Social Choices and Public Decision-Making in Mitigation of Hydrogeological Risk

Due to climate change effects, the EU is experiencing heavier rainfalls and storms and sea level rising, which resulted at local and regional level in an increasing intensity and frequency of flooding. Increasing territories resilience and mitigating hydrogeological risk have become, therefore, one of the greatest challenges that our society is facing today. In this context, the successfulness of public decision processes play a key role. Due to the dramatic complexity of these decision process, which involve different stakeholders and actors, whose stakes are high and who may have conflicting objectives, policy-makers and planners require robust, transparent and coherent decision tools to support them in pursuing their arduous task. In this paper, we propose a methodological approach, which aims at increasing legitimation, accountability and transparency in public decision-making related to prioritization of hydrogeological risk mitigation strategies, by creating consensus via a participative approach. In detail, we discuss the potential of absolute AHP models in the prioritization of hydrogeological risk mitigation strategies. We argue that, due to the specific characteristics of absolute AHP measurement, once the hierarchy of criteria has been set and weights have been determined, the absolute model can be implemented on any set of alternatives, which does not need to be defined a priori, but can evolve over time, thus accounting for changes in single-criterion valuation of alternatives, contingent to variations in boundary conditions of the decision environment.