Flood Prediction & Mitigation (DP IB Geography)

Revision Note

Flood Prediction

  • It can be difficult to predict floods

  • Flood prediction requires different types of data, including:

    • Real-time rainfall levels

    • Knowledge about the type of storm producing moisture

    • Knowledge about the characteristics of the river’s drainage basin

  • Weather satellites and radars are used to predict river flooding

  • They help to identify the areas most vulnerable to flooding

Flood prediction in Bangladesh 

A map of Bangladesh highlighting flood-prone areas in color-coded ranges from very low to extremely high. Key cities labeled; information on monsoon rains and flood prediction.
Flood prediction in Bangladesh
  • Warnings can be given through social media about potential flooding

  • Flooding is becoming more frequent as a result of climate change

Improving flood prediction

  • Improved flood prediction can be achieved by:

    • Mapping of channels

    • More detailed collection of meteorological information

    • More sharing of information about the risk of flooding between countries who share international drainage basins

Flood Mitigation

  • The two main categories of flood management are hard and soft engineering:

    • Hard engineering involves building structures or changing the river channel

    • Soft engineering works with natural processes of the river and surrounding environment

    • Soft engineering is increasingly popular

    • Soft engineering is an example of mitigation where schemes aim to minimise damage rather than trying to prevent flooding

Type of Engineering

Advantages 

Disadvantages 

Dams

Hold back water during times of flood

Release water when flood risk is reduced

Increase in loss of water due to evaporation

Channel erosion

Possible spread of diseases such as malaria

Afforestation

Could increase interception and reduce overland flow

Could possibly soak up excess rainwater

Young trees cannot absorb or intercept as much as more mature trees 

Most trees lose their leaves in the winter and so interception reduction is decreased

Channel modification

Can be done via straightening and enlargement

Enlarging the cross-sectional area increases the bankfull discharge and hydraulic radius

Velocity can increase if meanders are removed

Expensive

May have to remove buildings to complete channel modification

Levee strengthening 

Can protect buildings in the surrounding areas from flooding 

Barriers are less expensive than channel modification

Can be used to divert water to less valuable land

 

Planning

  • Personal insurance may not always be available for lower-income countries

  • Sand bags

  • Sealing doors and windows

  • Placing electrical generators higher up in the building

  • Building houses on stilts

  • Flood insurance, if available

  • Government officials can use disaster aid

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Briley Habib

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Briley is an experienced Head of Geography. With more than 16 years of teaching experience, Briley was awarded a PGCE from the University of Lancaster and has a degree in European Studies and Human Geography. Briley has worked in a range of schools around the world and has experience of teaching at all levels. Briley is a member of the Geographical Association’s special interest group on diversity and inclusion. She has also written articles for the Teaching Geography Journal, a book chapter on Place-Based Education and a report on Decolonising IB Geography.

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