The Mississippi River

• The Mississippi has a high flood risk because:
• It has over 100 tributaries.
• Its drainage basin covers 1/3 of the USA and some of Canada.
• Heavy rain in April 1993 saturated the upper basin so storms through June and July caused a large amount of surface run-off.
• An area of land the size of Britain was flooded.
• Road bridges had to be closed.
• 43 lives were lost and a lot of property was destroyed there were 50,000 evacuees.
• Long term effects included the fact that the water didn't go away quickly and it was still draining off the land months later.
• Sewage had been washed with the water so their was a great risk of disease.
• It took moths to clean out houses and offices.
• Stagnant water attracted mosquitoes and rats.
• Human activity: dams, no water could penetrate through the soil because of buildings and concrete.

Reducing the risk of flooding:

• Dams have been added to make large lakes.
• Strengthen the levees.
• Afforestation - trees are planted to slow down surface run-off.