A framework for selecting Nature-based Solutions: applications and challenges at the catchment scale

Nature-based Solutions (NbS) aim to address natural and anthropogenic risks, enhancing ecosystem-based approaches, biodiversity, human health, and socio-economic growth. Despite the growing interest in NbS applications, their integration into landscape planning at the catchment scale remains limited, given the multi-disciplinary comprehensive features related to them. To overcome this shortcoming, this study presents a multi-disciplinary GIS-based framework for identifying, selecting, and prioritizing NbS at the catchment scale, specifically focusing on water resources availability and management. The catchment is first categorized through a multi-level approach that considers the ecosystem types, climate class, and geomorphological characteristics (Stage 1). Through a literature review, an NbS catalog (Decision Matrix) was built, considering catchment classification (Stage 2). Finally, potential solutions from the decision matrix were mapped for each class (Stage 3). Stakeholder engagement was conceptualized by integrating the technical outcomes with the local perspectives to enhance the co-design and knowledge-sharing in the decision process. The framework was tested in the Bode River catchment (Germany), showing reliable results in detecting the potential areas for NbS implementation, and the framework's replicability to multiple contexts, given its ease of application and tailorable structure, even when different policy makers are involved in the process. The proposed framework supports baseline NbS map development to identify priority areas, engage stakeholders, and guide investments in alignment with long-term regional goals and the Sustainable Development Goals (SDGs).