What are the financial costs and benefits over time for sponge measure implementation? How can economic viability be ensured?

Presenting an economic case for sponge measures, as a type of Nature-based solution, requires overcoming the uncertainty over costs and benefits, which puts these approaches at a disadvantage compared to traditional ‘grey’ measures.

• SpongeWorks will use advanced stress testing and modelling tools to quantify the socio-economic performance of sponge measures.
• It will provide an integrated hydro-economic tool drawing on innovative biophysical modelling and monitoring, which will allow for the selection of optimal sponge strategies, combining green sponge measures with hybrid approaches as needed.
• It will provide an integrated socio-economic appraisal of sponge measures, taking into account the monetary value of direct costs, opportunity costs, the avoided risk of damages, and the value of co- benefits.
• It will develop innovative economic policy instruments for sustainable finance, summarised in a financial planning toolkit.

How can we sponge strategies at landscape scale, with complete action plans and roadmaps, be developed together with stakeholders?

Developing basin-scale ‘landscale strategies’ requires making the leap from focusing on individual measures, to modelling their combined effects against the background of the basin’s climatic and socio-economic conditions.

• SpongeWorks will employ quantified modelling methods to evaluate the effectiveness of overarching strategies at landscape scale for different hydrometeorological events, and under different future scenarios of socio-economic change.
• Participatory workshops will bring together relevant stakeholders to co-design sponge strategies with the help of a specially developed geo-design tool.
• Action plans and roadmaps for strategy implementation will be developed at the basin level.

How can we create enabling policies and institutional frameworks to support the implementation and scaling of sponge strategies?

Creating a clear and enabling framework of incentives and ownership which takes into account explicit and implicit costs and benefits over real time scales is a demanding task for Nature-based Solutions, putting it at a disadvantage vis-a-vis ‘grey’ solutions.

• SpongeWorks will employ a special Governance Assessment Tool and bring together stakeholders to analyse and understand how aspects of the broader structural governance context are supportive or restrictive.
• It will design and propose locally attuned governance models that are conducive to sustainable sponge measure implementation.

How can we help stakeholders come together through just and inclusive processes to co-create and ‘own’ these solutions?

Sustainable design and implementation of sponge measures requires bringing together dispersed and diverse stakeholders, addressing different power dynamics among them, and establishing may communication channels which may be completely lacking.

• SpongeWorks will develop local Communities of Practice, where different types of stakeholder can interact and collaborate.
• It will provide guidance frameworks for inclusive and just participatory co-creation in multi-stakeholder environments to bring together otherwise dispersed stakeholders.

How can we achieve upscaling and widespread replication in diverse European regions?

Sponge measures are very context-specific, depending on local environmental conditions, as well as the socio-economic context. Upscaling and replicating them in different regions requires pooling resources with similar efforts, to develop a broader integrated approach with specific tools which can address the needs of different contexts.

• Through its Associated Regions programme, SpongeWorks will provide a grant of up to 100,000 euros as well as focused support to 8 Associated Regions, to develop their own sponge strategies.

• SpongeWorks will engage with EU-level Communities of Practice and the EU Missions on Soil, Water and Climate, to support broader efforts to upscale and replicate NbS and sponge measures across Europe.