Author(s): Javier Montes; Maria Bermudez; Jeronimo Puertas; Manuel Alvarez

Linked Author(s): María Bermúdez

Keywords: Flood frequency hydrology; Snow-influenced; Rainfall-driven

Abstract: A regional flood frequency analysis was applied to the Cantabrian and North Atlantic basins of the Iberian Peninsula to study the physical differences between floods generated by purely rain processes and those originated under snow influence. Discharge data were obtained from 83 gauging stations under a natural flow regime and with high-quality records between 1943 and 2015. An extensive compendium of official cartographic information was used to physically characterize the basins. Two issues were analyzed: (i) the hydrological-statistical consistency of the delineated homogenous regions and (ii) the relationship between annual maximum daily/instantaneous flow series and the physical characteristics of watersheds. The methodology was based on the use of different multivariate analysis techniques complemented in the case of issue (i) with the statistical homogeneity and goodness-of-fit tests of L-moments proposed by Hosking and Wallis (1998). A clear phenomenological distinction between floods was found under which: (1) acceptably homogeneous hydrological regions can only include basins of the same typology (pluvial or nival) and (2) the magnitude, frequency and shape of flood hydrographs are particularly influenced by morphological aspects in the case of pluvial basins but not so in basins with snow influence where thermodynamic aspects dilute the relevance of morphology. Overall, the results highlight the usefulness of the so-called causal information expansion to assist in flood frequency estimation.

DOI: https://doi.org/10.3850/IAHR-39WC2521711920221191

Year: 2022