Beach Erosion Poses Problems for Coastline Management

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Debris piled up along the beach at Maho Bay in October.

Vacationers who are now just arriving at the beaches in the Virgin Islands National Park are in for a bit of a shock. Gone are most of the palm trees, sea grapes, and maho trees that have provided welcomed shade in the heat of the day.

The vegetation was a victim of Hurricane Irma’s powerful storm surge that brought massive destruction to natural vegetation, as well as to roads and buildings, and raises complicated questions of how to manage shorelines.

After the storm, the National Park Service went into high gear to clear shoreline roads and beaches of storm debris. But debris removal required constant judgment calls, according to Darrell Echols, acting superintendent of the Virgin Islands National Park. Some well-intended efforts to clean up the beaches could result in much more serious damage by erosion further down the line.

Trunk Bay beach still has a four-foot high berm composed of “root balls and cockeyed vegetation” that work crews compiled as they cleared the grounds.

“If we didn’t [create the berm], the beach would have eroded toward the parking lot,” Echols explained.

Beaches naturally change throughout the seasons. In general, when winter swells pound away at the shoreline, beaches tend to diminish. In the summer, gentle waves lapping at the shore tend to bring sand back, according to Echols.

VINP’s acting Superintendent Darrell Echols.

“What stabilizes a shoreline is some form of protection along the beach face. If there’s just sand, it will quickly be removed and rearranged,” he said.

Sometimes the sand moves down the shoreline, and sometimes it goes into deeper water.

“When we have vegetation removed, we see a retreat of the beach. If we cut the trees until they die, or damage the root system in our gusto to groom a beach, we can lose the beach, or like along Maho Bay, the road.”

The North Shore Road, which comes very close to the beach at Maho Bay, was completely undercut in stretches by storm surge, according to Echols.

“We tried hard not to remove any living vegetation to help stabilize the sand,” he said.

Their efforts seem to be paying off. The two-foot drop-off has slowly filled in during the five months since the storm.

But more drastic efforts to remove natural debris at Oppenheimer Beach, a part of Hawksnest Bay owned by the territory and not managed by the National Park Service, has caused some alarm.

The house at Oppenheimer Beach, which is managed by the Virgin Islands Department of Sports, Parks, and Recreation, was in the final stages of re-construction when Hurricane Irma struck. Overall the building survived with minimal damage, but the sand in front the building and the soil around it were washed away.

“Irma breached where the soil had been and took most of the remaining trees on the front line,” said Eleanor Gibney, an expert on native species who owns property nearby at Hawksnest Bay.

Oppenheimer Beach house, once surrounded by vegetation, now stands exposed on the beach. (Photo by Eleanor Gibney)

“After the storm, there were still several coconut trees and a few hardwoods that were alive and coming back,” said Gibney. But in January, crews working with Ceres, the company contracted to remove debris, cut down the remaining live trees surrounding the building, according to Gibney.

In early February, debris-removal crews returned and removed all the roots balls, precluding the possibility of regrowth of pigeon berry and genip trees which had flourished there before the storm.

Elroy Hill, deputy director of Sports, Parks and Recreation on St. John, defended the territory’s efforts to clear the property. He said debris-removal crews were funded by FEMA when he territory determined that liability issues could arise if the debris remained.

Darrell Echols said Ceres had also been contracted to remove woody debris along the roads within the Virgin Island National Park; at one point, one of its sub-contractors had been overzealous in its efforts, unnecessarily removing some vegetation along the North Shore Road by machine.

“The park started getting reports that Ceres had removed all the large vegetation except for the biggest trees, making it seem that it was acceptable to park along the road in places where parking was prohibited, thus exposing artifacts, ruins, and rare vegetation to damage,” Echols said.

Park officials met with Ceres management and with the U.S. Army Corps of Engineers, which has overseen debris removal in the territory since Hurricane Irma.

“Ceres acknowledged it was normal stuff for them to do, but this is a National Park, so we have higher expectations of what can be removed,” Echols said. “We came to an understanding that only ‘dead and down’ vegetation could be put in piles and removed.”

Since the meeting in January, Echols said, “The Corps and Ceres have been very responsive. They’ve done exactly what we’ve wanted them to do. Ceres has helped us maintain our roads, and we very much appreciate them.”

The Oppenheimer Beach driveway. (Photo by Teri Gibney)

Gibney said she wishes more oversight had taken place at Oppenheimer Beach when Ceres crews came through in January and February. The house at Oppenheimer Beach now sits upon the rocky shore with only one solitary cycad tree to provide shade. A nearby patch of sand remains denuded of any sign of vegetation.

Gibney says the difference in the foliage before and after the storm is apparent.

“I have a photo from 1994 showing the Oppenheimer house surrounded by trees, like seagrapes and almond trees,” she said.

However, the beach in front of the Oppenheimer house has been eroding for decades, according to Gibney. She remembers when the sand extended for some distance to the east of the house, where now only rocks remain.

“Oppenheimer Beach eroded probably because the reef in front of it died,” she said. Primarily composed of elkhorn coral, the reef mitigated the effect of wave action against the sand. Gibney said the reef started dying in the early 1980’s when the Myrah Keating Smith Clinic was built in Susannaberg. At that time, fill removed during construction was pushed into the top of a gut on the ridgeline above the beach. Then in April 1983, St. John was deluged with 18 inches of rain, and two inches of silt was deposited on the reef, according to Gibney.

“It was very dramatic. The elkhorn coral died within six months. It got the park to start looking at the effects of sedimentation.”

Elroy Hill, from the Department of Sports, Parks, and Recreation, said the territory might bring in sand to replace sand washed away at Oppenheimer Beach by Hurricane Irma.

But Echols said the process of replacing sand is far from simple, especially in a National Park where guidelines set forth in the National Environmental Policy Act (NEPA) must be followed. Even in sites not within the National Park, like Oppenheimer Beach, the territory must comply with NEPA guidelines if the sand is replaced using federal funds.

Echols, who has spent much of his career with the National Park Service in shoreline parks in Texas and North Carolina, said finding the right kind of sand from the right source is critical.

“You have to consider the sand composition, its size, its interstitial spaces that support bacteria which becomes a food source for shore birds. And you have to be sure the sand doesn’t have any contaminants.”

Replacing the sand may not solve the problem because the next big storm may wash it away.

“In order to keep the sand, do you also put in jetties? Fences? Groins?” Echols asked. “The longer it takes, the more expensive it is. No one’s thinking of large engineering plans that can take five years to develop.”

In general, the park prefers to rely on natural processes, Echols said, but when some mitigation is necessary, planning is essential. The park is considering planting vegetation to protect infrastructure like roads and buildings, but exactly what can be planted will require input from experts.

“The plants [along the shoreline] have evolved over time because they can handle the environmental stress, the amount of salt, and rainfall,” said Echols. Even the same species grown in another location, like Florida, may not be successful because it has different genetic material. When we do restoration, we want to make sure the assemblage [of multiple plant species] is natural, and determining that takes time.”

The NPS Incident Management Team that responded immediately after the storm completed a preliminary report and recommended further study, according to Echols. The Virgin Islands National Park does not have a terrestrial biologist on staff, but Echols said there are people in the community who have the expertise. A funding source will have to be identified.

“I always tell people,” Echols said, “that coastal areas are the most challenging to manage.”

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