rivers

• hydraulic action is the force of water hitting the river bed and banks
• abrasion is when sediments carried by the water hit the river bed and river banks
• attrition is when stones carried by the river hit into eachother
• corrosion is when chemicals in the water dissolves the rocks
• solution is when sediments are dissolved in water
• suspension are sediments carried by the water
• saltation is when sediments bounce on the river beds
• traction is when sediiments roll on the river bed
• The Hjulström Curve tells us the size of material that can be carried by a river of a certain velocity
• erosional landforms in the upper course

  • waterfalls
  • gorges
  • v-shaped valleys
  • interlocking spurs
• v shaped valley

  • upper course
  • vertical erosion
  • deep river banks collaps into the river channel
• interlocking spurs

  • areas of hard rock are too hard to erode so the river flows around it
• meander

  • middle course
  • the river flowing outside the bend travels faster ( thalweg ) than inside the bend
  • theres a faster rate of erosion near the thalweg
  • inside the bend the river deposits material
• oxbow lakes

  • middle course
  • loop of two meanders erode until they meet
  • river flows through new gap
  • old meander slows down and deposits material
• depositional landforms

  • floodplains
  • levees
  • estuaries
  • mud flats and salt marshes
• physical factors of floods

  • relief of the drainage baisin (steep , increases surface run off so reduces lag time )
  • heavy rainfall
  • prolonged rainfall
  • geology
• human factors of floods

  • urban areas
  • farmin practices
  • deforestation
• hard engineering

  • channel straightening
  • flood relief channels
  • raised embankments
  • dams and tidal barriages
• soft engineering

  • land use zoning
  • warning and preparation
  • afforestation
  • dredging
  • river restoration