Rivers

• what is saltation?


  bouncing of smaller sediments as they are transported along the river
• What is traction?


  Rolling of large pebbles along the river bed
• What Is long profile ?


  Gradient of river from source to mouth
• what is cross profile?


  Shows the shape of the river valley
• What course does lateral erosion widen?


  Lower and middle
• How is a v shape valley form?

  By erosion from a river or stream overtime
• What are interlocking spurs?

  Ridges of hard rock formed by erosion in a river valley.
• What Is a gorge?

  Narrow valley with steep sides.
• Where is gorge found?

  Downstream from a water fall
• How is a meander formed Step 1?


  meanders start with a slight bend in the river channel , water flows fastest on the outside bend eroding it forming river cliffs and slower on the inside bend depositing material forming slip off slopes
• What is a flood plain?

  wide , flat area on either sides of a river
• What is levee ?

  raised river bank
• What is an estuary ?

  Wide part of the river where it nears the sea
• How can rock type decrease lag time ?


  impermeable rocks such as clay increases surface run off
• How can we increase lag time 🪨🪨

  permeable rocks such as sandstone encourage ground water flow
• How does (relief)slopes affect lag time ?

  The steeper the river valley the quicker water flows into the river
• What does (urbanisation) land use do?

  concrete which is used to build buildings are impermeable so this will increase run off rather than absorbing it
• How can forests slow down water flow?

  Trees roots absorb water and reduce runoff as well as intercepting rainfall
• How do dams prevent flooding?

  Controls the river flow
• Advantages of dams?

  Hydropower, irrigation, flood control, water supply.
• Disadvantages of dams


  Expensive
• What is channel straightening

  cutting through meanders to create a straight river channel to speed up the flow of water along the river.
• How is channel straightening effective

  Long lifespan
• Disadvantage of channel straightening 


  Expensive , unnatural, flooding downstream
• What is embankment

  Raised levee increasing how much water a river channel can hold
• advantages of embankment

  Can look natural if vegetated , long lifespan
• Disadvantages of embankment

  Expensive, negative impacts on wildlife
• What is a flood relief channel

  Man made river channel which diverts water from urban areas
• Advantages of flood relief channels

  Effective to regulate river discharge
• Disadvantage of flood relief channels

  Expensive, negative impact on wildlife
• What is afforestation

  Planting trees to create forests
• Advantages of afforestation

  Trees increase lag time , provides habitats , cheap
• Disadvantages of afforestation

  Less effective than hard engineering
• What are wetlands

  Land left to flood
• What are advantages of wetlands

  Cheap , easy to maintain , create habitats , stores water so less is in river channel
• disadvantages of wet lands

  Short lifespan, constant maintenance
• What is flood plain zoning?

  Regulating land use in flood prone areas
• advantages of flood plain zoning

  reduces cost
• Disadvantages of flood plain zoning

  Doesn’t stop flood, less effective
• What is river restoration?

  Returning a river to its natural state