Vulnerability curves vs. vulnerability indices. Which method explains loss best?

Mountain rivers are characterized by dynamic flooding with variable amounts of sediment erosion, deposition and remobilisation (Sturm et al., 2018); typical hazard processes include fluvial sediment transport, debris flows and related phenomena. In Europe, such processes repeatedly result in considerable damage to infrastructure and buildings on a local and regional level.

The physical vulnerability of buildings to dynamic flooding has been approached mainly with two methods until now: vulnerability curves and vulnerability indices. Each approach has its drawbacks and advantages (Papathoma-Köhle, 2016; Papathoma-Köhle et al., 2019). In the present study, damage data from a relatively recent event in the European Alps are used for the application of both methods. The event occurred in the municipality of See situated in the Paznaun valley in Tirol, Austria, in 2015. A new vulnerability curve is developed based on data from 21 buildings. An existing vulnerability index is also applied in the area. The results of both methods are compared with each other and with the actual loss of the event. Additionally, a sensitivity analysis regarding two input parameters (intensity and degree of loss) is performed for both the vulnerability curve and the vulnerability index. The results are mirrored against a recently developed vulnerability model for dynamic flooding in mountain areas (Fuchs et al., 2019), and possible model improvements are discussed.

 

References

Fuchs, S., Heiser, M., Schlögl, M., Zischg, A., Papathoma-Köhle, M., and Keiler, M.: Short communication: A model to predict flood loss in mountain areas, Environmental Modelling and Software, 117, 176-180, https://doi.org/10.1016/j.envsoft.2019.03.026, 2019.

Papathoma-Köhle, M.: Vulnerability curves vs. vulnerability indicators: application of an indicator-based methodology for debris-flow hazards, Natural Hazards and Earth System Sciences, 16, 1771-1790, https://doi.org/10.5194/nhess-16-1771-2016, 2016.

Papathoma-Köhle, M., Schlögl, M., and Fuchs, S.: Vulnerability indicators for natural hazards: an innovative selection and weighting approach, Scientific Reports, 9, Article 15026, https://doi.org/10.1038/s41598-019-50257-2, 2019.

Sturm, M., Gems, B., Keller, F., Mazzorana, B., Fuchs, S., Papathoma-Köhle, M., and Aufleger, M.: Experimental analyses of impact forces on buildings exposed to fluvial hazards, Journal of Hydrology, 565, 1-13, https://doi.org/10.1016/j.jhydrol.2018.07.070, 2018.