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THERMAL CHARACTERISTICS OF RIVER WATERS

The rate of chemical and biological processes in surface waters, especially oxygen level, photosynthesis and algal production, are strongly influenced by temperature. Temperature is also an important variable for aquatic biota, particularly for fish. The thermal characteristics of lakes and reservoirs are a major factor in planning for effluent management and for withdrawal of water for industrial cooling purposes.

Temperature variation in surface water depends on local climate and on upstream influences such as snow and glacier melting, and occurrence of lakes. Siberian rivers, such as the Lena at its mouth, are frozen during eight months of the year while at the equator, the water temperature is nearly constant, 30°C at sea level (Surabaya) and 23°C at higher altitude (Thika). Seasonal variations are maximum at mid-latitudes where they can exceed 25°C. Thermal pollution, as in the Meuse, rarely exceeds a few degrees and is usually masked by larger seasonal trends.

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URL of this page: http://www.cciw.ca/atlas-gwq/thermal-e.html
Last updated: 2002-02-04