River science and flood risk management policy in England

We review the role of science in shaping river flood risk management policy in England, highlighting the relatively recent influence of fluvial geomorphology, river ecology, climate change and ecosystem services in evidence-based decision-making. These disciplines, together with an historical perspective, catchment-scale delivery, integrated land and water management planning, and adaptive management are crucial in managing future flood risk. A central tenet of previous land drainage policy was a professional (and public) mindset about flood 'prevention' solutions for river flooding. As a direct consequence, more than 8,500 km of rivers were 'improved' by mechanical dredging during the 1930s to 1980s; habitats were destroyed, but flooding continued. A more enlightened, long-term approach has since evolved in response to environmental imperatives and lessons learnt from several major floods during the last two 'flood-rich' decades. River science, local knowledge and land management incentives allow more natural processes to be restored in river catchments. The natural capital and ecosystem service benefits of river systems are now better understood and quantified, whereas the importance of sediment transport is fully recognised, with sources and sinks treated more holistically than in the past. Evaluating the outcomes of innovative runoff and river management techniques from both physical and socioeconomic perspectives will determine the success of a catchment-based approach. We highlight some of the uncertainties, nuances and assumptions associated with recent initiatives such as Natural Flood Management, Citizen Science and Flood Action Groups. Further integration between policy, strategic planning and local delivery is needed to anticipate and respond to climate and catchment land use changes. River science will play a crucial part in identifying the most effective way of improving flood management and in a way that helps to deliver the recovery of nature. It will inform adaptive management to cope with climate change.