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Functions
& Conditions -
Evaluating the Physical Features
Channel
becoming wider and shallower
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Figure
2-12
Streambank
collapse can result in a wider, shallower channel which
affects water quality and quantity as well as aquatic
habitat. |
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Stream channels
get wider and shallower when something causes the banks to break
down or when the amount of sediment in the channel exceeds the capacity
of the water to move it through the system. As the channel flattens
out, the amount of contact between the flowing water and the streambanks
is reduced (Figure 2-12). The banks and floodplain are unable to
absorb and store water, and late season flows are reduced. As the
stream becomes shallower, stream temperatures may rise, which can
increase bacteria, algae, and other organisms that respond to sunlight
penetration and that may reduce water quality. Stream temperatures
which exceed tolerance levels also adversely affect fish habitat.
These levels differ from species to species.
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