An analysis of flood levee reliability

In most studies of flood levee reliability the probability of failure is taken to be equal to the probability that the flood peak discharge will exceed the capacity of the channel‐levee system. Such an analysis assumes that levees fail only by overtopping, whereas in many cases, levees fail at discharges much below the channel capacity. In the present paper the discharge at which levees fail is assumed to be a random variable with a particular distribution. The results on the flood frequency curve are presented for two conditions: one for the failure discharge having a uniform probability density function and the other for failure discharges having a quadratic distribution. In a similar manner the effects on the net benefits from levee construction were also analyzed and results are given.