Silver King Mine Clean-up and Stream Restoration

By Alden Shallcross, State Lead - Montana/Dakotas Aquatic Habitat Management Program

The Missoula Field Office improved riverscape health, water quality, and associated fish/aquatic resource values in Sluice and Rock creeks by removing mine tailings contaminated with heavy metals, infilling a ditched stream segment, and restoring flow to the historic channel.

BLM and Trout Unlimited

restored flow to the historic

channel and enhanced aquatic

attributes. Using traditional​​

​​​​restoration practices (as

opposed to process-based

restoration), the project designer

sought to create the solution,

emphasize stability, and prioritize

sediment transport. This included

the use of heavy equipment to

enhance characteristics of a

single-thread channel (i.e., add

pools, riffles, and runs), as well

as vegetation transplants and

cuttings to stabilize the dimension,

pattern, and profile of the design

channel.

Sluice Gulch supports westslope cutthroat trout (a BLM Sensitive Status Species) and is a tributary to Rock Creek, which is a Blue Ribbon fishery that also supports threatened bull trout Designated Critical Habitat.

Despite the high resource values, a recent CERCLA evaluation noted moderate risk of heavy metal contamination associated with terrestrial, riparian, and aquatic habitat sediments within the historic mine area and adjacent Sluice Gulch Creek. Staff also noted that the miners had re-routed Sluice Gulch Creek into a ditch to drain the valley bottom and associated riparian-wetland soils, thereby facilitating access and related mining operations.

Rubber mats used to

minimize or avoid

streambank alteration

in Rock Creek, while

heavy equipment

removed and

transported heavy

metal contaminated

mine tailings from the

valley bottom and

adjacent terraces of

Sluice Gulch Creek.

To mitigate water quality and habitat degradation from these historic practices, the BLM planned and contracted for removal and reposit of contaminated sediments, then partnered with Montana Trout Unlimited (TU) to realign Sluice Gulch Creek with the historic channel (Photo 5).

BLM’s scattered ownership in the project area required close coordination with several private landowners, contractors and TU. Access to the site was especially challenging, ultimately requiring heavy equipment to ford Rock Creek. To minimize or avoid adverse impacts, the BLM implemented timing restrictions to protect cutthroat and bull trout and required the use of large rubber mats to protect the streambanks from tracked and wheeled equipment (Photos 6a-c).

The stream realignment and restoration converted approximately 1,000 feet of straightened, homogenous riffle habitat to 1,200 feet of meandering riffles, runs and pools, bolstered with logs, rocks and a plethora of live sod and willow cuttings. Lastly, the BLM installed a short segment of fence to exclude livestock from the restoration area until the vegetation recovers.

The BLM, TU, and Montana Fish, Wildlife, and Parks will continue to monitor project effectiveness, including the spawning and recruitment of trout, as well as the extent to which restoration has reactivated the processes that historically sustained riverscape attributes and resource values at the site.

Where this page came from

This page was imported from Bureau of Land Management. Published by the Bureau of Land Management and, as a work of the United States government, in the public domain; material credited to others is left out.

Nobody has written it yet — it is the source material at a new address, which is why search engines are asked to skip it and why no one earns from it. It is up for grabs: take it on, and it is yours to rewrite and to earn from.