Cleanup in the Upper Clark Fork began in 2010 and is proceeding in phases (from 1 to 22 according to the 2023 Strategic Plan). Current developments are described below. For more updates also see our February 2025 and May 2025 newsletters, and DEQ's February 2025 Clark Fork River News.
START DATE: Mid-January 2025
ESTIMATED TOTAL COST: $5 million+ (incl. monitoring & maintenance)
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LOCATION & DESCRIPTION:
==> See all Phase 7 cleanup design and related documents HERE.
A 40-acre site ~10 miles south of Deer Lodge to the east of Racetrack Pond, running 2.2 river miles SW to NE beginning just north of Gemback Road.
CHARACTERISTICS:
Relative to other phases, the Strategic Plan characterizes Ph. 7 as "Moderate Priority" for erosion and risk of contaminated sediments reaching the river; and "High Priority" for contaminated soil levels, as this area includes a public fishing access (see Strategic Plan, pp.11-12). DEQ estimates it will remove 135,800 cubic yards of mine waste-contaminated material from the site.
STATUS (as of May 2025)
Construction began in January and is proceeding on schedule (contractor is Intermountain Construction Services of Butte, who also worked on Phases 5/6, Silver Bow Creek, and the Trestle Area in Deer Lodge). Please observe signs and use the temporary parking area to access Racetrack Pond. The river, but not the floodplain, is open to public use during construction. CFRTAC raised numerous issues in its comments on the Phase 7 design, including the extent and location of contamination removal (reduced from previous phases); the preference for more woody debris on banks and instream; the need to monitor the river's response to lower bank designs; and more. CFRTAC was generally satisfied with the State's response to comments, though some issues, such as how the 100-year Channel Migration Zone is applied to determine removal boundaries, will not be considered until future phases. (Learn more in our Feb 2025 newsletter.) The State currently estimates work will be completed by October 2025.
ESTIMATED START DATE: Was 2025. Now likely moved to 2026
ESTIMATED TOTAL COST: $20.62M (may change)
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LOCATION & DESCRIPTION:
Includes Arrowstone Park. Extends through Deer Lodge from the I-90 bridge at Exit 187 (eastbound) north to the city's boundary with Grant Kohrs Ranch (near the Cottonwood Creek confluence).
CHARACTERISTICS:
This phase is of high concern primarily because previously capped soils at Arrowstone Park that contain arsenic and other contaminants have been exposed in some areas, creating public health risks. As noted in DEQ's 2024 Clark Fork River News, community concern led DEQ to prioritize cleanup here, install safety signage, and add temporary soil caps on bare spots with exposed toxic contaminants.
STATUS (as of May 2025):
DEQ will conduct additional sampling at the site to examine soils at greater depth in some areas, and to do additional surface-level sampling in other areas. These findings will help determine contamination removal boundaries and depths, which is necessary before a cleanup design can be drafted. DEQ has continued to coordinate with EPA's toxicologist and the MT Dept. of Public Health & Human Services to determine cleanup levels for arsenic, which are expected to be more protective of human health than originally considered in the ROD, given the level of public use of the park. Cleanup here has been delayed as the State and EPA reexamine the arsenic cleanup standard to be used at the site. A stricter standard will be more protective of human health, but will likely also increase costs and cause delays. While the site is being monitored to determine if additional soil caps are needed to cover exposed soil, the public is advised to obey caution signs, avoid areas with exposed soil, and wash hands, boots, pets, boats, etc. after any potential exposure to contaminated soils, especially on the river banks.
COMPLETED PHASES (maintenance & monitoring underway):
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NEXT UP AFTER PHASE 7 & PHASE 13/14 (described above):
Phases 7 and 10-14 (described above) were prioritized for cleanup based on the ranking criteria described on p. 12 of the 2023 Strategic Plan. Other phases will be addressed in an upstream-to-downstream sequence after these higher-priority phases are completed. These include: