Geography: River Landscapes

Path of a River
1. Upper Course
  1. Steep
  2. Narrow, shallow channel
2. Middle Course
  1. Sloping valley sides
  2. Wider, deeper channel
3. Lower Course
  1. Very wide
  2. Almost flat valley
Vertical Erosion
1. Deepens river valley and channel, making it V-shaped. In the upper course. High turbulence causes the rough particles to be scraped along the river, causing downwards erosion.
Lateral Erosion
1. Widens river valley and channel during the formation of meanders. Middle & lower course.
Processes of Erosion
1. 1
  1. Hydraulic Action
    1. Force of the water breaks rock particles away from the river channel.
2. 2
  1. Abrasion
    1. Eroded rocks, picked up by the river, scrape against the channel, wearing it away.
3. 3
  1. Attrition
    1. The eroded rocks smash into each other and break into smaller pieces. The further material travels, the more eroded it gets.
4. 4
  1. Solution
    1. River water dissolves some types of rock - E.G. Chalk and limestone
Transportation
1. Solution
  1. Soluble materials dissolve and are carried along.
2. Suspension
  1. Small particles are carried along by water.
3. Saltation
  1. Pebble-sized particles are bounced along the river bed by the force of the water.
4. Traction
  1. Large particles are pushed along the river bed by the force of the water.
Hard & Soft Engineering
1. Hard
  1. Man-made structures built to control flow of rivers and reduce flooding.
  2. Embankments - Raised walls built along the river banks.
    1. + River can hold more water so it will flood less frequently, protecting buildings.
    2. - A risk of severe flooding if the water rises above the level or if they break. - Quite expensive
  3. Channel Straightening - River's course is straightened
    1. + Water moves out of the area more quickly
    2. - Flooding may happen downstream instead, as water is carried there faster and more erosion.
2. Soft
  1. Flood Warnings
    1. + Impact of flooding is reduced + People can evacuate
    2. - People may not hear/access the warnings.
  2. Schemes set up to reduce the effects of flooding
  3. Planting Trees - Increases interception of rainwater and increases the lag time.
    1. + Discharge and flood risks are reduced + Vegetation reduces soil erosion
    2. - Less land is available for farming
Rivers Flood due to Physical and Human Factors
1. Heavy Rainfall
2. Prolonged Rainfall - Long Period of Rain
3. Relief - Change in the Height of the Land
4. Geology

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Geography: River Landscapes

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	Created by Blerta Morina almost 5 years ago