County says geotechnical testing underway on Old Highway 100 slide; recommendations due mid-July

Franklin County public-works staff told commissioners that a notable slide on Old Highway 100 is ongoing, that geotechnical testing of core samples is in progress, and that the county expects final test results and written recommendations in mid-July.

The county's consultant is conducting repeated tests on core samples because the material had to be dried and retested to ensure accurate results, given the slide's magnitude. Staff said the consultant anticipated delivering final test results "no later than the tenth of this month," and a written summary and recommendations by July 18. Staff asked commissioners to set aside time for a face-to-face meeting the week after the written recommendations are delivered so the consultant can present findings and suggested corrective actions.

Public-works staff described the slide as dynamic and continuing to settle and move. "It's still sliding," a staff member said, adding that the condition has progressed since it was first observed. Commissioners and the engineer agreed that it would be premature to attempt corrective work until testing and analyses are complete, and that the goal is to design a permanent fix rather than repeating corrective work.