River Landforms

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  • Created by: Ellie R
  • Created on: 10-06-13 18:14
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  • LANDFORMS
    • INTERLOCKING SPURS
      • Vertical erosion is most important near the source.
      • The river cuts down into the bed through hydraulic action, attrition and corrosion.
      • Slope movement leads to v-shaped valleys forming.
      • The ridges of land left around which the river runs are called interlocking spurs.
    • WATERFALLS
      • These form where hard and soft rocks are found together, usually in the upper stages of a river.
      • When hard rock is above softer rock erosion is quicker below (by hydraulic action in particular).
      • The hard rock is undercut, is unsupported and may collapse.
      • This leaves a plunge pool and a steep sided gorge where this feature once stood.
    • MEANDERS
      • In the middle stages of the river it has more energy to erode laterally (or sideways).
      • The fastest flow carries on to the outside of the bend causing erosion by hydraulic action or corrosion or corrosion.
      • The slower flow is found in the shallower inside of the bend where deposition takes place.
      • These bends can migrate over time leading to wide, flat valley floors in the lower stages.
    • RIVER CLIFFS
      • These occur on river banks in the middle and lower stages of a river.
      • The fast flow on the outside of a meander hits the bank and breaks off material.
      • This can be caused by hydraulic action or corrosion or corrosion.
      • Where the side collapses and is eroded is a steep bank.
    • OXBOW LAKES
      • When meanders bend so much their 'necks' become very narrow.
      • Erosion on both sides of the 'neck' of the meander narrows the gap until they almost touch.
      • Floods allow water to break through what remains of the neck and the river now flows in a straight line (or the most direct route).
      • These features are left behind as deposition blocks them off and they can even dry up completely (often in a crescent shape).
    • FLOOD PLAINS
      • Flat land found either side of a river in its middle and lower courses and often contain meanders.
      • Migrating meanders can push back or erode the valley sides to create a wide, flat valley bottom.
      • Flooding of the river can deposit silt or alluvium that flattens the landscape by covering it.
      • The flat valley created by deposition and erosion, are surrounded on both sides by low hills called bluffs.
    • LEVEES
      • These are natural banks found either side of a river in the floodplain (although humans can make them artificially higher).
      • When a river floods it deposits material like silt or alluvium.
      • The largest material is dropped first as it is heaviest.
      • The smallest material is carried further during floods as it is lighter. The banks grow larger over time and the material left is sorted by size.

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