An investigation into processes influencing the morphodynamics of an intertidal mudflat, the Dollard estuary, the Netherlands: I. Hydrodynamics and suspended sediment
Kr. Dyer et al., An investigation into processes influencing the morphodynamics of an intertidal mudflat, the Dollard estuary, the Netherlands: I. Hydrodynamics and suspended sediment, EST COAST S, 50(5), 2000, pp. 607-625
As part of an interdisciplinary experiment, a series of measurements have b
een obtained on the mudflats of the Dollard Estuary, the Netherlands. The a
im was to investigate the sediment transport and accumulation processes occ
urring during the covering and uncovering of the mudflats, particularly as
the area was known to be ebb current dominant. Current velocity measurement
s confirmed the ebb dominance, and suspended matter concentrations measured
over several tidal cycles in calm weather revealed that the highest concen
trations occurred at the beginning of the flood and the end of the ebb. The
resulting sediment flux, however, was flood dominant. During windy weather
the balance of flux changed to ebb dominance. Measurements of flee size an
d settling velocity show a major organic component produced by entrainment
of a thin surface layer during the early flood tide. During a windy period
settling velocities in the adjacent channel together with the concentration
variations showed a phase lag with water depth and velocity. The highest s
ettling velocities occurred at about slack water, and there were residual e
bb fluxes of suspended sediment. It is concluded that the ebb dominance of
the currents is not apparent in the sediment fluxes during calm weather, bu
t in periods of high winds the flux is likely to be ebb directed, except wh
en diatom productivity is high. The overall response is similar to that of
flood dominated mudflats. (C) 2000 Academic Press.