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Shape of a River - Geomorphology
Bankfull flows

A river's shape is determined over time through the continuous interaction between water and the landscape. Rivers and streams of all shapes and sizes have a tendency toward dynamic equilibrium, where the energy of the system is expressed in its pattern, dimension and profile.

While the largest floods move large amounts of sediment over short periods of time and shape the valleys and floodplain, they are relatively rare. Research over the past 50 to 60 years has increasingly demonstrated the importance of bankfull flows in defining a river's shape.

The term bankfull refers to the water level stage that just begins to spill out of the channel into the floodplain. Bankfull flows tend to occur fairly frequently, on the average every two out of three years. Because bankfull floods occur frequently, they move the most sediment over time and shape the stream channel itself. The range of forces-from major floodplain-forming events to recurring bankfull flows-are necessary for healthy river systems.


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Introduction
Flow
Shape
Description
Variables
Bankfull flows
Classification
Sediment
Patterns
Slope
Habitat
Change
Consequences
Stories
Connections
Quality
Life
Summary
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