UK Landscapes

• Weathering


  The breaking down of rocks in situ. This can be physical, chemical or biological.
• Main types of weathering at the coast


  • Physical
  • Chemical
  • Biological
• Mechanical (freeze-thaw) weathering


  Water gets into cracks in the rock, over night the water freezes and causes the crack to expand. This continues over time until the crack widens, and parts of the rock break off
• Mass movement


  The movement of material downwards due to gravity
• Main types of coastal erosion

  • Hydraulic action
  • Abrasion (corrasion)
  • Attrition
  • Solution (corrosion)
• Main types of coastal transportation

  • Traction
  • Saltation
  • Suspension
  • Solution
• Destructive waves


  • Backwash is stronger than the swash, steep and short, formed in storm conditions
• Geological factors affecting coastal landscape

  • Composition of the rock
  • Structure of the rock
  • Alignment of rocks to each other and the coastline
• Coastal deposition


  When waves do not have enough energy to carry the sediment they are carrying, they will then drop some of this material
• Longshore drift


  If the wind is blowing into the coastline at an angle, then it will cause the waves to come into the coast at an angle. The swash of the wave moves diagonally along the beach, moving sand and material along the coastline.
• Hydraulic action


  Waves force their way into cracks in the rocks and compress air in them. This puts pressure on the rocks and causes the crack to expand. Over time the rock breaks up
• Slumping


  If cliffs become saturated with water, they can become unstable. A slip plane forms (crack in the sediment). If the cliff becomes saturated enough, the weight is too heavy and the cliff gives way along its slip plane and slumps down under gravity. Tends to happen on clay cliffs
• Carbonation


  A type of chemical weathering
• Hydrolysis


  A type of chemical weathering
• Hard engineering


  When a structure is built at the coastline to reduce erosion processes eg sea wall
• Soft engineering


  When natural processes are used to reduce coastal erosion eg beach nourishment
• Sequence of landforms on a headland

  1. Crack

  2. Cave

  3. Arch

  4. Stack

  5. Stump

  6. Wave cut platform
• Coastal bar


  When longshore drift occurs along a coastline with a bay or inlet. A beach forms across the bay/inlet that is joined to the mainland at both ends eg Slapton Ley
• Formation of a wave cut notch


  When destructive waves attack a coastal cliff, hydraulic action enlarges the cracks at the base of the cliff. This causes erosion of the base of the cliff and a notch forms
• If sea walls are straight rather than curved, they can reflect the energy of the wave and increase erosion on other parts of the coast
• Groynes


  Coastal management used to reduce longshore drift
• Beach nourishment


  A type of soft engineering for coastal areas
• Main types of weathering


  • Chemical
  • Physical
  • Biological
• Mass movement


  The downward movement of material on a slope due to gravity
• Sliding and slumping on a river

  If the valley slides get saturated with water, they become unstable, they may then fracture along a slip plane and collapse. The material will slump or slide into the river.
• Processes of fluvial erosion

  • Hydraulic action
  • Abrasion (corrasion)
  • Attrition
  • Solution (corrosion)
• Fluvial deposition


  If the river does not have enough energy to carry the load it has, it will drop the material it is carrying. It will normally drop the heaviest material first
• How deforestation increases flood risk


  Once the trees are removed, there is less interception of precipitation, so more water reaches the ground, which will saturate quicker.
• Formation of a levee


  These are mounds at the banks of a river. As the river overflows, sediment is deposited on the banks of the river, the heaviest material deposited first. With every successive flood, the mounds build up. These are levees
• Floodplain


  A flat area of land at the sides of a river - found in the lower course of a river
• Formation of a waterfall


  When there is a hard and soft rock side by side, the river erodes the softer rock quicker, creating a drop in the river. The hard rock will form an overhang, until that will collapse.
• Processes of fluvial transportation

  • Traction
  • Saltation
  • Suspension
  • Solution
• Gorge


  A steep sided valley left as a waterfall erodes and retreats
• Source


  The start point of a river, normally in upland areas
• Confluence


  The point where two rivers meet
• Lag time


  The time between peak rainfall and peak discharge
• Factors influencing lag time

  • Antecedent weather conditions
  • Intensity of precipitation
  • Catchment size
  • Drainage density
  • Land use
• Discharge


  Volume of water that can flow through a given point in a given time. Units are m3/s
• Width and depth of a river downstream

  Both will increase, but width will increase at a faster rate
• How urbanisation can change river landscapes


  Water reaches the river more quickly due to impermeable surfaces and drainage systems