In geography and geology, fluvial sediment processes or fluvial sediment transport are associated with rivers and streams and the deposits and landforms created by sediments. It can result in the formation of ripples and dunes, in fractal-shaped patterns of erosion, in complex patterns of natural river systems, and in the development of floodplains and the occurrence of flash floods. Sediment moved by water can be larger than sediment moved by air because water has both a higher density and viscosity. In typical rivers the largest carried sediment is of sand and gravel size, but larger floods can carry cobbles and even boulders.When the stream or rivers are associated with glaciers, ice sheets, or ice caps, the term glaciofluvial or fluvioglacial is used, as in periglacial flows and glacial lake outburst floods. Fluvial sediment processes include the motion of sediment and erosion or deposition on the river bed.
>>>PUT SHARE BUTTONS HERE<<<
Stream valley in the context of Stream capture
Stream capture, river capture, river piracy or stream piracy is a geomorphological phenomenon occurring when a stream or river drainage system or watershed is diverted from its own bed, and flows down to the bed of a neighbouring stream. This can happen for several reasons, including:
- Tectonic earth movements, where the slope of the land changes, and the stream is tipped out of its former course
- Natural damming, such as by a landslide or ice sheet
- Erosion, either
- Headward erosion of one stream valley upwards into another, or
- Lateral erosion of a meander through the higher ground dividing the adjacent streams.
- Within an area of karst topography, where streams may sink, or flow underground (a sinking or losing stream) and then reappear in a nearby stream valley
- Glacier retreat