2025/09/05 by M. Taylor, Lucy Clarke, Anne Harrison +3 · 1 voice
Environmental Science · #Flood Risk Assessment and Management #Hydrology and Sediment Transport Processes #Hydrology and Watershed Management Studies
paper · doi:10.1002/rra.70029
openalex publication_date 2025/09/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/25
ABSTRACT The use of Natural Flood Management (NFM) interventions, and in particular woody dams, has become increasingly widespread over the last ca. 15 years. These interventions help to reduce flood risk downstream, diversifying geomorphology and hydraulics, and may influence aquatic biota. This study examines how the age of woody dams affects the hydrology, geomorphology and ecology in the Stroud Frome and Twyver catchments in Gloucestershire, UK. Our study examined three sites with similar environmental characteristics: (1) no woody dams (control); (2) woody dams recently installed; and (3) older woody dams installed more than five years previously. Five flow events of varying magnitude were monitored, with variables related to hydrology, geomorphology and ecology collected to enable a broad comparison between the sites. There was clear evidence that woody dams mitigated the impact of high magnitude flow events by reducing water velocity and increasing water storage compared with the control site, as well as reducing the amount of sediment transported downstream. Following installation, the woody dams altered hydrological conditions rapidly and maintained a good level of efficiency as they aged. The addition of woody dams also improved riparian vegetation structure and provided positive impacts on habitat availability, showing an increase for in‐stream macroinvertebrates and habitat complexity. This research provides evidence to stakeholders that woody dams can be implemented with minimal future maintenance and deliver multiple benefits to a high level of efficiency over at least a 5‐year time period. The management implications of siltation around woody dam structures are also discussed.