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Erosion and changes in the form of river banks may be measured by inserting metal rods into the bank and marking the position of the bank surface along the rods at different times. [23] Thermal erosion is the result of melting and weakening permafrost due to moving water. [24] It can occur both along rivers and at the coast.
River channel migration is the geomorphological process that involves the lateral migration of an alluvial river channel across its floodplain. This process is mainly driven by the combination of bank erosion of and point bar deposition over time. When referring to river channel migration, it is typically in reference to meandering streams.
The terms river morphology and its synonym stream morphology are used to describe the shapes of river channels and how they change in shape and direction over time. The morphology of a river channel is a function of a number of processes and environmental conditions, including the composition and erodibility of the bed and banks (e.g., sand, clay, bedrock); erosion comes from the power and ...
Lake bed downcutting is the erosion of cohesive material such as clay or glacial till from a shoreline by wave action. When the sand cover is stripped away and the cohesive layer is exposed, cohesive material is lost to the water column. Unlike sand, cohesive material cannot be replenished by natural events such as bluff erosion. This can ...
Stable material on the river bed mitigate erosion, [10] removing this armoring layer of gravel, boulders, etc. exposes the channel bed to the erosive force of the water. "On the Russian River near Healdsburg, California, instream pit mining in the 1950s and 1960s caused channel incision in excess of 3-6 m over an 11-km length of river." [5]
The faster the water in a river channel, the better it is able to pick up greater amounts of sediment, and larger pieces of sediment, which increases the river's bed load. [4] Over a long enough period of time, the combination of deposition along point bars, and erosion along cut banks can lead to the formation of an oxbow lake. [1]
The channel head is the most upslope part of a channel network and is defined by flowing water between defined identifiable banks. [1] A channel head forms as overland flow and/or subsurface flow accumulate to a point where shear stress can overcome erosion resistance of the ground surface. [1]
In addition to chemical and physical weathering of hydraulic action, freeze-thaw cycles, and more, there is a suite of processes which have long been considered to contribute significantly to bedrock channel erosion include plucking, abrasion (due to both bedload and suspended load), solution, and cavitation.