Integrating local and expert knowledge for System Dynamic Modelling: some hints from NAIAD project

Addressing complex issues, such as evaluating Nature-based Solution (NBS) effectiveness in reducing water-related risks and producing expected co-benefits, claims for modelling approaches capable to integrate different kinds of knowledge. Participatory System Dynamic Modelling is increasingly considered as powerful tool for supporting these processes. Nevertheless, several issues still need to be addressed in order to design an effective participatory modelling exercise. Firstly, modellers are required to solve the tension between the richness of the collected knowledge and the need to synthesize it in order to develop and run the model. Secondly, modellers are required to select the most adequate modelling approach. On the one hand, qualitative approaches are easily understood by stakeholders and facilitate the dialogue between stakeholders and modellers. Nevertheless, decision-makers requires quantitative results, rather than qualitative analysis for supporting their decision-making processes. On the other hand, quantitative models are often developed as “black-boxes” that can be hardly used for supporting learning processes, which is one of the main goal of the participatory modelling exercise. Starting from these premises, this contribution aims at supporting modellers in addressing the above mentioned issues and enhancing the effectiveness of Participatory System Dynamic Modelling. To this aim, the experiences carried out in the EU-funded NAIAD are synthesized and critically analysed. The stakeholders’ engagement processes carried out in three NAIAD demos – Ljubljana (Slovenia), Medina del Campo (Spain) and Lower Danube (Romania) – for co-designing and evaluating NBS are referred to in this work. An evaluation framework has been implemented in this work for comparing two system dynamic thinking approaches, i.e. the Fuzzy Cognitive Mapping (qualitative model) and the System Dynamic Modelling (quantitative model). The pros and cons of the two approaches are discussed, referring to both the stakeholders’ feedbacks and the modellers’ experiences, and suggestions on how to effectively integrate qualitative and quantitative modelling approaches are provided.