Effects of floodplain vegetation on hydraulics and sediment transport in compound meandering channels and implications for river restoration
Abstract
Floodplain vegetation plays important roles in controlling river-floodplain hydraulics and hydrologic exchange flows and therefore influences floodplain services and channel stability. However, the effects of floodplain vegetation are rarely considered in river restoration efforts because we do not adequately understand the hydraulic controls of floodplain vegetation on stable restoration designs nor the degree to which it affects exchange flows and floodplain services. Here we aim to better understand how floodplain vegetation influences the flow field, boundary shear stress, sediment transport, and channel stability in compound meandering channels. We are using numerical hydrodynamic models to simulate overbank flows in a compound sinusoidal meandering channel with floodplain vegetation. Vegetation density and discharge are varied to illustrate their effects on relative depth, flow velocity, boundary shear stress, the character of secondary currents, exchange flows between the channel and floodplain, floodplain residence times, and sediment transport. These numerical models are being complemented with physical flume experiments to assess how well the models can predict these dynamic flow processes. The results will provide insight for floodplain vegetation management practices specifically in relation to floodplain vegetation density in restored meandering channels.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMEP043..02B
- Keywords:
-
- 1803 Anthropogenic effects;
- HYDROLOGY;
- 1820 Floodplain dynamics;
- HYDROLOGY;
- 1825 Geomorphology: fluvial;
- HYDROLOGY;
- 1879 Watershed;
- HYDROLOGY