Integrated process understanding for next-generation nature-based stormwater solutions (2026–2029)

Urban flooding and stormwater pollution are interrelated challenges driven by climate change and increasing urbanisation. Together, these pressures reduce the resilience of urban catchments to extreme weathers and hinder the achievement of good chemical and ecological status in receiving waters.

Nature-based solutions (NBS), such as bioretention and swales, are increasingly implemented to address these challenges. However, despite their widespread use, their internal functioning is still not fully understood and is often treated as a “black box.”

To depart from the “black box” approach, the project develops a process-based understanding of how water and pollutants move through and are transformed within these systems. The research combines non-invasive monitoring techniques with advanced analytical methods. In particular, the project will:

• Use geophysical methods to characterise how water flows through biofilters and swales in space and time, including preferential flow paths and internal system dynamics
• Apply carbon-14 isotope tracing to track the fate of organic contaminants and resolve key processes such as sorption, degradation, and plant uptake
• Integrate these insights into process-based models to improve predictions of treatment performance

This project is funded by Kempe Foundation with SEK 695,000 and supports two other ongoing Formas projects - “Isotopic tracing and process-based modelling to identify pathways of toxic substances in stormwater biofilters” (2025-2029) and“Scanning Infiltration: re-evaluate hydrological dynamics in Nature-Based stormwater Solutions through a non-invasive approach” (2026-2029) by strengthening analytical and monitoring capabilities and enabling closer integration of hydrological processes and pollutant fate. Together, this work will generate new knowledge on how nature-based stormwater systems function, supporting more reliable design, operation, and maintenance.