Columbia subject headings:
Harvard subject headings:
Tides--Delaware Bay (Del. and N.J.)--Maps.
Tides--Delaware River (N.Y.-Del. and N.J.)--Maps.
Princeton subject headings:
Delaware Bay (Del. and N.J.)--Water level--Maps.
Maps.
Tidal currents--Delaware Bay (Del. and N.J.)--Maps.
Tidal currents--Delaware River (N.Y.-Del. and N.J.)--Maps.
Water levels--Delaware River (N.Y.-Del. and N.J.)--Maps.