Nature-based solutions for effective flood mitigation: potential design criteria

Abstract Few studies attempt to measure changes to discharge hydrographs during floods resulting from nature-based Solutions (NbS) for risk mitigation. The Q-NFM project in the UK has sought to measure and compare such changes for a wide range of NbS pilots applied to managed grasslands and woodlands. Also measured were underlying shifts in key hydrological processes leading to flood hydrograph changes of enhanced evaporation, hillslope-, channel- and floodplain-storage, and infiltration. How well particular NbS pilots changed these processes to reduce flood hydrographs was found to depend on the attributes of the NbS features and scheme. This learning is presented for the first time to highlight, with supporting evidence, seven potential criteria to help practitioners of flood risk management to improve existing and future designs of NbS for more effective flood mitigation within temperate grassland and woodland environments.