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The U.S. Army Corps of Engineers, Portland District has released public notice of proposed discharges of dredged and fill material for the Lower Columbia River Channel Maintenance works.
According to the notice, USACE proposes to discharge dredged and fill material during implementation of a Dredged Material Management Plan and integrated Environmental Impact Statement (DMMP-EIS) for the purpose of maintaining the congressionally authorized channel dimensions of the Lower Columbia River (LCR) Federal Navigation Channel (FNC), part of the Columbia and Lower Willamette Rivers (C&LW) Project.
LCR FNC maintenance dredging would occur annually utilizing a variety of dredge equipment. The intent of maintenance dredging is to reduce impediments to navigation by dredging to authorized dimensions, plus advanced maintenance dredging (AMD).
The overall purpose of the DMMP-EIS is to define the dredged material management practices for the LCR FNC to maintain the authorized dimensions for a minimum of 20 years.
The forecasted average volume of material needed to be dredged to maintain the authorized dimensions for the next 20 years is expected to be 9.2 million cubic yards annually. The channel is typically maintained using hydraulic (hopper and pipeline) dredges but mechanical dredges with material placement barges can also be used.