‘Snuffed Out’: Unannounced dam release covers Oconaluftee in sediment
It was around 1 p.m. on Monday, Oct. 4, when Ken Brown’s phone started lighting up with photo texts depicting a massive sediment load dropping into the Oconaluftee River below Ela Dam, also known as the Bryson Hydroelectric Project. Within half an hour, he was standing on the riverbank.
Brown, who is the executive director of the Watershed Association of the Tuckasegee River — the Tuckasegee’s confluence with the Oconaluftee occurs just half a mile downstream from the dam — was shocked by what he saw. On this stretch of the Oconaluftee, the river bottom is made of rocks and boulders with little to no sediment covering them, making it important habitat for sensitive aquatic species that require clean, oxygenated water.
When Brown arrived, that sediment-free habitat had vanished. He called the N.C. Division of Water Resources, and a representative arrived on scene by 4:30 p.m.
“You could literally walk across the river,” Brown said. “There was no rock exposed.”
While observing the river, Brown met a visitor from New Hanover County, who had been fishing before the release started. Once it began, he had to stop — within seconds, fishing became impossible. Then the release halted, the small impoundment filled up, and dam operators “started flushing as much water as they could” through the gates, said Brown.
The whole episode took only about 2.5 hours but caused lingering damage to downstream aquatic communities, likely erasing some species from that river section completely. As a result, multiple government agencies have issued violation notices and are actively investigating what happened, and why.
In a photo taken during a May compliance inspection by the N.C. Division of Water Resources, the riverbed is clearly visible beneath Ela Dam. NCDWR photo
No prior notification
Dam operators are supposed to notify the government agencies charged with overseeing them before releasing large amounts of water downstream, but Northbrook Carolina Hydro II, which owns Ela Dam, didn’t do that prior to the Oct. 4 discharge. Instead, President Chuck Ahlrichs wrote a letter dated Oct. 5 — after the release was finished — notifying the Federal Energy Regulatory Commission of a “required emergency maintenance drawdown of the Bryson reservoir beginning Oct. 3, 2021, and ending on Oct. 4, 2021.”
The release was necessary to evaluate a breach in one of the stoplogs used to control water flow, Ahlrichs wrote. In an Oct. 15 letter addressed to DWR Environmental Specialist Andrew Moore, he elaborated that a breach of the third bay’s gate structure was identified on Sept. 3, prompting Northbrook to notify FERC and put up warning signs and danger tape “to warn the public of a potential sudden water release in the event of total failure.”
On Sept. 30, Ahlrichs wrote, Northbrook contacted FERC’s Atlanta Regional Office to “ascertain approvals” for a “short-term drawdown” but concluded the situation qualified as an “emergency unscheduled drawdown” — meaning that Northbrook did not have to notify the pertinent agencies beforehand.
So, at 9 a.m. Oct. 3 Northbrook began drawing down the reservoir, inspecting the dam at 9 a.m. Oct. 4 and refilling the reservoir at 11 a.m., according to Ahlrichs’ Oct. 15 letter. The gates returned to automatic operation by 7:30 p.m.
Neither federal nor state wildlife agencies buy that excuse, according to written comments from the U.S. Fish and Wildlife Service and the N.C. Wildlife Resources Commission.
While delayed notification may be justified in case of an emergency that could cause “potentially imminent danger to life or property,” USFWS Field Supervisor Janet Mizzi wrote in a Nov. 24 letter to FERC Secretary Kimberly D. Bose, that does not seem to be what happened in October.
Northbrook knew about issues with the stoplogs for weeks before the release and discussed the potential for imminent danger with FERC on Sept. 30, three days before it started the drawdown Oct. 3. The lack of notification to natural resource agencies during that time is “troubling,” Mizzi wrote.
“Especially concerning,” she said, “is the lack of coordination and notice during the three days between deeming the condition a dam emergency and the actual drawdown.”
