This report presents estimates of land uses, concentrating on agricultural land in the Tualatin drainage basin. Acreage in different crop groups and agricultural water use and distribution in the watershed were estimated. The total amounts of nitrogen and phosphate applied to agricultural land and the average loading of nutrients per...
Water quality and stream flow data for tliree representative land uses in the Tualatin River Basin were evaluated to determine the comparative levels of various pollutants. In addition, the data were used in an effort to identify the extent to which observed concentrations of total and ortho phosphorus could be...
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 in northwest Oregon has been designated as water quality limited by the Oregon Department of Environmental Quality. Restoration and enhancement of riparian areas to improve water quality is one task to be pursued by management agencies. This paper examines some of the potential costs and benefits of...
About one-third of the land in the Tualatin Basin is used for agricultural production (Miner, Scott, and Wood, 1994). The variety of crops produced includes grains, specialty seeds, vegetables, fruits, berries, and nursery corps. Cattle and hog enterprises are the most prevalent livestock operations in the area (measured by number...
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...
Tributaries of the Tualatin River cascade down high gradient slopes for relatively short distances, then flow into the low gradient mainstem which meanders for much of its length. The gentle, east-facing slopes of Oregon's Coast Range provide the geomorphic and climatic template for the watershed's patterns of discharge, water quality,...
The Tualatin River Basin in Washington County, Oregon, is a complex area with highly developed agricultural, forestry, industrial, commercial, and residential activities. Population has grown in the past thirty years from fifty to over 270 thousand. Accompanying this population growth have been the associated increases in transportation, construction, and recreational...
The Tualatin Basin landscape has undergone extensive change since the initiation of Euro-American settlement, with important consequences for basin hydrology and water quality. Changes that include the isolation of the Tualatin River from its floodplain areas, losses of important wetlands and riparian areas, and urbanization associated with population growth in...
The Tualatin River Basin in Washington County, Oregon has been identified by the Oregon Department of Environmental Quality (DEQ) as "Water Quality Limited." Algal blooms have become commonplace in the lower , reaches of. the river during summer months. Phosphorus has been identified as the nutrient upon which to base...
The purpose of this study was to develop a mass-balance model for total suspended solids in the Tualatin River in order to better understand the clarity-turbidity problem in the river. Major sources and sinks of suspended solids in the river were identified, and seasonal effects were explored. The study also...
The goal of this phase of the study was to develop a model of the Tualatin River incorporating Scoggins Creek and Hagg Lake. This tool will be used in conjunction with a hydrologic model, the EPA HSPF model (Johnson, Imhoff, and Kittle, 1984), to analyze management strategies to improve water...
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)...
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...
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...
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...