rivers - physical features

includes most of the physical aspect of the rivers module.  river proccesses and landforms.  i have made a seperate one for flooding and management strategies.

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  • Created by: slackyboi
  • Created on: 19-05-16 14:24
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  • Rivers
    • river proccesses
      • erosion
        • hydraulic action - water enters gaps in the substrate ad expands, forcing the material apart
        • abrasion - the sandpaper action of fine material wearing away the river bank
        • corrosion - chemicals within the water such as calcium carbonnate dissolve  the water and erode the bed and banks
        • attrition - material moves along the river channel and collides with other pieces and disintegrates into smaller, rounded particles
      • transportation
        • suspended load
          • solution - material is dissolved and carried in the river
          • suspension - small particles are held within the river.  the lightest particles are nearer the surface.
        • bedload
          • traction - large rocks are rolled across the river bed
          • saltation -  when larger stones are bounced along the river bed
      • deposition
    • River landforms
      • the middle course
        • Meander - when a river flows over relatively flat land, it forms bends called meanders.  when the water goes around the meander, centrifugal force pushes the water outwards.  this erodes the outside of the meander and creates deposition on the inside of the bend which is known as a slip - off - slope.
        • Oxbow lake - when a meander becomes cut off due to erosion, it takes the shortest route and forms an isolated lake in a horseshoe shape.
      • the upper course
        • waterfall - when a river runs over vertical layers of soft and hard rock, it erodes the soft rock creating an overhang and plunge pool.  as the hard rock caves in above the overhang over time, the waterfall retreats to form a gorge.
        • V - shaped valley - a steep narrow valley created when vertical erosion is stronger than horizontal.
          • interlocking spurs - when a river cuts a V - shaped valley which winds between two or more hills or mountains.
      • the lower course
        • delta - when a river meets the sea or a lake, it branches into lots of small channels and deposits lots of sand and silt.
        • floodplains
          • levees - when deposited material from past floods builds up next to a river.
          • fertile soils due to silt from floods

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