Wetlands have many benefits, including flood mitigation, habitat restoration and the treatment of both wastewater and stormwater to within National Pollutant Discharge Elimination System (NPDES) limits. They are a form of green infrastructure that is both effective and ecologically friendly.
Wetlands have many ecological benefits. Full of natural vegetation and rich soil, wetlands provide habitat for birds, amphibians, fish, insects and more. Their natural sedimentation, filtration and biological activity treat the water within the wetland. In addition to these treatment capabilities, they serve as temporary storage to reduce flooding on downstream creeks, streams, rivers and properties during wet weather events.
Control Water Quantity and Quality Through Green Infrastructure
Sanitary Wastewater
At Camp Otterbein in Logan, Ohio, B&N evaluated alternatives and developed a green design to replace a 40-year-old extended aeration system. The system did not remain within NPDES permit limits throughout the year due to the seasonal nature of wastewater loading from the camp. The selected alternative was a green solution that created a treatment process using a new activated sludge pretreatment system with flow equalization, aerated sludge holding and a constructed wetland polishing cell. This system complies with NPDES permit limits to accommodate rapid loading fluctuations from the youth camp and retreat center. Additional benefits included lower operating costs and a natural setting that matches the outdoor appeal of the camp.
Acid Mine Drainage
The 62-acre sub-catchment area of Wills Creek Lake in Coshocton County, Ohio, had contributed to a serious decline in aquatic habitat potential in the receiving waters of the lake due to acid mine drainage (AMD) accumulation. B&N’s solution to improving this water quality included consolidating and capping more than 10 acres of coal spoil and treating AMD from multiple deep mine seeps. To accomplish this, B&N used green tactics, including land reclamation, water diversion and aerobic wetland treatment. In the second year of operation, the pH increased from an acidic 2.9 to a more neutral 8.3 at the wetland outflow and demonstrated a corresponding decrease in iron concentration. This allowed wetland vegetation to return to its natural state, benefitting the ecosystem in the area.
Before/After photos of Wills Creek Lake
Landfill Leachate
The 32-acre Stonewall Cemetery Road Landfill closure included installing seven wetland cells to treat leachate-impacted groundwater extracted from the trenches that were downgradient from the landfill waste. B&N selected this green alternative instead of the traditional method (pumping to the municipal wastewater treatment plant) as a cost-saving option for the City of Lancaster, Ohio. The completed wetland system effectively treats ammonia and metals – the primary constituents of concern.
Stormwater Runoff
The Big Darby Creek is a designated National Wild and Scenic River with an exceptional warm-water aquatic habitat. The Flat Branch is a significant tributary to the Big Darby Creek and passes through a large manufacturing complex in Central Ohio. B&N studied the 13.7-square-mile watershed of the industrial complex, including 16 sub-watersheds and 13 privately-owned stormwater management facilities,
Using this information, B&N developed green infrastructure improvements for water quality and quantity control that would reduce flooding within the manufacturing campus and the downstream neighbors, while also enhancing the Flat Branch water quality. Improvements included:
- A 6.4-acre constructed wetland that receives and treats stormwater from a conventional retention basin at the facility
- An 11-acre pond and wetland system with a forebay, constructed wetland cell, and stream diversion that intercepts incoming agricultural runoff to reduce stream flows and remove sediment, nitrogen and phosphorus from the flow
- A naturalized stream floodplain wetland area that reduces the force of flows from an existing stormwater retention facility that was not meeting current design standards for water quantity and quality
Infrastructure That Serves as Habitat
Half of all endangered species rely on wetlands for habitat. In the last 200 years, more than 90% of Ohio’s wetlands have been destroyed. Using green infrastructure like wetlands helps restore habitat and protect delicate ecosystems. B&N has worked with Columbus and Franklin County Metro Parks to restore more than 1,000 acres of wet prairie, swamp forest, and associated upland habitats in the Battelle Darby Creek Metro Park. Metro Parks has targeted species to return to the Darby Creek Region, and B&N has helped support this goal using habitat restoration techniques for the creation of over 1,000 acres of vernal pools, forested wetlands, deep pools wet prairie and associated upland habitats. These green infrastructure improvements protect ecosystem balance by reducing runoff rates from these former agricultural fields, while also improving water quality in the receiving streams.