Abstract
The objective of flood frequency analysis (FFA) is to associate flood intensity with a probability of exceedance. Many methods are currently employed for this, ranging from statistical distribution fitting to simulation approaches. In many cases the site of interest is actually ungauged, and a regionalisation scheme has to be associated with the FFA method, leading to a multiplication of the number of possible methods available. This paper presents the results of a wide-range comparison of FFA methods from statistical and simulation families associated with different regionalisation schemes based on regression, or spatial or physical proximity. The methods are applied to a set of 1535 French catchments, and a k-fold cross-validation procedure is used to consider the ungauged configuration. The results suggest that FFA from the statistical family largely relies on the regionalisation step, whereas the simulation-based method is more stable regarding regionalisation. This conclusion emphasises the difficulty of the regionalisation process. The results are also contrasted depending on the type of climate: the Mediterranean catchments tend to aggravate the differences between the methods.
Highlights
In France, floods by river overflowing are the first natural risk endangering the population, with more than 17 million people exposed [1]
A large number of catchments allows for reliable statistical analysis and splitting sample tests, whereas diversity in catchment types ensures the possibility of generalisation to other catchment sets
The very first step of the study was to calibrate all the flood frequency analysis (FFA) implementations for all sites using the whole set of local data
Summary
In France, floods by river overflowing are the first natural risk endangering the population, with more than 17 million people exposed [1]. To reduce disaster risk and to effectively protect people, goods and infrastructures, it is essential to correctly assess and map the natural hazard at the origin of any natural disaster In hydrology, this particular topic is called flood frequency analysis (FFA). This particular topic is called flood frequency analysis (FFA) It aims to associate flood intensity (generally in terms of discharge) with its probability of exceedance (in terms of return period). This kind of knowledge is essential for diverse operational applications such as flood prevention or civil engineering design (dams, dykes, any construction near a river). A quite abundant literature [2,3] has been published on developing and comparing different
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
