River Processes and Landforms

Hydraulic Action

this refers to the force of water itself, water splashes against the river banks and forces it’s way into the cracks and openings. This loosens material along the bed and banks and the river carries the material away

Attrition

this refers to the process by which material being carried by the river such as rocks and stones collide with each other. Overtime the become smaller and smaller they also become smooth and rounded

Abrasion or Corrasion

as the river flows it grinds it’s load against it’s bed and banks. This loosens material which the river carried downstream

Solution or Corrosion

some minerals in rocks and soils are soluble. They are slowly dissloved by the river water as they come into contact with them. Examples of this are salt and calcium carbonate( limestone and chalk)

Types of Flows in a River

the dynamics of stream flow in a stream is influenced by friction within a stream there are 3 types of flows:

Laminar Flow

water flow in a stream is not altered in it’s direction. Water flows as parallel molecular streams

Turbulent Flow

water flows as discrete eddies and vortices cause by friction and channel topology

Helical Flow

spiral flow in the river caused by channel shape meandering channels cause this types of flow

Transportation of Rivers

Transportation

The term refers to the ways in which a river carries material. The material a river carries is called a load. A load is carried in many ways:

Solution

materials which are dissolved in the water are carried downstream

Suspension

Tiny particles such as slit are suspended in the water as the river flows. When there is heavy rainfall the water often turns brown because all of the material suspended in it

Saltation

Particles such as small stones are bounced along the riverbed as they make their way downstream

Traction

the heaviest material in the river’s load such as large rocks are just rolled along the riverbed