LANDSLIDE SOILS AND GEOMORPHOLOGY IN CAMP DAVIS QUADRANGLE, BRIDGER-TETON NATIONAL FOREST, WYOMING

Abstract

Active landslides are evident throughout Bridger-Teton National Forest (BTNF), and northwestern Wyoming has one of the highest landslide densities in the country (Case, 1990 and Fallon, 1996). Land use changes and increased demands for infrastructure challenge BTNF to better understand landslide processes in order to make informed land management decisions. Landscape properties related to landslide occurrence were studied via field work and laboratory analysis on 18 landslides in Camp Davis quadrangle. Landslide activity level was characterized based on geomorphic features. Landslide soil characteristics including texture, shrink-swell potential, clay mineralogy and horizonation were studied. The results show that landslides are catastrophic to soil formation. Additionally, these results support the hypothesis that landslide occurrence here is related to geology. These preliminary findings provide BTNF with a method for assessing landslide activity based on a set of field observable geomorphic and soil features, enhancing existing methods for assessing slope stability.