GCSE Geo- rivers

Hyrographys
1. vocab
  1. discharge: the colume of water pasing a given point in a river at any moment in time
  2. lag time: the time it takes for rainfall to get to the river
  3. falling limb:water is still reaching the river but in decreasing amounts
  4. rising limb:the normal flow of the river starts to rise
  5. Flashy responce: river that responds quicky to rain to is has a high peak and short lag time
2. Built up area
  1. Higher Discharge
    1. Due to: artificial surfaces - tarmac and concrete= less surface run off
  2. Short Lag time
    1. Due to: little interception by vegetation etc
    2. little infiltration (small amounts of vegetation )
  3. Flashy Responce
    1. faster response = higher peak discharge
3. Forested Area
  1. long lag time
  2. low discharge
    1. - Infiltration high. -Ground water flow slower than surface run off. -Water flows slower over vegetetation
  3. subdued responce
    1. slower response = lower peak discharge
CASE STUDIES - FLOODING
1. Bangledesh
2. CockerMouth
Hard/Soft Engeneering
1. HARD
  1. Dams
    1. disadvantages
      1. resettlement
      2. very expensive
      3. Habitats effected
    2. Advantages
      1. turbines can be built into the dam to generate hydroelectric power
      2. steady water release allows irrigation to land
      3. the resevoir can be used for recreational water sports
  2. Straightening and deepening of rivers
    2. disadvantages
      1. Flooding may happen downstream because flood water is carried there faster
      2. more erosion occurs downstream
    3. advantages
      1. it time less time to nivagate the river because the channel is shorter
      2. we can harness the extra power to make electricity
  3. Levees
    1. advantages
      1. they allow flood plain to be built on
      2. the river can hold mor water
    2. disadvantages
      1. they are quite expensive
      2. if breached = risk of severe flooding
  4. Others
    1. Diversion spillways
    2. Flood walls
    3. Storage areas
2. SOFT
  1. -Forecasts and Warnings -Preperation
    1. advantages
      1. enables time to evacuate = lives + possessions saved
      2. sustainable + cheap
    2. disadvantages
      1. cannot always predict floods/ danger
      2. people may ignore warnings
  2. Floodplain zoning etc
    1. advangages
      1. there are no new buildings/ roads etc to be damaged so impact of flooding reduced
      2. lives/ property saved
    2. disadvantages
      1. its restrics development ( big problem when there is a shortage on housing
      2. it cant be used in areas that are already urbanized
  3. Afforestation + Reforestation
    1. disadvantages
      1. takes time
      2. large areas required to be effective/ land that could have been used for economic activity
    2. advantages
      1. very effective long term
      2. creates wildlife habitats
      3. vegetation protects against soil erosion

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GCSE Geo- rivers

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	Created by tash.rajan over 10 years ago