University of North Carolina at Chapel Hill
OP-23: Rainwater Management

UNC operates its own stormwater management program under a National Pollutant Discharge Elimination System (NPDES) Municipal Separate Storm Sewer System (MS4) Phase II permit. The UNC stormwater staff conducts activities that meet the six minimum measures of the NPDES Phase II permit plus other activities that meet regulatory, infrastructure management, and sustainability goals. These programs cover the following areas: staff stormwater education and good practices, mapping, illicit discharge detection and elimination, public involvement, construction site erosion and sedimentation control, post-construction stormwater management, stormwater system maintenance, stormwater system condition evaluations, and stormwater retrofitting. New development and redevelopment projects address water quality, stormwater runoff volume, and peak discharge rate. All projects are reviewed by the UNC Stormwater Engineer, the Town of Chapel Hill Stormwater Department and/or the State Division of Water Quality Stormwater Permitting Unit. The University of North Carolina at Chapel Hill Stormwater Performance Criteria, Design Standards, and Procedures can be found here: https://share.campus-services.unc.edu/Policy/EnergySvcs/Energy%20Services%20Design%20Guidelines/SW-Design-Guidelines.pdf

UNC has more than 300 stormwater control measures in use. Traditional measures include ponds, wetlands, underground storage, bioretention, and sand filters. More innovative control measures include green roofs, permeable pavement, infiltration beds, vegetated swales, cisterns, and underground water quality improvement devices. In 2016, a Battle Branch stream tributary that had been piped beneath the road for 75 years was released in an aboveground stream. This newly daylit stream was designed with a filtration process that naturally filters pollutants and contaminants out of runoff water, benefiting water quality downstream as well as in the immediate area. UNC has six green roofs, a vegetated swale connecting an intensive green roof to an infiltration bed, and six level spreaders, which are a form of vegetated conveyance that spread water to promote sheet flow. Four level spreaders are located at the Baity Hill Residence Halls. One is located at the Francis Owen facility. And one is located near the Giles Horney Building. The University's open channel conveyances include many vegetated and grassed swales. If these were not specifically constructed as a stormwater treatment practice, we do not inventory them as stormwater control measures.