Key West Parks
The Everglades began to be known after the US and Seminole Wars of 1835-42. The area started to change once Florida entered the Union in 1845 and Congress passed the Swamplands Act of 1850. This act authorized the transfer of 20 million acres to Florida for the purpose of drainage and reclamation.
The flood of 1903 devastated the crops in south Florida and caused considerable damage to farms in the region. Napoleon Bonaparte Broward was elected for Governor in 1905 and started the Everglades drainage project at once. In order to fund and manage the project, the legislature created the Everglades Drainage District in 1907. By 1917, four major muck canals crossed the Everglades from Lake Okeechobee to the Atlantic Ocean. The Everglades Drainage District also constructed 47 miles of sand and muck levee around the southern rim of Lake Okeechobee. The construction of the Tamiami Trail, which linked Miami with Naples, was the next major change in the area between 1915 and 1928.
Two devastating hurricanes struck the region in 1926 and 1928, claiming over
2500 lives and over $75 million in damage. Following the Mississippi River and
Tributaries Act of 1928, attention shifted from Everglades drainage to
controlling flooding around Lake Okeechobee. In 1930, the
US Army Corps of Engineers became a major participant with
In 1935, the Labor Day hurricane hit Matecumbe Key in the upper Florida Keys with an 18-foot surge and altered the ecology of the coastal portions of the Everglades. The Everglades National Park was established in 1947 to preserve and protect the southern section of the Florida Everglades. In 1947 and 1948, two major hurricanes hit the Everglades again. In one year 108 inches of rain fell and millions of acres of land were under water for up to 6 months.
Congress authorized a massive endeavor called the for Flood Control and Other Purposes in 1948. The project intended to lower water tables by 4-5 ft east of the Lake Okeechobee protective levee. It was designed and constructed by the Corps of Engineers. The Central and Southern Florida Flood Control District (whose successor is today's was the local sponsor of the project and was in charge of the operation and maintenance of the facilities built for the project .
In 1952, the first task for the Central and Southern Florida Project was the construction of a series of 9 to 18 ft high perimeter levees and borrow canals that stretched from Palm Beach to Dade County. The next step, in 1954, was to secure the western and northern boundaries of the Water Conservation Areas, which consist of 1372 square miles and install pumps in order to hold the water on the surface and control the amount of water discharged to the Everglades National Park and Dade County. That same year, about 1,100 square miles of swamp and marsh were enclosed by a levee to prevent overflowing from Lake Okeechobee and make the land suitable for agriculture ). This area was called the Everglades Agricultural Area
Around 120 square miles of mangrove swamp were destroyed on September 10, 1960, when Hurricane Donna crossed the Florida Keys with winds of 140 mph and a storm surge of about ten feet.
The Corps of Engineers transformed the Kissimmee River (102 miles) into a 56 mile canal in the 1960s. This change led to the deterioration in the quality of the water and the destruction of close to 40,000 acres of wetlands.
On August 24, 1992, Hurricane Andrew hit South Florida. It had a path of heavy impact of about 30 miles wide and winds of over 150 mph. Initially, the surveys indicated massive defoliation of coastal mangrove swamps (70,000 acres were demolished) and extensive damage to virtually all tall hammock trees in its path. Approximately 90 percent of the pines in Andrew's path had died, within a year, due to their weakened condition
The rocks beneath the Big Cypress Swamp are among the oldest in South Florida. Six million years ago a shallow sea covered this area. Sediments of silt and sand and particles of calcium deposited on the bottom of this sea gradually cemented into limestone. Today this rock is called the Tamiami Formation.
The Tamiami Formation is also found in the northwest corner of Everglades National Park. Here, fresh water flowing out of Big Cypress mixes with salt water from the Gulf of Mexico in a highly productive mangrove estuary. The resulting nutrient-rich soup supports a marine nursery for pink shrimp, snook, and snapper.
Other rocks beneath the Everglades were formed during the time of the Great Ice Age. Although no glaciers developed in Florida, their effects were felt here. As glaciers in other areas of the world expanded, much of the earth's water supply was trapped in the ice. Sea levels in South Florida lowered as much as 300 feet below present levels.
The Great Ice Age was actually four shorter ice ages with periods of warming in between. During these warmer "interglacial" stages, the ice melted and returned to the sea. The last interglacial stage occurred about 100,000 years ago. At its peak, the sea level in South Florida rose 100 feet above present levels.
The rocks beneath the southeast section of the Park were formed in this sea. Calcium carbonate settling out of the water coated tiny bits of shell or sand in layer upon layer. The resulting spherical grains of limestone are called ooids. The Atlantic Coastal Ridge which runs from Mahogany Hammock northeast to Miami was formed as long shore currents pushed the ooids up into a long ridge. The ooids later cemented into rock known as Miami Oolite. Miami Oolite also covers most of the area east of Everglades National Park and most of Florida Bay.
In quieter waters covering the central portions of the Park, tiny moss animals called Bryozoans flourished. As they died their calcium skeletons settled to the bottom. These sediments later cemented into rock known as the Miami Bryzoan Limestone.
As in most areas of South Florida, subtle changes in elevation result in dramatic changes in vegetation communities. Pine forests are found on the high ground of the Atlantic Coastal Ridge. Where fire has been excluded, pines give way to hardwood hammocks. In wetter areas near the end of the ridge, dwarf pond cypress grow. South of the ridge sawgrass prairies take over again. A narrow band of mangroves fringe the southeast coast, and the shallow waters of Florida Bay today provide an abundant food supply for great numbers of wading birds.
The Everglades used to cover over four million acres of South Florida. This area has been reduced by more than 50 percent. The Everglades has been through many changes, some due to natural factors but most changes have been a result of man's interaction. As a result of the 1,400 miles of canals and levees, 150 gates and spillways, and 16 pumping stations constructed in the 1950s and 1960s, the natural hydrologic cycle in the Everglades has been seriously altered. These modifications altered the ecology and created a shortage of water in the Everglades. In addition to reducing the wet areas for the fish, this reduction of water also means a smaller head exerting pressure against seawater, which leads to the reduction of the Biscayne aquifer and the closing of some wells due to salt contamination These man-made impacts have severely altered the ecosystem having negative effects on fish, waterfowl, wading birds, vegetation, and other natural resources. The wading bird populations of the park have decreased by about 90 percent and the alligator population has also decreased in a significant amount. The Florida panther is now an endangered species with only about 20 known survivors. The Everglades, Big Cypress Swamp, and developing regions of south Florida are the only places in the world were there are any Florida panthers left. Some other endangered or threatened animals include the American crocodile, West Indian manatee, snail kite, wood stork, and five species of sea turtles. A fast growing weed, cattails, is replacing the sawgrass and other native plants in some parts of the Everglades due to the higher level of phosphorous originated from fertilizer in the water draining from agricultural fields (mainly sugar cane and vegetable fields) south of Lake Okeechobee. The Everglades is also contaminated with mercury.
In the last 10 years, 68,000 acres of seagrasses have died in Florida Bay due
to saline conditions.