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The OPTAIN (OPtimal strategies to reTAIN and reuse water and nutrients) project is a five-year European research initiative funded with €7 million through the EU Horizon 2020 programme. Running from 2020 to 2025, the project brings together 21 partner organizations across 15 European countries.
Rather than implementing physical measures directly in the field, OPTAIN focuses on the analytical assessment of Natural Small Water Retention Measures (NSWRM) in agricultural catchments. To achieve this, the initiative develops and applies a process-based modelling and multi-objective optimisation framework. This framework evaluates how different NSWRM configurations influence water and nutrient dynamics under both current and projected climate conditions. By providing scientifically robust tools, the project enables structured comparisons of alternative NSWRM portfolios across diverse European biogeographical regions, offering simulation-based evidence on the performance trade-offs between environmental and agricultural goals.
The research focuses on 14 small catchments (ranging from 4.5 to 250 km²) across Europe, addressing key local issues such as floods, droughts, soil erosion, nutrient leaching, and crop yield losses that intensify conflicts among water users. To assess site-specific NSWRM effectiveness, OPTAIN integrates three core pillars: operational and historical knowledge from local Multi-Actor Reference Groups (MARG), theoretical foundations from existing literature and platforms (such as WOCAT and nwrm.eu), and integrated computer modelling aligned with regional future climate projections.
Below you will find a map showing the various case studies and their locations.
Now that you’ve studied specific case studies, this quiz will test your ability to apply what you’ve learned. You will be asked about the lessons, successes, and challenges that emerged from these real-world applications of NSWRM. Use this quiz to confirm your understanding of how case studies contribute to the broader goals of water and nutrient management.
Once you're ready, click here to begin!