Expected probabilities of exceedance for non-normal flood distributions

The concept and importance of expected probability of exceedance of flood quantiles is discussed. Theoretical derivation of expected probability of exceedance values for different sample lengths, has been so far limited to the normal distribution. A relatively simple numerical algorithm is introduced to calculate such values for non-normal flood distributions. The sensitivity of the expected probability to different combined flood frequency analysis procedures is demonstrated. The usefulness of the expected probability as an appropriate indicator to gauge relative merits of different flood frequency analysis procedures is also illustrated with a simple example.