To understand what the Everglades is today, you need to know what it once was. The pristine Everglades was a wetland that spanned the state of Florida south of Lake Okeechobee, about 2.9 million acres of mostly peatland covered by tall saw-grass growing in shallow water. When the lake was full, water overflowed into the northern Everglades and moved slowly to the south in a 50-mile-wide sheet, a foot deep. In the 1880's people began to drain the Kissimmee River-Lake Okeechobee-Everglades watershed. Drainage exposed the organic muck soil, which produced extraordinary crop yields.
The last 100 years have seen tremendous change in the Everglades. Water is controlled by a complex management system that includes canals, levees, and pumps. The region is divided into the Everglades Agricultural Area (the world's largest zoned farming area), three Water Conservation Areas, and Everglades National Park. The Everglades has been called "the biggest artificial plumbing system in the world."
Today more than 50 percent of the historic Everglades has been eliminated. Widespread population growth and land-use modification in Florida affect the quantity and quality of drinking water, alter natural wetlands, and increase human exposure to hydrologic hazards, such as floods. More than 1,400 miles of drainage canals and levees have altered the Everglades wetlands in Florida for flood control. These agricultural, industrial, and urban areas affect water quality in southern Florida. Farming involves the use of numerous chemicals, including fertilizers, insecticides, herbicides, and fungicides, that leak into the ground water or nearby surface waters. Stormwater runoff from urban areas commonly transports heavy metals and nutrients into canals and the Biscayne aquifer.