Study ranks 200 culverts within Black River Watershed to help prevent flooding

PENDER AND BLADEN COUNTIES, NC (WECT) - A pilot project will assess 200 culverts in the Black River Watershed to identify those most prone to blockages. The program will fund engineering assessments for up to five culverts most severely blocked for potential fixes later in a separate project.

The two main goals are to prevent backups causing flooding during major storm events, including hurricanes, and to help aquatic wildlife pass through the blocked culverts.

“A major issue identified in the Black River Watershed are obstructions that block or impede fish passage,” according to an information sheet.

A culvert is an open drain pipe under a road or railroad where water can pass through. A culvert can be blocked by an obstruction like a beaver dam, sedimentation or trash, but it might also have breakages or damage to the pipe itself.

The non-profit organization Cape Fear Resource, Conservation & Development is partnering with construction company Moffatt & Nichol, along with Bladen and Pender Counties and the North Carolina Department of Transportation.

There are more than 700 culverts in Bladen and Pender counties. Assessment organizers plan to select 100 culverts each in both counties, for a total of 200 culverts.

Organizers are now in the process of narrowing down which culverts to assess and are asking members of the public to help. They are purposely excluding culverts that NCDOT has recently inspected to not waste resources.

Field assessments will be completed by spring. The entire pilot project is scheduled to be completed by this December.

“If a culvert is blocked, then you don’t have the natural flow of the river and tributaries that contribute to the basin,” said Danielle Darkangelo, executive director of CFRC&D. “Then you’re negatively impacting the wildlife, the fish. And flooding would be a concern when you have excessive rain or as we’ve had recently with Hurricane Florence.”

Experts will analyze water flow upstream and downstream of the culvert to determine blockage level. They will also collect data like the structure material, shape, size and environmental conditions.

Once the culverts are assessed in this pilot project, experts will rank them using a "barrier prioritization tool" to identify those with the most severe barriers.

Residents attended two public meetings on Tuesday, one at the Rowan Fire Department in Bladen County, and another at Moores Creek Missionary Baptist Church in Pender County.

Maps spread out on tables allowed people to indicate with markers the culverts they personally know to be prone to blockage.

Jessica Holm, a Currie resident of about 13 years, said there are a lot of culverts near her home and neighborhood.

"There are lots of culverts in this area, a lot of concentrated culverts. And yes, there was a huge amount of flooding and once the floodwaters went down, had there been more free flowing of the water, the water would not have stayed around as long as it did," said Holm.

"Just think of your bathtub. And you have a plug in the bathtub, and then you just lift up the drain just a tiny little, the water will go down, but it will go down really slowly but if you pull the plug out it will go down much quicker."

The cost to a replace a smaller culvert ranges between $15,000 to $20,000, while a large culvert can cost up to $100,000.

The total grant money for this pilot project is $180,000.

If you did not make it to the public meetings, you can share your comments with project managers by emailing Dawn York at dyork@moffattnichol.com and Rebeckah Hollowell at rhollowell@moffattnichol.com.

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