Listen to the UVA Today Radio Show report on this story by Fariss Samarrai:
September 7, 2011 — When University of Virginia environmental scientist Arthur Schwarzschild wants to illustrate the dynamics of Virginia's Eastern Shore barrier islands, he points to a location where a boat – a large trawler – rests upon a barrier island beach, and a former beach house is standing out in the surf.
"A boat on the land and a house in the water. It says a lot about how the water and the land interact here," said Schwarzschild, site manager for U.Va.'s Anheuser-Busch Coastal Research Center. "There's an ongoing battle between the shore and the sea, and the ecosystems that develop at those junctions are part of the story."
The Anheuser-Busch Coastal Research Center is home to a Long-Term Ecological Research project conducted since 1986 by environmental scientists from U.Va.'s College of Arts & Sciences. The state-of-the-art facility is located on the Eastern Shore mainland in the town of Oyster, about 15 miles north of the Chesapeake Bay Bridge-Tunnel.
Change is natural to barrier islands, and change comes particularly quickly to the barrier islands of the Eastern Shore. These islands are made up of a very fine grain of sand and have the highest rates of movement on the East Coast.
Continually altered by wind and waves, currents, tides, rising sea levels, storms – including hurricanes and nor'easters – and the pounding of about 14,000 waves per day, most of the islands on Virginia's Eastern Shore are part of the Nature Conservancy's 45,000-acre Virginia Coast Reserve. This is vintage wild seacoast, uninhabited by people, accessible only by boat; serving as a sanctuary for large populations of migratory waterfowl, shore birds and song birds.
The islands are a natural laboratory for long-term studies of how land and water interact. Storms are a big part of the process – and afford an opportunity for environmental scientists to study rapid change.
"The barrier islands within the Virginia Coast Reserve are a great place to do research," said John Porter, a U.Va. environmental scientist who has been conducting small mammal research on the barrier islands since 1977, when he was a U.Va. graduate student. "Because the islands are changing so rapidly, we can do comparisons over time. One part of an island may be relatively young – deposited by a storm 20 years ago, for example – and another area of the same island may be centuries old. This allows us to look at everything from soil processes to vegetation change and movements of animal populations."
Researchers at the Virginia Coast Reserve monitor and study sea-level rise, storm frequencies, groundwater flow rates, marsh growth and erosion, water chemistry, finned fish and shellfish populations, vegetation (including a sea grass restoration project with the Virginia Institute of Marine Science) and bird and mammal populations.
When Hurricane Irene approached the region in late August, Schwarzschild and his staff readied for a large and potentially destructive storm. They moved their fleet of boats and trucks onto high ground, removed debris, secured and stowed equipment and downloaded data from remote monitoring instruments positioned at various sites on the barrier islands and on the Eastern Shore mainland.
"Originally Irene was bearing down on us as a Category 3 storm," Schwarzschild said. "By the time it arrived, though, it had been downgraded to a Category 1 and it passed by mostly offshore."
During the storm, the instruments recorded real-time data – tide levels, wind speeds and directions and barometric pressure. Cameras mounted on the dunes and in the marshes produced hourly photographs, as they continue to do in weather fair and foul.
Seas were about 4 feet above normal because of the storm surge and a high spring tide. Other than some wrack (dead marsh grass and other debris) that piled up on the station's dock and shoreline, and one antenna that blew over but was not damaged, there was little effect at the research center.
A few days after the storm, Porter surveyed the region by air. He found little change to the islands, except several areas of overwash – places where the surf had pushed up over the beach and dunes and had flowed down into the salt marshes behind.
"I was looking for conspicuous change driven by the storm," Porter said. "I videotaped the shorelines throughout the Virginia Coast Reserve so we can identify places of change for our researchers to go back and assess up close."
The high spring tides helped the marshes weather the storm. The high waves spent their energy over the marshes instead of crashing against the marsh edges. There appeared to be little or no change to the structure of these sensitive areas.
Because storms are a natural part of the shaping process of barrier islands, "damage" is a word that applies more to the effects of storms on people than on natural systems.
Hurricane Irene left significant damage on the Outer Banks of North Carolina, home to more than 40,000 people and a vacation destination for about 7 million visitors each year. Large sections of Highway 12, the primary road through the Outer Banks, were washed out and two new inlets formed north of Oregon Inlet.
"Barrier islands require change to remain barrier islands," Porter said. "If we try to arrest these processes by trying to keep sand in particular places to protect houses and businesses and roads and power lines, if we try to armor the coast by building groins and pumping in sand, we disrupt the natural flows of sands and can actually cause erosion to other areas."
The barrier islands of the Eastern Shore are small and have numerous inlets between them, allowing water to flow readily between the sounds and the ocean. The Outer Banks, by contrast, are very long and mostly thin islands with few inlets between. They are far more prone to washouts than the relatively stubby barrier islands of the Eastern Shore. With few inlets between the banks, ocean water that is pushed into the sounds by major storms frequently washes back out over the islands, damaging roads, flooding property and even creating new inlets that must be either filled or bridged.
"Changing the environment is a costly thing," said Bruce Hayden, a U.Va. climatologist. "It is costly whenever we put bulldozers on land to shape a landscape that naturally shifts on its own. When we do that, we have to pay certain prices, whether through the loss of property and the price of insurance and sometimes the loss of human life, and the ecological effects. But people like to live in exciting places – along the coast, along rivers – and we find ourselves continually defending our infrastructure. We can do this as long as we are willing to pay the costs."
By studying long-term alterations to the coastal landscape, researchers are getting much more than mere snapshots of nature in action, but rather a continuously running motion picture, so to speak, of ongoing processes; how geology and ecology interact. What they are learning from past and present events can help them make predictions regarding possible future changes to coastal environments.
"Because the barrier islands within the Virginia Coast Reserve are protected, we are able to observe natural processes as they naturally occur," Porter said.