![]() | Project title | What causes landslides? |
Difficulty Level | High school | |
Main link | Click here to view all details of this science project (Cached)  (View 3rd party site) | |
Description | ||
A landslide inventory of the Touchet subbasin of the Walla Walla River Watershed was completed in 2002 by the WDNR. Using a combination of 1:24,000 scale orthophotos from 1996 and aerial photographs, nearly 250 possible landslides were located in the total 93 km2 (234 were accessed by road or trail; gates, road closures, or other obstacles prevented ground-truthing of the remaining 15 or so). The sites were then transferred to a topographic map to be used for field reconnaissance. Landslides are recognized on aerial photos and orthophotos by their hummocky terrain, light-colored material, lobe shape, etc. Each landslide was given a code depending on which specific drainage basin it was associated with. Slope angle, slide dimensions, and type (planar, deep seated, etc.) were estimated on the orthophotos, and then ground-truthing determined the actual characteristics. |