Clark Fork River Operable Unit Remediation and Reclamation
The Clark Fork River Operable Unit (CFR OU) interactive web mapping application lets you view developments within the Operable Unit. In the map below you can turn on/off overlays, click in the map for more information about that location, and zoom in and pan around to view more detailed information about a location. This mapping application is an extension of The Clark Fork River Operable Unit webpage. If you have any questions please feel free tocontact us.
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- Overlay is not active. When an overlay is made active, it will be placed on top of all other overlays. If you want to have multiple overlays on at the same time, the last overlay made active will be on top. Map Notes Map notes are provide you with more information about the location of interest. By clicking with your left mouse button on the map more information about that location will be provided to you.Map Controls
To pan around the map use the arrows or hold down the left mouse button and drag you mouse.To zoom in or out move the slider up & down or use the scroll wheel on your mouse. The viewable area of the map is confined to the specific project area of interest so you will not be able to pan the map outside of that area. Map Search
You can search for a place, town, or address. You can also search for coordinates by typing in the latitude and longitude like 46.4, -112.7
** The study areas are approximate boundaries for each phase of the CFR OU.
Tested PropertiesView Metadata Sampled areas within the CFR OU (Label = LUID)
** During the fall of 2009, soil sampling was completed for 14 residential properties and a KOA campground in Deer Lodge, Montana, located in the Clark Fork River Operable Unit of the Milltown Reservoir/Clark Fork River Superfund Site. As part of this effort, the Montana Department of Environmental Quality (DEQ) contracted TerraGraphics Environmental Engineering, Inc. to identify areas at the properties that exceed the residential exposure Risk-Based Concentration (RBC) for arsenic (150 mg/kg) and/or the screening-level RBC for lead (400 mg/kg) and to identify areas at the KOA campground that exceed the recreational exposure RBC for arsenic (680 mg/kg) and/or the screening-level RBC for lead (400 mg/kg).
The sampling effort included a total of 15 properties, resulting in the collection and laboratory analysis of 532 primary soil samples and 94 quality control samples (i.e., rinsate blanks, field blanks, standard reference material, and field duplicates). The analytical results for all samples collected, including field quality control results, are shown in Appendix A. Out of the 532 results obtained for locations sampled in the Deer Lodge Properties focus area, less than 1%exceeded the recreational exposure RBC of 680 mg/kg arsenic and 10% exceeded the 150 mg/kgresidential exposure RBC for arsenic. Overall, 3% of the samples collected exceeded the 400mg/kg screening-level RBC for lead.
The highest arsenic concentration encountered in the Deer Lodge Properties focus area was collected from a source area (slicken) adjacent to the Clark Fork River at one of the residential properties (1,490 mg/kg arsenic). The highest lead concentration encountered was measured in a sample collected from a residential yard area adjacent to the Clark Fork River (1,070 mg/kg Lead).
Test PitsView Metadata Pit locations, laboratory analytical results and XRF results
** In general, the investigation sampling approach consisted of test pit locations, spaced on a north-south – east-west grid pattern with 125-foot centers. Additional sample locations were identified outside of the 125-foot grid system within historic channels or old oxbows. Samples were collected at 6-inch intervals and screened in the field until one of the following conditions was met:
- Evaluation of field XRF data indicated that the sum of As, Cu, and Zn concentrations (i.e.total COC concentrations) was below 500 mg/kg.
- Course alluvium having a rock content of 60% or more (visual estimation), or bedrockwas encountered. These conditions are believed to provide sufficient protection from erosion.
Sampling areas began with the RipES preliminary polygons (CH2MHill, 2004) including Slickens, Impacted Soils and Vegetative Areas, Miscellaneous Site Types and Slightly Impacted Soils and Vegetation Areas. Floodplain sampling activities began on August 24, 2009, and were completed on September 30, 2009. This DSR only present a summary of data collected from Part 1 of this SAP Addendum. Information collected under Part 2 of this SAP addendum will be summarized in a separate report. A total of 635 natural samples, 38 field duplicates, and 23 filed blanks were submitted for laboratory analysis from 269 test pits. Additional samples were collected but not submitted to the laboratory for analysis and archived for future analysis, if necessary.
Weed ControlView Metadata Weed control areas Weed areas that will be treated and/or identified by DEQ
Flood PlainView Metadata 100-year FEMA floodplain with additional delineation of historical floodplain at the time of the 1908 flood