Corps of Engineers finalizes sediment management plan for Lower Snake River

USACE logo

The U.S. Army Corps of Engineers issued a press release Nov. 17 regarding its Lower Snake River Final Programmatic Sediment Management Plan. Below is the text of that release:

Following intensive U.S. Army Corps of Engineers review and consideration of extensive public comments, the Corps’ Northwestern Division Commander, Brig. Gen. John S. Kem, signed two Records of Decision (RODs) on Nov. 14 for the Lower Snake River Final Programmatic Sediment Management Plan (PSMP) and a current “immediate need” action (dredging) to reestablish the congressionally authorized dimensions of the Lower Snake River federal navigation channel. The RODs are based on consideration of reasonable alternatives and evaluation of potential environmental effects contained in the PSMP Final Environmental Impact Statement (PSMP FEIS). Signing of the RODs marks completion of the Walla Walla District National Environmental Policy Act (NEPA) review process.

The first ROD signed by Kem was for the long-term, comprehensive PSMP for managing sediment accumulation that interferes with existing authorized purposes of the Corps’ Lower Snake River dam and reservoir projects. The affected authorized project purposes are navigation, recreation, fish and wildlife conservation, and flow conveyance. The Corps evaluated potential environmental effects of a range of sediment management alternatives, consulted with the public and other agencies, and developed a “toolbox” of measures for addressing future problem sediment.

The second ROD was for a current “immediate need” action (dredging) to re-establish two areas of the federal navigation channel — the navigation lock approach at Ice Harbor Dam and at the confluence of the Snake and Clearwater rivers — to congressionally authorized dimensions of 14-feet-deep by 250-feet-wide at minimum operating pool (MOP). Maintenance dredging last occurred in the lower Snake River navigation channel in the winter of 2005-2006.

Dredging is the only effective short-term tool available for maintaining the federal navigation channel to congressionally authorized dimensions. The Corps plans to dredge during the first available winter “in-water work window,” Dec. 15 to Feb. 28, when salmonid fish are less likely to be present in the river. The Corps plans to use the dredged material to create shallow-water habitat for juvenile salmon at Snake River mile 116, just upstream of Knoxway Canyon and 23 miles downstream of Clarkston.

In addition the Corps, Nov. 17, issued Clean Water Act Section 404 and Rivers and Harbors Act Section 10 permits to the Port of Lewiston, Idaho, and the Port of Clarkston, Wash., for ancillary/related berthing area maintenance dredging. Those berthing areas are adjacent to the federal navigation channel. The PSMP Final EIS considered potential environmental effects for the berthing area maintenance dredging, which is planned to occur in conjunction with the Corps federal navigation channel maintenance. The Ports are funding the berthing area maintenance dredging and all associated administrative and environmental review costs.

Signed RODs and related lengthy documents including the Corps response to PSMP Final EIS public comments will be posted on the Walla Walla District website on or about Tuesday, Nov. 18. Public comments were previously accepted on a draft PSMP EIS from December 2012 to April 2013 and on the final EIS from August to September of 2014. The Corps considered all public comments received during its decision-making process.

Final PSMP EIS documents and other information are available on the Walla Walla District website.


Previous articleKIUC gets go-ahead for 25-MW Hawaiian pumped-storage proposal
Next articleNova Group wins contract for electrical work at 1,076-MW Bonneville hydropower project
The Hydro Review content team brings you the latest in Hydropower news. Learn about recent developments in the industry and stay knowledgeable in your field.

No posts to display