A reassessment of the role of tidal dispersion in estuaries and bays

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The role of tidal dispersion is reassessed, based on a consideration of the relevant physical mechanisms, particularly those elucidated by numerical simulations of tide-induced dispersion. It appears that the principal influence of tidal currents on dispersion occurs at length scales of the tidal excursion and smaller; thus the effectiveness of tidal dispersion depends on the relative scale of the tidal excursion to the spacing between major bathymetric and shoreline features. In estuaries where the typical spacing of topographic features is less than the tidal excursion, tidal dispersion may contribute significantly to the overall flushing. In estuaries and embayments in which the typical spacing between major features is larger than the tidal excursion, the influence of tidal dispersion will be localized, and it will not markedly contribute to overall flushing. Tidal dispersion is most pronounced in regions of abrupt topographic changes such as headlands and inlets, where flow separation occurs. The strong strain rate in the region of flow separation tends to stretch patches of fluid into long filaments, which are subsequently rolled up and distorted by the transient eddy field. The dispersion process accomplished by the tides varies strongly as a function of position and tidal phase and thus does not lend itself to parameterization by an eddy diffusion coefficient.

Publication type Article
Publication Subtype Journal Article
Title A reassessment of the role of tidal dispersion in estuaries and bays
Series title Estuaries
DOI 10.2307/1352684
Volume 15
Issue 2
Year Published 1992
Language English
Publisher Chesapeake Biological Laboratory
Publisher location Solomons, MD
Contributing office(s) Woods Hole Coastal and Marine Science Center
Description 12 p.
First page 97
Last page 108
Online Only (Y/N) N
Additional Online Files (Y/N) N
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