Detailed and large-scale cost/benefit analyses of landslide prevention vs. post-event actions

Abstract

Abstract. The main aim of this paper is to test economic benefits of landslide prevention measures vs. post-event emergency actions. To this end, detailed-and large-scale analyses were performed in a training area located in the northeastern Italian pre-Alps that was hit by an exceptional rainfall event occurred in November 2010. On the detailed scale, a landslide reactivated after 2010 event was investigated. Numerical modeling demonstrated that remedial works carried out after the landslide -water-removal intervention such as a drainage trench -could have improved slope stability if applied before its occurrence. Then, a cost/benefit analysis was employed. It defined that prevention would have been economically convenient compared to a non-preventive and passive attitude, allowing a 30 % saving relative to total costs. On the large scale, one of the most affected areas after 2010 event was considered. A susceptibility analysis was performed using a simple probabilistic model, which allowed to highlight the main landslide conditioning factors and the most hazardous and vulnerable sectors. In particular, such low-cost analysis demonstrated that almost 50 % of landslides occurred after 2010 event could be foreseen and allowed to roughly quantify benefits from regional landslide prevention. However, a large-scale approach is insufficient to carry out a quantitative cost/benefit analysis, for which a detailed case-by-case risk assessment is needed. The here proposed approaches could be used as a means of preventive soil protection in not only the investigated case study but also all those hazardous areas where preventive measures are needed.

Nature-based solutions efficiency evaluation against natural hazards: Modelling methods, advantages and limitations

“…The analysis of the costs also facilitated the consciousness of the economic sustainability of the considered soil bioengineering techniques in developing countries ( Petrone and Preti, 2010 ). Salbego et al (2015) performed CBA to analyse whether the drainage trenches which promote slope stability by reducing water table could be an economically feasible solution to prevent landslides caused by heavy precipitation in Vicenta province, northeast Italy. The study estimated that the landslides that occurred in 2010 incurred remediation costs of US$367.4 million and infrastructure and building losses of US$1.22 billion.…”

Investment in Disaster Risk Management in Europe Makes Economic Sense

“…A detailed numerical model found that incorporating a drainage trench (aiming to reduce the water table, therefore slope instability) prior to 2010 would have been effective in preventing the landslide. BCA showed that compared to €57,000 in remediation costs, installing a drainage channel and maintaining it over 20 years would have saved 30% of the remediation cost, leading to a benefit of €17,000 (Salbego, et al, 2015b).…”

Effectiveness of a New Drainage System for Decreasing Erosion in Road Hillslopes

“…44 This fact modified the length between streams, which in turn varied the susceptibility to erosion and hillslope landslides. 73 As discussed by Salbego et al, 84 the use of preventive measures to protect road hillslopes from erosion is 30% more economical than applying passive or emergency measures a posteriori. Accordingly, the use of the branched drainage, instead of the traditional one, can be considered a preventive measure against erosion in road hillslopes.…”