Abstract

The Upper Clark Fork River is the site of one of the most well known and complex remediation & restoration efforts in the world. Over 100 years of mining & smelting in the upper watershed resulted in over 100 miles of river designated as a USEPA superfund site, mandating remediation of hazard and reclamation of lost resources. Silver Bow Creek, the focus of this paper, suffered from sediment loading that contained elevated levels of heavy metals toxic to aquatic life and humans. Toxic sediments settled in the streambed and deposited in the floodplain during overbank events. The contamination was so extensive that removing much of it required complete reconstruction of the stream channel and revegetation of the floodplain. Restoration efforts have created what will hopefully be “the last best disturbance”, so that Silver Bow Creek can recover to an ecologically viable system. To learn from the Silver Bow Creek experience, a rigorous monitoring scheme is in place to evaluate the progress of the restoration. The objectives of these analyses are to 1) Evaluate methods for homogenizing benthic invertebrate data from multiple sources and analytical methods. 2) Describe trends in both historic and current data. 3) Compare trends in Silver Bow Creek to trends from reference reaches. 4) Hypothesize limiting factors for benthic invertebrate recruitment in restored areas.

Start Date

5-3-2010 4:00 PM

End Date

5-3-2010 4:30 PM

Document Type

Presentation

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Mar 5th, 4:00 PM Mar 5th, 4:30 PM

Pre & post reclamation trends in benthic invertebrate communities in a metals laden stream, Silver Bow Creek, MT

The Upper Clark Fork River is the site of one of the most well known and complex remediation & restoration efforts in the world. Over 100 years of mining & smelting in the upper watershed resulted in over 100 miles of river designated as a USEPA superfund site, mandating remediation of hazard and reclamation of lost resources. Silver Bow Creek, the focus of this paper, suffered from sediment loading that contained elevated levels of heavy metals toxic to aquatic life and humans. Toxic sediments settled in the streambed and deposited in the floodplain during overbank events. The contamination was so extensive that removing much of it required complete reconstruction of the stream channel and revegetation of the floodplain. Restoration efforts have created what will hopefully be “the last best disturbance”, so that Silver Bow Creek can recover to an ecologically viable system. To learn from the Silver Bow Creek experience, a rigorous monitoring scheme is in place to evaluate the progress of the restoration. The objectives of these analyses are to 1) Evaluate methods for homogenizing benthic invertebrate data from multiple sources and analytical methods. 2) Describe trends in both historic and current data. 3) Compare trends in Silver Bow Creek to trends from reference reaches. 4) Hypothesize limiting factors for benthic invertebrate recruitment in restored areas.