A slow moving sheet of water. The Everglades is a shallow freshwater river a few inches to a few feet deep and 50 miles wide that creeps seaward on a gradually sloping riverbed. The river flow clocks in at a mellow quarter mile a day. Along its long course, the river drops 15 feet, finally emptying into Florida Bay and the Gulf of Mexico. Sawgrass covers most of the interior; the Everglades is often called the "river of grass." A fringe of mangrove forest defines the edge where sea and fresh water meet along the coast.
Higher ground, inches above the moving water, holds unique plant communities. Hammocks, which are groves of hardwood trees growing on slightly elevated limestone mounds, are small islands surrounded by marshland. Larger expanses of high ground, more subject to the occurrence of wildfires, support fire-dependent pine forest, a remnant of a forest once extending well into Dade County. Most of it was destroyed as Miami grew.
Warmed by the subtropical climate of south Florida, the river is a soup of algae and bacteria that sustains larger life forms such as insects, fish, mollusks, turtles, and snakes. These, in turn, support such predators as wading birds, alligators and panthers.