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Groups file complaint over Hebgen Dam malfunction

Posted at 4:18 PM, Jan 09, 2022

BOZEMAN - A citizen's complaint has been filed against NorthWestern Energy over a dam malfunction at Hebgen Lake in December 2021.

Montana Environmental Information Center (MEIC) says the owner of the dam, Northwestern Energy, in Butte, should be held accountable for the mishap. The environmental group is asking the Federal Energy Regulatory Commission (FERC) to require Northwestern to pay for an independent investigation of the dam malfunction. The incident reduced water flow in the Madison river by 57 percent within fifteen minutes.

MEIC says the federal agency should consider creating a fund to support ecological restoration projects on the river and a long-term study of the impact on the watershed.

MEIC was joined in the complaint by Upper Missouri Waterkeeper and the Madison River Foundation.

Northwestern Energy tells MTN it completed a $40 million modernization of the dam in 2018 and has already submitted a report to the FERC Northwestern says it is taking action to prevent a repeat of the gate failure, which led to the mishap.

From MEIC:

BOZEMAN, MT - Upper Missouri Waterkeeper, Montana Environmental Information Center, and the Madison River Foundation filed a citizens complaint [] on Jan. 5, 2022, with the Federal Energy Regulatory Commission (FERC) regarding NorthWestern Energy’s failure to uphold the conditions of Hebgen Dam’s license that resulted in the November 30 dewatering event on the Upper Madison River.

“This formal complaint is the means for holding NorthWestern Energy accountable for its dam’s failure, a thorough third-party investigation of impacts, and targeted action to make the river and downstream communities whole again,” said Guy Alsentzer, Executive Director of Upper Missouri Waterkeeper. “Two significant flow failures in fifteen years at NorthWestern’s Hebgen Dam sound the alarm call for much needed additional monitoring and redundancy to protect the river ecology and downstream economies that are directly dependent on stable outflows.”

NorthWestern Energy, the owner and operator of the dam under federal license No.P-2188, issued by FERC, violated two permit conditions when the gate shaft broke and drastically reduced outflows from the Hebgen reservoir. The provisions violated were (1) to maintain a continuous minimum flow of 600 cubic feet per second (cfs) at USGS Gauge No. 6-388 near the Kirby Ranch, and to (2) limit changes in outflow from Hebgen Dam to no more than 10 percent per day for the entire year. The USGS Gauge located at the Hebgen Dam measured outflow dropping from 648 cfs to 278 cfs within a 15 minute period (a reduction of 57%) and a maximum reduction down to 216 cfs (a reduction of 67%) within a 24-hr period. Similarly, Madison River flows dropped below the 600 cfs Article 403 minimum at Kirby Ranch, ultimately reducing to 395 cfs.

Upper Missouri Waterkeeper, Montana Environmental Information Center, and the Madison River Foundation are requesting that FERC require Northwestern Energy fund a thorough, third-party investigation of the malfunction and hold the permittee accountable to take the necessary steps in ensuring this tragedy is an isolated event.

“As a public utility, NorthWestern Energy must be held accountable for mismanagement of Montana’s natural resources, especially our water,” said Derf Johnson, Staff Attorney and Clean Water Director at MEIC. “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.”

If FERC determines there is good cause to proceed with an investigation, the complaint will trigger a formal process, overseen by FERC, investigating the dam failure and the adequacy of Northwestern’s oversight and monitoring equipment failures that led to the dewatering of one of Montana’s most famed blue ribbon trout streams during critical spawning season. Another outcome could be the creation of targeted funding to support ecological restoration projects and help affected downstream stakeholders.

“We have committed to our members, to Montanans, and to the Madison River, that we will protect its vital flows and be responsible stewards in maintaining a healthy watershed,” said Jonathan Malovich, Executive Director of Madison River Foundation. “This is just a single step in the right direction of many more to come to change the way we can all protect and manage the water that flows down the Madison River.”

Because the long-term ecological and economic impacts from Hebgen Dam’s dewatering on the Upper Madison River may remain unknown for years to come, it is critical that a formal, nonpartisan process ask these questions and investigate lasting solutions now. The Complaint filing is separate from ongoing late December 2021 public correspondence between Northwestern Energy and FERC concerning the Upper Madison’s dam failure and is specifically focused on addressing ecological degradation.

From NWE:

An investigation is underway now of the Nov. 30 Hebgen Dam gate failure.

Since taking ownership in 2014 of 11 dams in Montana, NorthWestern Energy invested hundreds of millions of dollars in the system. Those investments have increased the generating capacity, improved fish passage through the dam system, modernized the infrastructure and provided more recreational opportunities. That investment includes a $40 million upgrade at Hebgen Dam completed in 2018.

On Nov. 30 a component of a gate at Hebgen Dam-- installed in 2015 during the upgrade project -- failed.

NorthWestern Energy submitted reports to the Federal Energy Regulatory Commission about the failure and together with our federal regulatory agency and others, are taking purposeful steps to ensure a thorough analysis of the gate component. The analysis, based on sound engineering principles, will be used to understand why this relatively new part failed and to establish corrective actions. 

NorthWestern Energy will also be working with resource agency biologists and others to develop scientific studies to assess its effects on the fishery.


Hebgen Dam malfunction causes water level drop; brings community together to save trout