Water Use, Groundwater Conditions, and Slope Failure on Benchlands in Western Montana: The Darby Slide Example

摘要

Slope failures, a problem on benchlands of western Montana, affect all who live on the land. A better understanding of lithology and groundwater, both associated with this problem, will help land planners assess risks. The Darby slide provided an opportunity to study the geologic and hydrogeologic conditions existing at the time of failure, and to compare these conditions with those conditions existing now at past failures on the bench west of Darby. Two conditions were similar at the larger of the slope failures of the area: groundwater seeps occurring within areas of failure; and the presence of smectite rich sand similar to exposures of weathered bedrock.