Fluvial
From Wikipedia, the free encyclopedia
Fluvial is used in geography and earth science to refer to the processes associated with rivers and streams and the deposits and landforms created by them. When the stream or rivers are associated with glaciers, ice sheets, or ice caps, the term glaciofluvial or fluvioglacial is used.[1][2]
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[edit] Fluvial processes
Erosion by moving water happens in two ways. First, the movement of water across the bed has an effect (This is called hydraulic action). Second, the sediment being transported in the river wears away the bed (Abrasion) and the fragments themselves are ground down becoming smaller and more rounded (Attrition).
The sediment is transported as either bedload (The coarser fragments which move close to the bed) and the suspended load (Finer fragments carried in the water). There is also a component carried as dissolved material.
For each grain size there is a specific velocity at which the grains start to move, called Entrainment velocity. However the grains will continue to be transported even if the velocity falls below the entrainment velocity due to the reduced (or removed) friction between the grains and the river bed. Eventually the velocity will fall low enough for the grains to be deposited. This is shown by the Hjulstrøm curve.
[edit] References
- ^ K.K.E. Neuendorf, J.P. Mehl, Jr., and J.A. Jackson, eds., 2005, Glossary of Geology. American Geological Institute, Alexandria, Virginia. 800 pp.
- ^ Wilson, W.E. & Moore, J.E. 2003. Glossary of Hydrology, American Geological Institute, Springer, 248pp.
[edit] See also
[edit] Fluvial processes
This is also related to multistory deposits
[edit] Fluvial landforms
- bar
- basin
- confluence
- cutbank
- delta
- flood plain
- gorge and canyon
- gully
- meander
- natural levee
- ox-bow lake
- point bar
- natural pool
- riffle
- river
- spring
- stream
- stream terrace
- towhead
- valley and vale
- waterfall
- watershed
[edit] See also
list of landforms for a complete list
