Floods

• Floods are natural events. People cannot stop floods from happening but they can reduce the damage caused by floods.
• Ways to reduce the impact of floods

  • Build walls and barriers along the banks of rivers and coasts lines
  • Build settlements away from river banks
  • Improve drainage in settlements so that water can flow away quickly
  • Make laws that prevent people from living in high-risk flood areas
  • Teach people about the dangers of flooding
  • Use lakes, natural vegetation, and wetlands to prevent water from flowing too quickly into rivers
• Barrier


  An object that is made to block or get in the way of something
• Temporary dam wall lifted from the floor of the River Thames in London


  • This barrier prevents flood waters washing up the River Thames from storms at sea
• Flood


  When there is too much water on the land, for example, in the rivers and dams. Too much water causes rivers to overflow and flood the surrounding area.
• Causes of floods

  • Heavy rainfall
  • People
• How things to do with the environment help to cause floods

  1. Long periods of very heavy rain fill up rivers and dams

  2. Steep slopes cause rainwater to flow off the land quickly

  3. If fires have destroyed the vegetation, water flows quickly into rivers off the bare ground

  4. If animals have eaten all the grass, water flows quickly into rivers off the bare land

  5. Tsunamis and storms can flood coasts
• How people help to cause floods

  1. People build dams which can fill up and flood the land

  2. Farmers remove or burn natural vegetation to make fields, causing water to flow quickly off the bare ground

  3. In cities, water flows very quickly off streets and buildings

  4. People remove or fill in wetlands and lakes. These areas act like natural water stores. When they are destroyed, there is more water in the rivers because it is not being stored in the lakes or wetlands
• Floods


  • Can cause serious damage to land and property
  • Can result in many injuries and deaths
• Floods can cause serious damage to land and property and can result in many injuries and deaths
• Effects of floods on people and the land

  • People drown and are injured
  • Destroy crops and animals resulting in food shortages
  • Wash away soil making the land infertile and bad for farming (soil erosion)
  • Destroy buildings, property and transport systems
  • Wash sewage out of sewage works, polluting food and water supplies
  • Diseases can spread easily
  • Coastal flooding covers the land with salt water, killing plants and poisoning the soil
  • Serious flooding that destroys land and buildings may mean some people will have nowhere to live and have to move to another area
• Food shortages


  Not having enough food to feed people
• Coastal flooding

  Floods that affect areas next to the coast
• Places next to rivers

  • Often experience floods
  • Millions of people across the world live next to rivers
• Reasons why people live next to rivers

  • They use river water for drinking, washing and cooking
  • They need water to keep their soil fertile and make their crops grow
  • The land next to rivers is flat and easy to build on
  • There is not enough suitable land in other areas
  • They do not have money to live in areas where there is no risk of floods
  • They have ways of protecting themselves from the dangers of floods
• Poor people in Bangladesh farm land next to the Ganges River which often floods
• Ganges River floods


  1. Snow melts in the Himalayas

  2. Heavy seasonal rains fall
• Because there are so many people living in the areas that flood, many people are killed when the river floods
• Ways to protect from floods

  • Building walls and barriers that stop the flood waters washing over the land