Fluvial processes
In geography and geology, fluvial processes are associated with rivers and streams and the Deposition (geology), deposits and landforms created by them. When the stream or rivers are associated with glaciers, ice sheets, or ice caps, the term glac ...
have made
stream
A stream is a continuous body of water, body of surface water Current (stream), flowing within the stream bed, bed and bank (geography), banks of a channel (geography), channel. Depending on its location or certain characteristics, a stream ...
s,
stream bed
A stream bed or streambed is the bottom of a stream or river (bathymetry) or the physical confine of the normal water flow (Channel (geography), channel). The lateral confines or channel margins are known as the stream Bank (geography), banks ...
s, and
river valley
A valley is an elongated low area often running between hills or mountains, which will typically contain a river or stream running from one end to the other. Most valleys are formed by erosion of the land surface by rivers or streams over ...
s which have various classifications.
Classification
There are five generic classifications:
*Consequent streams are streams whose course is a direct consequence of the original slope of the surface
upon which it developed, i.e., streams that follow slope of the land over which they originally formed.
*Subsequent streams are streams whose course has been determined by selective
headward erosion
Headward erosion is erosion at the origin of a stream channel, which causes the origin to move back away from the direction of the stream flow, lengthening the stream channel.Essentials of Geology, 3rd Ed, Stephen Marshak It can also refer to ...
along weak strata. These streams have generally developed after the original stream. Subsequent streams developed independently of the original relief of the land and generally follow paths determined by the weak rock belts.
*Resequent streams are streams whose course follows the original relief, but at a lower level than the original slope (e.g., flows down a course determined by the underlying strata in the same direction). These streams develop later and are generally a tributary to a subsequent stream.
*Obsequent streams are streams flowing in the opposite direction of the consequent drainage.
*Insequent streams have an almost random drainage often forming dendritic patterns. These are typically tributaries and have developed by a headward erosion on a horizontally stratified belt or on homogeneous rocks. These streams follow courses that apparently were not controlled by the original slope of the surface, its structure or the type of rock.
See also
*
Geomorphology
Geomorphology (from Ancient Greek: , ', "earth"; , ', "form"; and , ', "study") is the scientific study of the origin and evolution of topographic and bathymetric features created by physical, chemical or biological processes operating at or n ...
References
Bibliography
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Fluvial landforms
Geomorphology
Water streams
Rivers
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