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Technical Report

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Water quality -- Spokane River (Idaho and Wash.) -- Mathematical models, Hydrologic models, Hydrodynamics -- Mathematical models, Water-supply -- Models -- Spokane River (Idaho and Wash.)


The Spokane River in Idaho originates in Coeur d’Alene Lake (Figure 1 and Figure 2). The section of the Spokane River from Coeur d’Alene Lake to the Washington state line is the subject of a water quality study for the US Environmental Protection Agency. The objective of this study is to create a water quality and hydrodynamic model of the Spokane River in Idaho using CE-QUAL-W2 Version 3.1 (Cole and Wells, 2002).

Since the Spokane River is water quality limited, a hydrodynamic and water quality model for the Spokane River in Washington was developed by Portland State University for the Corps of Engineers and the Washington Department of Ecology from the Idaho border to the outlet of Long Lake.

An earlier study of the Spokane River was undertaken by Limno-Tech (2001a, 2001b) for the domain shown in Figure 3. Limno-Tech used an earlier version of CE-QUAL-W2, Version 2, for the Reservoir portion of the Spokane River from Post Falls Dam to Coeur d’Alene Lake and a steady-state EPA model, QUAL2E, for the riverine section from Post Falls Dam to the Idaho-Washington border. The steady-state QUAL2E model was not adequate to deal with flow and water quality dynamics. Hence, the riverine portion of the model and the reservoir portion were both upgraded to CE-QUAL-W2 Version 3.1.

Because of the necessity of looking at the entire water basin, a model using CE-QUAL-W2 Version 3.1 of the Idaho portion of the Spokane River model was developed to assess water quality management strategies for the Idaho side of the Spokane River.


Technical Report EWR-02-03 produced by College of Engineering and Computer Science, Department of Civil and Environmental Engineering, Portland State University.

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