ABSTRACT
Flood frequency and magnitude have increased over the past 30 years in the UK and EU and are expected to continue to rise, including increased flash flooding. To mitigate flood impacts while working with natural processes, the Environment Agency and other organizations encourage natural flood management methods, including installation of engineered leaky barriers. However, limited evidence on structure performance and sediment transport effects impacts limits confidence in leaky barrier measures and project design capability. In order to identify barrier structural properties affecting local bedload transport, bed elevation changes induced by instream structures that spanned the upper channel were measured in a hydraulic flume containing a two layer, mobile gravel bed. A scour pit followed by a deposition mound formed when the barrier locally increased bed shear stress and exceeded the sediment threshold of motion. The pit and mound developed over time, with final Shields parameter approaching the critical value.
