U1: Rivers

• Abrasion is friction between rocks and the bank causing scraping of the bank
• Attrition is when jagged stones enter the river and travel downstream whilst bumping into other stones on the river bed and bank.
• Hydraulic action is when fast flowing water flows into cracks causing a change in air pressure causing the bank to weaken.
• Solution is when rocks like chalk and limestone dissolve in the water.
• Vertical erosion is the cutting down of the river (making deeper).
• Vertical erosion is the cutting down of the river (making deeper).
• Lateral erosion is the sideways erosion of the bank (widens the channel). Common in the middle and lower course.
• Traction is when big bits of sediment don't leave the river bed, and roll downstream.
• Saltation is when smaller rocks bounce along the river bed.
• Solution is when material that is so small it is dissolved in the river.
• Suspension is when the material doesn't touch the banks or bed and is just carried with the river.
• At the upper course:

  • Vertical erosion
  • Valleys
  • Thin channel
  • Shallow
• At the middle course:

  • Lateral erosion
  • Meanders
  • Oxbow lakes
  • Wider channel than upper course
  • Shallower valleys than upper course
• At the lower course:

  • Very wide channel
  • Very shallow valleys
  • Estuaries
  • Meanders
• The River Tees is in NE England and runs through the county Durham and North Yorkshire. Its source is in the Penines, as it flows East to West, to its mouth in Middlesborough, entering the North Sea. It is 137km long.
• Characteristics of a Gorge:

  • very narrow valley
  • very steep valleys
  • U-shaped valleys
  • located immediately downstream of waterfalls
• Waterfall formation:

  1. Waterfall forms where there is a junction between a hard rock capping upstream and soft rock downstream. Water erodes soft rock faster than hard rock, forming a drop.
  2. Splash back causes undercutting to weaken the rocks behind the waterfall, eventually leading to the retreat of the waterfall, forming a gorge.
• An Interlocking Spur is when a number of projecting ridges that extend alternatively from opposite sides of a valley.
• Meanders are bends in the river, found in the middle and lower course.
• Characteristic of Levees:

  • raised river banks
  • composed of gravel, stones and alluvium
  • steep sided
  • bigger rocks closer to river channel
  • fairly flat top (leads to recreational use, eg. footpaths)