“Since Northbrook was aware of the issue 30 days prior to initiating the drawdown and sediment release and had notified FERC on at least two occasions, we do not understand why the resource agencies were not notified until after the release had occurred,” agreed Wildlife Commission Hydropower Licensing Coordinator Christopher Goudreau in a Nov. 17 letter to Bose. “If the situation was truly an emergency, Northbrook could have been directed to notify the resource agencies and others who could be affected by a significant release of water and sediment.”
Detrimental to stream life
In his Oct. 15 letter, Ahlrichs dismissed concern over the sediment’s impact to aquatic life, writing that river flows had “largely removed” downstream sediment as of Oct. 8.
But that’s simply not true, resource agencies say.
On Oct. 18 — 10 days after the sediment had all but disappeared, according to Ahlrichs — Wildlife Resources Commission staff conducted a sediment survey below the dam and had to stop shortly after the confluence with the Tuckasegee because the sediment was so deep that it threatened their safety.
Out of 71 data points in the survey, only one produced a sediment depth of 0 inches, while 18 data points had sediment deposits a foot or more deep. Most of these exceptionally deep deposits were located in pool areas of the river, and the heaviest ones were downstream of the confluence with the Tuckasegee.
The deposits are significant enough to impart a drastic, long-term effect on the number and diversity of aquatic species living in there, said Mizzi.
“The sediment depths in this reach (downstream of the U.S. 19A bridge) have dramatically changed the bottom elevation of the river and destroyed the high-quality aquatic habitat that occurred here,” she wrote in her Nov. 24 letter.
The N.C. Department of Environmental Quality classifies the Oconaluftee River below the dam as High Quality Waters , and at the confluence, the Tuckasegee River is federally designated as crucial habitat for the endangered Appalachian elktoe mussel. While the mussels are not currently recorded as living there, the river is home to multiple state-listed and rare species, including the eastern hellbender, olive darter, wounded darter, smoky dace, Little Tennessee crayfish, Tuckasegee stream crayfish, smallmouth redhorse and Highland shiner. It’s also important habitat for sicklefin redhorse , a fish that occurs only in a few rivers in Western North Carolina and Georgia. Wildlife experts estimate that half of the known population in the Tuckasegee River basin spawns in the Oconaluftee River below the dam.
All these species require cold, clear water to survive. Layers of sediment smother aquatic creatures that live around or under rocks on the bottom of the stream, preventing oxygen-rich stream water from reaching them. Sediment also impacts fish, either by lowering the concentration of dissolved oxygen in the water, making it harder to find food or simply eliminating existing food sources that themselves rely on sediment-free water.
While detailed surveys have yet to be completed, the impact to the river’s aquatic inhabitants was likely devastating.
“Because the sediment deposit is so widespread and deep, we believe it is safe to assume that future species surveys will find that some species have been extirpated from the Oconaluftee River below the Bryson Dam,” Mizzi wrote.
In an Oct. 4 photo, mud covers the bottom of the river as seen from a viewpoint just below the dam. WATR photo
Both DWR and the U.S. Army Corps of Engineers have slapped Northbrook with notices of violation as a result of the October drawdown and subsequent release, with FERC also contacting Northbrook with a request for additional information concerning the drawdown.
The DWR notice came first, issued less than a week afterward on Oct. 8. DWR agents visiting the site Oct. 5 found sediment deposits 18-24 inches deep across the river’s entire width, with about 700 feet of the river’s reach below the dam visibly impacted and more than 2,000 feet of the river affected overall, the document says.
As a result, the agency found Northbrook in violation of two state water quality laws, each of which carries a maximum penalty of $25,000 per day, per violation. The DWR said that Northbrook violated a statute prohibiting the release of wastes in amounts that impact human, aquatic and wildlife health; and a statute requiring that state waters “shall be suitable for aquatic propagation and maintenance of biological integrity, wildlife, secondary recreation and agriculture.”
