The rocks in the West Branch of the Penobscot River were exposed and boats left high and dry after a recent failure at the McKay Station caused the hydroelectric project to stop moving sufficient water downstream. Credit: Courtesy of Sarah Sindo

Two weeks after an unexpected shutdown of the McKay hydroelectric station that left portions of the West Branch of the Penobscot River below Ripogenus Dam at extremely low levels for an extended period, two hydro units remain out of service.

The station is operated by Brookfield Renewable Energy Partners.

The July 7 shutdown killed fish and aquatic life, and hampered fishing, boating and other activities that require higher, flowing water, according to the Maine Chapter of Trout Unlimited. It was especially “catastrophic” for the landlocked salmon that recently hatched in the river, the organization said.

“Essentially, the entire West Branch 2023 salmon year class was eliminated,” said Ed Spear, a retired fisheries biologist formerly employed by Great Northern Paper, an owner of the Ripogenus Dam before Brookfield. “The timing of this disastrous outage could not be worse as it occurred during the peak fish and aquatic growing season and a prime angling period and it occurred during daylight hours.”

Spear said alevin, salmon in the larval stage, have difficulty dealing with the kind of sudden change in water flow that occurred on the West Branch. He said the part of the river designated for fish reproduction and rearing and protected under the FERC license would have been left without water during the event.

The rocks in the West Branch of the Penobscot River were exposed and boats left high and dry after a recent failure at the McKay Station caused the hydroelectric project to stop moving sufficient water downstream. Credit: Courtesy of Sarah Sindo

According to Brookfield’s report on the incident to the Federal Energy Regulatory Commission filed on July 21, a lightning strike involving a Versant Power transmission line caused all of the hydro stations on the Penobscot River to go offline. That and other lightning strikes damaged lightning arrestors and hydro units at McKay Station, which is located 30 miles west of Millinocket.

Brookfield responded by shutting down two units at McKay Station, which was unable to maintain its required whitewater recreation water flows. According to Maine Trout Unlimited, Brookfield’s SafeWaters website posted a flow of only 100 cubic feet per second at 7 p.m. on July 7.  The minimum flow on Fridays during the summer is set at 2,220 cubic feet per second.

The flow at McKay Station at 10 a.m. Monday was listed as 2,448 cubic feet per second. The condition persisted until Brookfield crews could open a deep gate located at Ripogenus Dam to increase the flows.

Evidence of the effects of the low water on fish in the river were noticeable the day after the McKay Station flow was slowed.

“From the boat I could only see part of the area, but I could see about 10 dead salmon, all about 10-inch fish lying on the bottom of the river, and I wondered how many salmon had perished due to the previous evening’s dewatering,” said Registered Maine Guide Todd Mercer of paddling near the facility.

Ripogenus Dam is currently in the relicensing process by FERC, which governs the regulations for the operation of such hydroelectric projects.

This isn’t the first time there has been water flow control problems at McKay Station, according to Maine Trout Unlimited. There were water drawdowns during the summers of 2020 and 2021 that rendered boat launches on Chesuncook Lake — including Ripogenus and Caribou lakes and Moose Pond — unusable, which made operating boats hazardous and hampered loon nesting.

“We are very concerned the severe drawdowns of the lakes under Brookfield’s operation of Ripogenus Dam and McKay Station are having a negative impact on the fish, aquatic communities, wildlife and recreational use and enjoyment of one of Maine’s premier lakes,” said Bill Houston, who represents the Chesuncook Caribou and Chesuncook Camp Associations.

A section of the West Branch of the Penobscot River is shown running low, with exposed rocks along the shore, after a recent failure of the Brookfield Renewable Energy hydroelectric project at McKayStation below Ripogenus Dame. Credit: Courtesy of Sarah Sindo

In another incident in April 2022, seepage at the Ragged Lake Dam led Brookfield to conduct an emergency release of water that resulted in the washout of the Ragged Lake bridge leading to the Greenville Road, according to Maine Trout Unlimited.


Betsy Ward, who owns a camp on Ragged Lake, said they have had to drive an extra hour to reach Greenville Road via the Golden Road with the bridge out of commission.

“The dam was finally repaired last fall and water levels have been restored, although we are reaching the time of year when the dam owners will probably start drawing it down,” Ward said. “As for the bridge, it is scheduled to be rebuilt later this summer.”

At the request of Maine Trout Unlimited, Brookfield conducted a study last fall to help determine the amount of fish mortality and stranding that occurs after an event during which flows are reduced rapidly to 500 cubic feet per second.

“Stranded fish were observed throughout seven distinct reaches of the West Branch between McKay Station and the Nesowadnehunk Deadwater,” Brookfield reported. “Approximately 450 stranded fish were observed during the study, representing nine species.”

It estimated that approximately half of the fish observed died, among which 55 percent were landlocked salmon.

This, some said, is a preventable thing.

“FERC has the ability to prevent and/or minimize future catastrophic flow interruptions caused by outages,” Spear said. “Long-term and short-term mitigation measures are needed.”

Spear said FERC should require Brookfield to hire an employee to staff the station and that the company should re-engineer and maintain its emergency flow mechanism. He said part of the licensing process should include provisions for determining and administering emergency outage flows into the river.

“Long-term mitigation is needed to rebuild salmon stocks, notably the loss of 2023 hatchlings and aquatic insects,” Spear said.