Geography

• Abrasion


  Stones and materials carried by the river hitting the river beds and banks, wearing them away
• Hydraulic action

  The sheer force of water hitting the river bed and banks, compressing air in the gaps in the soil and rocks which causes materials to be washed away
• Solution

  Slightly acidic river water dissolving chalk and limestone rocks which are made from calcium carbonate
• V shaped valleys 


  Found in the upper course of a river

  where the river is usually small and the land is steep
• 2 ways in which a waterfall can be formed

  Glacial erosion

  differential erosion
• Hard engineering strategies 


  Constructing defences to control natural processes

  often expensive and large scale
• Soft engineering strategies 


  Working with the environment rather than controlling it

  often cheaper and less impact on the environment, however can be less effective
• A graph to see how a river will react to a storm event

  Hydrograph
• Counter urbanisation 


  Movement of people out of cities and towns to rural ones
• Reasons for counter urbanisation

  Family status

  transport

  housing

  employment

  environmental factors
• Brownfield sites 


  Area for redevelopment that has previously been build on
• Mega cities

  Cities with over 10 million residents
• Globalisation

  The global web of links between countries involving people, trade, ideas and cultures
• Infrastructure 


  Basic structure and services needed by any society, for example roads, railways, water etc
• crust can be divided into 2 types

  Oceanic crust - 6 and 8 km thick

  continental crust - on average 35km thick
• What can tectonic processes cause?

  Earthquakes

  tsunamis

  volcanic eruptions
• Greenfield sites

  An area of land that has not been used before for building
• Green belts

  Areas of countyside around a city where building is restricted prevent the spread of cities