Complaints made over utility management of Hebgen Lake, dam

January 6, 2022 GMT

BILLINGS, Mont. (AP) — Summer drought followed by a Hebgen Dam component failure in late November led to complaints about how the dam’s owner managed summer water levels in Hebgen Lake and why it failed to notice a sudden reduction in water released into the Madison River this fall, potentially harming brown trout.

Owners of recreational businesses that rely on Hebgen Lake being full during the summer argue dam owner NorthWestern Energy was aware of the low snowpack and runoff in spring 2021, but continued to allow “excessive spring discharges” of water into the Madison River in southwestern Montana.

Instead of draining the lake, the Hebgen businesses argued in a complaint to the Federal Energy Regulatory Commission, NorthWestern should have sought a variance to its operating permit that requires it to maintain a minimum flow into the river.

In mid-July, NorthWestern Energy sent a news release notifying Hebgen Lake users that the reservoir would continue to drop to cool the Madison River, which is required under its operating license. At that time, lake levels were already a foot (30 centimeters) below the full pool minimum. By Oct. 1, the water level had dropped another 4 feet (1.2 meters), the businesses said.


Low water levels left docks and boat ramps high and dry and caused business losses as recreationists cancelled reservations. The lake was below its required level for 70 days, the companies said.

Firehole Ranch had to close early and cancelled 39 reservations at a loss of more than $356,000, it said. Other businesses filing a complaint with the FERC include Kirkwood Marina and Yellowstone Holiday Resort, The Billings Gazette reported.

With drought predicted to be more likely due to climate change, the businesses asked FERC to reevaluate the management requirements for Hebgen Lake and the Madison River.

Separately, three environmental groups filed a complaint on Wednesday asking for an independent investigation into the dam malfunction in November and for FERC to hold NorthWestern accountable for its effects.

NorthWestern Energy is investigating the cause of the failure of a part in the dam and will study the effects the low water levels had on the fishery, said spokesperson Jo Dee Black.

The failure happened at 2 a.m. on Nov. 30, but NorthWestern Energy wasn’t aware of it until shortly after noon, the utility told FERC. Volunteers from the area and state fisheries employees rescued stranded fish, moving them into deeper water.

The repair to the dam was made late on Dec. 1 and water flows were gradually restored. FERC last month told NorthWestern Energy it should install an alarm system and a camera to detect any future problems.


The conservation groups are concerned that the reduced flows killed some fish and may have exposed brown trout eggs laid in gravel to air, killing them.

“With already historically low brown trout population numbers greater than age 2, additional fish mortality as a result of this dewatering event will have long-term negative impacts on the fisheries’ health, particularly for brown trout,” the Montana Environmental Information Center, Upper Missouri Waterkeeper and the Madison River Foundation said in their complaint.

“NorthWestern needs to fully cooperate with a comprehensive and transparent investigation, mitigate the impacts to the environment, community and economy, take measures to ensure that this never happens again, and pay to fix the problem out of its shareholders’ pockets,” said Derf Johnson, staff attorney for the MEIC.