On the probabilistic structure of storm surface runoff

The mean and variance of storm surface runoff are derived under the assumption that storm events are rectangular pulses with a bivariate exponential distribution for the intensity and duration of the storm. The Philip infiltration equation is used to make the transformation between rainfall and surface runoff. The probability of zero storm surface runoff is also calculated under the same assumptions. It is shown that the correlation between intensity and duration of the storm has an important impact on the probabilistic structure of storm surface runoff.