The net benefit of public expenditures on avalanche defence structures in the municipality of Davos, Switzerland

Abstract

Abstract. Avalanches pose a threat to settlements as well as industrial and recreational areas in the Alps. As a counter measure, technical mitigation measures have been implemented since the 19th century, resulting in a raise in value of formerly endangered areas. This increase in value can be considered as a benefit due to prevented damage. This paper compares the total costs and benefits of technical mitigation measures in the municipality of Davos, Switzerland as a basis for evaluating their net social benefit. The benefit of avalanche defence structures is determined using two different approaches. First, the replacement value of buildings protected by mitigation measures is quantified. Second, the number of protected persons is monetarily assessed by means of a human capital approach. The quantified benefit is compared with the present value of cumulative capital expenditures on avalanche mitigation measures. In addition, distributional effects of the public expenditures on technical mitigation measures are discussed based on the average future tax revenues within protected areas. Depending on whether benefits are calculated in terms of protected buildings or protected persons, the results show a large range of cost-benefit ratios. Critical issues of cost-benefit analyses in the context of alpine natural hazards are highlighted, including problems related to the human capital approach and the sensitivity of results to how benefits are calculated. The applicability of cost-benefit analyses for evaluating avalanche mitigation measures is discussed.

Integrating rockfall risk assessment and countermeasure design by 3D modelling techniques

“…Moreover, data required for a detailed quantification of the value of elements at risk (e.g. insured replacement value of buildings; Fuchs and McAlpin, 2005) are not always accessible depending on the type of impacted elements and regulations in force in different countries, thus introducing further uncertainty in the resulting expected costs.…”

“…These data allowed to estimate the value W i of each building. An economic value of 10 6 Euro was assumed for human life using a human capital approach according to the literature (GEO, 1998;Fuchs and McAlpin, 2005;Porter et al, 2006;Jonkman, 2007). The spatial temporal probability P (I |T ) i of the elements at risk (see Eq.…”

Couplage données historiques - modélisation numérique pour la prédétermination des avalanches : une approche bayésienne

“…Ainsi l'Europe a-t-elle connu un hiver 1998-99 particulièrement coûteux et meurtrier (SLF Davos, 2000). Les dommages matériels ont été évalués à environ 500 millions d'euros (Fuchs et McAlpin, 2005) et plusieurs catastrophes majeures ont occasionné de nombreuses victimes, notamment à Galthur, Autriche, où 31 personnes sont décédées et 22 autres ont été blessées (Barbolini et al, 2004b). L'aléa avalancheux est caractérisé par sa soudaineté et sa brutalité.…”

“…De plus, des approches économiques commencent à voir le jour afin de prendre en compte le coût de construction dans la décision. Ainsi, des analyses de type coût-bénéfice ont été proposées afin de comparer différents scénarii d'aménagement (Wilhelm, 1997 ;Wilhelm, 1999) ou pour a posteriori évaluer l'efficacité de certains ouvrages sur le long terme (Fuchs et McAlpin, 2005). Néanmoins, bien que des progrès significatifs dans la compréhension des effets des ouvrages de protection passive sur les écoulement avalancheux aient été accomplis au cours des dernières années grâce à des expérimentations en sites réels (Lied et al, 2001), en modèle réduit (Primus et al, 2004 ;Faug, 2004) et grâce au recours à la modélisation numérique , Sampl et al, 2004, le dimensionnement des ouvrages paravalanches reste délicat.…”

Modelling woody material transport and deposition in alpine rivers

“…Consequently, considerable economic losses have resulted in recent years from events (Mitchell 2003;Autonome Brovinz Bozen-Südtirol 2006;Oberndorfer et al 2007) despite the efforts made towards the mitigation of flood hazards and the reduction of specific risks (Fuchs and McAlpin 2005). At critical stream geometry configurations in mountain streams (e.g., bridge cross sections), a remarkable increase in process intensities could be attributed to woody material transport phenomena (e.g., Diehl 1997;Lyn et al 2007).…”