How-to of dam removal still a source of debate: State, feds object to backlogged sediment being unleashed downstream
Duke Energy has cleared a major hurdle in its efforts to tear down the nearly 100-year-old Dillsboro dam.
Duke got approval from the Federal Energy Regulatory Commission last month to tear down the dam. Removal could happen as early as next year, or it could be two to three years away depending on whether critics of dam removal appeal the decision.
The federal approval for tearing down the dam was expected, but nonetheless marks a milestone in the years-long process leading up to dam removal. The news pleased Duke, state and federal environmental agencies, and river outfitters — who will now be able to offer longer rafting trips.
“I think a longer stretch of river will be a big boon to the economy of Jackson County,” said James Jackson with Tuckasegee Outfitters.
A one-mile stretch of river behind the dam will be restored to a natural, free-flowing river eco-system from its current status as a wide, sluggish backwater.
“Upstream and downstream fish populations will no longer be separated. The removal will enhance aquatic resource distribution within the Tuckasegee River system, and species richness of upstream areas,” the energy commission wrote in its decision. “The resulting free flow of the river will also improve recreational opportunities for whitewater boating and riverine angling.”
American Whitewater, a national paddling group based in Sylva, is among those cheering the decision.
“The removal of Dillsboro Dam is good for the river and good for the citizens of Western North Carolina,” said Kevin Colburn with American Whitewater.
All not pleased
The approval of dam removal was a disappointment to others, however, including Dillsboro merchants, some environmental camps and Jackson and Macon county leaders, for starters. All would rather see Duke provide other types of environmental and recreational measures in lieu of tearing down the dam.
Tearing down the old dam will count as the primary mitigation for 10 other dams Duke operates on various rivers in WNC, from the large Nantahala Lake and Lake Glenville dams to small dams on the Little Tennessee and Oconaluftee rivers. Duke’s permits to operate its dams are up for renewal. In order to get new permits, Duke has to provide environmental and recreational compensation to the public in return for manipulating the region’s rivers for its hydropower operations.
A coalition of Duke opponents suggested alternative mitigation: turning the Dillsboro dam over to Jackson County to operate as a green power source and ponying up money for river conservation efforts. In addition to Jackson and Macon counties, the coalition of opponents includes the town of Webster, the town of Franklin, the Jackson County Recreation Board and Greenway Commission, and the Jackson Soil and Water Conservation district.
Critics claim the removal of the dam is an easy out for Duke. The utility wants to be rid of the aging dam anyway and is getting mitigation credit in the process. Duke hasn’t used the dam to generate electricity in three years, since the floods of 2004. The dam produces a pittance of electricity compared to Duke’s total arsenal — one reason the dam hasn’t been put back in operation since the floods.
“You are sacrificing a non-operating dam that would actually cost Duke money to put back into operation,” said Paul Nolan, a Washington, D.C.-based attorney hired to fight Duke. Nolan said if the dam was overhauled, it could produce enough electricity for a minimum of 500 families, meanwhile reducing fossil fuel energy production.
But the energy commission said it could not require Duke to turn the dam over to another entity — or to keep running it — if Duke didn’t want to. Nolan said the energy commission had other ways of compelling Duke to turn over the dam, however. Instead of rewarding Duke for tearing down the dam with mitigation credit, it could have required a litany of additional mitigation along with dam removal, removing Duke’s motive to tear it down.
“What they could have done is set up the option for Duke,” Nolan said. “They could have said we are going to make you do all these other things that are so unpalatable that Duke will want to turn it over.”
Nolan said there have been other cases where the energy commission has forced the transfer of a dam to another entity when the power company that owned it wanted rid of it.
Duke has amassed a coalition of its own in favor of tearing down the dam. Duke’s coalition includes state and federal environmental agencies, paddling groups and outfitters, fishermen and some environmentalists. That coalition backed Duke’s mitigation plan of tearing down the Dillsboro dam. In addition to tearing down the dam, the mitigation package includes put-ins on some lakes, special whitewater releases for kayakers and $200,000 for sediment and erosion control efforts split among five counties over 30 years.
Although dam removal counts as the lion’s share of the mitigation, the energy commission could up the ante and require additional mitigation when it gets around to granting new permits for Duke’s other dams.
“The Commission could require measures, over and above those included in a settlement, should we determine that such measures have merit, are supported by substantial evidence, and are part of what the Commission believes is an appropriate balance among competing interests. In practice, this is a routine occurrence,” said Celeste Miller, spokesperson for the energy commission.
