A Final Problem -- Page 19 of 22



Page 19 of 22

Putting it all together: a final problem

Suppose your house is located on the flood plain of a river. There some concerns you should have:

When the river overflows its banks (and eventually it will) and spreads out onto the floodplain, what will be the magnitude of the flood?
What is the recurrence interval of this size flood?
If you have a 30 year mortgage, what's the probability of flooding during the lifetime of your mortgage?
Should you buy home owners flood insurance or take your chances hoping that flooding will not occur?

Assume that your home is located at the same elevation as the 15 foot stage of the river. Use the two curves above (the Rating Curve and the Recurrence Interval Curve) to help you answer the questions below.

1. What is the expected discharge (Q) if the river exceeds the 15 ft stage?	cfs
2 .Using the Q value determined above, what is the Recurrence Interval of flooding event?	yrs
3. What is the probability of flooding within the 30 years that you are paying on the mortgage?	%