Abstract
The Montana Department of Environmental Quality (DEQ) has developed total maximum daily loads (TMDLs) for metals in Silver Bow Creek and the Clark Fork River. TMDLs are watershed-scale pollutant budgets and are important planning tools because they provide a basin-wide context for individual pollutant sources. This context can provide a different perspective on individual point source discharges than a traditional point-of-discharge analysis and may result in different effluent limits.
The effects of decades of remediation in Butte and Silver Bow Creek are evident in trends of Clark Fork River water quality. Remediation of the Clark Fork River mainstem has begun in recent years, and the trend is expected to continue. Using the cleanup levels established in the Superfund Records of Decision, DEQ predicts the trajectory of these water quality trends. Presently, water quality targets (standards) are generally met below the Blackfoot River. DEQ predicts that assimilative (dilution) capacity will be provided from below the Blackfoot River confluence to as far upstream as the Little Blackfoot River for most metals of concern. Remediation work in major tributaries (e.g. Flint, Little Blackfoot) and/or exceeding Superfund cleanup targets can provide additional assimilative capacity within Silver Bow Creek and segments of the Clark Fork River.
Start Date
24-4-2015 10:30 AM
End Date
24-4-2015 11:00 AM
Document Type
Presentation
Metals TMDL development for the mainstem Clark Fork River
The Montana Department of Environmental Quality (DEQ) has developed total maximum daily loads (TMDLs) for metals in Silver Bow Creek and the Clark Fork River. TMDLs are watershed-scale pollutant budgets and are important planning tools because they provide a basin-wide context for individual pollutant sources. This context can provide a different perspective on individual point source discharges than a traditional point-of-discharge analysis and may result in different effluent limits.
The effects of decades of remediation in Butte and Silver Bow Creek are evident in trends of Clark Fork River water quality. Remediation of the Clark Fork River mainstem has begun in recent years, and the trend is expected to continue. Using the cleanup levels established in the Superfund Records of Decision, DEQ predicts the trajectory of these water quality trends. Presently, water quality targets (standards) are generally met below the Blackfoot River. DEQ predicts that assimilative (dilution) capacity will be provided from below the Blackfoot River confluence to as far upstream as the Little Blackfoot River for most metals of concern. Remediation work in major tributaries (e.g. Flint, Little Blackfoot) and/or exceeding Superfund cleanup targets can provide additional assimilative capacity within Silver Bow Creek and segments of the Clark Fork River.