The U.S. Army Corps of Engineers Walla Walla District is inviting public comments on a draft Environmental Impact Statement (EIS) for the Lower Snake River Programmatic Sediment Management Plan (PSMP).
Comments on the draft EIS will begin to be accepted on Friday, Dec. 21, when an official notice is expected to be published in the Federal Register, and are due to the Corps no later than Feb. 8, 2013.
The Corps is proposing to implement a long-term plan to manage, and prevent if possible, river sediment accumulation or “depositions” that are interfering with “authorized project purposes” of the Corps’ Lower Snake River Projects (LSRP) dams and reservoirs in southeastern Washington and north central Idaho. Those projects are Ice Harbor, Lower Monumental, Little Goose, and Lower Granite Locks and Dams. Authorized project purposes potentially affected by sediment include commercial navigation, recreation, and fish and wildlife conservation and mitigation. Maintenance dredging in the navigation channel has not been performed since the winter of 2005-2006.
The draft PSMP EIS identifies and evaluates the environmental effects of a range of seven sediment management strategies or “alternatives” developed by the Corps. In developing and evaluating alternatives, the Corps considered various methods of managing or reducing sediment. In the EIS, the Corps identified “Alternative 7, Comprehensive (Full System and Sediment Management Measures),” as the preferred alternative. Alternative 7 provides the Corps with a comprehensive “toolbox” of measures for addressing sediment that interferes with authorized project purposes.
The draft EIS also proposes an “immediate need action” to re-establish the LSRP navigation channel to Congressionally-authorized dimensions – 14 feet deep and 250 feet wide. This “immediate need action,” which is consistent with and considered the first action under the proposed PSMP, involves channel maintenance dredging at four locations: the federal channel at the confluence of the Snake and Clearwater rivers, Port of Clarkston, Port of Lewiston, and Ice Harbor Lock and Dam downstream navigation lock approach.
The Corps is following a well-established environmental review process. National Environmental Policy Act (NEPA) compliance requires Corps consideration of public comments about the draft EIS. The Corps also plans to hold a public meeting to provide information and answer questions about the PSMP EIS. The meeting is tentatively scheduled for Jan. 24, 2013, in the Lewiston-Clarkston area, prior to the end of the public comment period.
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Press Release, December 17, 2012; Image: usace