It required an extensive response from Northbrook, including a detailed account and timeline of the events leading up to the drawdown and refill, the decision-making process to determine that the drawdown and evaluation constituted an emergency situation and a sediment removal plan.
Five days later, the ACE issued its own violation, stating that undertaking the drawdown and release without a Department of Army permit constituted a violation of the Clean Water Act. That document also required a detailed response from Northbrook along similar lines to the one requested by the DWR.
So far, the agencies don’t appear to find Northbrook’s responses satisfactory. In an Oct. 15 letter that was his first response to the DWR, Ahlrichs denied the agency’s authority to penalize Northbrook and omitted much of the information requested in the Oct. 8 notice.
“While we very much appreciate NCDEQ’s (N.C. Department of Environmental Quality) concern for the health and proper protection of the Oconaluftee River and the larger Nantahala Watershed,” Ahlrich wrote, the company understands itself to be “exclusively subject” to FERC regulations.
“As such, we would have to contest any attempt by the NCDEQ to declare violations, mandate responses or impose penalties directly on the Bryson Project with respect to any aspect of its operations,” the letter reads.
The letter does provide a timeline for the drawdown but leaves out requested information such as reservoir level and precipitation data, evaluation of sediment conditions prior to the release and reasons why the company could not consult with DWR prior to the drawdown, among others.
“The drawdown was performed in good faith, consistent with the licensee’s responsibilities for dam and public safety and its obligations under the terms of the plan,” Ahlrichs wrote.
Regarding the “emergency situation” that spurred the drawdown, Ahlrichs said that Northbrook believes but does not promise that the situation will remain stable.
“While we cannot assure the situation will remain stable, based on our inspection we believe that it will and, in the absence of a change in conditions that again requires immediate action under the plan, we intend to consult with the NCDEQ and other appropriate agencies prior to a drawdown for repairs,” Ahlrichs wrote Oct. 15.
Northbrook wrote the DWR once more, on Nov. 4, to state that it had retained consulting firm Inter-Fluve to help evaluate the situation downstream, but that communication did not include the requested sediment removal plan, or any statement as to when one would be provided.
On Nov. 19, DWR Environmental Specialist Andrew Moore emailed Ahlrichs to state unequivocally that the response was insufficient, that none of the agencies involved had heard from the consulting firm regarding their assessment of the river, and to contradict Ahlrichs’ statement that sediment deposits had largely disappeared as of Oct. 8.
“Based on recent observations of the Oconaluftee River, significant sediment accumulation remains in the river below the Bryson dam and extending downstream to the Oconaluftee River’s confluence with the Tuckaseegee River, and now extending into the Tuckaseegee River,” Moore wrote. “In order to properly abate the stream standard violation and resolve the NOV, a Sediment Removal Plan is required.”
It wasn’t until five days after Moore’s letter, on Nov. 24, that FERC issued a five-page letter listing detailed questions it was requiring Northbrook to answer by Dec. 24.
Built in 1924, Ela Dam sits above an ecologically important stretch of river. Holly Kays photo
To be continued
The bureaucratic wranglings, made all the more complex because both federal and state agencies are involved, will likely go on for some time and the outcome — including any fines levied or lawsuits filed — is not yet known. The DWR is “continuing to investigate” and waiting for further response from Northbrook, said the agency’s spokesperson Anna Gurney.
Meanwhile, Northbrook maintains that residual sediment is “limited” and that it is cooperating with natural resources agencies.
“Northbrook is working with resource agencies to evaluate limited sediments in the river as the result of a dam evaluation performed to ensure the safety of the structure and protection of downstream residents,” said Northbrook Vice President Chris Sinclair via email.
Regardless of the regulatory outcome, Brown said, the fate of the creatures moving about the stream when the dam gates opened has already been sealed.
“The macroinvertebrate population is a great indicator of stream health, and before this sediment flush there was a really healthy macroinvertabrate population in the river below the dam,” he said. “But I will say at least most of that life was snuffed out when the sediment came up behind the impoundment.”