Case Study - Mississippi River

• Mississippi River


  • 3800km long
  • Flows through ten states
  • Has over 100 tributaries
  • Has a drainage basin covering 1/3 of the USA
• Causes of 1993 flooding

  1. Heavy rain in April 1993 saturated the upper Mississippi basin

  2. Thunderstorms in June caused flashfloods

  3. Mid July 180mm of rain in one day

  4. Levees in nearby towns collapsed
• Management


  1. 6 huge dams and 105 reservoirs

  2. Afforestation to delay runoff

  3. Strengthening the levees with concrete mattresses 25mx8m

  4. Making the course shorter and straighter - from 530km to 300km by cutting through the neck of meanders to get the water passed towns more quickly to the sea

  5. Diversionary spillways – overflow channels 9km long

  6. Less construction on the floodplain eg St Louis