Rattlesnake Creek – February Update

By Rob Roberts, Project Manager, Trout Unlimited National

For more than two decades, Montana FWP, the WestSlope Chapter, Trout Unlimited National and partners have attempted to conserve, protect and improve fisheries in Rattlesnake Creek through research projects, habitat improvement and fish passage projects such as screening irrigation ditches.  Historically, Rattlesnake Creek supported a significant population of migratory bull trout, currently listed as threatened under the Endangered Species Act, and Westslope cutthroat, a sensitive species according to the state of Montana and US Forest Service. 

The fishery was significant enough that the confluence of Rattlesnake Creek and the Clark Fork River was one of the largest and most important fish camps for the native Salish people, and the Salish name for the creek means “place of the small bull trout.”

When the City of Missoula acquired the lower Rattlesnake Creek dam and ten dams on mountain lakes in the Rattlesnake Wilderness Area in 2017, TU launched a new effort on Rattlesnake Creek to remove the lower dam, which had impeded migratory fish for more than 100 years. Since the lower dam was deteriorating and was no longer even viable as a back-up municipal system, the City, Montana FWP and TU developed a plan to remove all infrastructure on the dam site and restore the stream channel and floodplain.

With construction starting in June of 2020, more than 4,000 cubic yards of concrete demolition debris was removed from the site and the stream was rebuilt using large boulders and cobble from the site and included four logjams for overhead cover and pool development.

The dam demolition and stream channel reconstruction were completed by November 2020 and achieved the following results:

• More than 1,000 linear feet of stream reconstruction 
• 10,000 willow cuttings and 14,000 containerized plants in stream banks in floodplain 
• 4 wetland cells with the restoration of 5 acres of floodplain
• More than 180 volunteers from the local area participated in aspects of the project
• Reconnection of Rattlesnake Creek from headwaters to Clark Fork River for the first time in 120 years 

The City’s purchase of the water utility not only ensured that future generations would have access to clean, affordable and reliable water, but set the stage for the removal of the lower Rattlesnake Dam and the historic renovation of the entire water system including water mains, wells, tanks, and the defunct system on Rattlesnake Creek, including the dams on the wilderness lakes.

Currently, the wilderness dams have not been used for water delivery in more than 30 years, suffer from a lengthy maintenance backlog and are largely in-operational. These impoundments are capable of storing 2,585 acre-feet total water and there are great opportunities to remove the dams to improve public safety and wilderness character and allow for better water control to improve streamflow and temperature for the native fishery. 

A pilot wilderness dam decommissioning project could happen as early as 2022, while the evaluation of the other dams will be ongoing.  The City and TU plan to solicit public input and feedback about the general goals and visions for these future projects sometime in the spring of 2021.