Vegetation Hydrodynamics – Recent Developments and Future Challenges

Abstract:

For over a century vegetation has been removed from channels and coastal zones to facilitate navigation and development. In recent decades, however, we have recognized the ecologic and economic benefits of aquatic vegetation. It buffers against coastal eutrophication, damps waves and coastal storm surge, provides habitat, inhibits bank erosion, and provides significant carbon storage. The management of watersheds and coastal zones has turned from vegetation removal to restoration. In the past 20 years, the study of vegetation hydrodynamics has accelerated to meet the need to understand feedbacks between vegetation, flow and sediment transport. This presentation will describe key features of vegetation hydrodynamics, first at the meadow scale and then at the scale of individual patches, examining how vegetation density and meadow (or patch) morphology impact flow, with subsequent implications for sediment fate. Finally, the talk highlights differences in turbulence generation between bare and vegetated beds that may limit the transfer of open channel sediment transport models to vegetated channels, creating the future challenge of defining sediment transport models appropriate for vegetated regions.