Everglades Water Quality

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To see the glory of pristine water quality, you must view the water through the shoots and roots of native Everglades flora.


The beauty of water quality for the Everglades often escapes the human eye. It is very much unlike the beauty of the feathered Snail Kite or the secretive marsh bird. To see the glory of pristine water quality, you must view the water through the shoots and roots of native Everglades flora.

Historically, pre-drainage, the Everglades was one contiguous marsh network expanding from north of Lake Okeechobee down to Florida Bay. The Everglades developed under nutrient and mineral poor conditions and the plant life adapted to thrive under these conditions. With the invasion of man and their desire to convert the marsh lands into something habitable by mankind, they scored deep trenches through the peat down into the limestone underlying much of the Everglades, forming vast canals that would bleed off the water and deliver it to the surrounding ocean. Once it was determined that the lands were dried enough, farming practices would quickly follow. After decades of considerable tinkering, these farms would become bountiful and crop yields would become the new riches of the land, but at an extreme cost to those native plants.

Runoff from these farms became loaded with nutrients and minerals – the exact opposite of the conditions the native plants adapted to over centuries to millennia. Vegetation species that never had to compete for real estate would now be threatened by nutrient hungry species, such as the infamous cattail who would quickly gobble up real estate from the less competitive plant life, such as sawgrass, yellow-eyed grass, hatpins, banana water lily, and many more. These native species are the basis for establishing habitat for the expansive variety of animals in the Everglades.

Fortunately, people heard the cries of the Everglades vegetation communities and rose to the challenge of protecting the degrading habitats. Together with the Department of Justice and the U.S. Army Corps of Engineers, managers from the Arthur R. Marshall Loxahatchee National Wildlife Refuge (Refuge) and Everglades National Park (Park) led a charge to enforce existing water quality standards. But it would take more than another decade before we agreed on a path forward to fix the problem. The solution, outlined in the settlement of a federal lawsuit, was the most expensive and comprehensive restoration effort in history, calling for the state to implement several measures to improve the quality of water delivered to the Everglades. These measures include: establishing a strict water quality standards; developing and enforcing on-farm regulations to reduce nutrient runoff also known as best management practices; and building large-scale treatment wetlands to filter nutrients out of the water prior to delivery to the Everglades.

After almost a decade of research, scientists determined that periphyton (a complex mixture of algae and detritus that serves as the base of the Everglades food web) composition was adversely impacted at surface water phosphorous concentrations greater than 10 part per billion (ppb). The federal and state governments incorporated this 10 ppb as the strict water quality standard for surface water total phosphorus concentrations in the Everglades. However, interpretation and application of this standard would be unique for the various areas of the Everglades, particularly the Refuge and the Park.

Best management practices (BMP) have been developed and are currently in use in farms throughout South Florida. In general, these BMPs require farmers to reduce nutrient loss to runoff through activities such as recycling stormwater and using left-over nutrients. The BMPs for the Everglades Agricultural Area (adjacently situated west of the Refuge) are considered for the entire basin and requires an annual 25% reduction in total phosphorus loads delivered to the Everglades. By mid-2014, these BMPs have resulted in about 55% reduction in total phosphorus loads and more than 2,800 metric tons have been reduced since mid-1996.

The original goal of constructing 45,000 acres of large-scale treatment wetlands, or Stormwater Treatment Areas (STA), was accomplished in early 2004. To further protect the Everglades, since 2004 the original STAs have been expanded and now comprise approximately 57,000 acres across five unique treatment areas. Two of the STAs directly discharge water to the Refuge. The other three generally supply water to areas west and south of the Refuge and these waters ultimately pass down into the Park. In most recent years, the STAs have been delivering total phosphorus at concentrations ranging from 15 to 22 ppb. The success of these systems has resulted in more than 1,800 metric tons of total phosphorus removed from water delivered to the Everglades since late 1993.

Although these three tools have been in place for almost two decades and have shown considerable success, the quality of the water being delivered to the Everglades has not been reduced to levels that protect the habitats of the sensitive Everglades ecosystem. To address this challenge, the STAs are currently being expanded by another 6,500 acres. In addition to this expansion, new water quality targets for the STAs have been established to protect the downstream ecosystem. The goal is to achieve these targets by 2024.