1. A broken levee on the Mississippi near Gulfport Illinois June 18 2008

2. Thousands of acres of farmland under water after breaching of a levee June 18 2008

3. Flooding at River Grove, Illinois April 2013

4. Flooding near Wheaton Illinois, April

5. Mississippi and Missouri in drought
Mississippi and Missouri in 1993 Flood

6. Formation of Meanders and river action on bends

7. Flood Control

8. Flood Plain
Channel
Bluff
Bluff

9. Prediction of Floods Size of Past Floods Recurrence interval
Average length of time between Floods of the same size
2 year
100 year

10. W. W. Norton. Adapted from U.S. Geological Survey
Fig a
W. W. Norton. Adapted from U.S. Geological Survey

11. Probability of A Flood Probability = 1/Recurrence interval
Probability of 10 year flood this year = 1/
= 0.
= %
Probability of 10 year flood next year

12. Recurrence Interval from Probability
50% probability of a flood
What is Recurrence Interval?
50/100 = 1/
Recurrence Interval = years

13. 1993 Flood