S O U T H F L O R I D A W A T E R M A N A G E M E N T D I S T R I C T

Excess nutrients found in stormwater runoff pose a risk to the Everglades. These nutrients flow from lawns, farms, roadways and

other developed areas. Stormwater treatment areas are constructed wetlands that remove excess nutrients. They play a

vital role in protecting and restoring America's Everglades.

Rainfall is South Florida’s primary source of fresh water. It nourishes plants, fills ponds andseeps into the underground aquifer, replenishing the drinking water supply. In excess, it drainsaway in the canal system that protectsSouth Florida from flooding.

Stormwater runoff also carries nutrientsoff the landscape, especially fertilizersused in suburban, agricultural and urbansettings. Scientists have determined thata common ingredient in fertilizer, phos-phorus, has put the fragile Evergladesenvironment at risk. Phosphorus is amineral that is essential for all life. Itforms genetic material, builds bones andteeth and aids metabolism. But whenexcess phosphorus reaches natural wet-lands like the Everglades, it does moreharm than good.

ON THE INSIDE

n Phosphorus and itsimpact

n Investing in a solution

n “Green” technology atwork

n Meeting mandated goals

n Operating andmaintaining an STA

n Sustainability for thefuture

Everglades Stormwater Treatment AreasManaged wetlands improving water quality

Phosphorus and Its ImpactNutrient concentrations, particularlyphosphorus, were naturally ultralow in theEverglades. Its native wetland plants areadapted to this condition and thrive there.When a nutrient, such as phosphorus, entersthis ecosystem in excess, plant growth isstimulated, producing an overabundance ofundesirable vegetation. Cattail and otherspecies respond with vigor, crowding outnative wetland plants such as sawgrass andpreventing the sun’s rays from reachingplants in the water. When this happens,aquatic insects, crustaceans and otherinvertebrates do not have enough to eat orenough oxygen to live, which means the fishand birds do not have enough to eat either.

Investing in a SolutionThe State of Florida has invested more than$1.8 billion in water-quality improvementsaimed at lowering phosphorus levels. Twodecades ago, before these improvementswere put into place, phosphorusconcentrations in Everglades-bound watersaveraged more than 170 parts per billion(ppb). Today, as a result of Florida’s efforts,the concentrations in some discharges to theEverglades are as low as 12 ppb.Recognizing that more needs to be done toachieve the ultralow phosphorus waterquality standard established for theEverglades, the State is committingsignificant additional funding and resourcestoward implementing further strategies.

“Green” Technology at WorkFlorida’s Everglades Forever Act of 1994provided the momentum for this successstory to date. It mandated and fundedconstruction of treatment wetlands, knownas Stormwater Treatment Areas (STAs). Atpresent, 57,000 acres of land south of LakeOkeechobee have been converted to STAs. Inwestern Palm Beach County, STA-3/4, atmore than 16,000 acres, is the largestconstructed wetland in the world. And moreSTAs are on the way, along with additionalwater storage features designed to improveSTA performance.

Everglades Stormwater Treatment Areas use“green” technology to remove phosphorusfrom the water. Wetland plants, such as

cattail, southern naiad and algae, uptakephosphorus and use it in metabolic lifeprocesses. Phosphorus is stored in theirroots, stems and leaves. Even after the plantsdie, sediments in the wetland retainphosphorus from the decaying plant matter.As a result, water flowing out of an STA hassignificantly less phosphorus thanstormwater runoff flowing in.

By building STAs in key locations north ofthe Everglades, phosphorus in stormwaterrunoff can be reduced before it flows southinto protected wetlands. The South FloridaWater Management District’s regional canalsystem brings water to the treatmentwetlands and then carries it into theEverglades.

Meeting Mandated Goals forReducing PhosphorusThe Everglades Forever Act and other legalrequirements provided the District withspecific guidelines to improve Evergladeswater quality. A regulatory source controlcomponent required the implementation ofimproved farming methods to reducephosphorus amounts leaving the EvergladesAgricultural Area and the C-139 Basin.Another key component was the EvergladesConstruction Project, which provided forinitial construction of the STAs now inoperation. At most locations throughout theEverglades, the long-term targetconcentration of 10 parts per billion ofphosphorus is already being met.

In 2003, the Florida Legislature adopted theLong-Term Plan to provide for structural andvegetation enhancements to the STAs,including STA expansions completed in2006 and 2012. To further improve waterquality, in 2012, the State of Florida and theU.S. Environmental Protection Agencyreached consensus on additional EvergladesRestoration Strategies. The agreed-upontechnical plan includes more than 6,500acres of new treatment area and 116,000acre-feet of additional water storage.Expanded source controls will also beimplemented, and a science plan will ensurecontinued research to further improve STAperformance.

Stormwater treatment areasuse “green” technology to

remove excess phosphorus, anutrient that can harm theEverglades environment.

