Typical design hydrograph method based on a joint distribution approach combining flood peak discharge, volume and duration

Abstract

Determination of flood magnitude and shape characteristics are necessary to provide a more complete assessment of flood severity and its impact in scour development analysis. Our recent research has focused on a joint distribution approach to account for the multivariate nature of flood characteristics, resulting in probability of occurrence of different pairs of flood variables: flood peak (Q), volume (V) and duration (D). To extend the results of this research, a method for deriving a design hydrograph is applied to the study area by using the typical hydrograph method. As it is recommended to test multiple scenarios in a scour analysis, different typical flood hydrographs were selected at several gauging stations on the Sava and Drava rivers in Croatia and multiplied by the design discharge values. The aim of this study is to complement the ongoing research of the relationship between climate change indicators, flood wave characteristics and scour development next to the bridges crossing large rivers in Croatia with installed scour countermeasures by preparing hydrological input data for a hydraulic scour analysis.