The Process System Engineering community has an extensive knowledge and skills on supply chain de- sign: from the time dimension (production and flow planning) to the space dimension (geographic posi- tion of facilities). Nevertheless, supply chains are also social networks where multiple stakeholders have to collaborate while they have different, and sometimes, diverging objectives. For this reason, having a more realistic model representing collaboration between the various stakeholders involved is necessary and new methods that facilitate the development of a shared representation of the system must be in- troduced. We propose to import a participatory method, PARDI (Problematic, Actors, Resources, Dynamics and Interactions), from the Socio-Environmental System community to the practices of the Process Sys- tem Engineering community. Based on this method, we develop a participatory process in order to col- lect the necessary knowledge on the supply chain and its context. Following this participatory process, we then develop an Agent-Based Model as a simulation and decision making tool to support collective scenario analyses and collectively draw solutions with stakeholders. Our participatory modeling approach necessarily imposes a multi stakeholders vision (within the modeling but also in the result analyses) and therefore the search for a modeling consensus. Thus, it brings a better inclusion of social aspects in problem solving which are usually poorly considered leading to implementation failure sometimes. By comparing our approach with the classic one of the Process Systems Engineering community, we high- light the strengths and weaknesses of both and how complementary they can be. A case study on the already existing supply chain of the chestnut wood in Cévennes area (France) illustrates the capabilities of our participatory methodology. It focuses on the socio-economic model design of the first two steps (forestry activities to harvest) in the supply chain