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controlling the waters

| EAA | STAs | WCAs | Control Structures |

Everglades Agricultural Area

map showing EAA, STA and WCA locations
Map showing location of the Everglades Agricultural Area (EAA), Stormwater Treatment Areas (STAs), and Water Conservation Areas (WCA).
In the 1850’s, the state of Florida was selling cheap land to anyone who could drain it. Drainage and dredging of the peat soils in the northern Everglades continued through the 1920’s. Hurricanes and flooding in 1926 and 1928 caused thousands of deaths and the implementation of the Central and Southern Florida (C&SF) water management project in 1948. As part of the C&SF Project, the U.S. Army Corp of Engineers (USACE) constructed about 1,000 miles of canals, levees, gates, dams and pump stations. These structures were designed to protect against flooding, to prevent saltwater intrusion, and to provide water for agricultural irrigation and drinking water supplies.

The C&SF Project identified 800,000 acres of the northern Everglades as an area for agricultural development. The lands were drained and called the Everglades Agricultural Area (EAA). The EAA lies to the southeast of Lake Okeechobee. Crop production in the EAA includes sugarcane, winter vegetables (tomatoes, peppers, cucumbers, eggplant, Chinese vegetables), citrus, sod, sweet corn and rice. Canals are used throughout the EAA for water supply and flood control purposes. The four primary canals within the EAA are the Miami, North New River, Hillsboro and West Palm Beach Canals.

The Everglades Agricultural Area impedes the historic flow of water to the Everglades and adversely affects water quality. Soil subsidence, and fertilizers, pesticides, and insecticides found in agricultural runoff all contribute to decreased water quality.

To address phosphorus levels in "downstream" waters of the Everglades, the Everglades Forever Act (1994) mandated the construction of Stormwater Treatment Areas (man-made wetlands designed to remove excess nutrients from the water). The South Florida Water Management District (SFWMD) was directed to construct these STAs downstream from the primary canals of the EAA. The SFWMD will manage the STAs for optimal removal of nutrients and will restore historic sheet flow into tens of thousands of acres of the Everglades.

The Everglades Forever Act also mandated that farmers reduce phosphorus levels by 25 percent. While the farming community is meeting and exceeding the 25 percent phosphorus reduction, high levels of nitrogen still exist. These high levels of nitrogen produce algal blooms and decrease the amount of sunlight needed by submerged aquatic vegetation and coral reefs to survive.

Take a look at some of the agricultural activities found within the Everglades Agricultural Area.

A photo gallery is available for this page. [Photos taken December, 1999 and April, 2000]

Lake Okeechobee's Herbert Hoover Dike

IPIX - Herbert Hoover Dike  
This view brings us on top of Lake Okeechobee's Herbert Hoover Dike along State Road 715, about 2 miles south of Palm Beach County Glades Airport. Agricultural fields are on one side of the dike and Lake Okeechobee's Rim Canal is on the other side.

Navigate around this 360° view atop Lake Okeechobee's Herbert Hoover Dike.

  IPIX image of Lake Okeechobee's Herbert Hoover Dike, Rim Canal and agricultural fields
Note: You will need the free IPIX viewer to view this 360° image  

IPIX - Herbert Hoover Dike  
Stand atop Lake Okeechobee's Herbert Hoover Dike along US 27/80, about 2 miles southeast of Clewiston, and enjoy the sunny day. Sugarcane fields can be seen on one side of the dike. Turn and see Lake Okeechobee and some artificial islands on the other side.

Navigate around this 360° view from the top of Lake Okeechobee's Herbert Hoover Dike.

  IPIX image of Lake Okeechobee's Herbert Hoover Dike, artificial islands, and sugarcane fields
Note: You will need the free IPIX viewer to view this 360° image  

photo of dead melaleuca trees on artificial islands
[larger image]
Dead Australian melaleuca trees atop some artificial islands near Lake Okeechobee's shore. Australian melaleuca was introduced to Florida in the early 1900's. It now dominates the stands in which it grows and is moving in on many native plant communities.

The US Army Corps of Engineers (USACE) originally planted the Australian melaleuca trees on islands just inside the Herbert Hoover Dike. Due to their invasive nature, the USACE is killing the trees with pesticides and later clearing the dead trunks away.

Agricultural Water Management
A ditch excavation near the intersection of State Road 80 and Duda Road (top) shows muck soils overlying limestone bedrock. Limestone ditch spoils sit atop the muck layer (bottom).

Most farmers rely on these dark, rich, mucky soils for crop production. However, agricultural water management practices alternately cover and expose these soils and when muck is dry, it oxidizes and shrinks. Everglades Agricultural Area (EAA) soil subsidence rates have averaged about one inch per year. To reduce soil subsidence rates, recent water management practices involve elevated water tables to reduce oxidation.

Due to soil subsidence, it is predicted that agricultural practices in the EAA will diminish over time.

photo of ditch excavation site
[larger image]

photo of soil profile at ditch excavation site
[larger image]

photo of culverts lying in excavated ditch
Culverts lying in excavated ditch. [larger image]
Culverts are used to transport water from one location to another.

Related SOFIA Information

Below we have listed science projects and publications for studies that are being conducted, or have been conducted, in the vicinity of the Everglades Agricultural Area. Follow these links to read about each project and to see project-related publications and data.

Science Projects:

Related Publications:



U.S. Department of the Interior, U.S. Geological Survey, Center for Coastal Geology
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Last updated: January 15, 2013 @ 12:44 PM (HSH)