Creating Resilient River Systems by Mainstreaming and Upscaling Nature-based Solutions or ‘ResiRiver’ for short, is an EU Interreg project focusing on the creation of Resilient River Systems through the mainstreaming and upscaling of Nature-based Solutions (NbS). Today, most North-West European (NWE) river systems face significant challenges, largely resulting from past anthropogenic riverine alterations (regulations and interventions) which have greatly exacerbated the negative effects of climate change like flooding and drought. These changes also put additional pressures on existing land-use-claims, and other societal/economic interests like shipping, agriculture and water quality and cause continued biodiversity-loss. In recent years, NbS have emerged as a novel and sustainable approach in river management, cap able of mitigating these threats while also strengthening climate resilience. They fit well within the EU’s ‘Blue Economy’ ambition and provide undeniable benefits for both human well-being and biodiversity. However, the widespread integration (mainstreaming) and implementation (upscal ing) of NbS in riverine systems has yet to become common practice. The ResiRiver project there fore aims to accelerate the upscaling and mainstreaming of NbS through a curated partnership of full-scale North West Europe NbS projects by gathering, transferring, and synthesizing know ledge and experiences, whilst ensuring that this is done at all relevant partner/national/EU levels.

River managers today are faced with the challenge of adapting to climate change while also having to sustainably secure all important functions in a healthy river system for society. Nature-based Solutions (NbS) have proven themselves effective across a multitude of contexts; providing integrative approaches for river restoration, conservation and sustainable management, ensuring both climate change adaptation and contribute to climate change mitigation and biodiversity recovery for generations to come. NbS are multi-faceted and more importantly, they are effective when it comes to addressing complex societal challenges (e.g. reducing flood risk, increasing natural values and biodiversity, ecosystem services and human well-being), as they provide a novel, integrative and coherent approach. Despite the significant and rapidly growing base of scientific evidence regarding the effectiveness of NbS in riverine systems management, the actual uptake and application of NbS on a larger (EU) scale is still in its early phase. From where we stand today, a major barrier to the wider uptake and application of NbS in riverine systems remains (a) our limited experience in scaling solutions beyond their local contexts (so called ‘Upscaling’), and (b) make Nbs as a standard work practice within water management organisations throughout North-West Europe (so called ‘Mainstreaming’). Also, our lack of standardised methods for quantitative assessment and monitoring of ecosystem services and benefits related to NbS hinders replication and application at a wider scale.