Deliverable report D5.3 of the EU Horizon 2020 Project OPTAIN (Grant agreement No. 862756) The objective of this deliverable is to convey OPTAIN’s optimisation approach, methodologies and results to stakeholders of each case study’s Multi-Actor Reference Groups. More importantly, it will create a common understanding of the potential of the NSWRMs for improving water and nutrient retention in the CS, as well as of the associated trade-offs such as costs and potential reductions in crop production. Finally, this task will determine those NSWRM implementation plans preferred by individual actors using the tool, ParetoPick-R, developed in the previous task 5.3. This sets the stage for the subsequent in-depth, cross-sectoral discussion about a spatially targeted implementation of NSWRM. Summary This deliverable from the EU Horizon 2020 OPTAIN project presents the results from stakeholder interviews across eleven European case studies, focusing on the identification of preferred implementation plans for Natural/Small Water Retention Measures (NSWRMs). It builds on the modelling and multi-objective optimisation workflows employed in OPTAIN, which explored numerous options for potential measure implementation optimised for environmental and economic objectives. Stakeholders of each case study’s Multi-Actor Reference Groups (MARG) participated in structured interviews. Using the interactive ParetoPick-R app, they developed a common understanding of the potential of NSWRMs and explored trade-offs among four optimisation objectives, such as water/nutrient retention, crop production, and cost. They then selected their preferred implementation plans based on weights assigned to each objective and filter options applied to the solution space. Key Findings: Trade-offs & preferences: Stakeholders' preferences varied significantly across sectors and case studies. Agricultural actors typically prioritised crop production and cost-efficiency, while those in the water and nature conservation sectors leaned towards environmental benefits. Common measures: Frequently preferred NSWRMs included soil and/or crop management measures, followed by greening measures and engineered solutions. Feasibility issues: Technical feasibility, land ownership, and institutional hurdles (e.g., need for permits) influenced stakeholder choices. Tool feedback: The ParetoPick-R tool was generally well-received for visualising trade-offs and supporting decision-making. However, some users found it too complex and suggested improvements in usability, guidance, and map functionality. This deliverable D5.3 sets the foundation for the final MARG workshops in the case studies, which will seek to negotiate compromise solutions that are acceptable to all actors. The report underscores the importance of participatory modelling tools and multi-sector engagement in water and land management planning.
Strauch et al. (Tue,) studied this question.