Orrin Pilkey and "Strategic Retreat"

Orrin Pilkey, the James B. Duke Professor Emeritus of Geology at Duke University, has long been opposed to dredging and filling to renourish beaches. He wrote about the reasons for his opposition in his 1996 book The Corps and The Shore (with Katharine Dixon, Island Press, Washington DC and Covelo CA ).

One would think that, as a champion of healthy shorelines, Dr. Pilkey would be a tremendous supporter of Holmberg Technologies' Undercurrent Stabilizer Systems, which have been shown in more than 100 installations to actually reverse the course of erosion, rebuilding beaches that had entirely disappeared.

Sadly, he is not. In a June 1, 2006, edition of the Wilmington , NC , Star-News, Dr. Pilkey said of Dick Holmberg, "This guy's wrong. It doesn't work." The article then goes on: the North Carolina shoreline isn't like the Great Lakes, parts of Florida , or the Persian Gulf where the system has been installed and seemingly worked . (emphasis added to show self-contradiction)."

He has also gone out of his way to falsely characterize Undercurrent Stabilizers, calling them groins (which they are not), saying they would cause downdrift erosion (which they have never done) calling them hard structures because they are concrete (failing to acknowledge that they are considered "soft" because they bury themselves in sand as the beach elevates and expands), and saying a prototype 1980s installation in Captiva, Florida, was "broken up in storms" (which is untrue-it was successful in regenerating an entire beach within two months of installation, before being removed to make way for a dredging project).

For some reason, Dr. Pilkey is more interested in defending his notion (upon which he has built his following and his career) that barrier islands must migrate landward, not seaward, than on even considering a method that has proved itself to be a way to solve, relatively easily and inexpensively, the critical erosion problems the world faces today.

"If left alone," Dr. Pilkey said during a September, 2005, radio interview with Earth & Sky, "if human beings don't affect them too strongly, [barrier islands] can move back and up as the sea level is rising, which is one of the reasons why the shoreline of these islands is eroding right now. It's because of sea level rise."

Dr. Pilkey thinks the way the islands migrate is through storms. "Storms deposit sand on top of the islands to make them higher than the sea level rise. And also, they deposit sand on the back side of the island. So you have a three-part process here in island migration. One is the erosion of the front side. Two is deposition of sand on the top of the island, making it higher. And three is deposition of sand in the lagoon, on the back side, which actually widens the island. So between those three processes, islands move back and up in response to the sea level rise."

He feels human development on barrier islands is to blame for erosion, and advocates "strategic retreat," the practice of abandoning shore side homes and businesses and allowing erosion to follow what he contends is its natural course.

But is erosion the beach's natural course?

In a 1998 paper rebutting false allegations Dr. Pilkey made against Undercurrent Stabilizer technology that same year, W.A. Janis wrote, "But most barrier islands have prograded [migrated] seaward in recent geologic history (over the past four to five thousand years) during moderate rates of sea level rise as seen today. Carbon dating studies determine the youngest beach ridges on barrier islands formed seaward of the older sand ridges. Beaches have thus been migrating seaward during much of their natural history." (emphasis added)

In fact virtually the entire geologic history of the state of Florida, going back hundreds of thousands of years, has been a process of dunes and seafloors building seaward.

In the July 15, 2006, Daytona Beach News-Journal, Ronald Williamson writes, "Dunes and seafloors are the land upon which we live." He wrote that there are four major ridges of relic dunes in Volusia County , and two in Flagler. "Atop the DeLand Highlands [the name of the largest line of ancient dunes] today," he writes, "the view east is across the eight- or 10-mile-wide Talbot Terrace, formed when the sea level was about 40 feet higher than now .. At that time, perhaps 250,000 years ago, the [DeLand Highlands were] part of a 20-mile-long barrier island of dunes ."

"If there had been cities and tourists here (about a mile east of the DeLand Municipal Airport on U.S. 92).there would have been hotels and sun-tanned people along a strip of beach from DeLeon Springs to Deltona. Daytona Beach would be submerged, 20 miles offshore..

The column continues: "The Silver Bluff [Halifax Medical Center and Mainland High School sit atop it] was formed at the end of the last ice age, as little as 25,000 years ago, when the sea was five or six feet higher than it is now."

To take Williamson's article into the present and future, the barrier islands beyond the dredged Intracoastal Waterway (a project of the Army Corps of Engineers to create an inland north-south water route for the military) should be continuing this expansion process by building more and more beaches and dunes-at the rate of about two feet per year according to natural historical patterns. And in a few hundred thousand years Flagler Beach may be a small city miles from the beachfront.

The article Dr. Pilkey vs. The Army Corps of Engineers from Holmberg Technologies' website (www.erosion.com/armycorp.asp ) points out that this 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."

If coastlines are building,
why do they seem to be receding?

Janis continues: "The introduction of dredged and jettied navigation projects represents a significant modification to delicately balanced island chains. The seas have long been rising at rates similar to those seen today, yet beaches and barrier islands generally prograded [advanced] seaward until sand depletion reversed the trend.

"When a coastline's sediment supply is diminished, shorelines become progressively less able to form beaches..as the beach profile steepens in response to sediment depletion, it becomes increasingly energetic and progressively less able to hold sand." [This is precisely what has happened to Flagler's Beach.]

Perhaps Dr. Pilkey bases his global theory on a very small part of the world. Janis continues: "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.

"Dr. 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, (he).identifies coastal development as the primary cause of erosion on modern shorelines. Without development to "fix" island positions in place, he argues, barrier islands would maintain their sandy mass as they "rolled over" and migrated landward.

But University of Florida researcher Carrie Suter, in a study of eight beaches-four developed, four undeveloped-conducted after 1995's Hurricane Opal, found among them no difference in storm recovery. Ms. Suter said she had been hoping the undeveloped beaches would look better than the developed ones, but the data did not show that.

Which demonstrates, according to Jerry Berne of Sustainable Shorelines, Inc., that "it is not what is built on shore that is causing erosion, it is what we do in the water."

Dr. Pilkey (who denounced the Suter study) has been quoted as saying " There's just a bunch of well-off people who have been very imprudent, even stupid, and they've built their buildings right next to a beach. They're asking us to pay for restoring the beach when all we have to do is tell them to move their buildings and the beach will be restored."

Holmberg Technologies has shown us another way: Restore the natural sand patterns that allow the oceans to continue building beaches as before. Not only can erosion be reversed and beaches and dunes regenerated, but the barrier-island and beach life enjoyed by human beings — as well as the vanishing habitat and ecosystems of such concern to environmentalists — may continue unabated.

Which idea would you choose?

(photo credit Earth & Sky)
Orrin Pilkey