DR. PILKEY VS. THE
ARMY CORPS OF ENGINEERS
The best known opponent to present U.S. coastal policy is Orrin Pilkey, a shelf sedimentologist
teaching at Duke University. Generally, when the press seeks an opposing view to the standard
coastal engineering agenda, Dr. Pilkey is quoted. In the New York Times, for example, he calls
Corps of Engineer programs "criminal" for the deceiving performance projections that are inherent
in pre-construction plans for beach restoration projects. Pilkey notes, for example, that coastal
engineers, when predicting the longevity of a dredged beach, fail to account for the impacts normal
storm activity will have on the project. When storm activity does remove the artificial beach,
generally long before its projected life span, Pilkey ridicules engineers who typically defend the
work by suggesting that strong storms are "unexpected events."
Pilkey is one of a number of American geologists who have written scholarly papers faulting the
basic design concepts used by coastal engineers. This group of geologists has determined that the
Army Corps, and the industrial complex which has built up around the corps, ignore
well-established geological findings about how the beach system actually works.
Though his critique of corps policy coincides with that of other geologists, Pilkey's own theories
about coastal functioning are not well supported by scientific finding - just the thing that disturbs
geologists about coastal engineers. Within the geological community itself Pilkey is viewed as
something of an extremist.
Pilkey theorizes that the primary cause of coastal erosion today is shoreline development such as
buildings and parking lots. These structures, Pilkey believes, are the primary insult to natural beach
processes. Few coastal professionals accept this view, however. In fact, one of the few realizations
that unites both geologists and engineers (excepting the Army Corps of Engineers) is that dredged
and jettied navigation channels - not coastal development - cause most of the erosion problem on
modern shorelines. (The Corps contends that most coastal erosion today is "natural and
Pilkey adheres to a theory that all beaches and barrier islands migrate landward in response to the
moderately rising sea levels we see today. The scientific record, however, demonstrates just the
opposite. Offshore barrier islands and mainland beaches have steadily expanded seaward over the
past 5000 years in response to moderately rising sea levels. For well - known reasons, beaches
have been migrating seaward, not landward, in the present geologic era (late Holocene) before the
trend was reversed by ubiquitous navigation projects.
The beach ridge plain left behind as beaches grew seaward (successive sand ridges, parallel to the
shoreline, which are studied much like growth rings of trees) provides simple proof that Pilkey's
"landward migration" theory is largely incorrect for this geological era.
Only the narrowest, most ephemeral barrier islands, such as sections of the Outer Banks in North
Carolina (Pilkey's own backyard) may naturally migrate landward under present conditions. This
type of island, however, represents a vanishingly small percentage of the world's barrier islands.
Furthermore, even on the very narrow Outer Banks island chain, the beach ridge plain indicates
that much of this island chain has been migrating seaward under present geological conditions prior
to the introduction of large-scale navigation projects along the Atlantic Seaboard.
Pilkey dismisses dredged inlets as the primary cause of today's coastal problems (no doubt to the
joy of the Corps, which has installed many navigation projects). Rather, Pilkey misapplies the
"landward migration" theory of shoreline functioning, believing it applies to all beaches and barrier
islands under present oceanographic conditions. He consequently identifies coastal development as
the primary cause of erosion on modern shorelines. Without development to ³fix² island positions in
place, he argues, barrier islands would maintain their sandy mass as they "rolled over" and migrated
On naturally expanding shorelines, however, such as existed prior to intensive navigation projects,
coastal development would not be expected to significantly interfere with beach processes.
Homeowners Sue Army Corps of Engineers.)
Just as coastal engineers center beach restoration programs around what geologists call a
data-poor and scientifically contraindicated "river of sand" theory, the popular nemesis of coastal
engineers, Orrin Pilkey, adheres to a "landward migration" theory for natural beach and barrier
island functioning that is poorly supported for current geological conditions.
Press accounts of American coastal policy over the past decade report only two relatively extreme
positions. The Army Corps vs. Orrin Pilkey - in what amounts to a false debate. Missing is a
spokesman for primary scientific findings about natural coastal processes in the present geological
era. These findings differ substantially from the data-poor theories of both Pilkey and the Corps.
A representative example of the false debate is found in a recent Sarasota Herald Tribune article,
where Pilkey calls the Army Corps "not technically competent." The Corps, through leading
engineers James Houston and Bob Dean, calls Pilkey's ideas "simplistic and unrealistic." Ironically,
both Pilkey and the Corps are correct about each other.
The Corps (Houston) complains to the paper, "if the Corps recommends a structure, Pilkey says it
should have been beach fill. If we do a beach fill, he says we should have done nothing. The Corps
can't win." In fact, though Pilkey opposes all structural approaches to shoreline stabilization (his
geological colleagues joke "he never met a structure he didn't hate") Pilkey often supports beach
dredging. He apparently views dredging as problematic but the least of evils. Neither side,
however, notes that shoal removal and channel deepening implicate dredging of all kinds as the
primary insult to the natural system.
The Corps often relies on engineering theory in fielding complaints about the longevity of their
beach restoration programs. In response to Pilkey's scorn for a short-lived Folly Beach, South
Carolina project, for example, Houston notes "the beach is still largely there - it's like a big lie,
Pilkey shows no data to back up his claims." What Houston failed to tell the reporter is that the
Town of Folly Beach itself considers the project an unmitigated failure in terms of both recreation
and storm protection. The dry beach was soon lost, and coastal geologists monitoring the site
agree that the sand has generally vacated the nearshore as well. But because engineering theory
states that it is impossible for sand to exit the submerged section of the beachface, Houston assures
the reporter that the beach is "still largely there," submerged just offshore.
Houston further defends dredge maintenance programs by noting "roads wear out, and you repair
them - it's the same argument with beaches." The fact that the Corps' leading engineers compare
roadways to dynamic natural systems is telling.
One area where both Pilkey and the Corps agree is that you can't work proactively with natural
sedimentological processes. Pilkey claims we should retreat from a "naturally" migrating shoreline.
The Corps fights what it calls "natural and inevitable erosion" by armoring the coast (which
exacerbates erosion) and by throwing more and more dredging at an erosion problem that simply
did not exist before dredges began altering seabeds.
Dr. Pilkey is often appreciated by environmental groups for aligning with those coastal geologists
who point out that the Corps is using design parameters that do not work. To one degree or
another, Pilkey carries on where Stewart Udall, former Secretary of the Interior, left off. Udall
likened the Corps to the brachiosaurus, "a giant, water-loving creature with less brains per pound
of flesh than any other vertebrate."
Pilkey's own misapplied coastal theories, however, lead him to lobby for an abandonment of
coastal property. "Let nature take its course" is the popular environmental slogan based on Pilkey's
theories. This, however, would not solve an erosion problem caused by dredged channels. Nature
will not take its course until navigational cuts are either sealed or effectively neutralized by
technology designed for the purpose. ( For related information see
What's Wrong with Dredging,
Primary Causes of Erosion,
Sea Level Rise and Coastal Restoration,
Coastal Restoration Technology.)