Corps continues field studies at Willamette Valley dams

PORTLAND, Ore. – A drill crew will soon be on site at Cougar Dam, east of Eugene, Oregon, as the U.S. Army Corps of Engineers continues field investigation at some dams in the Willamette Valley.

The crews will also install instrumentation on the crest of Cougar Dam. The drilling and installation will require the eastbound lane across the dam to be closed intermittently. These closures will be from May 30 to June 13 between 7 a.m. to 6 p.m., reducing traffic to one lane.

The investigation at Cougar will give the Corps more information to better understand conditions within the dam and its foundation. Corps personnel have performed similar work at Hills Creek and Lookout Point dams.

“The information from these field investigations will improve our understanding of the risk at these dams and how it compares to current standards,” said Matt Craig, Portland District Dam Safety Program manager.

The data will provide more information on the engineering characteristics of the dam and foundation materials. This information also helps the Corps better understand how well the dams will perform under seismic events.

“Our highest priority is ensuring that Corps’ dams are fully able to reduce flooding in the downstream communities,” Craig elaborated. 

The field investigation work, one part of the Corps’ Issue Evaluation Studies, includes drilling and excavating test pits to collect soil and material samples, and installing instruments to monitor the structural condition of the dams.

The studies are part of the Corps’ national Dam Safety Program, which includes periodic inspections and risk assessments, Emergency Action Plan exercises, seismic and hydrologic studies.

For more information about the Program, visit www.nwp.usace.army.mil/missions/current/Dam-Safety-IES/.