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Estimated loads of suspended sediment and selected trace elements transported through the Clark Fork basin, Montana, in selected periods before and after the breach of Milltown Dam (water years 1985-2009)
Scientific Investigations Report
2011-5030
In cooperation with the U.S. Environmental Protection Agency
Milltown Reservoir is a National Priorities List Superfund site in the upper Clark Fork basin of western Montana where sediments enriched in trace elements from historical mining and ore processing have been deposited since the completion of Milltown Dam in 1908. Milltown Dam was breached on March 28, 2008, as part of Superfund remediation activities to remove the dam and excavate contaminated sediment that had accumulated in Milltown Reservoir. In preparation for the breach of Milltown Dam, permanent drawdown of Milltown Reservoir began on June 1, 2006, and lowered the water-surface elevation by about 10 to 12 feet. After the breach of Milltown Dam, the water-surface elevation was lowered an additional 17 feet. Hydrologic data-collection activities were conducted by the U.S. Geological Survey in cooperation with U.S. Environmental Protection Agency to estimate loads of suspended sediment and trace elements transported through the Clark Fork basin before and after the breach of Milltown Dam. This report presents selected results of the data-collection activities.
Suggested Citation
Sando, S.K., Lambing, J.H., 2011, Estimated loads of suspended sediment and selected trace elements transported through the Clark Fork basin, Montana, in selected periods before and after the breach of Milltown Dam (water years 1985-2009): U.S. Geological Survey Scientific Investigations Report 2011-5030, viii, 64 p., https://doi.org/10.3133/sir20115030.
ISSN: 2328-0328 (online)
Study Area
Publication type
Report
Publication Subtype
USGS Numbered Series
Title
Estimated loads of suspended sediment and selected trace elements transported through the Clark Fork basin, Montana, in selected periods before and after the breach of Milltown Dam (water years 1985-2009)