Geology Reference
In-Depth Information
Fig. 12.2
New Topsail Inlet
(
top
) and Drum Inlet
(
bottom
), North Carolina.
(Courtesy of William Cleary)
deltas (i.e. Rhode Island, North Carolina, Texas). Their
multi-lobate morphology is a product of different
periods of deposition. The small tidal range of these
coasts prevents their reworking by ebb-tidal currents
as occurs on mesotidal coasts, except in regions having
large tidal prisms (i.e., west coast of Florida).
Through time, some fl ood-tidal deltas accrete verti-
cally and/or grow in size. This is evidenced by an
increase in areal extent of marsh grass, which requires
a minimum elevation above mean low water to exist.
At many inlets sand contribution to fl ood deltas is
event driven. During storms, high wave energy delivers
large quantities of sand to the inlet via longshore trans-
port, while at the same time the storm surges augments
the hydraulic slope of the fl ooding tide. Thus, the
increased supply of sand to the inlet channel is directed
