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Channel Processes

Transportation
1. Types
  1. Traction
    1. Only operates in times of high discharge
    2. Large stones/boulders are rolled along the river bed by water moving downstream
  2. Suspension
    1. Contributes to a large amount of the river flows
    2. Small particles, are carried along by the flow of the river
  3. Saltation
    1. Assoited with high energy conditions
    2. Small stones bound/leap frog along the river bed
  4. Solution
    1. Dissolved minerals being transported within the mass of the water
2. The river obtains it's load through in two main ways
  1. Material being washed/fallen into the river
  2. Material being eroded from the river bed/banks
3. The capcity of the river is the amaont of material in a river
4. The competence of a river is the diameter of the largest particle it can carry
Erosion
1. Types
  1. Attrition
    1. The reduction in the size of fragments, in the river
    2. Sediment strike each other, becoming smaller, smoother and more rounded
  2. Corosion
    1. The most active rocks contain carbonates
    2. The minerals in the rock are dissolved by acids and carried away
  3. Abrasion
    1. Wear's away the river bed/banks
    2. The scraping, scouring, and rubbing action of materials along by the river
  4. Hydraulic Action
    1. The movement of loose material due to frictional drag
    2. Caused by the sheer power of water movement
2. Lateral erosion
  1. This energy is used laterally (against the river banks mostly)
  2. River processes a lot of energy
  3. Usually occurs in the middle/lower course of the river
3. River's erode because they process the energy too
  1. The total energy of a river depends on;
    1. Steepness of the Channel
    2. The weight of the water
    3. The height of the river above base level
4. Vertical erosion
  1. Often produces steep sided valleys
  2. Mainly caused by abrasion and Hydraulic Action
  3. River is attempting to erode down towards base level
  4. Dominates when rover is high above base level
Deposition
1. Usually occurs when;
  1. There is a reduction in the gradient
  2. The discharge is reduced
  3. There is shallow waters
  4. There is an increase in the size of the load
  5. The river overflows, its banks
2. A river deposit's its load when there has been a decrease in the rivers energy
3. The largest fragments generally get deposited first, followed by smaller particles. Although the finest particles may never be deposited

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Channel Processes

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	Created by Phoebe Fletcher over 9 years ago