Description of hydrological regimes in high waters: new formulation for flood-duration-frequency analysis and engineering applications

Abstract

This paper presents a Flood Frequency Analysis (FFA), which takes into account the notion of duration: the flood-duration-frequency (QdF) method. QdF analysis is similar to the intensity-duration-frequency analysis commonly used for rainfall. This article describes the general framework of the QdF approach and the theoretical aspects with detailed steps of calculation. Two applications are then presented. The first application concerns the derivation of Synthetic Mono-Frequency Hydrographs (SMFH) from the QdF fitted curves. The main advantage of this approach is that all the characteristics of the SMFHs are related to the same return period. The second application illustrates the potential for describing the impact of a presumed climate change, by analyzing simulated discharges under climatic scenarios. Results are compared to the present regime using two descriptors derived from the QdF analysis: an indicator of the flood dynamic behaviour and the 10-year-return period instantaneous peak flood.