Fluvial landscapes

From GeoClasses

The landscape surrounding the stream influences the character of the stream and is in turn affected by the stream. The primary differnce that may be noticed is the difference between upland streams and low-land streams.

• The primary control on stream profile is base level, which is the elevation below which the stream cannot erode. Typically, base level is the elevation where the stream runs into a water body, such as a lake or the ocean.
• The limitation of base level results in stream profiles that are concave, with steeper slopes on the headlands and lower slopes at the boundaries.
  • The areas of low slopes are not able to erode much sediment while the steep-sloped uplands are very effective at erosion.

Stream profile along the course of a typical stream.

Carrying capacity

The carrying capacity is the ability of the stream to transport sediment. As you might expect, the steeper the slope the more active the stream and the higher the sediment carrying capacity.

Carrying capacity is an important indicator of if streams will erode or deposit sediment. If there is less sediment in the stream than it is capable of carrying, then the stream has extra energy to spare for erosion. If the stream has too much sediment, then the stream will have to deposit that sediment. As the slope, velocity and volume of flow changes, then the carrying capacity of the stream will change and the stream will erode or deposit sediment. These relationships result in the concave downstream profile.

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