Conservation Groups Seek Emergency Court Action Over Beaverhead River Flows

BOZEMAN, Mont. — Three conservation groups are seeking emergency court action over plans to significantly reduce flows in the Beaverhead River beginning September 1, arguing that Montana Fish, Wildlife & Parks should explain why it has not exercised an instream flow water right held by the agency.

Upper Missouri Waterkeeper, Alliance for the Wild Rockies and Save the Bull Trout filed an emergency motion for a preliminary injunction in Lewis and Clark County District Court last week. The groups are asking the court to require FWP to explain its decision not to assert its Beaverhead River instream flow right as the river faces declining flows and concerns surrounding the health of the fishery.

The court filing comes as flows below Clark Canyon Dam are scheduled to decline substantially beginning September 1.

According to information released by FWP, the Bureau of Reclamation, Clark Canyon Water Supply Company and East Bench Irrigation District informed the agency of plans to reduce releases into the Beaverhead River. The conservation groups say flows are expected to fall to approximately 25 cubic feet per second (cfs).

Current flows were reported at approximately 217cfs, compared with what the groups describe as an average of roughly 400cfs for this time of year.

The scheduled reduction has also resulted in FWP announcing a full fishing closure on the Beaverhead River from Clark Canyon Dam downstream to Pipe Organ Fishing Access Site beginning September 1.

Groups Question FWP's Instream Flow Right

At the center of the dispute is an instream flow water right held by FWP.

According to the conservation groups, FWP holds Water Right 41B 194351-00, an instream flow right on the Beaverhead River with a priority date of June 12, 1931 and a maximum flow rate of 200cfs.

The groups argue that the right could potentially be used to protect river flows and are asking why FWP has not asserted it as conditions decline.

“FWP has systematically shirked its obligations to enforce the very water rights it owns, which have the potential to mitigate one of the many problems plaguing Southwest Montana’s rivers — low flows,” Upper Missouri Waterkeeper Executive Director Guy Alsentzer said in the organization’s announcement.

Alsentzer also argued that declining trout populations, water quality concerns and the approaching spawning season make the agency's decision particularly important.

The claims are part of a larger lawsuit originally filed in August 2025 challenging FWP's administration of instream water rights. The lawsuit alleges the agency has failed to exercise and enforce those rights when rivers approach minimum flows and argues that FWP's actions violate its public trust responsibilities and provisions of the Montana Constitution.

Those allegations remain subject to the court proceedings.

Outfitters Raise Concerns About Beaverhead Fishery

The conservation groups' court filings include statements from fishing outfitters who say they're concerned about the potential effect of extremely low flows on the Beaverhead River's trout population.

Montana fly fishing outfitter Toby Swank expressed concern about the lack of information surrounding FWP's decision not to use its instream flow right.

“The Beaverhead's brown trout population spawn in the fall, and stable flows generally improve spawning and population recruitment in wild trout fisheries,” Swank said.

Longtime Beaverhead River outfitter Shaun Jeszenka also submitted an affidavit questioning why the water right has not been exercised.

The groups contend the upcoming reduction could further strain a Beaverhead River fishery already facing declining trout populations and other environmental pressures.

Emergency Restraining Order Requested

Following FWP's announcement of the September 1 fishing closure, the conservation groups took another legal step, filing an application for an emergency temporary restraining order.

The groups are asking the court to issue a temporary restraining order while their preliminary injunction request is considered and before the scheduled flow reduction takes effect.

Importantly, the preliminary injunction motion does not ask the court to order FWP to make a specific water-right call or require the release of water already stored in Clark Canyon Reservoir.

Instead, the groups say they want FWP to publicly explain why it is not asserting its senior instream flow right under the current conditions.

The court filings raise questions about how water is allocated between agriculture, irrigation and the protection of Montana's public fisheries during periods of limited water availability.

With flows scheduled to begin dropping September 1 and a fishing closure set to take effect on a portion of the Beaverhead River, the dispute could have implications for anglers, outfitters, agricultural producers and other water users throughout Beaverhead County.

Southwestern Montana News will continue to follow developments involving the Beaverhead River fishing closure, scheduled flow reductions and the ongoing court case as additional information becomes available.