Six headwalls in the central Oregon coast range were selected for study of soil engineering properties and vegetativecharacteristics important for analysis of slope stability. The headwalls were considered representative of those which would be candidates for timber leave areas due to geomorphic and topographic features, including steepness of slope and...
A hypothesis used to explain the relationship between timber harvesting
and landslides is that tree roots add mechanical support to soil, thus increasing
soil strength. Upon harvest, the tree roots decay which reduces soil strength and
increases the risk of management -induced landslides. The technical literature
does not adequately support...
The John Day Reservoir, a large reservoir between the John Day and the McNary Dams on the Columbia River, must be lowered several feet below design level during salmon migration season in order to preserve anadromous fish habitat. This research assessed the north shore of the John Day Reservoir for...
Two hilislope sites in the central Oregon Coast Range were instrumented and monitored for winter precipitation and saturated and unsaturated subsurface conditions. The study sites were near-ridge depressions typically known as headwalls. Based on results of the monitoring, two existing mathematical models
were adapted to predict piezometric levels in headwalls...
