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
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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