The U.S. Geological Survey (USGS) has worked cooperative with the Unified Sewerage Agency of Washington County (USA) since 1990 to assess water quality in the Tualatin River Basin. The objectives of this study were to: assess the occurrence and magnitude of trace element and selected organic contaminants in streams of...
Throughout the Applegate watershed, dense, overstocked, immature stands of mixed
conifers and hardwoods and declining stands of mature conifers present significant
and complex silvicultural problems. Stand stagnation is common, as is loss of largediameter
conifers from insects and wildfire. Treatments designed to maintain or
encourage development of large-diameter conifers have...
This thesis documents a period of ecological and cultural change on a Willamette Valley, Oregon landscape. In particular, this study examines the Peavy Arboretum area and the cultural changes that accompanied the transformation of the landscape from an oak savannah in the mid-nineteenth century to a dense Douglas-fir forest in...
The Upper Grande Ronde River Watershed in northeastern Oregon is considered important habitat for threatened stocks of chinook
salmon (Oncorhynchus tshawytscha). Documented reductions in channel complexity and riparian vegetation within the watershed have increased concern over loss of viable habitat. An important component of salmonid habitat is stream temperature during...
The pages which follow contain the authors responses to a series of comments that were received in response to "A Project to Collect Scientific Data and Provide Evaluation and Recommendations for Alternative Pollution Control Strategies for the Tualatin River Basin, 11 submitted to the Oregon Department of Environmental Quality (DEQ)...
In response to Oregon House Bill 3338, the Oregon Department of Environmental Quality requested proposals in 1991 to assemble available information on Tualatin River Basin conditions to provide a scientific basis for improving river water quality. An interdisciplinary team of researchers from Oregon State University and Portland State University was...
The Tualatin River is a major water resource for Washington County. In its course, the river drains forest lands, farmlands, and urban areas receiving toxic materials from non-point source runoff: Wastewater treatment plant effluents from municipalities and industries also contribute toxic materials to the river. Many materials discharged into the...
This report summarizes the conclusions reached in "A Project to Collect Scientific Data and Provide Evaluation and Recommendations for Alternative Pollution Control Strategies for the Tualatin River Basin."
This study was funded by the Oregon Department of Environmental Quality as a grant to the Oregon Water Resources Research Institute on...
Dionysius said that history is philosophy learned from examples. As one of the original four counties of the Territory of Oregon, the Tualatin River Basin is rich in history. While still a prime agricultural region, the Tualatin Valley is one of the state's fastest developing areas. The slow accumulation of...