Flathead Basin dam operators defend management decisions

Dam managers in Northwest Montana reiterated in a public presentation Thursday that reservoir operations during drought years require a delicate balance of competing objectives.

“There will be tradeoffs,” cautioned Jennifer Carrington, regional director for the Bureau of Reclamation, which oversees the Hungry Horse Dam above Columbia Falls.

Power production, flood-risk management, fish and wildlife mandates, recreation and downstream obligations all must be taken into account when determining the water levels at Hungry Horse Reservoir and Flathead Lake. And during a drought like the summer of 2023 — when the basin’s streamflows hit historic lows — water management becomes even more fickle.

“Last year was really an unprecedented drought with record low flow [on the Flathead River] at Columbia Falls,” Carrington said. “With such extreme conditions, reservoirs will inevitably look different during years like last year, and management operations during drought are often complex and challenging.”

Carrington was one of six panelists to take part in the online presentation Thursday — each explaining water management decisions in the Flathead Basin from the last two years, while looking forward to what is expected to be another low water year in 2024.

The presentation came on the heels of a letter issued last month by the Federal Energy Regulatory Commission that dismissed allegations that Energy Keepers Inc. mismanaged operations at the SKQ Dam on Flathead Lake in 2023, when the summertime lake level was approximately 2 feet below full pool. Energy Keepers is an entity of the Confederated Salish and Kootenai Tribes.

Prior to Thursday’s presentation, Flathead County commissioners sent a rebuttal letter to the energy commission stating their disapproval of how the dam was managed, accusing Energy Keepers of prioritizing power production over maintaining the lake level at full capacity, which they said resulted in financial damages for lakeside businesses. “Robust regulatory oversight” is needed going forward, they concluded.

Montana’s congressional delegation also expressed concerns about the lake’s low water level last year, with U.S. Rep. Ryan Zinke going as far as introducing a bill that would direct the Interior Department to maintain Flathead Lake’s water level between 2,892 and 2,893 feet from June 15 to Sept. 15 by providing water from Hungry Horse Reservoir and releasing excess water downstream.

Carrington noted that last year’s dam operations drew ample feedback from stakeholders. While she didn’t address Zinke’s proposed legislation directly, Carrington said that releasing more water and decreasing storage of Hungry Horse Reservoir in the fall and winter “can impact the reliability of reservoir refill” and affect fish species.

Carrington said she hoped the online presentation would clarify “the physical and legal constraints, the government’s operation, and the process for implementing any changes” to planned dam operations.

“What is controllable and what isn’t,” she said.

LEEANN ALLEGRETTO, with the National Weather Service in Missoula, painted a picture of what dam managers faced last summer as all of Northwest Montana’s snowpack melted out by early June.

The average temperature in the Flathead Valley in May 2023 registered at 72.7 degrees, compared to the normal average of 65.1. That early warm-up accelerated the rate of snowmelt and corresponding streamflows.

“It just kept melting and melting, and the runoff got lower and lower and lower,” she said of last May. “By June 1, we just ran out of runoff and that was the trend going into June.”

Flathead Lake hit full pool briefly during that time, but soon afterward began to drop as historically low stream inflows couldn’t keep up with the amount of water being released at Polson to meet minimum flow requirements.

Chris Runyan, a hydrologic engineer for the Bureau of Reclamation, said operations at Hungry Horse Dam were similarly affected by the early melt out in 2023.

“The reservoir did not completely refill, faded earlier, and complete refill of the reservoir was sacrificed to keep flows down at Columbia Falls a more constant flow to benefit resident fish,” he said.

In giving an overview of Hungry Horse Reservoir, Runyan noted that the Hungry Horse Dam is just one of 14 projects on the Columbia River system that must be operated to meet congressionally authorized purposes, including fish and wildlife management.

Likewise, the SKQ Dam operators have myriad obligations to consider under its license, said Eve James with Energy Keepers.

She pointed to the dam’s operating license, which acknowledges that there are some streamflow conditions where meeting the flood risk management elevation, filling the lake and meeting the lower Flathead River minimum flow requirement cannot all be met.

In her presentation, she noted a 2010 draft drought management plan for Flathead Lake and SKQ Dam that was never formally adopted. Since data in that plan is nearly two decades old, she said Energy Keepers is currently working to craft an updated document that will be submitted to the Department of Interior.

DROUGHT IS a possible scenario again this summer, Allegretto cautioned, with snowpack in the Flathead Basin trending below average. However, hydrologic conditions can change in the coming months, she said.

“It’s not ideal, but we still have plenty of time,” Allegretto said. “With additional snow or rain on snow as we get into May, not all hope is lost.”

Runyan said thus far in 2024 streamflows at Hungry Horse have been elevated above last year’s level, which has helped keep the reservoir’s current elevation significantly higher than 2023.

“The reservoir refill is likely,” he said, “but I’d say it’s not 100% as there are still extremely low snowpack values in the far end of the basin.”

Meanwhile, James said the Flathead Basin’s 2024 water supply forecast is trending below the 30-year average, but it is above the volumes needed to meet minimum flows for the lower Flathead River.

The current level on Flathead Lake is about 2 feet higher than it was at this time last year.

“If an early runoff is detected like last year, we will again coordinate flood risk management to refill the lake,” she said.