Oregon District Active Projects
OR164 Temperature Modeling Tualatin River
PROJECT CHIEF: John C. Risley
LOCATION: Tualatin River
PROJECT EXTENT: Principally Washington County
TOTAL AREA IN SQUARE MILES: 712
As part of an overall program to protect the health of aquatic
ecosystems in Oregon, regulatory agencies have imposed stringent
guidelines on allowable temperature modifications to water bodies.
There is clear evidence that fish survival decreases markedly as water
temperatures warm past a critical theshold, particularly during
sensitive life-stages of fish. In the Tualatin River, water
temperatures periodically reach and surpass the critical theshold for
cold-water fish during the low-flow season in the summer and fall
months. During these times, it is important that human-caused
increases in water temperature are minimized.
Urban runoff, effluent from WWTPs, and incomplete riparian vegetation
in the drainage basin may contribute to warm water temperatures in the
Tualatin River. However, these impacts are not well characterized or
Quantify the temporal and spatial patterns of water temperatures in the
main-stem Tualatin River and the mouths of major tributaries; determine the
relation of water temperatures in the Tualatin River and major tributaries to
climatic condiditons, seasonal and diel variations, and human-caused factors;
and quantify the potential effectiveness of urban and agricultural management
strategies for controlling impacts on stream temperatures during the base-flow
season (May through October).
The study approach includes the following three elements: (1) collect water temperature, meteorological, discharge, and channel geometry and shading data to support model development and calibration; (2) calibrate and validate a dynamic water-temperature model of the Tualatin River (Scoggins Creek Dam to the Lake Oswego Dam); and (3) use the model to test various management scenarios to remediate water temperature problems associated with human activities in the basin.
OFR 96-315. Water-Temperature, Specific-Conductance, and
Meteorological Data for the Tualatin River Basin, Oregon, 1994-95, by
John C. Risley and Micelis C. Doyle. Abstract
WRIR 97-4071. Relations of Tualatin River Water Temperatures to Natural and Human-Caused Factors, by John C. Risley.
WRIR 00-4071. Effects of Hypothetical Management Scenarios on
Simulated Water Temperatures in the Tualatin River, Oregon, 1998, by
John C. Risley.
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Last modified: 12/19/00