North Carolina Construction News staff writer
The Raleigh-Durham Airport Authority has been granted state approval to construct the largest sustainable stormwater management system in North Carolina.
Known as a submerged gravel wetland, the facility will be implemented to manage stormwater from the Park Economy 3 Expansion (PE3) project. It promises to be more efficient than traditional systems in filtering pollutants from runoff.
In partnership with North Carolina State University, the submerged gravel wetlands were specifically designed for this project. This innovative approach involves using plants in an above-ground wetland to process runoff through biochemical means. Beneath the surface, gravel layers maintain consistent water levels and facilitate water treatment processes.
The new system is anticipated to outperform other stormwater management methods such as dry ponds in removing sediment and nutrients. All water discharged from the basins will be analyzed to ensure effective treatment, with results submitted to permitting officials.
The design will accommodate at least a 50-year storm event, surpassing state stormwater treatment requirements. It will handle over one inch of runoff and enhance nutrient removal. The N.C. Department of Environmental Quality issued a stormwater management permit in June, allowing construction to proceed.
