Participatory System Dynamics modelling for Water-Energy-Food Nexus characterization and for supporting the analysis of management measures

There is a growing awareness on the existence of dynamic interdependencies between the Water-Energy-Food sectors that cannot be ignored in identifying sustainable sectoral and cross-sectoral policies. In addition, the increasing demand for resources creates trade-offs that are exacerbated by the impacts of climate change, such as drought and flood with increasing frequency and magnitude. The Water-Energy-Food Nexus approach is a powerful concept to address the interrelationships of resource systems and move towards better coordination and utilisation of natural resources, considering existing trade-offs and promoting positive synergistic impacts. However, the incorporation of this approach into policies is making slow progress. This means that a gap exists between science (Nexus thinking) and policy (Nexus doing). 

The present work, carried out in the framework of the REXUS project (H2020, GA 101003632), aims to develop a process, strongly based on the use of participatory approaches, to support decision‐makers in designing sustainable and actionable forward-looking solutions that increase resilience across sectors. Integrated modelling based on System Dynamics is used for this purpose. In fact, it i) accounts for real-world complexities; ii) allows for future scenarios development and analysis, with clear options for policymakers; iii) allows for the integration of stakeholders’ knowledge.

Specific reference is made to one of the REXUS pilots, namely the Isonzo‐Soca watershed between Italy and Slovenia, for which current cross‐border flow regulation agreements are insufficient to guarantee a good status of ecosystem services in the Italian territory. The participatory System Dynamics modelling approach is combined with results of sectoral models, hydropeaking indicators, and ecosystem services indicators for a clear framing of the problem and its effects on the system. Through stakeholder engagement, some strategies for limiting sectoral conflicts are co-designed and fed into the System Dynamics simulation model to assess their effects on the system - and on different aspects (social, environmental, economic, etc.) - under various multidimensional future scenarios. The approach, organised in several steps, is based on a common framework replicable in different study contexts.