River Management: Soft Engineering
Geography: Edexcel IGCSE, topic 1.1.19
Flood Defences - Soft Engineering
Soft engineering strategies aim to reduce the effects of flooding using our knowledge of nature and the natural courses of rivers. Examples of soft engineering strategies include:
Flood warnings
- We know that floods are more likely when there has been a lot of rainfall or when river levels are high.
- Flood warnings are sent out by the Environment Agency and government.
- Warnings allow people to put out sandbags to protect their homes, minimise the effect of floods or even leave their houses if they need to.
- Not all people watch the news and may miss flood warnings.
- Warnings cannot prevent floods.
Flood plain zoning
- Flood plain zoning creates zones of a flood plain where building cannot happen. This is usually in zones that are at high risk of flooding.
- If there are fewer impermeable surfaces, surface runoff will be lower and flooding should be less common.
- However, this involves having smaller towns and cities. This can increase house prices and create housing shortages.
Planting trees
- Planting trees in river basins will increase the proportion of rain that's intercepted by trees, increasing the lag time between peak rainfall and peak discharge.
- River discharge, flood risk, and soil erosion are all reduced. Additionally, wildlife can create homes in the newly planted trees.
- If trees are planted, there is less space available for building housing or farming.
River restoration
- River restoration returns a river to its natural state.
- This allows a river to swell its banks and flood the flood plain naturally.
- This does not do much to stop flooding.
- It feels a bit like a passive approach, a bit similar to managed retreat.
Preparation
- Buildings could be adapted to mitigate floods.
- Building houses on stilts is an example of this.
- This should reduce the financial and personal impact of flooding when it does happen.
- Putting all buildings on stilts can be expensive! However, putting all valuables on the second floor of a house could also count as preparation. So could putting sandbags in front of your door.
Test yourself on River Management: Soft Engineering
Which of the following are soft engineering strategies for flood management?
What do we call it when building is restricted on parts of a flood plain that are at high risk?