The Everglades are a subtropical wetland located in the southern portion of the U.S. state of Florida, comprising the southern half of a large watershed. The system begins near Orlando with the Kissimmee River, which discharges into the vast but shallow Lake Okeechobee. Water leaving the lake in the wet season forms a slow-moving river 60 miles (97 km) wide and over 100 miles (160 km) long, flowing southward across a limestone shelf to Florida Bay at the southern end of the state. The Everglades are shaped by water and fire, experiencing frequent flooding in the wet season and drought in the dry season. Writer Marjory Stoneman Douglas popularized the term "River of Grass" to describe the sawgrass marshes, part of a complex system of interdependent ecosystems that include cypress swamps, the estuarine mangrove forests of the Ten Thousand Islands, tropical hardwood hammocks, pine rockland, and the marine environment of Florida Bay.

Human habitation in the southern portion of the Florida peninsula dates to 15,000 years ago. Two major tribes eventually formed in and around Everglades ecosystems: the Calusa and the Tequesta. After coming into contact with the Spanish in the late 16th century, both tribes declined gradually during the following two centuries. The Seminoles, a tribe of Creeks who assimilated other peoples into their own, made their living in the Everglades region after being forced there by the U.S. military in the Seminole Wars of the 19th century. Draining the Everglades was first suggested in 1848, but was not attempted until 1882. Canals were constructed throughout the first half of the 20th century, and spurred the South Florida economy, prompting land development. However, problems with canals and floods caused by hurricanes forced engineers to rethink their drainage plans. In 1947, Congress formed the Central and Southern Florida Flood Control Project, which built 1,400 miles (2,300 km) of canals, levees, and water control devices. The South Florida metropolitan area grew substantially at this time and Everglades water was diverted to cities. Portions of the Everglades were transformed into farmland, where the primary crop was sugarcane. Approximately 50 percent of the original Everglades has been turned into agricultural or urban areas. When the construction of a large airport was proposed 6 miles (9.7 km) north of Everglades National Park, an environmental study predicted it would destroy the South Florida ecosystem. Restoring the Everglades then became a priority.

National and international attention turned to the environment in the 1970s, and UNESCO and the Ramsar Convention designated the Everglades as one of only three wetland areas of global importance. Restoration began in the 1980s with the removal of a canal that straightened the Kissimmee River. The water quality of Lake Okeechobee, a water source for South Florida, became a significant concern. The deterioration of the environment was also linked to the diminishing quality of life in South Florida's urban areas. In 2000, a plan to restore the Everglades was approved by Congress; to date, it is the most expensive and comprehensive environmental repair attempt in history. The Comprehensive Everglades Restoration Plan was signed into law, but the same divisive politics that had affected the region for the previous 50 years have compromised the plan.

Origin of the word

.The first written record of the Everglades was on Spanish maps made by cartographers who had not seen the land. They named the unknown area between the Gulf and Atlantic coasts of Florida Laguna del Espíritu Santo ("Lake of the Holy Spirit"). The area appeared on maps for decades without being explored. Writer John Grant Forbes stated in 1811, "The Indians represent [the Southern points] as impenetrable; and the [British] surveyors, wreckers, and coasters, had not the means of exploring beyond the borders of the sea coast, and the mouths of rivers".

British surveyor John Gerard de Brahm, who mapped the coast Florida in 1773, called the area "River Glades". Both Marjory Stoneman Douglas and linguist Wallace McMullen suggest that cartographers substituted "Ever" for "River". The name "Everglades" first appeared on a map in 1823, although it was also spelled as "Ever Glades" as late as 1851. The Seminoles call it Pa-hay-okee, meaning "Grassy Water", and the region was labeled "Pa-hai-okee" on an American military map in 1839, although it appeared as "Ever Glades" throughout the Second Seminole War.

Geology

The geology of South Florida, together with a typical subtropical climate of warm, wet features, provides conditions well-suited for a large marshland ecosystem. Layers of porous and permeable limestone create water-bearing rock, soil, and aquifers that affect the climate, weather, and hydrology of South Florida. The properties of the rock underneath the Everglades can be explained by the geologic history of the state. The crust underneath Florida was at one point part of the African region of the supercontinent Gondwana. About 300 million years ago, North America merged with Africa, connecting Florida with North America. Volcanic activity centered around the eastern side of Florida covered the prevalent sedimentary rock with igneous rock. Continental rifting began to separate North America from Gondwana about 180 million years ago. When Florida was part of Africa, it was initially above water, but during the cooler Jurassic Period, the Florida Platform became a shallow marine environment. Through the Cretaceous Period, most of Florida remained a tropical sea floor of varying depths. The peninsula has been covered at least seven times by seawater since the bedrock formed.

Climate

The climate of South Florida is noted for its variability, as average annual temperatures range from 60 °F (16 °C) to 80 °F (27 °C). Temperatures in summer months typically exceed 90 °F (32 °C), although coastal locations are cooled by winds from the Gulf of Mexico and the Atlantic Ocean. Freezing in winter months occurs with varying severity and frequency. The region's subtropical to tropical climate features a 7-month wet season from April through October, when 75 percent of precipitation is related to tropical cyclones and thunderstorms. Only 25 percent of the annual precipitation falls during the dry season from November to March, usually sparked by cold fronts tracking southward. Annual rainfall averages approximately 62 inches (160 cm), with the Eastern Coastal Ridge receiving the majority of precipitation and the area surrounding Lake Okeechobee receiving about 48 inches (120 cm).

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