Northeast Region Low-Impact Development

Low-impact development (LID) is a relatively new approach to land development that reduces and prevents stormwater pollution. The N.C. Coastal Federation promotes LID because it mimics nature's water cycle and is a key tool to protect and restore coastal waters.

Current Projects

Improved Manteo Airport Drainage Plan Protects Swimming Hole

Unusually heavy rains last winter and spring flooded much of the Outer Banks. But nowhere was the inundation worse than the Scarborough Square trailer park near the Dare County Regional Airport on Roanoke Island.

The Airport Authority bought the trailer park last year, along with an adjacent cemetery, to control air space over the approach to a major runway. Dozens of trees were cut, reducing turbulence in the air—but whipping it up on the ground. Residents with family members in the cemetery decried the logging, which left the cemetery barren.

Shortly thereafter the rains began. With water pooling up to four feet in the trailer park, residents demanded that the Airport Authority get rid of the flooding. The Authority asked its engineer, John Massey of Talbert & Bright in Wilmington, to come up with a solution. Massey designed a drainage swale that would have dumped stormwater through existing pipes into Croatan Sound. The extra runoff would likely have polluted open shellfishing waters and potentially caused public health advisories to be posted at the Old Swimming Hole, a nearby and popular park.

Jan DeBlieu, our regional coastal advocate, asked Massey and the Airport Authority to consider installing low-impact development techniques that allow runoff to soak into the ground rather than pollute surrounding waters. She and Erin Fleckenstein, the Northeast Region coastal scientist, worked with authority member George Wood to find suitable sites for two basins and a constructed wetland. They would slow the stormwater and allow it to soak into the ground. The basin would then dry out in a couple of days. Massey revised his design for the swale to include these features.

There was just one problem. The Federal Aviation Administration wouldn’t provide money for the techniques because the design wasn’t consistent with its guidelines. They also expressed concerns that the basins and wetland would attract wildlife and birds, which could cause safety hazards for planes using the runway.

To solve the problem, Massey widened the swale along its entire length—effectively providing an even larger area for stormwater to soak into the ground. Although not technically a BMP, the redesigned swale accomplishes the same goal.
The Airport Authority board approved construction of the swale in late August. The $80,000 cost will be paid by an FAA grant. At DeBlieu’s request, Massey agreed to design two weirs that could be placed at key positions in the swale to further slow water.
The constructed wetland was not part of the final design. But Wood told other Authority members he is hopeful they can find grant money to fund its construction within a year.

• Original LID stormwater plan
• Revised plan

It was the kind of outcome that leaves everyone smiling. “What I love about this project,” DeBlieu said, “is that we were all able to look at the situation and say, no, we don’t want to use the easiest, most conventional solution— dumping stormwater into the sound. We figured out how to protect residents from flooding without causing more problems downstream.”

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