Intent To Prepare a Draft Environmental Impact Statement, Programmatic Sediment Management Plan, Lower Snake River Reservoirs, in the States of Washington and Idaho
The U.S. Army Corps of Engineers (Corps) intends to prepare an Environmental Impact Statement (EIS) for a Programmatic Sediment Management Plan that will address sediment management within the four lower Snake River reservoirs and that portion of McNary reservoir contained within the lower Snake River The plan will identify and evaluate ways the Corps can manage sediment within these reservoirs and examine the sediment input (sources) on a programmatic basis in the near-term, mid-term, and long-term. The reservoirs extend from the mouth of the Snake River upstream to the communities of Lewiston, Idaho, and Clarkston, Washington; and include the lower 2 miles of the Clearwater River from its confluence with the Snake River at Lewiston upstream to the U.S. Highway 12 Bridge. In the plan the Corps will also include all tributaries that could significantly contribute sediment to the lower Snake River. The Corps is preparing this plan because sediment management has been an ongoing maintenance issue since the completion of Ice Harbor Dam, the first dam and reservoir on the lower Snake River, in 1961. Rather than addressing sediment-related problems on a case-by-case basis, the Corps has determined that it would be more effective to evaluate sediment management as a whole and on a watershed basis. The intent of the plan is to identify ways to reduce the amount of sediment entering the reservoirs, identify how to manage the sediment once it enters the reservoirs, and identify possible changes to structures or operations to reduce maintenance and associated impacts while still providing for authorized project purposes, including navigation.