Stormwater runoff is the leading source of water pollution in urban areas. Stormwater is rain or snowmelt that runs off hard (impervious) surfaces such as parking lots, roads, and roofs. Pollutants are picked up by stormwater which then flows untreated to the nearest waterway and eventually the French Broad River. Common pollutants in stormwater include trash, oil & gas, lawn fertilizer, pesticides, and bacteria. Impervious surfaces also prevent rain or snowmelt from soaking into the ground and recharging our groundwater supply.
Did you know that 650 gallons of water runs off an average sized home’s roof during a 1” rain? Now, imagine the amount of runoff from one city block being piped into a stream. The energy behind this large amount of stormwater scours streambanks leading to erosion, property loss and sediment pollution.
Increasing development in Western North Carolina has led to an increase in impervious surfaces and stormwater runoff within the French Broad River watershed. In order to protect our water quality, communities must pursue low impact development (LID), which puts an emphasis on green infrastructure (GI). GI works with nature to manage stormwater as close to its source as possible. The goal is to keep it on site, slow it down, and let it soak in. As stormwater soaks into the soil, microbes break down pollutants while native plants absorb water removing any excess nitrogen and phosphorus.
RiverLink’s Watershed Resources Program pursues grant funding to install green infrastructure known as stormwater control measures (SCMs), which capture, store, and filter stormwater runoff before it enters our waterways. SCMs include rain gardens, bioretention cells, and wetlands. In addition to protecting water quality, SCMs can be beautiful additions to the landscape and provide important habitat for wildlife.
RiverLink received an innovative stormwater grant from Clean Water Management Trust Fund to install stormwater control measures on the Givens Estates campus. The project goals were to: 1) improve water quality in Dingle Creek by preventing stormwater runoff, 2) study the effectiveness of stormwater control measures in a steep slope watershed, 3) provide community education and outreach opportunities focused on water quality.
Dingle Creek is a priority watershed for RiverLink and the City of Asheville due to its rapid development and the resulting stormwater runoff which threatens water quality. Givens Estates is a non-profit Methodist retirement community with a strong ethic of environmental stewardship. Their campus contains steep slopes and two tributaries of Dingle Creek, which is an important tributary of the French Broad River.
Construction was completed by Miller Brothers Construction in May 2019. The SCMs, which were designed by Robinson Design Engineers, include a new stormwater wetland and bio-swale, along with retrofits to an existing wetland and roadside bio-swales.
In addition to improving water quality, this project will advance our knowledge on stormwater management in the steep slopes of Western North Carolina. The State design standards for SCMs were primarily developed in the Piedmont and Coastal Plain regions. The findings of this research will help guide design standards for stormwater management in Western North Carolina.
In July 2017, RiverLink and partners, City of Asheville and New Belgium Brewery, completed an extensive project to mange stormwater runoff within the Penland Creek Watershed. With funding from the Clean Water Management Trust Fund, a combination of green infrastructure and stormwater control measures were installed along Craven St. and throughout the campus of New Belgium Brewery. A heavily impaired section of Penland Creek was also restored and now serves as a beautiful focal point on New Belgium’s campus.