Predicting the Natural Water Temperature Profile Throughout a River Basin

Richard D. Noble
Alan P. Jackman


DOI: 10.2190/HYVQ-75JB-7GA6-7TYP

Abstract

A one-dimensional mathematical model is presented for predicting natural water temperatures throughout an entire river basin. The model contains an accumulation term, convective term, dispersive term, and source term. Mathematical representations of each term contributing to the heat flux are presented.

This model can assume major importance in the planning and management of a river basin. Natural water temperature and the effects of alteration of this temperature regime have a large effect on the ecology of the entire river basin.

This model is solved numerically utilizing extensive synoptic meteorological and flow rate data obtained for an entire river basin. This solution is compared to experimental data. The results indicate that calculated water temperatures can be obtained which typically have a daily root-mean-square deviation of less than 3°C, a daily amplitude ratio of ± 0.20 of 1.0, and a daily mean within 2°C of observed data. These results can be improved with improved measurement of incoming radiation and average depth. The effects of the average depth, convection, and dispersion are also discussed.


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