Making Way for the Next Generation

Efforts Afoot to Remove Obstacles to Fish Spawning Migration

By Patricia Smith
Fish Eye News
Aug. 2011 Archive

Home is Where the Habitat Is.

It’s not just a slogan for the N.C. Coastal Habitat Protection Plan; it’s a hard truth that is impacting coastal fish populations.

“Certain species need special habitat,” said Kevin Hart, marine fisheries biologist in the N.C. Division of Marine Fisheries’ Habitat Protection Section.

For instance, anadromous fish, such as striped bass, river herring and shad, go up the rivers into the rocky hard-bottom, freshwater habitats to spawn.

“If they can’t get upstream of the dams, they won’t be able to spawn,” Hart said.

The N.C. Coastal Habitat Protection Plan identifies dams and other barriers to fish migration as a threat to fish reproduction capability. That’s why the N.C. Division of Marine Fisheries is working with other state and federal agencies and the American Rivers River Restoration Program to find solutions to this problem.

American Rivers is a non-profit conservation organization dedicated to the protection and restoration of the nation’s rivers. The organization has put together a taskforce – the N.C. Aquatic Connectivity Team – made up of staff from several state agencies within the N.C. Department of Environment and Natural Resources, the N.C. Wildlife Resources Commission, the National Marine Fisheries Service, the U.S. Army Corps of Engineers, U.S. Fish and Wildlife Service and the Environmental Protection Agency.

"For dam removal and restoration projects, we're looking for outdated dams that are no longer serving a functional purpose like hydropower or water supply,” said Lynnette Batts, associate director of American Rivers River Restoration Program for the Southeast region. “Surprisingly, over half of the dams in the state fall into this category of being outdated and unused, and many could be candidates for removal to restore the river."

The group is also looking at removing dams to enhance the rivers’ ecology.

Other than blocking fish passage, there are a number of other ecological factors that dams can impact, Batts said.

Dams cause slack water – a lake-like effect – that has less diverse habitat than a free-flowing river, Batts said. Studies have shown there can be three times the number of species in free-flowing rivers as there are in dammed waters, she said.

“You have potentially tens of thousands of dams around the state,” Batts said. “Think about the fragmentation of habitat that causes.”

Dams can also impact sediment transport and the hydrology of floodplains, Batts said.

American Rivers has formed a cooperative partnership with the National Oceanic and Atmospheric Adminstration’s Community-Based River Restoration Program that awards grants of up to $100,000 for barrier removal projects that benefit migratory fish. Dam owners can apply for this grant to help fund dam removal, Batts said.

If dam removal is not an option – some dams function as a community water supply or produce hydro-electric power – building passageways is an alternative, Batts said.

Such was the case with Lock and Dam 1 on the Cape Fear River in Bladen County. Originally constructed in 1915 for commercial navigation purposes, the dam now plays a vital role in Wilmington’s water supply.

The U.S. Army Corps of Engineers is in the middle of a two-phase repair and renovation project on the dam. The first phase, which began last year, will repair a 40-foot-deep scour hole that, if left uncorrected, could lead to dam failure. The second phase, which began in June, will build rock rapids to aid in fish migration.

“We’re starting on the east side of the river, working westward toward the rock wall,” said Frank Yelverton, biologist with the Corps of Engineer’s Environmental Resources Section in the Wilmington District.

The rock rapids will enable fish, such as shad, striped bass and sturgeon, to swim up and over the dam, Yelverton said.

A two-year monitoring program will record the migration of shad and striped bass in cooperation with a Division of Marine Fisheries sturgeon monitoring program, Yelverton said.

The entire project is scheduled for completion by March 2013, Yelverton said.

There have been other successes in North Carolina dam removal efforts. Several dams were removed in the late 1990s on the Neuse River and its tributaries, including Quaker Neck Dam, Cherry Hospital Dam and Rains Mill Dam. Lowell Mill Dam, also in the Neuse basin, was removed in 2005.