Portland State University. Department of Civil Engineering
Roy W. Koch
Term of Graduation
Date of Publication
Master of Science in Civil Engineering (MSCE)
McKenzie River (Or.) -- Temperature
1 online resource (2, xi, 96 pages)
A one dimensional, steady flow, unsteady temperature model is used to evaluate the effects of two U.S. Army Corps of Engineers (COE) dams and resulting reservoirs on hourly water temperatures of the mainstem McKenzie River from Delta Park (RM 62.1) to Leaburg Dam (RM 38.8). Both COE projects are on tributaries to the McKenzie River and at present have only bottom withdrawl capabilities.
Water temperatures were simulated using the equilibrium temperature approach with air temperature used to estimate equilibrium temperature and also using computed hourly equilibrium temperature. Results obtained using computed equilibrium temperatures were less satisfactory than results using air temperature to estimate equilibrium temperature. The much larger diel fluctuation of hourly equilibrium temperature as compared to air temperature accounts for this apparent contradiction.
A heat exchange parameter, HEP, was introduced during calibration to account for the additional surface area of a stream effectively available for heat transfer created by a multitude of riffles. Use of this parameter improved model results by increasing simulated daily maximums and diel fluctuations. Calibration produced a HEP value of 2.5 for the McKenzie River.
The model had a mean accuracy of near zero with a mean absolute deviation (MAD) of less than 0.4 °C at Finn Rock (RM 54.2). A mean error of 0.6 °C and MAD of over 0.6 °C at Leaburg Darn (RM 38.8) indicates that accuracy decreased downstream from Finn Rock.
COE reservoir effects were examined for a one week period in each of the months of July, August, and September, 1984. COE reservoirs had a cooling effect at Finn Rock during all three periods. Cooling effects were found at Leaburg Darn during August and September with no effects found in July. The overall result of COE reservoirs during these periods was a decrease in mean water temperature and a decrease in diel fluctuation at Finn Rock, but an increase in diel fluctuation at Leaburg Darn.
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Hansen, R. Peder, "Analysis and Prediction of the Water Temperature of the McKenzie River, Oregon Using the Equilibrium Temperature Approach" (1986). Dissertations and Theses. Paper 3610.