Document Type

Technical Report

Publication Date



Hydrology -- Oregon -- Willamette River, Water quality -- Oregon -- Williamette River, Streamflow -- Oregon -- Willamette River Watershed, Hydrologic models, Hydrodynamics -- Mathematical models, Water -- Pollution -- Total maximum daily load


The State of Oregon Department of Environmental Quality (DEQ) is developing a TMDL for temperature in the Willamette River basin shown in Figure 1. The study area included the Willamette River and all major tributaries (except the Tualatin River where a TMDL process was already concluded). A large section of the Columbia River was also modeled to provide adequate boundary representation of tidal flows in the lower Willamette River. The Willamette River below the Oregon City Falls in the Portland metropolitan area has a typical diurnal tidal range of 1 m. The development of a dynamic model of temperature and hydrodynamics of the entire river basin incorporating shading were primary requirements of this modeling study. The model would be used by DEQ to set temperature limits on point source dischargers and to evaluate the impact of management strategies on river temperatures to improve fish habitat. Some of these strategies included modifications of the dam at the Willamette River Falls south of Portland and channel reconfigurations.

The river basin model was originally divided into several reaches. Individual models were developed for each reach.

The models were set-up for each section of the Willamette basin as described in Annear et al. (2004a), the models were calibrated to field data and management strategies were evaluated as described in Annear et al (2004b).

This report outlines the model calibration of each of these model sections or elements for both the calibration time periods. The calibration period for each model section differs due to the availability of boundary condition data. The model management simulation scenarios (Annear et al, 2004b) also required boundary condition data that extended past the calibration periods.


Technical Report EWR-02-04

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