Clark Fork cleanup: A kinder, gentler approach helps retain, restore habitat

“We seined the river very thoroughly in the vicinity of Deer Lodge and did not find any fish whatsoever,” the report observed.

It takes a whole lot longer to bring a river back.

Remediation of mining and smelting wastes long bedeviling the Clark Fork River and related restoration of natural resources began in 2010. Current projections suggest the work will continue until at least 2038 on the 47 river miles between the river’s headwaters near Warm Springs and Garrison — the reach of the Clark Fork considered most injured by historic mining and smelting pollution.

Contaminants of concern include arsenic, cadmium, copper, lead and zinc.

The latest work, described as Phase 7, began in January near Racetrack Pond upstream of Deer Lodge and is expected to continue until mid-December. Phase 7 has addressed about 1.4 river miles.

The Montana Department of Environmental Quality and the state’s Natural Resource Damage Program are supervising the cleanup and restoration, with EPA providing oversight.

On Tuesday afternoon, DEQ, NRDP and EPA participated in a tour of Phase 7 work to date. The Clark Fork River Technical Assistance Committee organized the outing. More than 40 people participated.

The key phrases Tuesday were “lessons learned” and “a double-edged sword.”

DEQ had promised its approach for Phase 7 would be kinder and gentler than earlier phases that removed just about everything, including riparian vegetation providing shade and cover for fish. One wag compared the desolate result to a Walmart parking lot.

A once abundant population of brown trout in the upper river declined dramatically. Many believe the forceful approach to remediation played a role in that population slide. Related research continues. 

For Phase 7, DEQ used new streambank treatments, incorporating live willows, large wood and log structures to provide better aquatic habitat.  

And the agency elected to leave select stands of riparian vegetation, even if they were rooted in contaminated soils, as one strategy to preserve habitat.

These approaches were among the lessons learned from previous interventions that were more aggressive.

Yet the more attenuated approach presents a few double-edged sword dilemmas, said Logan Dudding, DEQ’s Clark Fork River project manager.

For example, leaving a section of riparian vegetation and the soil in which it is rooted can perpetuate issues from an abnormally high floodplain built by the catastrophic flood in 1908 that deposited contaminated sediments there and in streambanks of the Clark Fork River.

One goal of the remediation is to restore a more natural interaction between the river and its floodplain. A high point could cause seasonal high flows to sluice and erode.

DEQ expects to remove about 135,000 cubic yards of contaminated materials during Phase 7. One cubic yard is roughly equivalent in size to a standard washing machine. Workers for contractor Intermountain Construction Services truck the wastes to a repository in the Opportunity Ponds.

Tuesday’s tour launched from Arrowstone Park just outside Deer Lodge. The park has been controversial from the beginning because it was built by an Atlantic Richfield contractor atop contaminated mining and smelting materials treated solely with deep-tilled lime and then capped.

In recent years, contaminants have begun leaching to the surface, creating areas called “slickens” that won’t grow vegetation. Several people on the tour said they are regular users of the park.

The U.S. Fish Commission bulletin from 1891 demonstrates that the river’s pollution began years before the big flood as copper mining escalated in Butte and the smelter in Anaconda processed that ore.

Atlantic Richfield, a U.S. subsidiary of bp America, purchased the Anaconda Co. in 1977 and is responsible under Superfund law for funding cleanup and restoration.  

A 2008 settlement with Atlantic Richfield provided about $94 million for remediation and roughly $27 million for restoration. Before initiation of Phase 7 the sum of remaining funds totaled about $98.4 million. 

Observers worry the money will run out well before Garrison. If that happens, a so-called round robin process would kick in, requiring additional, alternating funding from the EPA, Montana and Atlantic Richfield.

To date, not including Phase 7, the remediation-restoration effort has completed 7.5 phases of 22.

DEQ adopted a new strategic plan in 2023 that, among other things, narrows the zone of cleanup — an approach designed to save money and destined to leave more contaminants in the floodplain. The state says it is updating the plan and the revision will include newer budget numbers.

DEQ has said it hopes to complete construction of all 22 phases stretching to Garrison by 2038 — a goal that seemed ambitious Tuesday.

Both Dudding and Jessica Banaszak of DEQ said they don’t anticipate there will be remedial/restoration construction during 2026 because of the complexities of access, landowner coordination, communicating with other stakeholders, final sampling and more. That will leave less than 12 years for 13 phases, some more complex than others.

Banaszak and Dudding said the state has not yet identified which phase will be tackled next.