NV5 provided geotechnical and geological services to Marion County, Oregon, in the evaluation and remediation of the “Bear Trap” landslide, which affected a major arterial road that provides access to a popular resort area.
Our services included emergency response, including recommendations on lane restrictions and temporary mitigation work. We then conducted a geotechnical investigation to characterize landslide conditions and subsequently developed slide mitigation approaches.
Because a retaining wall to support the roadway was cost prohibitive, we recommended constructing the wall downslope of the current road alignment. This allowed a shorter and less expensive wall design than would have been required to maintain the existing alignment. Construction was completed in the fall, and the road reopened to all traffic before the start of the rainy season.
The County estimated that our recommendation for roadway realignment and wall modifications decreased the cost of the project by approximately $700,000.