On behalf of the EcoAdapt research-action project, participatory modeling exercises took place and resulted in diagrammatic representations of the functioning of the territory concerned with the problem of water availability and water quality conditions. The process of modeling began with a reflection about the principal problems and challenges faced by the different stakeholders of the territory in order to formulate a shared problematic. By stating the intervention of stakeholders in this problematic and the resources they manage in the territory, it was possible to understand what participation means in an Ecosystem-based adaptation project and to identify critical knowledge gaps about the natural resources. Finally by clarifying processes and interactions between actors and resources in each site, the modelling exercise emphasized the links between different aspects that hadn't been considered before. Participatory modelling constituted a learning process and highlighted coordination failures that compromise the sustainability of the current social-ecological dynamics.