Earth Science

Water on Earth

Flooding

Study Tip
Just as there are two sides to every coin, there are two ways to look at flooding. What are some ways we can utilize floods?

Starting a Flood

  • Floods typically start when the amount of precipitation that falls is greater than the amount that can be absorbed.
  • Flash Floods are sudden floods that occur when there is a lot of rainfall in a short period of time.
Study Tip
Just as there are two sides to every coin, there are two ways to look at flooding. What are some ways we can utilize floods?

Effects and Prevention

  • Floods are very costly and deadly; hundreds of thousands of people can be killed in one flood. Water from floods can travel down streams for many miles, increasing their destructive potential.
  • To protect areas from flooding, people can build dams and levees to control or even utilize the energy that flooding could have.
  • A dam blocks off water from going through a river, while a levee consists of high walls on the banks or rivers to prevent floods from causing shoreline damage.
  • An area with heavy vegetation is less likely to flood because the vegetation can absorb and slow the rate of flooding.
Dam
A dam can be used to control the amount of flooding in a region, and can generate hydroelectric power from the floodwater

Positive Flooding

  • Floods can deposit nutrient-rich sediments, which are very suitable for farming. The Egyptians were able to sustain agriculture along the Nile River because of the river’s flooding.
  • Some organisms rely on the movement of flood-based sediment in order to survive each season.
Concept Check
  • What can cause a flood?
  • Are floods a completely destructive?
  • What can we do to control a flood?