Updrift Migration of Tidal Inlets
Aubrey, D.G. and P.E. Speer
Journal of Geology, Vol. 92, pp. 531-545, 1984 WHOI-R-84-009
Migration of tidal inlets and the associated changes in adjacent barrier beaches have profound implications on both the geological evolution of inlet/estuary systems and the short-term stability of these features. Past studies have documented many instances of inlets migrating in the direction of the net littoral drift along sandy shores but have uncovered few cases where inlets appear to migrate in directions opposed to the dominant longshore transport direction. Previous attempts to explain a reversal in direction of inlet migration suggest a change in direction of net littoral drift, causing a change in migration direction. This explanation is not realistic for some inlets where wave forcing and nearshore bathymetry have remained constant through time. This study presents three alternatives to explain the tendency of some inlets to migrate updrift, each supported by historical observation at a site with a large-volume, directionally-biased littoral drift.