Globally, we are facing massive challenges on how we manage our catchments, in both rural and urban areas, in the next decades. With a changing climate and increased pressure on our land resources we need to ensure we manage the water in our catchments more sustainably. The European Commission (2015) define Nature-based solutions (NBS) as 'living' solutions inspired by and continuously supported by nature or natural processes. NBSs are designed to address various societal challenges in a resource efficient and adaptable manner to provide simultaneously economic, social and environmental benefits (European Commission 2015). Therefore NBS can be used within both rural and urban areas to mitigate catchment flood risk, provide drought resilience, protect and enhance engendered freshwater ecosystems and reduce diffuse pollution. Alongside NBS, catchment scale monitoring experiments, engagement, models and decision support tools are needed to provide a robust evidence–based evaluation of methods or measures to meet policy needs of environmental directives and underpin catchment science (for example, in Europe the Water Framework Directive and the Flood Directive). Policy and stakeholder issues must be addressed at many scales in order to build appropriate NBS within our sustainable catchment water management plans. Hence it is crucial to characterise the underlying problems and arising resource needs within our catchment systems and look to mitigate and adapt those systems to solve local and global water issues.

This session focuses on key research and policy questions associated with NBS. How do we develop locally adapted solutions in catchments with different farming intensity, different pressures, drivers and issues? How can we address multi-disciplinary benefits whilst maintaining the basic need for food, water protection and water production? How can we do more for less? Many hydrologists and catchment scientists believe that the smart management of hydrological flow pathways throughout catchments is the key to resolving this multi-disciplinary issue. How does land use and management alter flow pathways that either cause or cure problems? And importantly, how can we provide the evidence base around the concept of Nature Based Solutions.

Examples of cross cutting studies that cover water resource management, water pollution, flooding, drought and ecology (both in the rural, peri-urban and urban context) are at the heart of this session. We invite (but not limit to) papers that demonstrate good quality experiments around NBS (e.g. rural and urban land management techniques to mitigate diffuse pollution, evaluating Green Infrastructure in catchments for providing flood and drought resilience); new developments within monitoring of water quality at various scales; and studies that help to isolate the effect of mitigation methods or effect of weather changes. Field monitoring and modelling studies that help to underpin catchment policy are also strongly encouraged. We particularly would like to invite papers on multi-scale catchment experiment and modelling, environmental observatories, stakeholder engagement/uptake and decision support tools. Case studies where Nature Based Solutions are being applied globally are also warmly invited.