Bedrock river

The type of bedrock may change as a river flows downstream, affecting erosional processes.

The main processes being: stream power, abrasion, quarrying, wedging, and dissolution.

[2] The rate of the potential energy loss is calculated in the stream power of the river.

[1] This equation suggests that stream power might be the single most important factor in bedrock incision.

In an alluvial river the stream power would be more of a transport because it would be picking up loose material and depositing it, but with a constant influx of sediment it would not be incising.

[3] Forms of erosion include "abrasion, plucking, cavitation, debris-flow scour and weathering" (4).

[3] The most common indicators of abrasion is potholes in the bedrock or a trough-like shape to the river.

[2] Traction is where the sediment is too large to be picked up in the river flow but is small enough to be pushed or rolled along at a slower rate.

Quarrying (also known as plucking) is the process by which a chunk of the bedrock must be somehow removed from the bed of the river and then forced along the planar surface of the riverbed.

[2] If the bedrock is already highly jointed, fractured or a bedding plane it will be easier for the chunk to be removed.

[1] Highly jointed or bedding plane bedrock can make it easier for the blocks to be lifted or shifted out of their position.

The blocks will eventually erode, but will cause headward erosion of the river while it exists.

Wedging is the process by which small cracks appear in the bed of the river which are enlarged by smaller particles.

[1] It can cause large blocks of the river to be removed from the bed starting the quarrying process.

The initial cracks appear due to a flux in the bedrock itself which is caused by a "rapid and large pressure variation".

[1] When the bedrock flexes back into its original position the crack is left open due to the wedging.

[1] This process typically only affects a bedrock river when the rock is already prone to dissolution, such as a sandstone.

[3] Grain stability is increased where the bedrock is rougher and where there is less kinetic energy in the water.