Established in 1998, the Anaconda Regional Water, Waste & Soils (ARWWS) Operable Unit (OU) is the largest and most diverse Operable Unit in the Anaconda Smelter NPL site. As a result, the OU was separated into fifteen Remedial Design Units (RDUs) based upon factors such as location, source and type of contamination, and remedial needs. Click here for more information about the ARWWS OU.
Remedial designs for RDU 10 specifically establish Superfund remedies for contaminated riparian and wetland areas along Warm Springs Creek, as well as surface water contamination of the creek. Contamination was a result of runoff from upland soils that were contaminated by smelter emissions and waste releases from the Old Works area. For the purpose of remediation, Warm Springs Creek is considered in three sections: the upper section, which flows through a glacial valley before entering Anaconda; the middle section, the part of the creek flowing through Anaconda and the Old Works Golf Course; and the lower section, which begin east of Galen Road to the creek’s end.
Surface water data for RDU 10 was collected in 1999, with soils data being gathered the following year. This data was utilized to develop final remedial designs for all sections of Warm Springs Creek included within the boundaries of RDU 10. The 2001 Design Criteria Report, created using the data collected in 1999 and 2000, defined increasing copper concentrations in surface water during high flow, unstable stream reaches due to channelization, and high copper concentrations within the lower section of Warm Springs Creek.
An additional area of concern, referred to as Section 32 Project Area, was identified in 2005. The Section 32 Project Area is located between Galen Road and the airport. The area is characterized by elevated arsenic levels in surface soils and waters. Remediation of this area was completed in 2010 as part of RDU 7 – North Opportunity.
Specific remedial designs for the middle section of Warm Springs Creek included construction of storm water control ditches and sedimentation basins, as well as stream channel reconstruction. Remediation of the middle section of Warm Springs Creek, which flows through Anaconda and the Old Works (including the Drag Strip area), was addressed as part of RDU 13 – Old Works Groundwater of the Anaconda Regional Water, Waste & Soils (ARWWS) OU.
The lower section of Warm Springs Creek flows through a portion of RDU 7 – North Opportunity Uplands, the Anaconda-Deer Lodge County Airport, and a wet meadow environment before reaching the Clark Fork River. Small, localized tailings deposits are also present in several locations throughout this section of Warm Springs Creek, specifically on the Gochanour and Johnson ranches. The EPA, in consultation with the Confederated Salish and Kootenai Tribal Cultural Resource Office, identified a historic hunting and gathering encampment, Yellow Gopher, within the lower section of Warm Springs Creek. Remedial designs were developed with consideration for the preservation of this cultural resource.
Soil and surface water sampling began within the lower section of Warm Springs Creek in 1999 and continued on nearly an annual basis throughout the early 2000’s. The Lower Warm Springs Creek Project Area was developed after significant surface water copper concentrations were identified in the lower section of Warm Springs Creek. Sampling with limited remediation has and will continue to take place in the Lower Warm Springs Creek Project Area as copper concentrations increase significantly during high flow events. Remediation within the lower section also included channelizing to minimize contaminant migration to adjacent lands. Additional contamination associated with the lower section of Warm Springs Creek, which impacts the Clark Fork River floodplain, has and continues to be addressed in the Clark Fork River Operable Unit under the Milltown Reservoir/Clark Fork River NPL Site.
Visit the Superfund Library, located on the Arrowhead Foundation’s website, to review documents and research regarding the Anaconda Smelter NPL site. Specific documents of interest to RDU 10 include the 2013 Final Design Report (available online) and the 2006 Section 32 Final Design Report (available online). Additional information can also be found on the EPA’s website.