Document Type

Technical Report

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


The Washington Department of Ecology is interested in a water quality model for the Upper Spokane River system for use in developing Total Maximum Daily Loads (TMDLs). The goals of this modeling effort are to:

• Gather data to construct a computer simulation model of the Spokane River system including Long Lake Reservoir and the pools behind Nine Mile dam, Upper Falls dam and Upriver dam

• Ensure that the model accurately represents the system hydrodynamics and water quality (flow, temperature, dissolved oxygen and nutrient dynamics)

A hydrodynamic and water quality model, CE-QUAL-W2 Version 3 (Wells, 1997), is being applied to model the Spokane River system. CE-QUAL-W2 is a two dimensional (longitudinal-vertical), laterally averaged, hydrodynamic and water quality model that has been under development by the Corps of Engineers Waterways Experiments Station (Cole and Wells, 2000).

In order to model the system, the following data were required:

• Spokane River flow, water level and water quality data at the upstream system boundary (the State of Idaho boundary)

• Tributary inflows and water quality

• Meteorological conditions

• Bathymetry of the Spokane River, the dam pools along the river, and Long Lake Reservoir

• Point source (wastewater treatment plants, WWTPs) inflows and water quality characteristics

Data have been primarily collected from 1991 to 1992 and again during 2000. This report summarizes the data used in the modeling effort.


Technical Report EWR-4-01 is a production of the College of Engineering and Computer Science Department of Civil Engineering, Portland State University and the U.S. Army Corps of Engineers Waterways Experiment Station.

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