Importance of restoring an historic flood in evaluating the statisticalproperty of the flood flow

摘要

Many historic flood events occurred during the era in which the hydrological observation systemwas not fully established.Also, in many parts of the world, the availability of the hydrological data withhigh degree of reliability dates back some 30 to 50 years.Under such circumstances, an historic event that happened100 years ago or older is extremely difficult to restore in the hydrological sense.Yet, these historic datacould have a profound meaning in the statistical property of the hydrological data.This paper first describes how the peak flood discharge of the devastating, historic flood event that occurredmore than 100 years ago and this estimated discharge data is shown to be an occurrence of the rare event whichis assumed for the design flood discharge.Finally, the paper briefly discusses the significance of analyzing a rare event in achieving the public awarenessand understanding in the public works.