Duke must dredge
Exactly how the dam will be torn down is yet to be determined. The energy commission has approved dam removal in theory, but has yet to sign off on how. Duke has to submit a detailed plan of how it plans to remove the dam, which the energy commission must approve before demolition starts.
If large sections of the dam come down at once, the rush of water could blow out riverbanks downstream or disrupt aquatic life. Fish that live in the backwater behind the dam could be stranded on dry land if the water level is reduced too quickly.
According to preliminary dam removal plans, Duke plans to make a notch in the dam to gradually lower the water level. Then it will take down the dam in three- to four-foot sections.
The biggest sticking point is what Duke will do with some 100,000 or more cubic yards of backlogged sediment behind the dam. Duke initially wanted to let the sediment wash downstream. The energy commission doesn’t seem too pleased with that idea, however.
“A large release of sediments from the (dam) could cause many ecological problems downstream. Depending on the grain size of the sediment, mussel beds could be smothered; and insect larvae, and fish eggs or larvae could be buried by the sediments. Furthermore, suspended sediments could cause gill erosion in fish,” the energy commission ruling states.
State and federal environmental agencies voiced these concerns in filings with the energy commission, making the case that should Duke dredge the sediment.
The energy commission isn’t saying exactly how much Duke must dredge, however. Instead, it is requiring to Duke to develop a “Sediment Management Plan.” The energy commission has to sign off on the sediment plan before dam demolition can occur. State and federal environmental agencies will have input on plan.
That input will be significant. The U.S. Fish and Wildlife Service has authority to protect habitat of the endangered Appalachian elktoe mussel downstream of the dam and therefore is given “considerable weight” in how dam removal is conducted, according to Miller, the spokesperson for the energy commission. U.S. Fish and Wildlife Biologist Mark Cantrell has said he will insist that Duke dredge.
So has John Dorney, water quality specialist with the N.C. Division of Water Quality. The state water quality agency not only gets input on the federal sediment removal plan, but issues its own state permit for dam removal. The agency has made it clear that sediment removal will be a condition of its permit, which Duke must follow.
Nonetheless, Duke claims dredging is still an undecided issue.
“It is too soon to tell,” said Fred Alexander, Duke spokesperson for the Nantahala region, in a written response to the question on whether Duke plans to dredge.
Duke hopes to sell the sediment behind the dam to offset the cost of dredging it. Duke is negotiating a contract with a commercial “sand mining company” to remove the sediment. Alexander said the cost of sediment removal will play a role in how much is removed.
“Duke has been working with a sand mining company to explore the feasibility of removing a substantial amount of the accumulated sand in the reservoir,” Alexander said in a written statement. “The amount of sand that would be removed depends on the permitting requirements as well as the commercial value of the sand to the sand mining company.”
Dam removal logistics
Duke has two species it has to look out for in the removal of the dam and adjacent powerhouse. One is the endangered Appalachian elktoe mussel downstream of the dam. The mussels will be temporarily relocated as a precaution prior to dam removal.
The other species of concern is the little brown bat. A colony of 500 little brown bats currently roost in the wooden rafters of the powerhouse, which is also slated to be torn down. To provide new roosting habitat, Duke will build numerous bat boxes and hang them nearby, enticing the bats to take up residence in these new homes by transferring some of their droppings from the power house to the boxes.
As part of dam removal, Duke pledged to build a boat put-in upstream of the current dam. Duke would not elaborate on plans for the boat put-in at this time, such as the exact location, the number of parking spaces or type of put-in. Duke is required to develop a plan for the public boat launch as a condition of tearing down the dam.
“This plan has not yet been developed, so these details have not yet been worked out,” Alexander said in a written response to questions. Alexander said no decision has been made on the put-in location other than somewhere in the one-mile stretch upstream of the current dam.
Duke Power will not maintain the put-in after constructing it, and exactly who that responsibility will fall to is yet to be determined.
Another part of Duke’s plan to remove the dam includes donating land around the current dam and powerhouse to the town of Dillsboro for a park. Alexander could not say exactly how much land around the current dam and powerhouse this might include.
The energy commission said it will not require Duke to turn over the land to Dillsboro, so technically, Duke does not have to keep this pledge. Alexander said Duke will do so anyway, however, honoring the obligations it made to the town of Dillsboro even if the energy commission doesn’t require it. Duke previously gave Dillsboro a check for $50,000 to keep town leaders from formally opposing dam removal, although several aldermen who are also business owners personally signed a petition against dam removal.