News Releases

Corps drills into Cottage Grove Dam during geotechnical investigation

Published May 3, 2018
PORTLAND, Ore. – The U.S. Army Corps of Engineers’ Dam Safety team is conducting a geotechnical investigation at Cottage Grove Dam near Eugene, Ore., beginning Thursday, which includes drilling borings in the dam embankment. 

The work is part of a larger geotechnical assessment in which where data from the borings will provide information on the physical properties of the dam. The dam safety team will then use the data to study how the dam will perform under various conditions.

The drilling will begin on May 3 with a planned completion date of May 13.

“This (drilling) activity is not going to impact the integrity of the dam,” said Ross Hiner, Portland District dam safety program manager. “These investigations improve our understanding of the risk at our dams.”

The Corps' dam safety program is to make the dams it owns and operates as safe as possible, and minimize risks to the public, said Hiner. 

“We’re conducting this investigation in conjunction with our routine dam safety program which includes inspections, performance monitoring and risk assessments,” Hiner said.

The study will also include Emergency Action Plan exercises, seismic and hydrologic studies.

Cottage Grove Dam is located on the Coast Fork of the Willamette River south of Eugene, Ore. The Corps completed construction of Cottage Grove Dam in 1942, making it Portland District’s second-oldest dam. 

The U.S. Army Corps of Engineers operates 13 dam and reservoir projects in the Willamette River drainage system. Each dam contributes to a water resource management system that provides flood risk management, power generation, irrigation, water quality improvement, fish and wildlife habitat and recreation on the Willamette River and many of its tributaries. Since their completion, the dams have cumulatively prevented more than $20 billion in flood damages to the Willamette Valley. 

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Tom Conning

Release no. 18-025