Effects of LiDAR-derived, spatially distributed vegetation roughness on two-dimensional hydraulics in a gravel-cobble river at flows of 0.2 to 20 times bankfull

摘要: Abstract The spatially distributed effects of riparian vegetation on fluvial hydrodynamics during low flows to large floods are poorly documented. Drawing a LiDAR-derived, meter-scale resolution raster canopy height as well an existing algorithm distribute stage-dependent channel roughness, this study developed two-dimensional hydrodynamic model ~ 28.3 km gravel/cobble-bed river corridor for ranging from 0.2 20 times bankfull discharge, with and without roughness. Results were analyzed gain insight into scale-dependent velocities, depths, flow patterns. At the floodplain filling 597.49 m 3 /s, adding roughness parameters caused 8.0 7.4% increases in wetted area mean depth, respectively, while velocity decreased 17.5%. Vegetation has strong channelization effect flow, increasing difference between mid-channel bank velocities. It also diverted away densely vegetated areas. On floodplain, stands high preferential paths that otherwise unaccounted unvegetated runs. For whole, discharge increases, overall well, contrary popular conception.