The largest constructed treatment wetland project in the world: The story of the Everglades stormwater treatment areas

Abstract

The Everglades Stormwater Treatment Areas (STAs) are the largest complex of constructed treatment wetlands in the world with a current treatment area of over 25,000 ha which will total approximately 25,900 ha by the end of 2025. They are designed to remove phosphorus from agricultural and urban stormwater runoff, and when there is available capacity, they can also receive and treat water from Lake Okeechobee. STA-treated water is then sent south to the Everglades to support restoration and maintenance of this unique ecosystem. The recommendation to build treatment wetlands began in 1988 with the Lake Okeechobee Technical Advisory Committee, and the mandate to operate and maintain the STAs continues today through operating permits and consent orders issued to the South Florida Water Management District (SFWMD) by the Florida Department of Environmental Protection. The permits and consent orders set forth a stringent phosphorus water quality-based effluent limit (WQBEL) that must be met starting in 2026. SFWMD has conducted extensive research on treatment wetland function and phosphorus removal efficiency to support construction, management, and operation of the STAs to achieve the WQBEL. The most recent work has been conducted under the Restoration Strategies Science Plan. This 11-year research program began in 2013 and will continue through 2024 to address six key scientific questions aimed at assisting the SFWMD in meeting the WQBEL for discharges from the Everglades STAs. What follows in this Special Edition are articles discussing the results and conclusions from several of these studies.