Factors that affect flood risk
This presentation is the property of its rightful owner.
Sponsored Links
1 / 11

Factors that affect flood risk… PowerPoint PPT Presentation


  • 142 Views
  • Uploaded on
  • Presentation posted in: General

Factors that affect flood risk…. Natural & Human. The hydrograph – a reminder!. Key Fact: Shorter Lag Time + Steeper Rising Limb = Increased Flood Risk. Tasks:. With partner list all of the things that may increase flood risk in a drainage basin / river system…

Download Presentation

Factors that affect flood risk…

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Factors that affect flood risk

Factors that affect flood risk…

Natural & Human


The hydrograph a reminder

The hydrograph – a reminder!

Key Fact: Shorter Lag Time + Steeper Rising Limb = Increased Flood Risk


Tasks

Tasks:

  • With partner list all of the things that may increase flood risk in a drainage basin / river system…

    • Make one list of natural factors that may increase flood risk or cause flooding and another for human factors that may increase flood risk or cause flooding

    • Now try to decide what are the most important three factors in each list! – explain why each factor increases flood risk (think about hydrographs and lag time)

    • Share your answers with the class.


Natural factors 1

Natural Factors 1

  • Weather & Climate

    • Precipitation type (Rain Vs Snow)

    • Length of storm in time (leading to saturation)

    • Intensity of rainfall (precipitation exceeds infiltration rate)

    • Seasonality

    • Temperature


Natural factors 2

Natural Factors 2

  • Surface Type & Geology

    • Permeability of surface

    • Soil type

    • Rock Type


Natural factors 3

Natural Factors 3

  • Vegetation

    • Type (trees, bushes, grasses)

    • Seasonal effects on vegetation (summer vs. winter)

    • Coverage (bare ground Vs Vegetation cover)

    • Interception & storage


Natural factors 4

Natural Factors 4

  • Relief (shape of the land)

  • Shape of drainage basin

  • Size of drainage basin

  • Drainage density


Human factors 1

Human Factors 1

  • Urbanization

    • Surface permeability

    • Drainage systems

    • Vegetation removal


Human factors 2

Human Factors 2

  • Agriculture

    • Changes to vegetation

    • Animals

    • Erosion and runoff


Human factors 3

Human Factors 3

  • Changes to the drainage basin

    • River management (dams, flood relief channels)

    • Flood prevention schemes (levees, dredging)

    • Straightening

    • Deforestation


Tasks 2

Tasks 2:

  • Now use your text book (New Wider World)

    • Read pages 280 – 281 to reinforce your understanding of these flood risk ideas

    • Now read the case study of flooding in Bangladesh p.288-289… make a mind map to represent this flood event – include all of the factors hat led to this flooding… use one color for the natural factors and another color for the human factors.


  • Login