What do you know?
What is flooding?
Flooding is when water covers land that is usually dry. Flood water can come from swollen rivers following heavy rainfall or the sea during high tides.
Key Points
- There are many physical and human causes of river An overflow of water onto surrounding land.. They include heavy rainfall, steep surfaces, The removal of trees. This is sometimes done to make land for farming, roads or settlement. and When somewhere becomes more urban. This means a greater percentage of people live in cities and towns rather than the countryside..
- Consequences of flooding include damage to property, loss of power, injuries and deaths. The impacts of flooding are often more severe in Countries recognised by the World Bank as having a lower income than other countries. This classification is reviewed yearly..
- River floods can be managed using hard and soft engineering strategies. Hard engineering strategies aim to control natural processes and soft engineering strategies work alongside natural processes.
What are the causes and consequences of river flooding?
Game - Living by the river
Play a Planet Planners mission and help to look after those that rely on and live by the river.
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Causes of flooding
Rivers are managed to ensure that there is a plentiful supply of freshwater for use, but that any When there is more of something than is needed. An energy surplus means there is more than enough to go around. water does not cause An overflow of water onto surrounding land. which could lead to harm to people and property.
Causes of river flooding include physical and human factors.
Physical factors
- Heavy rainfall or snowmelt leads to an An amount of something that is more than necessary. of water.
- Rocks that do not allow water to pass through them, e.g. granite. do not allow water to soak into them and so more water flows over the land.
- Steep surfaces encourage the rapid The draining away of water from the surface of an area of land or buildings. of rainwater into nearby rivers. The rivers become full very quickly and so they flood onto the surrounding land.
Human factors
The removal of trees. This is sometimes done to make land for farming, roads or settlement. removes trees and vegetation that would ordinarily To obstruct or divert someone or something. For example, trees intercept rainfall when they stop it from reaching the ground. and soak up some of the rainwater. This allows more water to enter rivers.
When somewhere becomes more urban. This means a greater percentage of people live in cities and towns rather than the countryside. leads to an increase in Manufactured by humans rather than being natural. Examples of artificial surfaces are bricks, concrete and tiles. surfaces, such as roads and buildings. These are Something that does not allow liquid such as water to pass through it. and so water runs off them very quickly. This run-off can then create problems with flooding.
Consequences of flooding
Consequences of flooding include damage to property, loss of power, injuries and deaths. The impacts of flooding are often more severe in Countries recognised by the World Bank as having a lower income than other countries. This classification is reviewed yearly. than Countries recognised by the World Bank as being wealthier. This classification is reviewed yearly.. This is because LICs have fewer Something of value due to its usefulness such as food, water or raw materials and less money to deal with Something that causes risk or danger to people and property. For example, floods and earthquakes..
Question
What physical factors lead to flooding?
Heavy rainfall or snowmelt leads to an excess of water. Impermeable rocks encourage more water to flow over the land and straight into rivers. Steep surfaces encourage rapid run-off.
Quiz: Causes and consequences of flooding
Managing rivers activity
Play this game to see how rivers are managed.
How are river floods managed?
Game - Flood management
Play a Planet Planners mission and identify the causes of flooding to protect the river, its banks and the surrounding communities.
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Video: Managing river flooding
Find out about how river flooding is managed
HISHAM: Managing river flooding.
Hi, I'm Hisham and I'm currently working in the Environment Agency as a flood risk team member.
When there's a risk a river might flood my team is responsible for developing flood defence projects.
Flooding occurs when the volume of water increases and becomes too great for the river to contain.
River flooding can devastate communities businesses, farmland, and the natural environment.
To prevent this devastation flood prevention schemes are developed for areas at risk.
These schemes can use hard engineering options building artificial structures to control the river. Examples include dams and reservoirs and river straightening.
Or soft engineering. This is about working with natural processes and local knowledge. It can include putting parks along river banks rather than businesses or homes, knowing they will flood. This is floodplain zoning.
Here in Burton-upon-Trent, we are using hard engineering to reinforce the bank of the river with a new embankment.
SOFT MUSIC
Climate change has increased the risk of flooding. Bigger and more frequent floods are expected in the coming years. And that is why my role is so important.
CLANK
GENTLE MUSIC CONTINUES
River An overflow of water onto surrounding land. is managed using flood defences. These take the form of hard and soft engineering A plan or a way of doing something. For example, flood defence strategies are ways to stop flooding..
Hard engineering
Hard engineering strategies include measures that are usually more expensive and require Manufactured by humans rather than being natural. Examples of artificial surfaces are bricks, concrete and tiles. structures or changes to the The space through which river water flows.. They have an immediate impact on the river and the surrounding landscape. For example:
- building Strong walls built to hold back water - usually a river. to control the flow of the river
- making the river channel wider and deeper so that it can hold more water
- straightening the river so that water leaves the area more quickly
Soft engineering
Soft engineering strategies include measures that are usually less expensive and work more with the natural surroundings. They often take longer to work and will attempt to manage floods rather than prevent them. For example:
- planting trees to To obstruct or divert someone or something. For example, trees intercept rainfall when they stop it from reaching the ground. rainfall and reduce the amount of water reaching the river
- providing flood warnings by monitoring rainfall and river The amount of water that passes a point in a river at a given time. and alerting people to potential floods
- land use zoning, which involves using land beside the river for activities like When animals eat grass. Farmers put animals like cows in fields to graze. and Activities done for enjoyment when people are not working or at school or college, eg sports., which can be When people or activites are moved to another place. This can be temporary or permanent. during times of flood
Question
Which type of flood defences work with natural surroundings?
Soft engineering flood defences work with the natural surroundings, eg planting trees.
Quiz: Managing flooding
Quiz: River management
Case study: River flooding in Todmorden
Todmorden in West Yorkshire has experienced severe river flooding from the river Calder for many years. The town is surrounded by steep hillsides, making the area vulnerable to floods.
Storm Eva hit the UK on Christmas Day of 2015. Heavy rainfall led to flooding in Todmorden as well as the surrounding settlements of Hebden Bridge and Mytholmroyd. Over 3,500 homes and businesses were affected and an estimated £150m worth of damage was caused.
The Calderdale Flood Action Plan
The Calderdale Flood Action Plan was put together to prevent future flooding of the river. The plan included hard engineering strategies, such as:
- new flood walls
- the relocation of a bridge
- the widening of the river channel
The plan also included soft engineering strategies to absorb and store rainwater, such as:
- planting trees
- restoring the An extensive flat peat bog formed in cool regions of high rainfall that can hold large amounts of water.
Unfortunately, regular floods are still affecting Todmorden and work to strengthen flood defences still takes place.
Question
What soft engineering strategies were included in the Calderdale Flood Action Plan?
The Calderdale Flood Action Plan included soft engineering strategies such as planting trees and restoring blanket bog. Both of these strategies will absorb and store more rainwater, which will prevent more water from entering the river.
Game - Urban rivers
Play a Planet Planners mission and help to meet the demands of the people who depend on the river.
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Quiz: River flooding in Todmorden
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More on Rivers
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