Content
A central analytical contribution of OPTAIN lies in the application of multi-objective optimisation to explore alternative Natural Small Water Retention Measure (NSWRM) portfolios across diverse European catchments. Rather than identifying a single optimal configuration, the optimisation framework generates sets of Pareto-optimal portfolios, in which no objective can be improved without reducing performance in at least one other objective.
The objectives evaluated simultaneously include:
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Water retention efficiency
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Nutrient retention efficiency
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Agricultural productivity
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Cost-related indicators
The optimisation results clearly demonstrate structural trade-offs between environmental and socio-economic objectives. For example, portfolios that maximise water retention may require spatial configurations that influence productive land use, while strategies prioritising agricultural productivity may provide more moderate hydrological buffering. Similarly, improvements in nutrient retention efficiency can involve cost implications depending on spatial allocation and measure intensity.
These findings highlight that NSWRM planning cannot rely on single-indicator optimisation. Instead, balanced portfolio evaluation is essential to understand trade-off structures and decision space constraints.
Stakeholder-Informed Interpretation of Optimisation Results
Stakeholder engagement contributed to interpreting optimisation outcomes through structured evaluation exercises and surveys. Participants reviewed alternative portfolios and expressed preferences based on perceived feasibility, economic implications and environmental performance.
Across regions, stakeholders often indicated stronger support for management-oriented measures, such as reduced or no-tillage systems and cover crops, compared to more structurally intensive configurations. Portfolios combining management practices with strategically placed structural elements were frequently perceived as more acceptable than portfolios dominated by large-scale structural measures.
This stakeholder-informed interpretation did not involve field deployment of measures. Instead, it enriched the analytical evaluation by integrating socio-economic perspectives into the interpretation of model-derived trade-offs.