Mississippi

1993 - mississippi burst its banks.
150 levees collapsed
dam burst - bridges closed
by July mississippi spread between 10 - 25 km

Effects:
9 states affected
23million acres covered 48 killed
26.5m sandbags used
70000 evacuated
final damage cost 10 billion US dollars (25% crop losses)
Town of valmeyer abandoned
River closed for 2 months (15% freight uses river)

Climate prior flood:
Heavy rain due to high pressure over bermuda
torrential rain June/July added to water level most water in 2 months since 1895

Taming mississippi:
- Vital Transport route
- Wing dykes
- Straightening
- 1600km of levees
- Many dams
- Much of river lined with concrete slabs

engineers caused floods
1993 worst flood ever despite engineering

- shortening the river caused it to flow more quickly increasing erosion
- restricting flow inside levees speeded up flow and increased pressure on levee. 1993 a large no. of levee's broke
- altering natural flow created bigger flood despite less water in the river than previous floods
- Increasing energy in river reduced sediment movement.