Variability of Fine-Grained Suspended Sediment Concentrations In a Back-Barrier Tidal Channel During Calm Weather Conditions
Dennis Anthony, Jesper Bartholdy, 1998. "Variability of Fine-Grained Suspended Sediment Concentrations In a Back-Barrier Tidal Channel During Calm Weather Conditions", Tidalites: Processes & Products, Clark R. Alexander, Richard A. Davis, Vernon J. Henry
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Concentration of fine-grained suspended sediment in a microtidal estuarine environment (northern part of the European Wadden Sea; mean tidal range = 1.5 m) is examined in order to clarify how this is influenced by flood/ebb, diurnal inequality and neap/spring during calm weather conditions. The diurnal inequality was reflected in the fine-grained suspended sediment concentration as an alternation of the maximum and minimum concentrations caused by the variation in advection as well as an alternation in the resuspension strength. The onset of the ebb current generally caused higher resuspension than the onset of the flood current, which presumably was due to the fact that a larger portion of the tidal flats was affected by the ebb current than by the flood current because of the difference in water level. The variability of the concentration of fine-grained suspended sediment over a neap/spring/neap cycle is found to be controlled primarily by the changes in the mean water level. A decrease in mean water level caused a rise in the concentration level because of a seaward extension of the turbidity maximum. An increase in mean water level could also cause a rise in the concentration level, presumably because of exposure of the tidal flats to the current. Because of the relatively low tidal range, however, the resulting long-term tide is strongly modified by the wind effects even in relatively calm periods.