Structured Multi-Actor Engagement in OPTAIN

Stakeholder engagement within OPTAIN was organised through a structured and transparent framework designed to connect scientific analysis, governance realities and territorial knowledge. Rather than relying on ad hoc consultation, the project established formal mechanisms to ensure continuous interaction between researchers and regional actors.

Central to this approach were the Stakeholder Mapping process and the creation of Multi-Actor Reference Groups (MARG) in each case study region.

Stakeholder Mapping: Identifying Relevant Actors

The first step consisted of systematically identifying actors relevant to NSWRM planning and uptake. This mapping process ensured representation from:

• Water management authorities

• Agricultural administrations

• Farmers and land managers

• Regional planners

• Advisory services and research institutions

This structured identification process clarified roles, responsibilities and potential areas of influence. It also helped highlight institutional interactions that shape how retention measures are discussed and evaluated within each territorial context.

Multi-Actor Reference Groups (MARG)

The MARG structure created a stable platform for dialogue throughout the analytical process. These groups were not symbolic consultation bodies; they were integrated into key project phases, including:

• Discussion of local conditions influencing NSWRM performance

• Review of modelling assumptions and scenario design

• Interpretation of catchment-scale and field-scale results

• Exploration of optimisation outcomes and trade-offs

• Consideration of socio-economic feasibility

Through regular meetings and workshops, MARG members contributed practical insights that helped contextualise modelling outputs within regional governance realities.

Importantly, these exchanges did not transfer decision-making authority to the project. Instead, they strengthened the transparency and policy relevance of analytical findings.

Integration with Modelling and Optimisation

Multi-actor engagement was closely linked to technical analysis.

Hydrological modelling (SWAT+), field-scale soil–water assessment and climate scenario simulations generated quantitative outputs. These were presented in accessible formats to stakeholders, enabling discussion of:

• Environmental performance under different scenarios

• Trade-offs between nutrient reduction and agricultural productivity

• Long-term resilience under projected climate variability

Stakeholder feedback informed the interpretation of results and helped refine assumptions regarding feasibility and governance constraints.

Similarly, the multi-objective optimisation protocol incorporated socio-economic indicators alongside environmental metrics. This allowed measure combinations to be evaluated not only for hydrological effectiveness, but also for economic attractiveness and practical viability.

Governance and Incentive Perspectives

Engagement activities also addressed broader governance questions, including:

• Alignment between retention measures and regional planning frameworks

• Interaction between environmental objectives and agricultural incentives

• Administrative feasibility and long-term maintenance considerations

By integrating these dimensions, the structured engagement process strengthened understanding of how NSWRM interact with existing institutional contexts.