1974). Acquisition for and management of lands within the National Reserve 

 are the responsibility of the National Park Service. 



Water Regimes 



The Big Cypress Area has unique natural features. Its watershed is a 

 major hydrologic unit characterized by a low-lying, poorly drained, sand and 

 limestone flatland. The elevation ranges from mean sea level to 7.6 to 9.0 m 

 (25 to 30 ft), but most of the area is below 4.6 m (15 ft) in elevation. 

 Slopes range from 0.2 to 0.5 ft per mile north to south and 0.3 ft per mile 

 east to west, and are covered with extensive areas of standing and slowly 

 moving water during the wet season. Much of the area consists of marshes, 

 strands, and sloughs (Florida Department of Administration 1973). 



The Big Cypress Area is one of the Everglades National Park's primary 

 water sources. Any further urban development of the Big Cypress A'^ea would 

 reduce the vital southward flow to the park and potentially pollute the water 

 with pesticides, sewage, and other wastes. During the rainy season the area 

 soaks up water like a giant sponge. The runoff flows into the park, but much 

 of the rain recharges the shallow aquifer on which Collier County depends for 

 its freshwater supply. Nutrient levels in nearby estuaries are partly depen- 

 dent upon the runoff from the Big Cypress Area and unusually severe interrup- 

 tions or changes in flow could damage fish or shellfish nursery and fishing 

 grounds (Blake 1980). 



The shallow aquifer of Southwest Florida is the primary source of potable 

 groundwater for the Big Cypress Area and urban and agricultural use in adja- 

 cent areas. Sometimes saltwater intrusion occurs inland of coastal areas 

 during dry years, so it is important to maintain the Big Cypress Area's capac- 

 ity for shallow aquifer recharge. 



The water resources of the Big Cypress Area also provide other natural 

 habitats. The sloughs, hammocks, and cypress-domes are inhabited by nearly 

 all wildlife species native to semi tropical Florida, as well as nine threat- 

 ened or endangered species. Estuaries of the Big Cypress Area and the adjacent 

 Everglades National Park are important as natural resources because they com- 

 prise the single most important commercial and sport fishing nursery grounds 

 in the State of Florida and they provide recreation, particularly boating and 

 fishing, for millions of residents and tourists (Florida Department of Admin- 

 istration 1973). 



Urban Development and Drainage 



The conversion of agricultural or undeveloped land to residental, commer- 

 cial, or industrial urban uses replaces valuable natural habitats and usually 

 alters the quantity, quality, and flow of water in the area. Drainage canals 

 lower ground and surface water levels because they are designed to drain a 

 site for urban or industrial construction. Canals form artificial water 

 tables that tend to reduce the natural storage capacity of the aquifers. The 

 seriousness of the effects of canal drainage is dependent upon the location, 

 size, and design of the canal. In some areas canal drainage has increased the 

 incidence of forest fires. 



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