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Completed Water Quality Improvement Projects

  • Aerial of the Tropical Farms STA
Page Updated: 
January 05, 2021 at 12:50 PM

What is a Stormwater Treatment Area?

Stormwater treatment areas (STAs) are constructed living wetlands divided into flow-through treatment cells that remove nutrients from agricultural and urban runoff water prior to discharging to our creeks and river. The nutrients are consumed through plant growth, and captured by accumulation of dead plant material that is slowly converted to a layer of peat soil. The flow-through system of the STA cleanses the water and assists the county in meeting state mandated water quality targets.

How it works: Agricultural and urban runoff water containing excess phosphorus and nitrogen is diverted to STAs that have been planted with a selection of native wetland vegetation with useful characteristics for water purification. These plants species absorb phosphorus and nitrogen, storing it in their roots, stems and leaves. In addition to filtering water, STAs serve as a storage basin to ensure water availability in times of drought, and provide valuable habitat for wildlife species.  

What is Hybrid Wetland Treatment Technology?

A Hybrid Wetland Treatment Technology (HWTT) system is designed to harness and integrate strengths of both wetland and chemical treatment technologies. The goal of HWTT systems is to provide the effectiveness and reliability of chemical treatment systems for phosphorus removal; to utilize wetland processes to effectively transform/remove additional contaminants such as nitrogen; and to provide environmental benefits via wetland and wildlife habitat restoration and creation. 

How it works: The facilities are comprised of both vegetated (primarily with floating and/or submerged plants) and non-vegetated zones. Chemical coagulants are added to the front-end of the process, which is equipped with one or more deep zones to capture and store the resulting chemical particles. The water then flows through the wetland portion of the system which further clarifies and treats the water prior to discharge to the estuary.


  • Willoughby Creek (2020)
  • Manatee Creek Phase II & III (2012)
  • Tropic Vista (2005)
  • St. Lucie Shores (2017) 
  • Old Palm City Phase III East (2012)
  • Coral Gardens (2005)
  • Hilltop Street (2017)
  • Old Palm City Phase III West (2012)
  • Fern Creek (2005)
  • Veteran's Memorial Bridge - Pond West (2016)
  • Warner Creek / Leilani Heights Phase II (2012)
  • Cedar Pointe (2004)
  • Veteran's Memorial Bridge - Pond East (2016)
  • Tropical Farms (2011) 
  • Golden Gate Phase III (2004)
  • Danforth Creek HWTT (2016)
  • Warner Creek / Leilani Heights Phase I (2010)
  • Old Palm City Phase I & II (2003)
  • Martin County Golf Course (2016)
  • Indian River Drive Baffle Boxes (2010)
  • Poinciana Gardens (2003)
  • Manatee Pocket SW Prong Baffle Box (2016)
  • Rio St Lucie Phase II (2008)
  • Salerno Creek Retrofit Phase I (2003)
  • Bessey Creek HWTT (2015)
  • Hibiscus Park Phase II (2007)
  • Golden Gate Phase I & II (2003)
  • Kitching Creek (2015)
  • Kitching Creek / Flora Ave (2007)
  • Palm Lake Park (2002)
  • Rio St. Lucie Exfiltration Trench 2014) 
  • Little Club Phase I & II (2007)
  • Hibiscus Park Phase I (2002)
  • Old Palm City Bee Mats (2013) 
  • Rio St Lucie Phase I (2006)
  • North River Shores Baffle Boxes (2001)
  • Warner Creek / Leilani Heights Phase III (2012)
  • Manatee Creek Phase 1 (2006)
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