Dauphin Island, AL
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Insight: Options for an island
By Press-Register Editorial Board
February 21, 2010
Dauphin Island's beach erosion solutions
There are options when it comse to restoring Dauphin Island
By SCOTT L. DOUGLASS
Special to the Press-Register
Go stand on the beach on
the west end of Dauphin Island today, look south at the beautiful
Gulf of Mexico, and imagine going back in time to when Alabama became
Instead of being on the Gulf beach, you would have been standing
in the waters of Mississippi Sound looking at the back (north) side
of the Dauphin Island of 1819. This is because the west end of the
island has migrated more than 1,000 feet - more than its entire
width - to the north since 1850.
Dauphin Island, seen from the extreme west
end, seems to be growing a narrow, courling tail since Hurricane
Katrina struck in 2005. This knife edge of a new beach separates
the Gulf water seen on the right side of the picture from
the Mississippi Sound seen on the left side. The Island
has brown about 300 yards longer since Katrina chopped it
in half. The other half of the island, which is about 8
miles long, lies to the west across nearly a mile of open
Press-Register file photo.
Descendents of Europeans have lived on Dauphin Island for more than
300 years. But that is on the east end of the island, the "village"
in the maritime forest, behind the extremely high sand dunes that
protect that middle part of the island from hurricane storm surges
and Gulf waves.
There is a tremendous amount of sand moving onshore from the migration
of Pelican/Sand Island onto Dauphin Island near the now land-locked
fishing pier and the golf course. The same thing has probably happened
for thousands of years including 150 and 300 years ago.
Meanwhile, both ends of the island have suffered from major storms
and chronic erosion. The rock seawall built by the U.S. Army Corps
of Engineers in 1906 and rebuilt in the 1990s has protected Fort
Gaines from succumbing to beach erosion like Fort McRae - the fort
that used to sit on the west side of Pensacola Pass.
However, there is no beach in front of the seawall around Fort Gaines,
and there is severe beach erosion immediately to the west of the
A seawall is probably not desired, nor is the public expense justified,
on the west end of the island. The tremendous migration of the west
end of Dauphin Island to the north since 1850 is due to two natural
processes: storm overwash and inlet breach formation/healing. Both
have occurred repeatedly. Storm overwash is most obvious during
hurricanes like Frederic, Georges, Ivan and Katrina, as storm surge
rises to an elevation where waves roll right over the smaller dunes
on the west end. However, once the dunes are flattened, the overwash
occurs in much smaller storms.
The west end of the island has overwashed more than half a dozen
times some years. The overwashed sand moves into Mississippi Sound,
leaving former boat docks high and dry in the sand while the Gulf
beaches move permanently to the north, too. The barrier island is
rolling over to the north.
There is no precedence for living on a barrier island that overwashes
as frequently as the west end of Dauphin Island has been overwashing
Most of us remember (just 20 years ago) when Bienville Boulevard
was located on the northern portion of the west end of the island.
Today, it is on the southern portion of the island near the surf.
And the road location hasn't moved: The island has rolled over it.
The road is so close to the surf today that it is essentially where
the primary sand dune field should be located on the island.
The repeated breaching and healing of new inlets may be just as
important for island migration in the long run. The west end of
the island has been breached repeatedly over the last 300 years,
including today's "Katrina Cut" west of the end of the road. Other
similar breaches located between there and the Little Red Schoolhouse
are documented in the 1850s, the 1910s, 1920s, 1930s and 1940s.
Today's "Katrina Cut" is over a mile wide and sand is moving north
into Mississippi Sound due to waves and incoming tidal currents.
While each of the previous breaches has eventually sealed itself
off due to wave-driven sand transport along the beaches, the island
and its Gulf beaches have re-established farther north each time.
The "Katrina Cut" may seal itself off in the next decade, but it
will do so with the island and the beaches even farther north. In
the meantime, it will continue to cause tremendous changes in the
Mississippi Sound, including wetland losses and a decimated oyster
So, is there a solution? The so-called "FEMA berms" built twice
on the west end of Dauphin Island in the last decade did not solve
the problem. They cannot if the Corps of Engineers just stacks a
relatively small, expensive amount of sand on the beach face. Attempts
to build something similar yet again seem misguided.
There are only three general approaches to an erosion problem such
as this: retreat/abandonment, stabilizing with "hard" structures
such as a seawall, or stabilizing with "soft" solutions such as
beach nourishment and sand bypassing.
The recently announced federally funded studies will focus on beach
nourishment - the placement of large amounts of good-quality sand
on the beach to widen the beach and, in this case, establish a dune
system. Beach nourishment has worked very well for Gulf Shores and
Orange Beach. Their beaches are, on average, much wider and higher
than they were in 2000. The 2001 beach nourishment project in central
Gulf Shores has probably paid for itself a dozen times over in reduced
storm-induced damages to public and private property.
The Dauphin Island studies will determine how much sand is needed,
find the most cost effective sand for nourishment, model the expected
future behavior of the new sand and the environmental impacts of
the project, and estimate the costs of initial construction and
Dr. Scott L. Douglass is professor of civil engineering at the University
of South Alabama and author of "Saving America's Beaches: the Causes
of and Solutions to Beach Erosion."