RDU 1 Stucky Ridge

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 Design Unit (RDU) 1 – Stucky Ridge is situated on the north side of Anaconda between Warm Springs Creek and Lost Creek. The site is approximately 31 square miles and includes a portion of the Deer Lodge National Forest. Both Warm Springs Creek and Lost Creek intersect the RDU, which is characterized by mixed landownership including State, Federal, County, and private properties. 

Feasibility studies identified a region of shallow bedrock aquifer, in which restoration of ground water to levels compliant with the Montana Groundwater Quality Standards was considered impracticable. As a result, in the 1998 Record of Decision, the EPA established the Stucky Ridge Technical Impracticability (TI) Zone. A TI Zone is an area in which the EPA has determined that remediation to levels compliant with established standards is not practically feasible.

Contamination due to smelter fallout is the primary area of remedial concern for RDU 1 – Stucky Ridge. Specifically, this includes arsenic level in surface soils and surface water above those established for open space and residential land use. Remedial action within RDU 1 – Stucky Ridge has included soil remediation, improving soil pH, re-vegetation (application of seed mixture and/or planting indigenous trees/shrubs), installation of surface water controls, as well as monitoring and establishment of institutional controls. 

Under the 2008 Clark Fork River Operable Unit (OU) Consent Decree, the Montana Department of Justice – Natural Resources Damage Program assumed responsibility for certain remedial actions within a portion of RDU 1 – Stucky Ridge as well as portions of RDU 15 – Mount Haggin. Atlantic Richfield Company remains the responsible party for all other remedial action within RDU 1 – Stucky Ridge. Remedial action within RDU 1 – Stucky Ridge continues to take place.

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 1 include the Stucky Ridge Final Design Report and the ARWWS OU Record of Decision. Additional information can also be found on the EPA’s website.