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Introduction How Rivers Run Stories Value Of A River What We Can Do
Quality of a River - Water Quality
Temperature (pg 1 of 5)

Each stream displays characteristic temperature regimes, depending on the source of water in the headwaters (constant groundwater or intermittent runoff, for example). Most North American rivers gradually warm as they flow downstream. Large rivers, because of their great volume of water, tend to fluctuate less in temperature than smaller, shallower midreaches (Hynes, 1975).

Certain physical processes are influenced by temperature. The most obvious is the formation of ice on the surface, along the banks, and even on the bed of a stream. Other effects are subtler.

Because water becomes more viscous as it gets colder, cold water can hold more sediment than warm water can. Consequently, cold water has greater erosive power. Cold-water releases from a newly constructed dam can be expected to cause new erosion to the stream channel because (1) cold water is more erosive than the warm water it replaces, and (2) the reservoir traps sediment, leaving the released water with greater capacity to pick up new sediment.


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Introduction
Flow
Shape
Connections
Quality
Description
Temperature
Oxygen
Alkalinity
Nutrients
Sediment
Contaminants
Status
Life
Summary
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