Report challenges old understanding of beaches

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The county’s defense was brief but incendiary when attorneys for the county and the plaintiffs—Southampton Town and a Sagaponack property owner—rested their cases last week in the trial in federal court in Brooklyn over beach erosion blamed on the county’s Georgica groins.

As expected, the crux of the county defense was a report prepared for the county by Dr. David Aubrey, a coastal geologist from Woods Hole, Massachusetts. His testimony outlined the findings of a detailed study of the movement of sand off the southern shore of the South Fork.

According to the study, sand generally flows east along the south shore, not west.

Mr. Aubrey’s report ran directly counter to what has long been the conventional wisdom about beaches along the South Shore: that near-shore currents carry sand from east to west along the shoreline—an effect known as littoral drift.

Mr. Aubrey instead said that just the opposite was true, particularly in the area around Georgica Beach and Main Beach in East Hampton, where the four stone groins were built in the 1950s and 1960s to catch sand and build up beaches in front of an influential property owner’s home.

Mr. Aubrey could not be reached for comment after the trial but, according to the text of his report, he argued that sand in the area of Georgica flows both east and west, with the overall effect being “a relative state of equilibrium.” In other areas, he says the majority of sand moves to the east, not west.

“It’s a pretty amazing claim,” said Gary Ireland, the attorney representing his mother, Cynthia Ireland, a Sagaponack homeowner, in the lawsuit against the county. “He even says that no other studies have ever shown this. He’s telling the Army Corps and a dozen others that they got it all wrong. If he had this great revelation, why hasn’t he told anyone, I wonder?”

A decision in the case may not come for weeks and will be handed down by the judge. The trial began on March 24. Although both sides rested their cases last week, testimony by Southampton Councilman Steve Kenny was postponed until sometime this week.

A report by the Army Corps of Engineers in 1964, which was also submitted as evidence in the trial, shows that federal engineers at the time warned that the groins would cause erosion to the west and could lead to lawsuits by homeowners.

“There’s been a dozen [studies of sand movement] done and they’ve all said the sand is moving to the west,” said Aram Terchunian, a Westhampton coastal geologist who testified on behalf of Southampton Town in the trial. “It’s like telling them that the theory of gravity is a fallacy.”

Attorneys for the county did not return phone calls seeking comment and have declined to discuss the lawsuit throughout the two years of preparation before the recent trial.

Despite the evidence offered that sand movement is at equilibrium around Georgica, Mr. Aubrey in his report does acknowledge that there has been a scouring along the beach to the west of the groins. But he says the effect extends only some 900 feet west. The homes in Sagaponack and eastern Bridgehampton, where once vast dune systems have been erased by erosion in the last 30 years, are 10,000 feet or more to the west of the last groin.

Ms. Ireland and Southampton Town both filed lawsuits claiming the groins caused the erosion by blocking the westward flow of sand and have demanded that the county pay to pump thousands of tons of sand back onto the beaches. The county has claimed the groins could not be responsible for the erosion.

Mr. Aubrey’s report claims, as one point to back his theory about eastward sand movement, that observations around Montauk show that “Montauk Point has been growing out toward the east.” The report continues with the conclusion, “Since the only source of sand is from the west, this growth indicates that the net longshore sand transport is from the west to east at Montauk Point.”

That assertion should come as a surprise to those who have been laboring for more than 30 years to keep the Montauk Lighthouse from falling into the ocean because the bluff has eroded hundreds of feet since the lighthouse was built in the late 18th century.

“I’m a little bit shocked by that,” said Greg Donohue, the director of the on-going erosion control project at the Montauk Lighthouse. “I‘ve never heard anyone say that sand migrates west to east. It can migrate east in the summer but that is a seasonal thing, when the southwest winds are pushing it around.”

Mr. Donohue noted that, in all of Montauk, east of Hither Hills, the beaches have been steadily eroding for most of the last 30 years. He noted that beaches all over the East End have been eroding steadily except in East Hampton Village, where the groins to the west have kept the beach to the east broad and deep—evidence that the groins are working as they were intended to. He questioned, however, whether the effect of just a few groins could have as far reaching an effect as to cause the erosion in Sagaponack.

“I was there during the debacle at Potato Lane in the 1990s; it was a mess,” he said, referring to a time when homeowners feared their houses would collapse onto the beach. “Those groins are definitely keeping the village’s beaches stable. The scouring effect is there but 8,000 or 10,000 feet [to the west] might be a stretch.”

Larry Penny, director of the East Hampton Town Department of Natural Resources, noted that surveys being conducted by his department seem to counter Mr. Aubrey’s claims. They show that the dune line in Montauk has been retreating steadily in the last 10 years.

Measurements conducted by surveyor William Walsh in 1999, 2005 and 2007 show that the bluffs between Shadmoor and Montauk Point have been retreating an average of about 10 feet over that time period.

“Certainly Montauk is not gaining any sand,” Mr. Penny said. “I don’t know where he would be saying it is going. We’ve lost 200 feet at the lighthouse. The north side is losing material even faster than the south side, I would imagine.”

But Mr. Penny concurred with Mr. Donohue and Mr. Aubrey’s report that the groins at Georgica are unlikely to be the sole cause of the severe erosion problems in Sagaponack.

“Sagaponack’s problem can’t be just the groins,” he said. “It’s hard to believe that those little groins are responsible for something miles away.”

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