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In geomorphology fluvio-thermal erosion is the combined mechanical and thermal erosion of an unfrozen river or stream against ice-rich soils and sediments.The erosional process includes the thawing of ice sediments by a strong water flow and once the surface is unfrozen, mechanical erosion occurs only if hydraulic forces are powerful enough to incise the riverbank material. [1]
Long-lived river systems can produce a series of terrace surfaces over the course of their geologic lifetime. When rivers flood, sediment deposits in sheets across the floodplain and build up over time. Later, during a time of river erosion, this sediment is cut into, or incised, by the river and flushed downstream. The previous floodplain is ...
Splash erosion is generally seen as the first and least severe stage in the soil erosion process, which is followed by sheet erosion, then rill erosion and finally gully erosion (the most severe of the four). [10]: 60–61 [13] In splash erosion, the impact of a falling raindrop creates a small crater in the soil, [14] ejecting soil particles. [4]
There are two primary mechanisms of stream bank erosion: fluvial erosion and mass failure. Fluvial erosion is the direct removal of soil particles by flowing water. The rate of fluvial erosion is determined both by the force of the flowing water (e.g. faster flow equals more force) and the resistance of the bank material to erosion (e.g. clay is generally more resistant to erosion than sand).
A concurrent process called lateral erosion refers to the widening of a stream channel or valley. When a stream is high above its base level, downcutting will take place faster than lateral erosion; but as the level of the stream approaches its base level, the rate of lateral erosion increases.
A river bank can be divided into three zones: Toe zone, bank zone, and overbank area. The toe zone is the area which is most susceptible to erosion. [2] Because it is located in between the ordinary water level and the low water level, it is strongly affected by currents and erosional events. [2]
Hydraulic action, most generally, is the ability of moving water (flowing or waves) to dislodge and transport rock particles.This includes a number of specific erosional processes, including abrasion, at facilitated erosion, such as static erosion where water leaches salts and floats off organic material from unconsolidated sediments, and from chemical erosion more often called chemical ...
The process is often a result of a sudden fall in sea level or the rise of land. The disturbance enables a rise in the river's gravitational potential energy change per unit distance, increasing its riverbed erosion rate. The erosion occurs as a result of the river adjusting to its new base level. [1]