In July of 2001, the Environmental Protection Agency (EPA)
activated the Total Maximum Daily Load (TMDLs) provisions of the
Clean Water Act. As the first river in Oregon to implement TMDL
regulations, people and agencies in the Tualatin basin face many
challenges. Non-point source pollution affects water quality in the...
Human activities may contribute to the eutrophication of surface waters by
providing nutrients to aquatic ecosystems. Phosphorus is frequently identified as a
nutrient that is limiting to most aquatic ecosystems under natural conditions. Sources of
phosphorus contributing to eutrophic conditions often include nonpoint sources that are
dispersed across the landscape....
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...
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,...
Survey In 1995, the Washington County Soil & Water Conservation District interviewed 90 farmers in northwest Oregon's Tualatin River Basin, using a survey developed by the USDA - Natural Resources Conservation Service (NRCS) and Oregon State University (OSU) Extension Service. Crop rotations, yields, tillage, fertilizer and irrigation practices were recorded....
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 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 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...
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...
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...