Presentation on theme: "The causes of flooding Aim: To know about some of the causes of flooding. Starter activity: There will be 5 questions. You have 30 seconds to answer each."— Presentation transcript:
The causes of flooding Aim: To know about some of the causes of flooding. Starter activity: There will be 5 questions. You have 30 seconds to answer each one.
What are floods? Floods occur when a river gets more water than its channel can hold. So water flows over the banks and onto the flood plain. Floods are usually caused by heavy rain – but sometimes by ice or snow melting. A burst of heavy rain can cause a sudden flash flood. People get no warning so they may get trapped and drown.
Today we are going to experiment to see how humans can effect their environment and the risk of flooding in their area.
Factors that increase the risk of flooding ExampleDescriptionExampleDescription Impermeable rock Cutting trees down Steep slopesVery wet soil Hard dry soilBuilding in a drainage basin
Main activity In your group test: Experiment with what happens to the water in your experiment. Write down your findings. When the whistle blows move to the next experiment.
Plenary Annotate (label with information) your copy of the diagram to show the factors that increase the risk of flooding. HINT: Adding detail (reasons why) will improve this piece of work.
Use the headings to help you add detail to the correct place Heavy rain Soggy soil Steep slopes Built up areas Flat flood plain The flood plain is flat land around the river that the river floods naturally when it gets too full. If you live on a river’s flood plain you are at risk of flooding. Loss of trees Impermeable rock
Remember… …tick of the skills that you have used or learnt this lesson.