As sea level rose and fell over millions of years, the Florida Platform, wrenched from Africa when the Atlantic Ocean opened, has been covered by numerous layers of sediment; these deposits have since solidified into a mosaic of limestone formations, which vary in composition and porosity. Over time, these rocks have been sculpted by tropical rains, hurricanes, waves, rivers and invading arms of the sea; deeper, porous layers have become aquifers while harder, surface formations define the modern landscape.
The Everglades ecosystem, which includes Lake Okeechobee, has developed within the past 6000 years, well after man had settled parts of the peninsula; indeed, archaeological records indicate that he had reached Cuba by 7000 years ago. Fed by the Kissimmee River and a number of smaller streams, Lake Okeechobee formed in a broad, shallow basin, which spills southward onto a flat plain; the latter, bordered by higher ridges to the east and west, dips gradually toward Florida Bay, at the southern edge of the State. During the wet season (June to November) the Lake would overflow onto this plain and a shallow "river," sixty-miles wide, would move steadily toward the coast, covering the 100 mile distance in 200 days or more.
This produced the Everglades ecosystem, with its vast expanse of sawgrass and isolated hammocks of pine, palm and subtropical hardwoods; these woodlands occupy islands of higher terrain where hard sediments have resisted erosion.
World renowned for its fabulous scenery and diverse wildlife, the Everglades have been under constant siege since white settlers colonized the State. Water diversion, fire suppression and pollution have all taken a toll. Today, Lake Okeechobee, the natural source of this River of Grass, is ringed by a levee, controlled by floodgates and choked with pollutants (primarily from agricultural lands to the north). Though recovery efforts continue, it may be too late to fully restore this fragile ecosystem.
