Beneficial water reuse project serves southwest Florida
To address decade-long concerns of groundwater depletion, Pasco County (Fla.) Utilities and the Southwest Florida Water Management District developed a reclaimed water project, known as the 4G Ranch Wetlands. This multifunctional project, constructed on privately owned property and consisting of a 176-acre groundwater recharge wetland system built on uplands pastures, reverses groundwater drawdowns in areas affected by public water supply wellfields in Southwest Florida and is an important addition to the Pasco County Master Reuse System. The wetlands add a beneficial capability to an already flexible reuse system and successfully demonstrate an example of a public-private partnership between Pasco County, Southwest Florida Water Management District, and the Phillips Family, who owns the 4G Ranch.
The 4G Ranch Wetlands are designed to work in unison with a newly constructed, 500-million-gal reclaimed water reservoir to balance wet-weather supply and dry-weather demands. The system is sized to receive 5 million gal per day of advanced secondary reclaimed water to passively recharge the surficial and Floridan Aquifer Systems, the region’s drinking water supply, while protecting the water quality. In addition to the benefits to the aquifer and the regional water resources, the project is helping to restore the ecological functions of degraded regional lakes and wetlands, and create 176 acres of new wildlife habitat within the 15 constructed wetland cells.
The wetlands are an important component of the district’s objective to provide recharge in an area of hydrologic stress. Diverse wetland habitats were created by establishing a range of wetland ecotones that will be sustained naturally over the long term by ecologically appropriate and carefully controlled water-level operation. The grading and planting plans build on existing cell topography to minimize earthmoving and establish plant communities adapted to varying water depths within each cell. Species chosen for each zone in the project plans are based on water depths, such as floating aquatic species in deep zones, emergent wetland species in march zones, cypress trees in shallow zones, and transitional grasses along the berms at the waters’ edge.
Savings & Benefits
In addition to improving the natural environment of the area, the project’s life-cycle costs to Pasco County are approximately half of what a conventional system would have cost, making it an example of sustainable water management. The cost benefit considers cost-sharing opportunities and compares life-cycle costs to conventional infiltration systems, such as rapid infiltration basins and sprayfields that require constant maintenance. The construction cost for the 4G Wetlands project was approximately $14 million, shared between Pasco County and Southwest Florida Water Management District.
The 4G Ranch Wetlands is the first project of its kind undertaken by the Southwest Florida Water Management District or Pasco County. The natural wetlands in the area are expected to significantly benefit from the additional recharge with no discharge from the facility to surface wasters. The natural design of the wetland cells blend in with the natural environment, creating biological diversity and providing significant additional acreage of wildlife habitat. The wetland cells also naturally provide water quality improvement, including the removal of nitrate-nitrogen inherent in the reclaimed water, to protect groundwater and adjacent surface water quality. Water quality improvements occur through biological processes of wetland surface treatment and soil treatment as water infiltrates through the wetland subsoils protecting aquifer water quality.
Since 2010, CH2M, Pasco County Utilities and the Southwest Florida Water Management District have provided a full range of design, permitting, and services during construction for the 4G Ranch Wetlands. This reclaimed water project facilitates a more holistic watershed management approach by helping improve an area that has seen severe ecological degradation. The project recently received two accolades, Florida Water Environment Assn.’s 2016 David W. York Water Reuse Project of the Year Award and Tampa Bay Association of Environmental Professionals’ Environmental Excellence Award in 2017 for outstanding environmental contributions. It is intended to become a model for future facilities as a multifunctional system that addresses many regional needs associated with managing regional water resources. Additionally, the multifunctional 4G Wetlands are an example of how organizations can utilize public-private partnerships to maximize the benefits of water reuse, and use this valuable resource for its highest purpose: ecology and water supply.
The conceptual plan used to overlay existing ground topography within the cells with wetland plant communities to create a mosaic of different habitat ecotones.