Cape Hatteras National Seashore gains approval for beach nourishment plan/NPS file

Turbulent seas long have created problems for Cape Hatteras, a long barrier island off the North Carolina coast that is home to the country's first national seashore. Pounding waves and storm surge related to hurricanes and nor'easters shift beaches around, and even erase them.

Decades of those natural processes have meant dune erosion and almost annual repairs to the highway that runs down the scenic island that lures beachgoers, surf casters, and summer vacationers.

Against those impacts, a plan by Cape Hatteras National Seashore has been approved to allow state and local governments to haul in sand from the seabed, when needed, to buttress the island against storms. It's a 20-year plan that could somewhat disrupt wildlife and marine life, but which includes about 13 miles of beach to serve as a control of sorts against which to measure the impacts of dredging or pumping up sand and dumping it onshore.

"It's a great plan, and the reason that it is, is this is an opportunity, without a permit on my desk, to kind of sit back and say, we know these projects have some beneficial impacts. We also know they have some negative impacts," said Cape Hatteras Superintendent Dave Hallac. "If we were able to design a series of conditions, mitigations, to ensure that these projects in the future really minimize all the negative things and really maximize the beneficial impacts, what would the framework look like? And that's what we did."

But it also might be viewed as folly to some, as barrier islands by their very nature move about, and the growing potency of the Atlantic hurricane season could erase any beach nourishment work in a matter of days.

"The story here really is the pressure is being put on that particular park by development that surrounds it," said Rob Young, director of Western Carolina University’s Program for the Study of Developed Shorelines. "Left to its own devices, that superintendent would not really be very interested in putting beach nourishment sand on any of those beaches to try to hold the shoreline in place. The Park Service in principal has a policy to allow natural processes to find their own way. 

"But the problem is you have all of these communities around the park, the park does not control the road, Highway 12, and so there's a lot of pressure to hold the shoreline in place where there is civilian infrastructure, resort homes and where the road is," he continued. "And so, I think Dave Hallac was worried that he and his staff would be spending the next 10-15 years just going through the NEPA (National Environmental Policy Act) process of approving or disapproving requested beach nourishment projects from communities like Avon and Buxton and from the state of North Carolina for Highway 12."

While Young is correct that the Park Service generally prefers to let natural processes run their course, in the approved Sediment Management Framework Environmental Impact Study the agency also points out that intervention is allowed in several cases, such as to "restore natural ecosystem functioning that has been disrupted by past or ongoing human activities ... or when a park plan has identified the intervention as necessary to protect other park resources, human health and safety, or facilities."

"Where shoreline processes are 'natural' (that is, not altered by human activities or structures), the NPS policy is to allow those unaltered processes," the document points out. "However, where shoreline processes have been altered by human activities or structures, the NPS policy is to investigate alternatives for: mitigating the effects of those activities or structures; and restoring natural conditions."

Humans have indeed altered the environment of Cape Hatteras. As the document notes, "At the seashore, human activities and structures have contributed to the alteration of natural shoreline processes. These activities and structures include dredging of navigation channels, hardened structures such as groins, dune building, overwash scraping (the process of removing/scraping overwash sand deposition off the road or other built features), and relative sea-level rise resulting from the warming temperatures caused by human-driven emissions. Sand fencing, grass planting, and dune building occurred in the 1930s and continued into the 1960s at the Seashore. Beach nourishment began in the 1960s and continues today. These human activities are changing the pace, magnitude, timing, and other aspects of natural ecosystem processes at the seashore."

Further complicating things at Cape Hatteras is climate change, which is driving more potent hurricanes and sea level rise. The plan adopted by the National Park Service will help protect Highway 12 from being washed over and washed away by future storms, said Hallac last week during a phone call. The plan, he added, also allows for habitat restoration.

"I can have you stand in places where we have lost more piping plover habitat in a matter of ten years, than even still exists at the park," the superintendent said. "And so, we have agencies like the Army Corps of Engineers coming to us saying, 'We're dredging one area, do you have any places to put this sediment that would benefit species, endangered species, or ecosystems,' and the answer is yes, we do. Because you talk to most of the scientists that work on things like shorebird conservation at Cape Hatteras Seashore, and habitat is absolutely limited.

"And we don't have a naturally functioning barrier island ecosystem like they have just down the coast at Cape Lookout, where wash-over events occur, the island can migrate."

The plan won't cost the Park Service anything to implement, Hallac said, as state and local entities would pay for the work when it's called for.

"This is a framework that we put into place recognizing that beach nourishment is going to be continually proposed in the future. This is a framework that allows us to avoid and minimize any of the negative impacts that come along with a beach nourishment project," he said. "We're not proposing to perform any projects ourselves."

The plan also provides for roughly 13 miles of beach, in five sections, to serve as control zones. Project managers for beach nourishment projects would have to monitor conditions at their site, and at "an untouched reference area," before and after the project to measure any impacts.

"Those comparisons may provide information that influences future modification of the frequency, timing, and other methods associated with nourishment projects," the document adds. Indeed, it also states that "if monitoring data demonstrates that recovery is not occurring at a project site, then a permit would not be issued until recovery metrics are met."

Young raised concerns that repeated beach nourishment work in the same area could eventually lead to ecosystem problems.

"I think the basic problem is for shorebirds. When you place the project on the beach it kills all the infaunal organisms, and shuts down foraging for shorebirds for a certain amount of time," he said. "And if you never did it again, the ecosystem would recover. But that's not how it works. You have to do it over and over and over again forever, because it's not a permanent solution. So, if you look at beaches that have repeatedly been renourished, there's a long-term cumulative degradation in that habitat."

Additionally, the scientist also pointed out that beach nourishment projects could be wiped out rather quickly by storms.

"It could go in less than a year," said Young. "You get a nor'easter that parks off the coast for two or three days, those things just eat beaches."

According to the EIS performed for the plan, sea-level rise at points along the national seashore is approximately 5 millimeters (0.19 inches) per year. Beach erosion rates at Cape Hatteras have reached 10 feet, and sometimes more, per year and are expected to continue at that rate. With 67 miles of beach at the national seashore, erosion losses of "5 to 10 feet per year over 20 years is equivalent to 35 to 70 million cubic yards" of material.

"In comparison, beach nourishment under (the adopted approach) may help maintain the continuity of the barrier island system at a management scale (months to years) by increasing or maintaining the volume of sediments available for erosion along some sections of the beach, dune, and sound side shorelines," the document states.

The plan also limits beach nourishment work to no more than six miles per year within the national seashore, with repeat work allowed every three years.

Though the plan anticipates that beach nourishment work would impact shorebirds and sea turtle nesting and hatchling emergence, "it is anticipated that mitigation measures associated with (the approved alternative) would limit adverse impacts to nesting sea turtles."  Some of that mitigation calls for removal of sea turtle nests from within "a sediment management study area before or during construction" to areas outside of the project.

Since dredging at borrow areas offshore could also impact sea turtles, monitors would be placed on ships to watch for them.

There are nine villages, including Nags Head, Rodanthe, Waves, Salvo, Avon, Buxton, Frisco, Hatteras, and Ocracoke, located adjacent to or within the seashore.