Riverkeeper pleased with effort to keep stormwater out of White Oak River

SWANSBORO — The pink blooms popping out on newly planted crape myrtles along Broad Street and Shore Drive are only part of the beauty of a water quality initiative in the Town of Swansboro.

The trees catch the eye above ground; and below ground, out of view, are concrete boxes filled with filtration media that help filter pollutants from stormwater run-off before it reaches local waters.

The tree box filters are a favorite part of the Swansboro project for White Oak-New Riverkeeper Tess Sanders. It’s an unobtrusive way of making a big impact on water quality along the White Oak River.

“Tree boxes filter sediment and pollutants out of stormwater run-off and can reduce the pollution reaching the White Oak River and Hawkins Creek by up to 85 percent,” Sanders said.

Sanders recently got a look at projects that are part of the Swansboro’s new water quality initiative.

With the help of grant awards of $214,000 from the North Carolina Clean Water Management Fund and $7,000 from the Community Conservation Assistance Program administered by Onslow County Soil and Water Conservation, the town has constructed five structures to intercept and treat stormwater run-off to help reduce pollution of local coastal waters.

Rainwater washes oil, metals, sediment, animal waste and litter from the roads, rooftops, and pavement and the untreated run-off can make its way into storm drains or directly to waterways.

The new structures, or best management practices, put in place by the town will catch the first flush of run-off after rains and storms and help to remove pollutants such as nitrogen, phosphorus, fecal coliform and other bacteria, heavy metals, suspended solids and hydrocarbons, said Town Manager Pat Thomas.

At a waterfront park, stormwater from Front Street will be caught in a shallow, grassy swale and infiltrated slowly into the soil rather than the run-off washing rapidly into the adjacent White Oak River, he said.

The four tree box structures use a new technology called Filterra, manufactured by a Virginia company, and the Town of Swansboro is one of the first communities in eastern North Carolina to use it, town officials said.

“These structures contain special media that help to filter stormwater before allowing it to continue through the drainage system,” Thomas said.

Completion of the project follows a year and a half of work on the design and resolving property issues. While one of the structures is located on town park property, the four tree box filters are located on street right of way.

The total cost of the project is $289,000, with local funds contributed along with the grant funds, Thomas said.

The completion of the project doesn’t end the town’s water quality initiative. The 2010-2011 town board goals include a plan to explore the feasibility of a municipal program to control stormwater run-off from developing properties. The board also plans to look at adopting requirements for proper maintenance of required stormwater management structures and devices in larger developments.

Sanders approves.

“Our local economy is so dependent on the health and productivity of our waters,” she said. “I’m proud of the Town of Swansboro for doing their part to protect the White Oak River.”