Human versus natural mud fluxes in the Scheldt estuary: are they significant and if so, how can they best be optimised?
van Kessel, T.; Vanlede, J.; van Holland, G. (2015). Human versus natural mud fluxes in the Scheldt estuary: are they significant and if so, how can they best be optimised?, in: Scheldt Estuary: physics and integrated management - Special Session on of the 36th IAHR WORLD CONGRESS, 28 June – 3 July, 2015, Delft and The Hague, the Netherlands. pp. 34-37
In: (2015). Scheldt Estuary: physics and integrated management - Special Session on of the 36th IAHR WORLD CONGRESS, 28 June – 3 July, 2015, Delft and The Hague, the Netherlands. Deltares: Delft. 110 pp.
The mud dynamics of the scheldt estuary is governed by the interplay between tidal flow, freshwater discharge, marine and fluvial mud supply and local sources and sinks. a question is how large human impacts are on these mud dynamics. using a process-based mud transport model of the scheldt estuary, these impacts have been quantified by evaluating different scenarios representative for present or alternative maintenance dredging procedures. the results show that although the ‘human’ fluxes caused by maintenance dredging are typically small compared to natural gross fluxes, they are very significant compared to natural residual fluxes, notably in the narrower section of the estuary near antwerp. here more than half of the available mud is ‘second-hand’, i.e. it has been dredged from and released back into the estuary at least once. this implies that an optimization of the dredging and release cycles, including the smart selection of release locations, offers the perspective of smaller human impacts, possibly even at lower costs. a down-estuary shift of release locations would be favourable. also, locations closer tidal flats may contribute to interrupting the vicious circle between dredged mud dispersion and maintenance dredging by enhancing the accretion rate of these flats. however, the surface area of these flats has to be substantial to provide more than just a short-term solution.
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