Forest roads produce fine sediment with traffic during wet weather. If the forest road is connected to a stream it can be a source of turbidity and fine sediment that may be detrimental to aquatic organisms especially salmonids.
The goal of this work was to investigate turbid runoff during wet-weather...
An 18-year record of nitrate (NO₃), orthophosphate, total nitrogen and total phosphorus in four streams of the Bull Run
watershed, Oregon, was examined to determine its precision and time resolution. Of these four species, only NO₃ was found to be known to a sufficient level of detail for modeling and...
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...
Mass wasting events are a principal form of erosion that occurs on steep forest land throughout the Pacific Northwest. Numerous studies have reported that tree roots help stabilize steep forest land. A complete
understanding of the mechanism by which roots strengthen soil would enable modeling to more closely approximate field...
This thesis describes the results of a project conducted to determine the economics of forest road maintenance alternatives
between periods of timber harvesting. An open road and a closed road alternative will be compared to the economics of clearcutting an
entire area and obliterating the road system until reentry at...
Consider the bole of a tree to consist of a linear elastic material that is orthotropic with respect to the cylindrical coordinates. When the bole of a tree is subjected to resultant loads in the directions of the Cartesian base vectors, the S₁₁, S₂₂, S₃₃, and S₁₂ stresses in Cartesian...
Peakflow frequency analysis is used in forest hydrology for designing stream crossing structures such as culverts and bridges. The traditional approach to frequency analysis is based on the assumption that the observed sample of peakflows represents a homogeneous population. It is not clear if using the "homogeneous" population of the...
The use of the triaxial test to characterize the strength of soils for civil engineering applications is widespread. These tests are typically conducted with confining stresses in excess of 5 psi. To characterize the
strength of a soil located in the upper layers of the subgrade of an aggregate
surfaced...
The Lookout Creek Earthflow is located in the Cascade Mountain
Range in western Oregon. The Cascade Mountains are mainly volcanic
in origin, and deposits in and around the slide have a complex geomorphic
history,, affected by glacial, mass movement, and fluvial
processes. The currently moving land mass is about 1600...
High intensity sampling was undertaken to characterize the temporal and spatial
variability of oxidized nitrogen (NO3-N + NO2-N), ammonia-nitrogen (NH3-N), total
dissolved phosphorus, total unfiltered phosphorus and orthophosphorus (PO4-P) from two
adjacent small streams in Western Oregon's Coast Range, Deer Creek (303 ha) and Flynn
Creek (203 ha). Deer Creek...