Plants are sometimes airlifted andreleased into an STA to help establishsubmerged aquatic vegetation.

Collecting and analyzing water samplesis vital to wetland management.

Wildlife in the WetlandsStormwater treatment areas are built specifi-cally for improving Everglades water quality.However, their vast, shallow waters and richplant life also make them outstanding habitatfor wildlife, including threatened and endan-gered species.

Wading birds, ducks and American alligatorsare found year-round in the treatment wet-lands. Migratory birds use them, too, visitingin abundance during winter months. Rabbits,bobcats, wild hogs, deer and the occasionalFlorida panther roam the banks and levees.

Because the STAs have a specialized cleansingfunction, public recreation is limited to activi-ties that do not disturb the water and soils.Visitors can enjoy nature viewing, and somefishing and hunting is allowed, under guide-lines of the Florida Fish and WildlifeConservation Commission.

Keeping the treatment wetlands healthy andundisturbed is vital for Everglades restoration.Enhanced wildlife habitat is a great bonus!

Operating and Maintaining an STAAn STA is a living wetland, affected by natural conditions such as weather (rainfall,drought, hurricanes), plant growth rates, wildlife and invasion of undesirable plantspecies. STAs have never before been used on the large scale now at work in theEverglades, so their operation and management is a process of ongoing learning andcontinual improvement.

Water quantity and water quality monitoring is a vital part of STA operations. Eachtreatment cell is monitored regularly to determine how the STA is performing.Operational decisions are then based on real-time data. STA performance data arecontinually assessed and are reported weekly, monthly and yearly. An annual summaryis available in the South Florida Environmental Report, viewable online atwww.sfwmd.gov/sfer.

Structural components of the STAs must be operated and maintained as well. Theseinclude more than two dozen pump stations, 350 water control structures and morethan 600 miles of levees and canals. Mechanical repairs, preventative maintenance,erosion control and debris cleanup are essential and ongoing tasks.

Responding to extreme weather is a large part of the job, too. In 2005, hurricane windsuprooted much of the aquatic vegetation in the STAs and stirred up sediments. Repairingthese living wetlands presented challenges, and the District has incorporated new designstrategies to help protect STAs during high wind and rainfall events. The District hasalso learned to deal with prolonged droughts by altering STA operation andincorporating more water pumping flexibility into STA designs.

Sustainability for the FutureProtecting Everglades water quality is a core mission responsibility and a strategicpriority. STAs will continue to play a vital role in this effort. Sustaining and improvingtheir effectiveness is essential. Continued construction, research and monitoring will helpoptimize the performance of water quality treatment technologies. The State of Floridaand the South Florida Water Management District remain committed to achievingoptimum phosphorus-reducing results.

Great egret

American alligator

Stormwater treatment areas are constructed wetlands that remove and store nutrientsthrough plant growth and the accumulation of dead plant material in a layer of sediment.

The South Florida Water Manage ment District is a regional, governmental agency that oversees the water resources in the southern half of the state. It is theoldest and largest of the state’s five water management districts.

Our Mission is to manage and protect water resources of the region by balancingand improving water quality, flood control, natural systems and water supply.

JW06/14

DID YOU KNOW?

n Plants that cleanse water instormwater treatment areasinclude emergent aquaticvegetation (EAV) like cattail,bulrush and spikerush.Submerged aquatic vegetation(SAV) examples include hydrilla,southern naiad and algae.

n Vegetation management is vitalto STA success. Some herbicidesare used to prevent invasivespecies from crowding out targetplants.

n Treatment wetlands are also usedin other parts of South Florida toimprove water quality. North andeast of Lake Okeechobee,treatment wetlands removenutrients from water flowing intothe lake, St. Lucie estuary andIndian River Lagoon.

n During the dry season, the STAsprovide important foraginghabitat for a wide variety ofwading birds and ducks.

n Birds found in the treatmentwetlands include roseatespoonbills, whistling ducks, whitestorks, little blue herons, eaglesand hawks.

Varying in size, configuration and period of operation, STAs are shallow, freshwater marshesdivided into treatment cells by interior levees, with water flows managed via pump stations, gatesor culverts. By building STAs in key locations north of the Everglades, phosphorus in stormwaterrunoff can be reduced before it flows south into protected wetlands. The Everglades StormwaterTreatment Areas collectively comprise 57,000 acres of effective treatment area.

For more information

Up-to-date information about STA research, enhancement projects and other componentsof managing and improving the stormwater treatment areas can be found atwww.sfwmd.gov/sta.

South Florida Water Management District3301 Gun Club RoadWest Palm Beach, Florida 33406561-686-8800 • 800-432-2045www.sfwmd.gov

MAILING ADDRESS: P.O. Box 24680West Palm Beach, FL 33416-4680

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