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.

COMPLETED STORMWATER QUALITY IMPROVEMENT PROJECTS

PROJECT

YEAR

Willoughby Creek

2020

St. Lucie Shores 

2017

Hilltop Street

2017

Veteran's Memorial Bridge - Pond West

2016

Veteran's Memorial Bridge - Pond East

2016

Danforth Creek HWTT

2016

Martin County Golf Course

2016

Manatee Pocket SW Prong Baffle Box

2016

Bessey Creek HWTT

2015

Kitching Creek

2015

Rio St. Lucie Exfiltration Trench

2014

Old Palm City Bee Mats

2013

Warner Creek / Leilani Heights Phase III

2012

Manatee Creek Phase II & III

2012

Old Palm City Phase III East

2012

Old Palm City Phase III West

2012

Warner Creek / Leilani Heights Phase II

2012

Tropical Farms

2011

Warner Creek / Leilani Heights Phase I

2010

Indian River Drive Baffle Boxes

2010

Rio St Lucie Phase II

2008

Hibiscus Park Phase II

2007

Kitching Creek / Flora Ave

2007

Little Club Phase I & II

2007

Rio St Lucie Phase I

2006

Manatee Creek Phase 1

2006

Tropic Vista

2005

Coral Gardens

2005

Fern Creek

2005

Cedar Pointe

2004

Golden Gate Phase III

2004

Old Palm City Phase I & II

2003

Poinciana Gardens

2003

Salerno Creek Retrofit Phase I

2003

Golden Gate Phase I & II

2003

Palm Lake Park

2002

Hibiscus Park Phase I

2002

North River Shores Baffle Boxes

2001