The U.S. Army Corps of Engineers, Portland Division commissioned the installation of new sensors in the foundation of Willow Creek Dam, located in Morrow County, OR. The sensors would provide early warning if the dam’s performance changed over time, something the existing design did not incorporate.

Team Members

Army Corps of Engineers

Shannon & Wilson

Crux Subsurface

Crux’s Role

Crux was selected to provide confined space core sampling and instrument installation from within the interior gallery of the dam. Drilling included upward vertical, downward vertical, and various downward angle borings to depths between 15 and 120 feet. A combination of vibrating wire piezometers and standpipe piezometers were then installed in each boring.

Challenges included setting up and drilling in extremely narrow locations with low overhead clearance. Crux’s compact equipment had to accommodate access points as small as 45 inches wide by 79 inches high, and had to operate with as little as 7 feet of overhead clearance. Additional project challenges included capturing and handling 100% of artesian water produced during drilling. Crux collaborated with the owner to design a unique system involving pumps, hoses, and settling tanks as large as 21,000 gallons. All drilling and instrumentation was completed successfully and ahead of schedule.

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