Ebb tide advects low-salinity estuarine discharges onto the continental
shelf where they mix with ambient shelf water.  Only a portion of the
mixture returns on the flood tide into the estuary.  The remainder often
forms a low-salinity zone detached from the parent estuarine plume. 
Shipboard and aerial surveys conducted in autumn were used to determine the
fate of the estuarine discharge from Charleston Harbor, South Carolina.  We
used a simple momentum balance to estimate the wind generated alongshelf
current.  We found that the plume deflection was predicted by the vector
addition of the wind generated current and the tidal current operating at
the observation times.  Thus, the plume is easily deflected downwind since
wind stress in shallow water is transferred directly to the bottom.  A
sequence of cross-plume sections was obtained during a portion of the ebb
and flood tidal cycle.  Ebb flow carried low salinity estuarine water
seaward where it turned abruptly southward as it encountered the southward
current that prevails along the shelf in autumn. The front separating
estuarine discharge from shelf water was significantly stronger on the
upstream side than it was on the downstream side, as indicated by salinity
and suspended matter content that sharply distinguished the two water
masses.  During the flood stage, the upstream front weakened significantly.