Processes affecting river valleys
- Created by: Niamh
- Created on: 29-04-14 08:56
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- Processes affecting river valleys
- Erosion is the wearing away of the banks and bed of a river. These processes help remove material
- A river can erode laterally or vertically
- Weathering is the wearing away of the river valley sides
- Takes place in situ but the weathered material may move due to gravity and form scree slopes
- Examples
- 1. Physical - Freeze-thaw - water freezes and the crack is widened
- 2. Chemical - Acid Rain - rain water is slightly acidic, the acid reacts with minerals in the rocks and dissolves them
- 3. Biological - roots grow into cracks and split rocks apart
- Mass movement
- Over time the sides of a river valley become less steep as material is moved from the top to the bottom
- 1. Soil creep - soil particles move down the slope under influence of gravity
- 2. Slumping - the river erodes the bottom of the valley slope making it steeper. Material above slides downwards, particularly if it is saturated with rain water
- 3. Rock fall - rocks at the top of valley are affected by freeze-thaw. Parts of the rock break off and move down the slope
- Over time the sides of a river valley become less steep as material is moved from the top to the bottom
- Erosion is the wearing away of the banks and bed of a river. These processes help remove material
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