Identification of homogeneous regional classes for flood frequency analysis in the light of regional taxonomy / Identification de classes régionales homogènes pour l'analyse fréquentielle des crues à la lumière d'une taxinomie régionale

Abstract

The paper analyses delineation of hydrological regional classes in the light of regional taxonomy. A brief review of terminological and methodological aspects of regional taxonomy is outlined. The analysis of identification of hydrological regional classes from the point of view of the definition of the basic spatial unit, formulation of the regional taxonomic problem and evaluation of the hydrological response of the physical regional classes is then followed. A more detailed delineation of physical regional classes and a marked separation concerning their hydrological response are achieved if the basic spatial unit is defined as a small basin. Formulation of a hydrological regionalization or regional typification by means of problems defined in regional taxonomy can remove ambiguous and inconsistent features in identifying regional classes. The physical regional classes formed for the purpose of regional flood frequency analysis are considered as regional also from the hydrological point of view only if they satisfy both conditions of intra-class similarity and of inter-class dissimilarity regarding the hydrological attributes.