WRIGHTSVILLE BEACH—Living by the coast comes with responsibilities that other communities do not face, like protecting coastal creeks, river and sounds from pollution. The biggest polluter for these coastal waterways is not directly man-made, but results from stormwater runoff.
One of the man-made problems where stormwater is concerned is the addition of non-permeable surfaces like asphalt and other pavements. When rain falls on the ground, instead of being absorbed, it remains on top of the surfaces and collects pollution before making its way to the waterways.
The North Carolina Coastal Federation is working on several projects in Wrightsville Beach, as well as Wilmington, to help prevent polluted water from reaching Banks Channel and other coastal waterways.
The projects are funded by the North Carolina Clean Water Management Trust Fund and the Environmental Protection Agency’s Section 319 Grant Program.
“The series of stormwater retrofit projects throughout the county includes two sites where impervious paving was replaced by permeable paving at a public parking lot and at Hanover Seaside Club, both in Wrightsville Beach,” according to a press release from the North Carolina Coastal Federation. “These sites are both documented sources of polluted stormwater runoff along Banks Channel. These projects, which move runoff through soil to be filtered and cleaned rather than directing it to Banks Channel.”
While pollutants like oil, gasoline, and other hydrocarbons are a concern for the federation, the biggest concern comes from bacteria, Coastal Scientist Tracy Skrabal said.
Permeable Pavement
So, what exactly is permeable pavement? According to Skrabal, typical pavement is made of gravel, cement, and fine sand. Because the sand fills even the smallest holes, water is unable to penetrate the ground. The water, instead of flowing through the ground, flows into concrete pipes and directly to local waterways, she said.
“The whole point of this is, when polluted stormwater goes into a storm drain … there is no way to treat that polluted water,” Skrabal said.
When polluted water goes into a drain, it does not have the chance to filter. But when it is able to drain into the ground both physical and biological filtration take place before the water returns to the waterways, she said.
Permeable pavement comes in two forms, a mix of gravel and cement without the fine sand, and regular pavers like bricks, but with spaces left between them open to allow for water penetration.
The goal of the North Carolina Coastal Federation is to “disconnect that straight pipe system,” she said.
Although permeable pavement can be costlier, residents who are looking to do their part can still be cost effective with future projects, according to the federation. For example, anyone looking to make improvements to a driveway or patio can replace just a portion of standard impermeable pavement with more eco-friendly pavement and still have a positive effect.
Send comments and tips to Michael.p@localvoicemedia.com
