Luncheon – October 5, 2001

Title: DeBeque Canyon Landslide

Speaker: Jonathan L. White, Colorado Geological Survey

Date: October 5, 2001

Publication: The Outcrop, October 2001, p. 4

The DeBeque Canyon landslide is located 21 miles east of Grand Junction in Mesa County, Colorado. Interstate 70, near milepost 50, passes through the toe of the landslide. The complex landslide has occurred in Cretaceous Mesa Verde Group strata on the west flank of the Piceance Basin. The morphology includes low angle creep movements within a thick shale stratum that has created large fissures and extensional structural features in the overlying interbedded sandstone, translational down-slope movements of landslide rubble in the middle portions of the slide, and lower slope deep rotational failures that periodically impact the highway.

Major re-activation of the slide occurred in April 1998 where the interstate roadway, at the toe of the rotational slide, heaved upward 14 feet. Earlier activation occurred in February 1958 when the toe heaved 24 feet. An even earlier re-activation near the turn of the century resulted in much larger movements of the slide where the slide toe entered the Colorado River and partially blocked it. Significant portions of the railroad alignment and the work camp of Tunnel on the opposite riverbank were subsequently washed out. This presentation will discuss the geology, geomorphology, and relative age of the landslide, the current investigation and monitoring work, and current mitigation plans by Colorado Department of Transportation.