A range of innovative stormwater management strategies significantly reduce sediment and nutrient loading in area watersheds and prevent downstream flooding.
Underground cisterns hold rainwater to irrigate the intensive green roof at Rams Head Plaza and Fetzer Field. There are two cisterns installed under the historic quad in front of Hanes Hall and beneath the parking structure at Boshamer Stadium. The cistern at Hanes is unique in that it is not provided with backup water from OWASA. The cistern at the Boshamer baseball stadium is the first to capture water used to irrigate the turf. This recycles the fertilizer and avoids sending nutrients downstream. The Boshamer cistern is also the first to use reclaimed water as a backup. The FedEx Global Education Center is the first building on campus to use rainwater to flush toilets. The Genome Sciences Building also features a 350,000 gallon cistern that captures rainwater from the roof to be used as reclaimed water.
Permeable pavement is another structural approach to stormwater management that has been employed extensively at Carolina. Gravel beds under the porous surface store rainwater until it slowly infiltrates into our clay soils. The soil then filters out pollutants conveyed from the parking lot. Porous pavement is installed at both the 800-space Friday Center park-and-ride lot and a remote parking lot for students with 465 spaces. The University saved approximately $500 per parking space in these lots by selecting a permeable pavement system instead of building an additional detention basin or drainage system. Additional porous asphalt lots have been installed at the Facilities Complex, on Cameron Avenue across from the cogeneration plant, in front of the EPA building on campus, and at the Hedrick lot. The park and ride lot in Chatham County is a porous lot designed to infiltrate into a sandy soil layer.
Coupled with infiltration beds and permeable pavement, there are now more than 180 structural best management practices installed across the campus. Energy Services maintains an inventory of all stormwater management features installed to date in the University’s geographic information system (GIS) that identifies the location and type of each installation. This facilitates long-term maintenance of the University’s large and growing stormwater system.
Water supply shortages, new water quality rules, and campus growth are driving this unprecedented and comprehensive approach to water management. As part of a $2.3 billion capital improvement program, UNC has completed the construction and renovation of 7.5 million square feet of space since 2010. This is more square footage than exists on most college and university campuses and equals 56 percent of UNC’s space in 2000. This expansion has occurred at a time when local, state and federal government agencies are working to regulate more stringently both the quantity and quality of stormwater runoff.
In addition to common stormwater management requirements for flood control and total suspended solids removal, the University also controls volume and nutrients. Infiltrating stormwater and harvesting rainwater for reuse benefits groundwater recharge and downstream habitat and reduces the volume of stormwater leaving campus following rain events. Regional Jordan Lake rules limit the amount of nutrients, namely nitrogen and phosphorous, leaving new development. The rules also require a 35 percent reduction in nitrogen runoff from existing development. The University is identifying retrofits in the current stormwater system to meet this goal.
To coordinate UNC initiatives designed to comply with these rules, a full-time stormwater engineer was hired by Energy Services in 2008. At Environment, Health and Safety (EHS), a water quality specialist was hired to monitor stormwater runoff and to educate members of the UNC community. Grounds Services staff maintains the stormwater infrastructure, including quarterly vacuuming of the University’s seven permeable pavement parking lots.
One of the requirements of the University’s National Pollutant Discharge Elimination System permit is to raise community awareness of the importance of stormwater management. Some of the outreach strategies to date include training sessions for shop staff, information tables at on and off campus events, and a new stormwater management website. To date, over a thousand University employees have participated in stormwater training sessions. Storm drain signage across campus asks people to refrain from dumping any waste products, and multiple creek cleanups are held each year.
The restoration of Chapel Creek is another effort to improve water quality. Approximately 1,400 linear feet of stream channel and five acres of riparian buffer were reconfigured to allow the creek to access its floodplain again and meander in a natural way. This project, on an unused portion of the old Finley Golf Course, was supported by the N.C. Ecosystem Enhancement Program and will provide educational opportunities in stream restoration processes. The entire area, currently used for running trails and environmental education, was replanted with a variety of native plants. A conservation easement was created to protect the area permanently.
Stormwater Management Program Assessment 2013
UNC Stormwater Management Overview - http://ehs.unc.edu/environmental/stormwater/
UNC Energy Services - http://www.energy.unc.edu
UNC Environment, Health and Safety - http://ehs.unc.edu
N.C. Ecosystem Enhancement Program - http://www.nceep.net