If the risk of a flood occurring in the next 10 years is accepted to 10%, then the return period for design should be
A) 1 + 0.9°10
B) 1 - 0.9°10
C) 1/1?0.9?10
D) 1/1+0.9?10

Question

Quizplus · Accepted Answer

The return period for design, given a certain risk level, is calculated as the inverse of the probability of the event not happening. If the risk of a flood occurring in the next 10 years is 10%, then the probability of it not occurring in any given year is 90% or 0.9. The return period is calculated as 1/(1-0.9^10), which matches the formula given in option C.

If the Risk of a Flood Occurring in the Next