Allegations: Oregon Not Forthcoming With Landslide Hazard Information
Geologic Hazards
US 89 Bitter Springs Landslide Video Updates
Since I last posted about this landslide, ADOT has added several videos to their YouTube channel. It’s clear that this highway is going to be closed for the long term. ADOT and their on-call geotechnical consultant tasked with this project, Kleinfelder, are currently drilling boreholes to attempt to characterize the failure surface and determine what the geometry of the failure surface is. They are installing at least 10 inclinometers to try to determine the location of the slip plane or planes at depth and they have two extensometers to measure if any additional movement occurs. They are also performing LIDAR surveys as well. Check out the videos below.
Initial ADOT Video Describing the Failure
Click through for the videos!
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Clatskanie Landslide
Dear geo blogger,
My take on this slide is that the old railroad crossing or road crossing that held up the water for the Clatskanie Event on or about Jan 11, was not “put to bed”. The crossing should have been destroyed and the abutments pulled out of the channel. The slide volume and extent of travel of the subsequent debris flows would have been much smaller and shorter.
I served for a year as an ERFO Hydrologist at the Detroit Ranger Station, up the Santiam Canyon from Salem in 1997 and 1998. An about-to-retire civil engineer, Bill Day, used the “put to bed” term and practice. He also said something else that was useful, “it takes trees to be twenty years old or more before their root systems hold back natural landslides. The trees on the reforested property above the Clatskanie debris flow section were not that old.
I agree with Bill Burns and, to reinforce his statements, I like what he said about the recent spate of landslides.
John Rehm
Registered Geologist G1137
Salem, Oregon
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Note: This is a Opinion based on literature (Dryness, c. 1964), my MS Thesis published on the Rutgers University Geosciences website, and professional experience under registered engineer supervision by Bill Day (1997-1998 (just in case OSBGE is reading this)
Put to bed
Thanks for your insights John. I’ve never heard the term “put to bed” before, but I couldn’t agree with you more. And the factoid about tree root systems seems like a very useful rule of thumb. — Randy Post (aka Rockman)