SpongeScapes and SpongeWorks: two innovative European projects come together in Toulouse to combat the impacts of climate change

Following on from a project led by OiEau on Natural Water Retention Measures (MNRE), developed in 2013-2015 and enhanced with the OPTAIN project in 2020, the SpongeScapes and SpongeWorks projects focus on ‘sponge measures’. These are natural solutions aimed at slowing down the water cycle to limit flooding, mitigate droughts, and improve biodiversity and soil quality. These measures include improving soil permeability, planting hedges and restoring wetlands.

While SpongeScapes provides the scientific basis, SpongeWorks focuses on large-scale implementation.

Three major European watersheds have been selected to become demonstration sites, including the Lèze basin. Located in southwestern France, the Lèze Valley (Ariège/Haute-Garonne) has become an open-air laboratory for testing these solutions, where researchers, farmers, local authorities and residents are working together to co-develop resilience scenarios.

Two years after its launch, the SpongeScapes project has already made significant contributions:

• Updating the catalogue of 51 sponge measures and 140 case studies identified by the MNRE project, and adding new entries, resulting in a critical review of sponge functions across Europe, identifying both evidence and gaps in knowledge.
• Publication of a series of scientific articles on topics ranging from the role of vegetation in water retention to the trade-offs between floods, droughts and biodiversity.
• Collection of hydrological data: Researchers presented the results of two years of monitoring, with advanced modelling of the impacts of sponge measures.
• Development of a mapping tool called ‘opportunity maps’ to show on a large scale the most suitable locations for implementing sponge measures across the territory.
• Launch of SpongeLabs, participatory workshops in the Netherlands and France, where stakeholders co-design land use scenarios using an interactive tool, GeoDesign, to visualise the impact of sponge measures on the territory according to different scenarios.
• Organisation of webinars.

Next steps:

• Finalisation of the opportunity mapping tool.
• Finalisation of the GeoDesign tool.
• Strengthening links between science and local action for effective implementation.

In SpongeWorks, the demonstration basins in France (Lèze basin), Greece (Pinios basin) and on the border between Germany and the Netherlands (Vecht basin) are testing the practical effectiveness of various sponge measures, with the support of eight additional “associated regions” across Europe.

In the Lèze valley, the project has brought together nearly 50% of farmers with dedicated funding for the implementation of sponge measures (hedge planting, riparian forest restoration, stream renaturation, infiltration basins, pond creation/restoration, wetland restoration).

The initial results are encouraging, with a significant reduction in erosion and mudslides on the equipped plots.

Rigorous scientific monitoring carried out in collaboration with the CNRS (French National Centre for Scientific Research) is used to evaluate the effectiveness of the measures.

Next steps:

• Translation of results into economic models to quantify socio-economic benefits (e.g. impact on the health of citizens in urban areas).
• Extension of tests to other European regions.

All knowledge accumulated during field experiments will be compiled in a catalogue of measurements and feedback (case studies) accessible on the Sponge Knowledge Platform (le. spongescapes.eu), a shared, available and sustainable website.

In 2026, the modelling tools are expected to be finalised and the results published in scientific journals and mainstream media.

In 2027, these sponge measures will be extended to other European territories, with a focus on urban areas.

Throughout the projects, close collaboration between SpongeScapes and SpongeWorks will be strengthened to harmonise methods and maximise impact.