Appropriate model use for predicting elevations and inundation extent for extreme flood events

Flood risk assessment is generally studied using flood simulation models; however, flood risk managers often simplify the computational process; this is called a “simplification strategy”. This study investigates the appropriateness of the “simplification strategy” when used as a flood risk assessment tool for areas prone to flash flooding. The 2004 Boscastle, UK, flash flood was selected as a case study. Three different model structures were considered in this study, including: (1) a shock-capturing model, (2) a regular ADI-type flood model and (3) a diffusion wave model, i.e. a zero-inertia approach. The key findings from this paper strongly suggest that applying the “simplification strategy” is only appropriate for flood simulations with a mild slope and over relatively smooth terrains, whereas in areas susceptible to flash flooding (i.e. steep catchments), following this strategy can lead to significantly erroneous predictions of the main parameters—particularly the peak water levels and the inundation extent. For flood risk assessment of urban areas, where the emergence of flash flooding is possible, it is shown to be necessary to incorporate shock-capturing algorithms in the solution procedure, since these algorithms prevent the formation of spurious oscillations and provide a more realistic simulation of the flood levels

How to Model Stakeholder Participation for Flood Management

Stakeholders participation for Flood Risk Management is a key factor for the improvement of policy and decision’s quality of and to create consensus. Nowadays there are many studies on this topic aimed to take into consideration the involvement of stakeholders in different phases of the process and with the use of different procedures. In Italy the situation seems to be critical compared to the international panorama, since there are no regulation or protocols to prevent disaster or repair the damage. The paper proposes a critical overview of methodologies able to engage stakeholders in decision-making process with a detail on case studies focused on the Flood Risk Management. Different aspects will be investigated and compared in order to outline considerations and possible conclusions

How to Use Ambiguity in Problem Framing for Enabling Divergent Thinking: Integrating Problem Structuring Methods and Concept-Knowledge Theory

Collective behaviors and participatory models could be hampered by the presence of ambiguity that reflects the multiplicity of interpretations that different actors bring to a modeling exercise. Despite commonly overlooked in modeling, how ambiguity in subjective problem frames is embraced determines the quality of the participatory modeling process. This work describes an innovative approach based on the integration of Problem Structuring Methods, specifically Fuzzy Cognitive Mapping (FCM), and Concept-Knowledge (C-K) design theory, as a means to transform ambiguity from a barrier to an enabling factor of divergent thinking in participatory modeling. The integration of methods allows to identify and analyze ambiguity in problem framing, avoiding viewpoints’ polarization that hampers the development of collective behaviors. However, individualistic problem frames can still yield organized collective actions when these frames are sufficiently aligned. Often environmental policies fail because decision-makers are not aware of the misalignment and their decisions are based on wrong assumptions about the others’ problem frames. This work discusses the results of two case studies aimed to design environmental policies for groundwater protection in Kokkinochoria area (Republic of Cyprus) and Apulia Region (South-East Italy), demonstrating the potential of FCM and C-K theory integration in supporting divergent thinking in participatory modeling