Efficiency of hanging silt curtains in cross-flow

Efficiency of hanging silt curtains in cross-flow

Radermacher, M.
De Wit, L.
Uijttewaal, W.S.J.
Winterwerp, J.C.

Civil Engineering and Geosciences

Hydraulic Engineering

2015-06-20

When dredging in sensitive environments, efforts have to be made to limit the free dispersal of suspended fine sediment from the dredging spill. Especially the use of hanging silt curtains as an environmental mitigation measure is widespread. Despite frequent application, their ability to reduce turbidity levels through vertical diversion of sediment-laden currents remains subject of debate. This paper addresses a series of laboratory measurements and numerical model simulations in order to determine the efficiency of hanging silt curtains, defining a new efficiency parameter. The model was validated against the laboratory experiments. Model simulations focusing on vertical diversion of the sediment-laden current suggest that hanging silt curtains do not have a favorable influence on the settling of suspended sediment when applied in cross-flow. Diversion of currents underneath the curtain causes flow separation and intense turbulent mixing, which counteracts settling of suspended sediment particles. The results imply that the widespread application of hanging silt curtains should be reconsidered from a physical point of view.

dredging
turbidity
environmental issues
turbulence
numerical models
laboratory tests

http://resolver.tudelft.nl/uuid:55649654-2924-42bc-aff9-eb174399b2e2

ASCE

0733-950X

https://doi.org/10.1061/(ASCE)WW.1943-5460.0000315

Journal of Waterway, Port, Coastal, and Ocean Engineering, 2015; Authors version (post print)

Institutional Repository

journal article

(c) 2015 ASCE
The Author(s)