Flooding
Flooding happens when river discharge exceeds channel capacity, and is influenced by rainfall, land use and geology.
▶ Interact
Play with the controls to see the idea in action.
📘 Learn
Flooding happens when river discharge exceeds channel capacity, and is influenced by rainfall, land use and geology.
- Impermeable surfaces increase run-off
- Hydrographs show discharge over time
- Levees and dams help control floods
🧠 Quick quiz
Three questions. Score 2 or more to complete the topic.
What is Flooding?
Within Geography, which covers maps, landforms, weather, climate, population and settlements: understand how our planet and people connect, this topic explains Flooding. Geography explains how places, people and natural processes connect, so each topic here combines a clear definition with a visual model.
Check that you can explain Flooding in your own words and give one example from everyday life. If you can do that, you have understood the core idea.
Understanding Flooding helps you explain patterns on maps and in the news, and make reasoned decisions about places and environments.
Flooding in detail
A flood occurs when a river's discharge exceeds the capacity of its channel. Physical causes include heavy or prolonged rainfall, rapid snowmelt, steep slopes, impermeable rock and saturated soil. Human causes include deforestation, urbanisation with impermeable surfaces and drains, and building on floodplains.
A storm hydrograph shows discharge against time after a rainfall event, with a lag time between peak rainfall and peak discharge. Effects include loss of life, damage to property, disruption and sometimes benefits such as fertile silt. Hard engineering (dams, levees, channel straightening) and soft engineering (flood warnings, floodplain zoning, planting trees, flood storage) are used to manage the risk.
How the interactive helps you understand Flooding
Watch the bar chart in the interactive. Use any sliders or buttons it offers to change the values and see how the bar chart responds.
Before you change anything, predict the result. Then change one value at a time and check whether your prediction was right. This is a quick way to build a correct mental model of Flooding.
Real-life uses and examples
- Describe a real place where Flooding can be seen, using a map or photograph.
- Explain how Flooding affects people, jobs and land use in a region.
- Support an answer about Flooding with a named case study and specific evidence.
Common mistakes to avoid
- Writing general statements without a named place or example.
- Mixing up cause, effect and consequence when you explain Flooding.
- Learning the definition without testing it. Use the quiz and the interactive to check that you can apply the idea.
Frequently asked questions about Flooding
What is Flooding?
Flooding happens when river discharge exceeds channel capacity, and is influenced by rainfall, land use and geology.
What are the most important points about Flooding?
The main points are: Impermeable surfaces increase run-off; Hydrographs show discharge over time; Levees and dams help control floods.
Why is Flooding useful?
Understanding Flooding helps you explain patterns on maps and in the news, and make reasoned decisions about places and environments.
How can I practise Flooding?
Open the interactive at the top of this page and change the controls one at a time. Predict the result before each change, then take the three-question quiz. A score of two or more marks the topic as complete on this device.
Which topics are related to Flooding?
Related topics in Geography include Coastal Management, Weather vs Climate, Wind and Global Circulation.