Integrated Frequency Analysis of Extreme Flood Peaks and Flood Volumes Using the Regionalized Quantiles of Rainfall Depths as Auxiliary Variables

Abstract

In its 1988 report, the U.S. National Research Council identified principles to be followed in order to improve estimation of extreme flood quantiles. In spite of the many advances attained by more recent research on extreme flood estimation, the NRC principles remain useful recommendations to be considered, which are used in the methodology to be described herein. According to the proposed method, flood peaks that have exceeded an arbitrary threshold and their associated flood volumes are modeled as a marked point process. The estimation method consists of separately estimating the marginal density function of flood volumes and the density function of flood peaks conditioned on volumes. The annual probability distribution of flood peaks can then be estimated by double integrating the product of both densities. Regionalized quantiles of rainfall depths have been used as auxiliary variables for guiding the estimation of the upper tail of the marginal density function of flood volumes by postulating simple ...