State gives dam removal a go Duke to be forced to dredge sediment
Duke Energy has received clearance from the state to tear down the Dillsboro dam but will be forced to dredge a backlog of sediment from behind the dam first.
The mandate runs counter to Duke’s wishes. Duke has vigorously protested the suggestion that it should dredge the backlogged sediment. Instead, Duke wants to cut a notch in the dam and simply let the backlogged sediment escape downstream. To help flush out the sediment, Duke proposes opening the flood gates on its dams upstream to raise the river levels and carry the sediment away.
That is a bad idea, however, according to the state water quality officers.
“That additional sediment would impact the river from Dillsboro down to Fontana. Too much sediment in the river clearly would impact water quality standards,” said John Dorney, a state water quality specialist.
The state recently granted Duke a necessary water quality permit to tear down the dam, but on the condition Duke remove sediment first. Duke is considering an appeal of the order, according to Fred Alexander, Duke spokesperson.
Duke has tried to find a way to sell the sediment to offset the costs of dredging it. In fact, Duke has insisted it wouldn’t remove any sediment otherwise — and wouldn’t remove any more than it could sell.
“Duke believes that if the sand is not marketable, Duke should be allowed to remove the dam as originally planned with the use of flushing flows to move the sediment downstream,” Duke stated in recent filings with the state. Duke stated there would be no “long-term negative environmental impacts” by flushing the sediment downstream, and that the sediment behind the dam was equal to no more than two years worth of sediment that would enter the river anyway.
The slow-moving backwater behind the dam is eight-tenths of a mile long. Sediment deposits behind the dam are as much as 11 feet deep in some places, based on core samples taken by Duke. Those same core samples pegged the volume of sediment behind the dam at 100,000 cubic yards. The state is forcing Duke to dredge 70,000 of those.
Dorney said removing 70,000 cubic yards is enough to ensure water quality won’t be compromised.
“We think 70,000 is about the right number,” Dorney said. Dorney said the river should be left with some sediment for ecological purposes.
According to Roger Clapp, director of the Watershed Association of the Tuckasegee River, the state is doing the right thing by requiring Duke to dredge the sediment should the dam come down.
“I am happy with that decision,” Clapp said. “If the dam is to be removed, we are very excited that the sediment will be removed as well.”
Advocates for dredging spoke up at a public hearing on the state permit held in August, including Clapp. Clapp said failure to dredge could result in a “harmful blanket of sediment” downstream.
“It is a gamble with water quality,” Clapp said at the hearing. “Clean it out and clean it out well before you get going.”
Clapp has long been hoping to pin a dollar figure on the cost of sediment removal. A hard cost associated with sediment — such as the price per cubic yard to remove it — could be used as ammunition in the fight to keep sediment out of waterways in the first place. For example, it could be more cost effective to hire additional erosion control officers than to remove sediment after the fact. Clapp hopes Duke will share the cost of sediment removal with the public to facilitate these types of equations.
“When you don’t know the number, you can’t make economic decisions,” Clapp said.
At this point, the cost of removing the sediment is unknown, Alexander said.
“It would be premature to make any cost estimates until our analysis and other steps are complete,” Alexander said.
Aside from the dredging mandate, Duke is pleased to have received its permit from the state to remove the dam.
“We’re glad to see the process reach this stage,” Alexander said.
A win of sorts
Duke’s opponents are chalking up the state’s mandate to remove sediment as their first — and possibly only — win in the on-going fight over the Dillsboro dam. Duke has proposed tearing down the dam as compensation for impacts caused by 10 other dams it operates in the region. Duke is obligated to provide environmental and recreational benefits in exchange for renewed permits to keep operating the other dams.
Tom Massie, a Jackson County commissioner and a member of the Jackson County Soil and Water board, said he felt somewhat vindicated by the state’s mandate to remove sediment. Duke is granted a monopoly by the state to provide power and is allowed to profit off the public’s rivers as a result, Massie said. Yet Duke wanted to unleash sediment into the river to avoid paying for dredging.
“That doesn’t sound very responsible to me,” Massie said.
Both boards Massie serves on have opposed various elements of Duke’s plans, but this was the first time their arguments prevailed.
“We finally won one,” Massie said.
Opponents would have preferred the state not grant Duke a permit to remove the dam at all. However, the state had a rather limited framework for judging the dam removal. The state simply had to decide whether removing the dam could be done without violating water quality standards. The answer, apparently, was yes.
There was little room for the state to consider the public’s primary objections to dam removal: that the dam’s value as a green energy source and historic landmark should be preserved.
“In terms of green power, there is nothing in our rules whatsoever to consider that,” Dorney said. “Aesthetics are also outside our purview.”
Another complaint is that Duke is short-changing the region. Opponents claim that another form of mitigation would be more helpful to water quality that removing the dam — such as money to combat sediment plaguing the region’s waterways. In terms of recreational benefits, creating a greenway along the river would benefit more people than removing the dam for paddlers.
The state did not weigh in on that issue either, however. Whether Duke’s mitigation package was fair or unfair was not relevant as far as the state permit was concerned.
Those issues fall under the control of the Federal Energy Regulatory Commission. The Federal Energy Regulatory Commission has consistently sided with Duke.