Evolution of Tidal Inlet - Drainage Basin Systems

Abstract

As well as causing estuarine shorelines to move landward, rising sea level modifies the small tidal inlet - drainage basin systems that fringe estuaries. The small tidal inlet - drainage basins on the Potomac River and nearby Chesapeake Bay are examples of an evolutionary sequence that progresses from larger, generally free flowing inlets, through smaller inlets which significantly modify the estuary's tidal characteristics, to ephemeral inlets associated with enclosed ponds. Shallow seismic data and vibracores demonstrate that a rising sea level drowns a drainage basin and reduces the basin's area. Consequently the tidal prism is decreased and the associated inlet moves toward the next evolutionary type.