The U.S. Army Corps of Engineers does not intend to dredge the Snake River shipping channel from Lewiston to McNary Dam this winter. Instead, it will manage the river's water level to maintain a 14-foot depth in the shipping channel and attempt to do the work next winter. Army engineers hoped to dredge last winter during a 2-month period when few juvenile or adult salmon and steelhead migrate through the lower Snake River. That plan was opposed by the tribe and a coalition of environmental groups that asked for additional studies to make sure endangered salmon and steelhead would not be harmed. The National Marine Fisheries Service, charged with protecting the fish, reviewed the dredge plan and agreed more studies were needed before it could move forward. The corps began work on an environmental impact statement and a draft is ready for public review. But completing the study means the shipping channel and ports, filling with silt, will have to endure one more year before being cleared. 'We are anticipating we will be able to still provide the required depth by those operating modifications,'' said project manager Jack Sands. That will help barges and tug boats continue to move grain through the river system.