Shape of a River - Geomorphology
Rates of change
Natural river channels change gradually over
time. Banks scour. Bends increase. Oxbows form.
Dramatic changes in the variables governing
channel formation force rapid changes to the stream
channel. Occasionally these changes are natural. A
landslide may temporarily block the flow of a
mountain stream and provide an abundant supply of
More often, dramatic changes in the factors
governing channel formation are the result of human
activities, such as dam construction or removal,
channelization, or clearing of forest land.
Compare the rates of flow and the width of the
channel in the two video clips below.