The City of Missoula has completed a pilot dam decommissioning at McKinley Lake designed to return a constricted reservoir to its historic footprint and restore stream and fish habitat, city ecosystem services lead Morgan Valiant told a Rattlesnake Creek Watershed Group presentation. Valiant described multiyear planning, engineering, controlled blasting and hand restoration that produced a functional stream channel and a recovering riparian area.

Valiant said McKinley was selected as a pilot because of a head‑cut erosion scar and seepage threatening dam integrity, modest storage (quoted in the presentation as about 168 acre‑feet) and detailed historic engineering records that simplified design. "We picked McKinley Lake," he said, "so the rest of this talk I'm going to really be focusing on the work we've done up at McKinley." He told the audience the team rebuilt roughly 1,500 feet of stream, installed about 15,000 native plants and 10,000 willow cuttings, and leveraged volunteers to complete much of the work.

Why it matters: the McKinley project demonstrates a repeatable approach to aging dams on federal wilderness lands where the City of Missoula holds water‑storage rights. Valiant said the removal work and channel reconstruction reconnected fish passage "all the way 30 miles into the Rattlesnake full fish connection" with the Clark Fork River, and that the site has shown rapid wildlife and bird returns since restoration.

Project design and approvals: planners ran a comprehensive set of environmental reviews (the team completed MEPA and NEPA‑level assessments and a Forest Service minimum‑tools analysis) and consulted partners including Trout Unlimited, the Forest Service and engineering consultants. Valiant described five construction alternatives, from purely hand labor to heavy mechanical options, and said the team settled on a hybrid minimum‑motorized approach that included two days of helicopter support, motorized pumps and an auger for short periods to reduce overall site impact.

Field operations and blasting: to manage flows and work in dry conditions crews installed siphons and pumps, flew in camp and gear, and prepared the site with Montana Conservation Corps crews and Forest Service packers and blasters. Valiant gave a detailed account of two controlled blasts used to breach the McKinley dam, describing the precautionary closures and trail guards put in place: "We ended up doing it in two blasts" and the team salvaged rock and historic valve structures to reuse in the stream design.

Funding and volunteer contributions: Valiant said the project secured a mix of funding including a $700,000 FEMA grant and approximately $2 million raised from grants and donations in two years; he emphasized that an estimated 80% of the project funding came from non‑taxpayer sources (donations and grants) and that thousands of volunteer hours contributed to planting and handwork.

Restoration approach and invasive‑species precautions: the team used case studies of other drawn‑down lakes (Little Lake, Glacier Lake) to shape a largely passive restoration strategy with targeted interventions where needed. Valiant described multi‑year prework to prevent invasive species introductions, strict cleaning protocols for brought‑in materials, and ongoing volunteer and city crew weed control.

Legal and operational context: many of the upper Rattlesnake lakes and dams sit within federal wilderness with special provisions that allow the water‑right owner customary access for maintenance. Valiant cautioned the audience that those special‑use permits and easements give the city more explicit rights to maintain than to decommission, which required careful legal work. "We had to kind of get through some legal gray areas to allow us to actually decommission," he said.

Next steps: Valiant said the city is continuing work on Sanders Lake (efforts to address blocked valve and piping), and that staff plan to pursue a full NEPA process in winter 2025–26 for six additional dams prioritized for removal based on small water rights and feasible logistics. He said the long‑term plan is to turn fully restored pilot sites over to the Forest Service and rescind the city's easement; McKinley turnover is targeted for 2027, contingent on monitoring and successful restoration results.

Audience questions focused on beaver recolonization, channel rebuilding, invasive species mitigation, Forest Service cost participation (Valiant said the Forest Service generally does not fund renovations and legal arrangements are complex), and lessons learned on balancing motorized tool use with wilderness character. Valiant credited collaboration with the Forest Service and said the McKinley approach — a mix of limited motorized support, handwork and controlled blasting — will be adjusted to site conditions on future projects.

The city plans continued monitoring of McKinley through the coming runoff cycles, further data collection for Sanders and other prioritized dams, and the NEPA process that will guide removal or rehabilitation decisions for the next set of sites.