Attribution of regional flood changes based on scaling fingerprints

Abstract

Changes in the river flood regime may be due to atmospheric processes (e.g., increasing precipitation), catchment processes (e.g., soil compaction associated with land use change), and river system processes (e.g., loss of retention volume in the floodplains). This paper proposes a new framework for attributing flood changes to these drivers based on a regional analysis. We exploit the scaling characteristics (i.e., fingerprints) with catchment area of the effects of the drivers on flood changes. The estimation of their relative contributions is framed in Bayesian terms. Analysis of a synthetic, controlled case suggests that the accuracy of the regional attribution increases with increasing number of sites and record lengths, decreases with increasing regional heterogeneity, increases with increasing difference of the scaling fingerprints, and decreases with an increase of their prior uncertainty. The applicability of the framework is illustrated for a case study set in Austria, where positive flood trends have been observed at many sites in the past decades. The individual scaling fingerprints related to the atmospheric, catchment, and river system processes are estimated from rainfall data and simple hydrological modeling. Although the distributions of the contributions are rather wide, the attribution identifies precipitation change as the main driver of flood change in the study region. Overall, it is suggested that the extension from local attribution to a regional framework, including multiple drivers and explicit estimation of uncertainty, could constitute a similar shift in flood change attribution as the extension from local to regional flood frequency analysis.

Detection of trends in magnitude and frequency of flood peaks across Europe

“…However, regional patterns of significant flood trends do exist and are not an artefact of the methods used. Areas where consistent flood trends are detected can serve as prime locations for future studies aimed at attributing the causes of the trends at a regional scale using a scaling fingerprint approach (Viglione et al 2016) or other appropriate methods.…”

Auswirkungen der Klimaänderung auf Österreichs Wasserwirtschaft – ein aktualisierter Statusbericht

“…Hochwässer können im Wesentlichen durch drei Faktoren verstärkt werden: Klima, Landnutzung und wasserbauliche Maßnahmen (Hall et al 2014;Viglione et al 2016;Alaoui et al 2018;. Hinweise auf Ände-rungen von hochwasserrelevanten Faktoren im Klimasystem in Mitteleuropa liegen vor (Hofstätter et al 2015(Hofstätter et al , 2017Blöschl et al 2017b).…”

Integrating Local Scale Drainage Measures in Meso Scale Catchment Modelling

“…Hydrological processes occur at a wide range of scales: from local diverse surface covers (e.g., of garden plots or detached housing) of some square meters to monoculture farming of thousand square kilometres (= heterogeneity in space) and from flash floods of several minutes duration to flow in aquifers over hundreds of years (= variability in time). In recent research, scales in hydrological systems are redefined [12][13][14]. One of the main reasons is the availability of more detailed topographical and geographical data.…”