| Lower Snake River Navigation Maintenance Environmental Impact Statement | |
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Lawsuit Dismissed Need for Maintenance and Brief Description of Alternatives Historical Information |
This final Environmental Impact Statement (EIS) presents the U.S. Army Corps of Engineers’ (Corps) plan for performing routine channel maintenance by providing a 14-foot depth throughout the federal navigation channel in the project area and restoring access to selected port berthing areas. This channel maintenance would facilitate navigation and commodity movement and increase public safety.
The Corps’ authority to maintain the lower Snake River federal navigation channel was first established in the River and Harbor Act of 1945 (Public Law 79-14, 79th Congress, 1st Session). The Corps is authorized by Congress to maintain the federal navigation channel that is 250-feet wide and 14-feet deep in the project area. Historically the Corps has routinely maintained the navigation channel through dredging actions. The Corps has not performed maintenance dredging in the channel since the winter of 1998-1999, when the Lower Monumental navigation lock approach was dredged. The purpose of the routine channel maintenance is to provide a 14-foot depth throughout the designated federal navigation channel in the project area, and to restore access to selected port berthing areas. Channel maintenance would increase public safety and facilitate navigation and commodity movement. Sediment is deposited in the navigation channel primarily during spring runoff periods. Because channel maintenance has not occurred since 1998-1999, shoaling in the navigation channel has become critical in some locations, and is now as shallow as 8.5 feet and 10.6 feet near the Ports of Clarkston and Lewiston, respectively. Also, the total surface area of the navigation channel having depths less than 14 feet in the Snake/Clearwater rivers confluence area has risen from approximately 38 acres in 2003 to approximately 52 acres in 2004. The navigation industry is impacted when the navigation channel is less than 14 feet because of an increased safety risk, increased risk of damage to equipment, increased risk of grounding, continued light loading, and lost efficiencies due to modified approach, loading, and unloading procedures. Grounding can cause damage to vessels, puts human life at risk, and can result in leakage or loss of cargo into the river, which is a significant environmental concern since petroleum products and fertilizer are among the commodities carried on the river. Eight alternatives were considered to address the immediate need to restore the authorized navigation channel. The alternatives include actions that would change reservoir levels, manipulate water flows, or remove sediments using mechanical methods. After considerable analysis, the preferred alternative selected is to dredge the navigation channel to its authorized dimensions at five particularly shallow and/or narrow areas, and use in-water disposal of the dredged material to create shallow-water habitat for listed salmonids. The Corps believes this alternative would best fulfill its statutory mission and responsibilities, giving consideration to economic, environmental, technical, and other factors. The Corps circulated a Draft EIS for this proposed action in March 2005 for public review and comment. The Corps received 224 comment letters on the Draft EIS. The Corps responded to the letters by either changing the text of the EIS, or explaining why the Corps felt changes were not needed. The comment letters and the Corps' responses to the comments are in Appendix E of the Final EIS. The Notice of Availability for the Final EIS was published in the Federal Register June 10, 2005. General Grisoli, the Northwestern Division Commander, signed the Record of Decision (ROD) for this project on July 13, 2005.
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