At 7 p.m. on July 7, there was an unexplained shutdown of the McKay Hydroelectric Station below Ripogenus Dam. This so-called “trip event,” that lasted over 4 hours, left the fabled West Branch of the Penobscot River and the popular Big Eddy salmon and trout fishery virtually dry for that period, according to a press release from Trout Unlimited. TU said that this resulted in “devastating impacts to fish and aquatic communities, harmed the river system, and impacted boating and recreational activities.”

According to the power station owner, Brookfield Renewable Energy Partners, McKay outflows normally range from 3000 to 1800 cubic feet per second (CFS). The Brookfield SafeWaters website posted an “outage” flow of 100 CFS at 7 p.m. on July 7, and it remained low at 11 p.m. Brookfield has offered no explanation for the extreme flow reduction. The resulting water flow drop was catastrophic for the recently hatched landlocked salmon in the river.

“Essentially, the entire West Branch 2023 salmon year class was eliminated,” said Ed Spear, 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. Recently emerged alevin (larval salmon) are extremely vulnerable to rapid flow change and the initial dewatering and subsequent flooding of the riverbed.”

In a letter to the Federal Energy Regulatory Commission (FERC), which oversees such dams, in response to the Brookfield Ripogenus disaster, Spear wrote: “FERC has the ability to prevent and/or minimize future catastrophic flow interruptions caused by outages. Long-term and short-term mitigation measures are needed. Initially, FERC should order that a McKay Dam Tender position be created and staffed during the aquatic growing season, housing is readily available. Secondly, McKay Station emergency flow mechanism should be ‘reengineered’ and maintained. Thirdly, during the ongoing licensing, the appropriate emergency outage flow should be determined as well as methods of delivering that flow to the river. Long term mitigation is needed to rebuild salmon stocks, notably the loss of 2023 hatchlings (alevin) and aquatic insects. This can be accomplished by requiring minimum flows of 2200 CFS accompanied by requiring the Licensee to follow a Ripogenus Impoundment storage curve that guarantees storage will be available to meet the year-long minimum flow goal.”

Water-level problems are not new to the lake above the dam and the tailwater below the power station. The July 7 incident is the most recent in a series of events hurting the West Branch of the Penobscot River below Ripogenus Dam and Ripogenus-Chesuncook Lake, Maine’s third largest. In the winter of 2021, the lake was refilled from a previous drawdown by drastically reducing power generation at McKay Station below the flow levels required to protect salmon spawning and incubation.

The Ripogenus Dam (Project No. 2572) is currently facing FERC relicensing. The federal licensing of McKay Station expires in September of 2026.

Like the fabled tailwater salmon fishery at Grand Lake Stream, the West Branch of the Penobscot River below McKay Station is a popular Maine sport fishery like no other. As the date approaches for Brookfield’s license renewal with FERC, other state fisheries conservation organizations besides Trout Unlimited, as well as sportsmen themselves, might serve the greater good by taking a keen interest in this license renewal process.

V. Paul Reynolds is editor of the Northwoods Sporting Journal, an author, a Maine guide and host of a weekly radio program, “Maine Outdoors,” heard at 7 p.m. Sundays on The Voice of Maine News-Talk Network. Contact him at vpaulr@tds.net.

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