Details of Award
NERC Reference : NE/G009333/1
How does aquatic vegetation modify the kinematic & geometric characteristics of coherent flow structures in open channels?
Grant Award
- Principal Investigator:
- Professor R Hardy, Durham University, Geography
- Co-Investigator:
- Professor SN Lane, University of Lausanne (UNIL), Faculty of Geosciences and Environment
- Co-Investigator:
- Professor DR Parsons, Loughborough University, Vice Chancellor's Office
- Grant held at:
- Durham University, Geography
- Science Area:
- Freshwater
- Atmospheric
- Overall Classification:
- Freshwater
- ENRIs:
- Environmental Risks and Hazards
- Biodiversity
- Science Topics:
- Water Quality
- Earth Surface Processes
- Hydrological Processes
- Abstract:
- Vegetation within river channels has a profound influence on the functioning and therefore management of fluvial systems. It can significantly effect: i) the flow resistance and thus influence water conveyance and therefore potentially increase flood risk; ii) erosion, deposition and sediment transport rates; and iii) the biological activity within the fluvial system. On a smaller spatial scale, vegetation also generates turbulence that drives both mixing and diffusion processes with strong velocity gradients generated around and above submerged macrophytes and canopies. Fluvial flow has traditionally been analysed and modelled on a time-averaged, continuum basis, but it is well known that large turbulent fluctuations exist in near-bed velocity. The aim of this research is to develop an enhanced quantitative understanding of the effect of aquatic vegetation on the generation, evolution and dissipation of Coherent Flow Structures in the fluvial system. This will be achieved by a series of state of the art laboratory flume experiments using novel automated turbulence mapping techniques in the UK's best-equipped environmental fluid dynamics laboratory. The techniques give a combined Eulerian and Lagrangian view of Coherent Flow Structures revealed by injecting tracers into the flow that allows us to monitor and thus understand both the kinematic (size, scaling, shape, vorticity and energy) and dynamic properties (origin, stability, growth, genesis into new forms and contribution to the time average flow) of these Coherent Flow Structures as they are produced and move over and through aquatic vegetation. The proposed methodology will allow us to both increase our phenomenological understanding of Coherent Flow Structures in fluvial systems and develop a framework for including aquatic vegetation into numerical model (a Computational Fluid Dynamics scheme) of river flow. This will provide a first order estimation of the increased drag from the presence of vegetation which will enable an improved parameterisation of the roughness coefficient in flood models.
- NERC Reference:
- NE/G009333/1
- Grant Stage:
- Completed
- Scheme:
- Small Grants (FEC)
- Grant Status:
- Closed
- Programme:
- Small Grants
This grant award has a total value of £37,396
FDAB - Financial Details (Award breakdown by headings)
| DI - Other Costs | Indirect - Indirect Costs | DA - Investigators | DA - Estate Costs | DI - Equipment | DI - T&S | DA - Other Directly Allocated |
|---|---|---|---|---|---|---|
| £6,045 | £7,281 | £11,750 | £1,291 | £7,776 | £3,226 | £28 |
If you need further help, please read the user guide.