Compound inland flood events: different pathways, different impacts and different coping options

• Published in: Natural hazards and earth system sciences Vol. 22; no. 1; pp. 165 - 185
• Main Authors: Thieken, Annegret H, Samprogna Mohor, Guilherme, Kreibich, Heidi, Müller, Meike
• Format: Journal Article
• Language: English
• Published: Katlenburg-Lindau Copernicus GmbH 27-01-2022; Copernicus Publications
• Subjects: Accounting; Analysis; Catchment area; Catchments; Climate change; Communication; Drainage systems; Economics; Flash flooding; Flash floods; Flood control; Flooding; Floods; Geomorphology; Households; Receptors; Risk communication; Rivers; Sediment load; Sediments; Sediments (Geology); Socioeconomic aspects; Storm damage; Surface water; Germany
• ISSN: 1684-9981; 1561-8633; 1684-9981
• DOI: 10.5194/nhess-22-165-2022

Several severe flood events hit Germany in recent years,
with events in 2013 and 2016 being the most destructive ones, although
dynamics and flood processes were very different. While the 2013 event was a
slowly rising widespread fluvial flood accompanied by some severe dike
breaches, the events in 2016 were fast-onset pluvial floods, which resulted in surface water flooding in some places due to limited capacities of the drainage systems and in destructive flash floods with high sediment loads and clogging in others, particularly in small steep catchments. Hence,
different pathways, i.e. different routes that the water takes to reach (and
potentially damage) receptors, in our case private households, can be
identified in both events. They can thus be regarded as spatially compound
flood events or compound inland floods. This paper analyses how differently
affected residents coped with these different flood types (fluvial and
pluvial) and their impacts while accounting for the different pathways
(river flood, dike breach, surface water flooding and flash flood) within
the compound events. The analyses are based on two data sets with 1652 (for
the 2013 flood) and 601 (for the 2016 flood) affected residents who were
surveyed around 9 months after each flood, revealing little
socio-economic differences – except for income – between the two samples. The
four pathways showed significant differences with regard to their hydraulic
and financial impacts, recovery, warning processes, and coping and
adaptive behaviour. There are just small differences with regard to
perceived self-efficacy and responsibility, offering entry points for
tailored risk communication and support to improve property-level
adaptation.