The Montana Department of Environmental Quality, Montana Fish, Wildlife & Parks, and the Bureau of Reclamation began monitoring several parameters in Spring 2016 that may have contributed to severe turbidity and algae blooms in Clark Canyon Reservoir and the Beaverhead River over the past two summers. The river again turned turbid in late July and over the first weeks of August, 2016.
DEQ deployed instruments to measure dissolved oxygen, pH, water temperature and turbidity every half hour throughout the summer in the Beaverhead River, the Red Rock River, and Horse Prairie Creek.
A Press Release notes DEQ will also monitor for nutrients, common ions, total dissolved solids, total suspended solids, volatile suspended solids, oxidation reduction potential, and phytoplankton in Clark Canyon Reservoir in addition to the streams mentioned above. Monitoring of these parameters increased in frequency as the clarity issues began to reoccur this summer.
Most of DEQ's field monitoring sites have been withdrawn for the season and the reservoir is currently ice covered.
A public meeting was held on February 7, 2017 in Dillon. A joint presentation by Montana DEQ, FW&P, and the Bureau of Reclamation addressed the following:
- Current understanding of the chronology of the turbidity in the Beaverhead River and the reservoir.
- Review of data collected during the past two years and how it compares to historic information, including identification of the turbidity material and minerology.
- Analysis and interpretation of potential mechanisms causing the turbidity. A review of the importance of factors like water movement and reservoir mixing, whether fish and other biota contribute to the turbidity, and geochemistry that could further exacerbate such events.
- Potential effects on fish and other aquatic life.
- Potential next steps.
Presentations from the February 7, 2017 Public Meeting in Dillon include one by Montana DEQ followed by one from FW&P.
Montana DEQ also held a Public Comment Period in spring 2016 for a Section 401 Water Quality Application for a proposed Hydroelectric Project on the dam at Clark Canyon Reservoir.
Clark Canyon Dam is a Bureau of Reclamation facility designed for irrigation and flood control. The proposed hydroelectric facility is being forwarded by a private company and would be a run-of-the-river retrofit to the existing dam and would operate under existing withdrawals and flows.