress Watershed covers about 2,470 mi2 of southern Florida west of the Everglades and south of the Caloosahatchee River (fig. 1). The northern part of the watershed is poorly drained sandy flatlands. Much of this area is dotted with small, shallow circular ponds, which generally are less than a foot deep and several hundred feet in diameter. Altitudes in the watershed are highest on the Immokolee Rise (25-42 ft), a sandy ridge that was formed at higher sea levels and which now contains the divide that separates the Caloosahatchee River drainage from that of the Big Cypress. In the northwestern part of the watershed, water drains westward into Estero Bay. On the Immokolee Rise and to the south, the sandy flatlands are dissected by several drainage ways that include the Okaloacoochee Slough, the Devil's Garden, and the Corkscrew Swamp (fig. 17). The Okaloacoochee Slough extends southward about 50 mi from the vicinity of the Caloosahatchee River into the Big Cypress Swamp. Its average width is a little more than 2 mi. The Okaloacoochee Slough drains northward and southward from about the latitude of the Devil's Garden, a prong of the Slough that extends to the northeast. The Devil's Garden normally drains westward to the Okaloacoochee Slough, but in times of high water, it may overflow in all directions. The southern end of the Okaloacoochee Slough drains into the Fakahatchee Strand in the Big Cypress Swamp. Corkscrew Swamp, which begins near Lake Trafford and extends southwesterly, contains one of the last virgin cypress forests in north America. Some trees tower 130 ft and have a girth of 25 ft. Part of Corkscrew Swamp is a National Audubon Society Sanctuary. Figure 20. Cypress pine forests in the Big Cypress Swamp (top of page), and a generalized section of a cypress dome (above). (McPherson, 1974.) Click on image to open larger picture (28.8k). The Big Cypress Swamp lies south of the sandy flatlands and west of the Everglades. The swamp is characterized by an abundance of small, stunted cypress trees and by cypress trees of moderate size associated with depressions in the bedrock. Pine and hammock forests occur on land slightly higher than cypress forest land. Numerous ponds and cypress domes are in deeper water areas (fig. 20). Water levels fluctuate seasonally, and during prolonged droughts, water levels fall below even the deep ponds (fig. 20). Natural drainage is by slow, overland flow to the south. Well defined streams do not exist except along the southwestern coast where the swamp merges with the estuarine mangrove forest. The soil in the swamp is usually a thin (less than 2 ft) layer of marl, sand, or a mixture of the two or is absent where limestone is at the surface. Muck and peat, however, accumulate to depths of 3 ft or more in depressions in the bedrock (Davis, 1943). Next: Charlotte Harbor Watershed Go to top Return to Publications Page

U.S. Department of the Interior, U.S. Geological Survey
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