The U.S. Army Corps of Engineers, Portland District (USACE) conducted the 20-year Columbia River Channel Improvement Project (CRCIP) to deepen the navigation channel between Portland, Oregon and the Pacific Ocean to allow transit of fully loaded Panamax ships (100 ft wide, 600 to 700 ft long, and draft 45 to 50 ft). In the vicinity of Warrior Point, between river miles (RM) 87 and 88 near St. Helens, Oregon, the USACE conducted underwater blasting and dredging to remove 300,000 yd3 of a basalt rock formation to reach a depth of 44 ft in the Columbia River navigation channel. Blasting was necessary in a 1-mile stretch of the total ~100 miles of navigation channel.
The purpose of this report is to document methods and results of the compliance monitoring study for the blasting project at Warrior Point in the Columbia River. The permit for blasting operations granted by regulatory agencies required the USACE to monitor impacts on aquatic animal species, including marine mammals, diving birds, sturgeon, and salmonids. The USACE developed an approved monitoring plan and the Pacific Northwest National Laboratory (PNNL), in collaboration with the University of Washington and under contract to the USACE, performed compliance monitoring and reported results daily for all 99 blasting events conducted from November 1, 2009 through February 5, 2010. The USACE, in coordination with the regulatory agencies, used compliance monitoring data in near real-time to evaluate whether blasting operations were meeting standards set forth in the permit, most importantly, presence of marine mammals in the study area and take of salmonids as a result of blasting operations— no marine mammals inside the 500-ft (radius) marine mammal monitoring zone at blast time and no more than 10 adult and 50 juvenile listed salmonids taken for all blast events combined (NMFS 2002).