Carling, Paul, Leyland, Julian, Kleinhans, Maarten G., Duranton, Pierre, Besozzi, Louison, Trieu, Hai Q and Teske, Roy (2020) Quantifying fluid retention due to natural vegetation in a forest floodplain analogue using the Aggregated Dead Zone (ADZ) dilution approach. Water Resources Research.
Abstract
Fluid retention and flow resistance due to natural vegetation remain poorly understood despite the importance of understanding these for flow routing and floodplain revegetation projects. Experiments were undertaken in a shallow earthen channel containing a natural cover of small trees, herbaceous plants and leaf-litter which were sequentially removed and subjected to a range of flows. A dilution monitoring approach within the Aggregated Dead Zone framework was applied to a series of floodplain vegetated flows, yielding information on bulk flow parameters including tracer dispersion, fluid retention and flow resistance at the reach-scale. The primary response of flow to vegetation removal was a small increase in bulk velocity, with depth and wetted width decreasing only slightly. Reach mean travel time and the advective time delay decreased by about a factor two with the removal of herbs, grass and leaf litter, leaving only trees. Removing the trees, leaving a bare earthen channel, only slightly decreased travel times. Flow resistance and retention exhibited large values for low discharge and converged on a constant low value for relatively high discharges. It is concluded that flow resistance during low flow is higher than in a high flow with the same vegetation. Consequently, sparse vegetation has a prominent effect on hydraulic retention compared with an unvegetated channel at low discharges but this becomes negligible during high discharges as momentum increasingly dominates the flow. This outcome casts doubt on the efficacy of scrubby vegetation to impede higher-velocity floodplain flows, showing need for field-scale determination of integral floodplain resistance.
More information
Identifiers
Catalogue record
Export record
Contributors
University divisions
- Faculties (pre 2018 reorg) > Faculty of Engineering and the Environment (pre 2018 reorg) > Southampton Marine & Maritime Institute (pre 2018 reorg)
- Current Faculties > Faculty of Environmental and Life Sciences > School of Geography and Environmental Sciences
School of Geography and Environmental Sciences - Faculties (pre 2018 reorg) > Faculty of Social, Human and Mathematical Sciences (pre 2018 reorg) > Geography & Environment (pre 2018 reorg)
Current Faculties > Faculty of Environmental and Life Sciences > School of Geography and Environmental Sciences > Geography & Environment (pre 2018 reorg)
School of Geography and Environmental Sciences > Geography & Environment (pre 2018 reorg) - Current Faculties > Faculty of Environmental and Life Sciences > School of Geography and Environmental Sciences > Landscape Dynamics and Ecology
School of Geography and Environmental Sciences > Landscape Dynamics and Ecology
Download statistics
Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.