Nature-based Solutions (NbS) — from restored wetlands and riparian forests to agroforestry and urban green infrastructure — offer a powerful and increasingly well-evidenced pathway to building hydrological resilience. When designed and placed thoughtfully, NbS can attenuate floods, recharge groundwater, reduce erosion, improve water quality, and support biodiversity simultaneously.
Research at HydroLAB focuses on the systematic identification, selection, and mapping of NbS at the catchment scale, addressing the gap between the growing theoretical evidence and operational deployment. The central question is straightforward: How do we move from knowing that NbS are beneficial in theory to deploying the right ones, in the right places, with measurable outcomes?
Research Line
The research is structured around three interconnected pillars, each feeding into the next:
Pillar 1 — Spatial Identification and Selection of NbS
The foundation is a GIS-based multi-disciplinary framework that classifies any catchment by its ecosystem type, climate, soil, and topography, and automatically matches those conditions to the most suitable NbS from a literature-validated Decision Matrix. The framework covers five ecosystem types (urban, agricultural, forest, freshwater, coastal) and produces spatially explicit NbS priority maps that stakeholders can directly use in planning and investment decisions. It has been validated in the Bode River catchment in Germany and is currently being applied across Mediterranean demo sites through the OurMED PRIMA project.
Pillar 2 — Hydrological Modelling and Performance Quantification
The next step is predicting what selected NbS will actually do to water. We are coupling the NbS selection framework with process-based hydrological models (including the DREAM Model) to simulate catchment-scale effects of different NbS portfolios on the water balance under current and future climate scenarios. Outputs provide stakeholders with quantitative Key Performance Indicators (KPIs), translating spatial selection into an economic and hydrological business case for investment.
Pillar 3 — Stakeholder Co-Design and Policy Integration
The most technically rigorous framework is worthless if it cannot be acted upon. Our research treats stakeholder engagement not as an add-on but as a structural component. Local authorities, farmers, civil society organizations, and policymakers are involved through workshops, living labs, and online participatory platforms. This pillar also aligns NbS deployment with EU policy instruments including the Water Framework Directive, the Nature Restoration Law, and Horizon Europe funding streams.
The Three-Stage Framework
The multi-disciplinary framework, presented in the 2025 publication, is structured into three stages operating within a broader baseline–design–monitoring workflow.
| Stage | Title | Description |
|---|---|---|
| Stage 1 | Catchment Classification | GIS overlay of four freely available global datasets — Corine Land Cover 2018, Global Aridity Index, USDA soil texture, SRTM elevation — producing up to 40 distinct catchment class labels (e.g. Agri-Humid-Perm-Mild). |
| Stage 2 | NbS Decision Matrix | A catalog of 34+ validated NbS interventions, each assigned a low / moderate / high adaptability score per catchment class, built from a systematic review of peer-reviewed literature (2010–2024). |
| Stage 3 | NbS Solutions Map | Prioritized solutions spatially mapped in GIS and co-validated through stakeholder workshops. The map links interventions to IUCN societal challenges (water security, disaster risk, climate adaptation, biodiversity) and feeds directly into planning decisions. |
Latest Publication
This paper presents a three-stage GIS-based framework for identifying, selecting, and prioritizing NbS at the catchment scale, with a specific focus on water resource management. The framework integrates freely available global datasets and was validated on the Bode River catchment (~3,300 km², Germany), demonstrating reliable results in detecting priority areas with a replicable and tailorable structure suitable for diverse policy environments.
Keywords
References
- Sarwar, A.N., Caramiello, C., Pugliese, F., Jomaa, S., Guelmami, A., Ronse, M., Roggero, P.P., Marrone, N., De Paola, F., Daloglu Cetinkaya, I., Copty, N.K., Rode, M., Manfreda, S., A framework for selecting Nature-based Solutions: applications and challenges at the catchment scale, Journal of Environmental Management, 394, 127220, (doi:10.1016/j.jenvman.2025.127220), 2025. [pdf]
How to cite:
Sarwar, A.N., et al. (2025). A framework for selecting Nature-based Solutions: applications and challenges at the catchment scale. Journal of Environmental Management, 394, 127220. https://doi.org/10.1016/j.jenvman.2025.127220
