Allegations: Oregon Not Forthcoming With Landslide Hazard Information
In case you missed the background on the Kilbuck Landslide (or here or here), it happened in Kilbuck Township, PA back in in September of 2006. To deal with the political hot potato and media nightmare, Wal-Mart bought out the developer on the unfinished property and began handling remediation of the slide itself. Now, it appears as if they want their money back from the developer! Read on for more details.
Geology.com pointed out a very nice PDF version of a Power Point presentation by the North Carolina Geologic Survey on their landslide hazard mapping efforts in western North Carolina. The presentation was dated August 1 of last year. The NCGS also has their landslide mapping products available for download, and those so inclined can download the GIS data sets as well. (Photo by NCGS)
Devil’s Slide is an infamous landslide along California’s Highway 1 or Pacific Coast Highway near Pacifica, just south of the San Francisco Bay area. Caltrans’ Devil’s Slide Tunnel project is an effort to bypass that slide and make the heavily traveled roadway safe for drivers and to eliminate the maintenance and traffic hassles caused by slope failures blocking the road. We first covered the project back in September of 2007 when the tunnel portion of the project commenced. In that post, you can find a Google Earth KML File showing the location of the tunnels and the new bridges associated with the project. In this post, I’ll provide you with some updated progress information as well as some background on the geotechnical and other aspects of the project. More links and videos are at the end of the post. (Photo by Kim Komenich, San Francisco Chronicle). […]
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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)