Application of a Random Cascade Model to Estimation of Design Flood from Rainfall Data

Abstract

The objective of this study is to develop a new method for deriving statistical distribution of maximum discharge from the distribution of annual maximum daily rainfall by using a random cascade model. This model is used to probabilistically downscale daily rainfall into hyetographs in which the daily rainfall is randomly generated according to its probabilistic distribution. Then maximum discharge is calculated from downscaled hyetograph by means of a rainfall-runoff model. Finally, the distribution of maximum discharge is derived numerically. This technique is applied to the Doki River Basin, a small basin in Japan, where the influence of human activities is limited. The observed annual maximum discharge data from 1976 to 1998 are used to verify the calculated distribution of maximum discharge. It is shown that the distribution of maximum discharge was well reproduced.