Featured Treatment Wetland Projects
The Great Swamp Effluent Management System includes 400 acres of riverine hardwood swamp forest for final polishing of over 3 mgd of highly treated municipal effluent. This system works in concert with land application areas to provide year-round effluent management options in this water-quality limited coastal area. The natural wetland treatment system is the only available and affordable option in this rapidly developing area to deal with wet weather disposal. WSI has provided consulting services to the Beaufort-Jasper Water and Sewer Authority on this project since original conception. WSI has directed or participated in planning, design, construction, and continues to provide monitoring and permitting services.
WSI is conducting a multi-phase project for GRU to demonstrate the feasibility of using constructed treatment wetlands as a means of further polishing reclaimed water while providing a reuse alternative that recharges groundwater levels. While this project uses reclaimed water as a source, rather than stormwater, this project has been designed to demonstrate the use of treatment wetlands in karst environments. The Infiltrating Wetlands Demonstration Project has been implemented to compare the denitrification capacity and infiltration rates in wetlands dominated by emergent vegetation, open water ponds, and traditional rapid infiltration basins (RIBs). WSI provided design guidance and construction oversight for the project and has conducted monitoring and data analysis at the Kanapaha Middle School (KMS) and the Kanapaha Water Reclamation Facility (KWRF) wetlands. GRU’s long-term goal is to diversify their reclaimed water system by constructing large-scale infiltrating wetlands that provide reliable and beneficial disposal capacity with water quality that is more protective of the region’s springs and aquifers.
Lake Hancock is a large, highly eutrophic lake in Polk County that discharges to Saddle Creek. Saddle Creek flows to the Peace River (a surface water drinking source) and ultimately to Charlotte Harbor. The Lake Hancock Outfall Treatment Wetland project includes the design, permitting, and construction of a large-scale (1,000-acre) wetland that will reduce the annual nitrogen load to Saddle Creek. WSI assisted in development of the conceptual plan and feasibility assessment to treat the highly eutrophic water from Lake Hancock. WSI evaluated the wetlands hydraulics and hydrology, estimated inflows and nutrient loads, determined potential effects to down-stream flows, calculated nutrient (N and P) mass removal expectations, and estimated downstream water quality with respect to Class III water quality standards. WSI also provided engineering review to the prime consultant regarding inflow and outfall structures, grading plans, and berm structures. WSI conducted a detailed site assessment of the 1,500+ acre site regarding habitat mapping, wetland delineation, and wildlife survey. WSI conducted a vegetation establishment study and developed the full-scale wetland planting plans and specifications. WSI is currently providing as-needed services during construction, especially as related to wetland grading and plant establishment.
WSI assisted Gainesville Regional Utilities, the City of Gainesville Public Works Department, and managers from Paynes Prairie Preserve State Park to improve water quality and meet a nitrogen TMDL in Sweetwater Branch, an urban stream that discharges stormwater and highly treated reclaimed wastewater to Paynes Prairie and Alachua Sink. To improve water quality and hydrologic conditions on Paynes Prairie, WSI prepared a conceptual plan and process design for a 125-acre enhancement wetland that will capture and treat flows from Sweetwater Branch and re-establish sheetflow of polished water to the northern edge of Paynes Prairie. The work performed by WSI included development of recommended allowable nutrient levels for re-establishment of desirable herbaceous wetland plant communities; a conceptual layout for a multi-compartment treatment wetland that will provide operational flexibility and facilitate access for public recreational activities such as hiking and bird watching; calculation of existing nutrient and pollutant loads delivered to Paynes Prairie from the Sweetwater Branch watershed and maximum flows that could be diverted from Sweetwater Branch to the enhancement wetland that would maintain compliance with the proposed nutrient levels; estimation of nutrient assimilation that will naturally occur within the Sheetflow Restoration Area (1,300 acres) such that average background nutrient levels (estimated at 1.4 mg/L total N and 0.1 mg/L total P) would be achieved before the sheetflow water reaches Alachua Sink; environmental and wetland data collection for support of the project Environmental Resource Permit; development of the final planting plans and specifications; and senior review of construction plans prepared by others.
WSI designed a 4.6-acre treatment wetland to improve cooling water discharge quality from a biomass-fueled power generating facility in Liberty County, FL. The wetland was designed to lower effluent copper and ammonia concentrations and to reduce temperature differences between the cooling water and receiving stream. In parallel with the design effort, WSI also developed and permitted a mitigation plan to enhance and preserve existing on-site forested wetlands to compensate for construction of the treatment system in an area that included disturbed shrub wetlands.
WSI designed a 6-acre, tidally-influenced treatment wetland to improve the quality of stormwater runoff that discharges to King's Bay in Crystal River, Florida. The project was envisioned to provide water quality benefits while also enhancing wildlife habitat value and creating opportunities for education and passive recreation. The wetland project is one component of an overall master plan to convert the 57-acre Three Sisters Springs parcel to a preservation area with nature trails, an interpretive center, and overlooks for manatee viewing in the springs.
The Beltway 8 Stormwater Treatment Wetland encompasses 220 acres and is located northeast of the Houston, Texas metropolitan area. This project is part of the Greens Bayou Wetland Mitigation Bank and serves the dual purpose of water quality enhancement and wetland habitat creation. The project incorporates a treatment “train” of processes that include an initial surge basin, two polishing ponds, four polishing marshes, and a large area of natural-appearing wetland habitats. High pollutant treatment efficiency has been recorded through operational monitoring, while wildlife use and habitat diversity are outstanding. WSI has provided consulting services to the Harris County Flood Control District on this project since original conception and assisted with project planning, design, construction, and operational monitoring.
WSI has participated in many of the large-scale reservoir and stormwater treatment area (STA) projects in South Florida. WSI provided modeling and design assistance for full-scale projects such as the C-43 Storage Reservoir, C-44 Reservoir/STA, Taylor Creek STA, Nubbin Slough STA (including the expansion), Ten Mile Creek Reservoir/STA, and STA-3/4. WSI authored a design criteria manual for the implementation of STAs in the Northern Lake Okeechobee Watershed. WSI staff are proficient in using the DMSTA model and have provided modeling support for a number of District/USACE projects including the Lake Okeechobee Watershed Project, Compartment C Build-out (STAs 5 and 6), Everglades Agricultural Area storage reservoirs, Lakeside Ranch STA, and Caloosahatchee and St. Lucie reservoirs. In addition, WSI staff worked with Dr. Bill Walker (co-author of the DMSTA model) to compile reservoir and treatment wetland data sets to upgrade DMSTA calibration parameters and expand the model's utility for watersheds with higher inflow phosphorus concentrations. WSI prepared an independent analysis of operational data from STA-1E for the U.S. Army Corps of Engineers. This work included the preparation of period-of-record water and phosphorus mass balances and estimation of phosphorus removal rates. Follow-on work included an analysis of potential remedial actions that could be taken to improve water quality performance. WSI staff were part of the project team for the District's Periphyton Based Stormwater Treatment Area (PSTA) and Managed Wetlands Treatment System projects. WSI's Dr. Knight was the principal investigator for research and development of the PSTA technology. WSI prepared a conceptual plan, sampling plans, and construction cost estimate for mesocosm-, test cell-, and field-scale natural treatment system facilities to investigate nitrogen removal dynamics in the C-43 basin (C-43 Water Quality Test Area Project).