Channel Processes

Rivers erode because they have energy.

Erosion:

Erosion involves the wearing away of rock and soil found along the river bed and banks. Erosion also involves the breaking down of the rock particles being carried downstream by the river.

Potential energy:

A still body of water at any point above sea level has a certain amount of stored energy, this is called potential energy, and its quantity depends on the height of the water.

Kinetic energy:

Kinetic energy is due to the movement of the water and is derived from it's potential energy. The amount of kinetic energy is determined by the discharge, gradient and average velocity. An increase in velocity and/or discharge will see an increase in kinetic energy

Wetted perimeter:

Refers to that part of the channel that is in contact with water. It represents the friction that slows down the river velocity, so the longer the wetted perimeter, the more friction between channel and water.

Hydraulic action:

the force of the river against the banks can cause air to be trapped in cracks and crevices. The pressure weakens the banks and gradually wears it away.

Abrasion/corrasion:

rocks carried along by the river wear down the river bed and banks.

Chemical Action (Corrosion):

Water dissolves minerals from the rocks and washes them away.

Attrition:

Rocks being carried…