Alachua County Sweetwater/Paynes Prairie Sheetflow Restoration
Paynes Prairie Preserve State Park in Alachua County, Florida, became Florida’s first State Preserve in 1971 and is widely known as a world-class wetland. The Prairie has been designated an Outstanding Florida Water as well as a Florida Natural and Historical Landmark. Stormwater runoff from the City of Gainesville, Paynes Prairie’s closest neighbor, has had a marked effect on the water quality and quantity of the Prairie’s wetlands and lakes.
In combination with a long history of ranching operations that included the construction of extensive drainage canals, pollution from the Gainesville urban area flowing downhill in Sweetwater Branch onto the Prairie Basin has contributed to the alteration of Paynes Prairie’s wetland and aquatic plant communities. Alachua Sink, a natural lake within Paynes Prairie, is considered an impaired water body, and FDEP has established a regulatory TMDL that requires nitrogen discharging to this lake to be reduced from all sources. The Sweetwater Branch/Paynes Prairie Sheetflow Restoration Project presents a unique opportunity to rectify these problems while providing additional wildlife habitat, wildlife viewing, and public recreation opportunities.
Two primary goals were addressed by the Sheetflow Restoration Project. Goal Number 1 was to satisfy the nitrogen-load reductions from the Main Street Water Reclamation Facility and urban stormwater to Sweetwater Branch as part of the TMDL requirements for the Alachua Sink. Goal Number 2 was to restore the rehydration mechanisms of Paynes Prairie to their natural condition. These goals are being met by:
- Eliminating low-quality water in Sweetwater Branch from flowing directly to Alachua Sink and the Floridan aquifer.
- Restoring the hydroperiod of over 1,300 acres of formerly impacted wetlands through environmental reuse of wastewater effluent and stormwater treatment.
- Achieving regulatory TMDL requirements for the City of Gainesville for nitrogen in a cost-effective way.
- Removing trash and debris from water discharging to Paynes Prairie.
- Reducing sediment load from Sweetwater Branch.
- Restoring part of the overall water balance to Paynes Prairie.
- Creating approximately 125 acres of wetland wildlife habitat.
- Providing public access with a Visitors Center.
- Naturally assimilating nutrients, sediments, and other pollutants to
- Protect Paynes Prairie and the Floridan aquifer.
A secondary benefit of the project is the public-access element that includes a network of walking trails, boardwalks, and elevated berms integrated throughout the stormwater treatment mechanisms. Other public amenities include a Visitors Center, a security residence and classroom facilities (all with associated utility services), and numerous shade pavilions and viewing towers. The design entailed developing detailed site grading plans for a project footprint of over 250 acres and more than 1 million cubic yards of combined excavation and embankment, coordination of architectural designs and design of electrical and mechanical systems associated with the three on-site buildings with a target of LEED Gold certification, and use of low-impact development stormwater controls. An extensive hydrologic and hydraulic modeling was performed to develop tools for the design and operation of stormwater conveyance, wetland treatment system, and sheetflow restoration.