Battle of the Beaches

© Dr. Christopher J. Woltemade/Shippensburg University

Every summer, millions of Americans hit the beach. Some two-thirds of the Earth’s people live within 50 miles of the sea, and nine of the world’s 10 largest cities are in coastal zones. U.S. shorelines support a third of the nation’s jobs. But coastal populations around the world are growing faster than the global population as a whole, and this is particularly true in the U.S.

With such increased human activity comes intensifying threats to this fragile environment. Between 1983 and 1991, 90 percent of all construction in Australia took place within the coastal zone. Around the world, more people often means more pollution from industrial and household wastes and agricultural run-off, more oil spills, more water intakes by power plants, and diversions of water for dams, irrigation and desalinization.

Not only do human beings have a powerful attraction to that narrow strip of land between earth and sea, but also countless wildlife depend heavily on it. About two-thirds of all fish caught for human consumption spend their early lives in coastal ecosystems. As Beth Milleman of the Washington, D.C.-based Coast Alliance puts it, “The coasts have been described as underwater rainforests because of the incredible diversity of life they contain.”

Recently, I met some friends for a day of fun and sun on a beautiful beach on Long Island, New York’s southern shore. We had the privilege of enjoying the spectacular Atlantic views from the comfort and exclusivity of a private beach club. While the changing rooms, lounge chairs, swimming pool and beachfront bar were all nice amenities, I couldn’t help but wonder about the impact of the club’s prominent groins, which are walls that run perpendicular to the shoreline. “The groins are wonderful: They prevent loss of our beach’s sand from erosion,” explained my friend’s father. But what was the impact of such structures farther up the shore, on the public beaches and waterfronts frequented by lower income, and often minority, New Yorkers without the resources to build groins of their own?

True, beach erosion has both human and natural causes. In fact, without erosion, there would be no beaches in the first place. It is the dynamic processes of wind and waves that develop and reshape coastal settings. But a host of human activities have greatly accelerated this natural process, often to considerable detriment. Overbuilding right to the water’s edge (a practice often protected by federal flood insurance) is one problem, as is a rapid rise in sea level (a well-documented phenomenon, even if you don’t believe in human-assisted global warming). The Environmental Protection Agency estimates that the sea level of U.S. waters will rise two feet over the next century.

Another problem is the widespread dredging of inlets, which are designed to let people take their boats from many places on the shore into open water. But as a 2002 article in the Fort Myers, Florida News-Press explains, “The deeper channels [of inlets] have swifter currents, so instead of moving to the next island, sand in longshore currents [which run parallel to the shore] is blown out to sea on outgoing tides or sucked into the estuary on incoming tides.” This process means many beaches next to inlets can become severely eroded. The News-Press reported that inlets on Florida’s Atlantic coast are responsible for 80 to 85 percent of all beach erosion.

Per Bruun wrote in The History and Philosophy of Coastal Protection, “It is a deplorable fact that all coastal protective measures apart from artificial nourishment (may) have an adverse affect on adjoining shores.” While groins and the similar jetties do result in a buildup of sand on the side updrift of the longshore current, they prevent sand from flowing down the coast, causing accelerated erosion of the downdrift side than would occur naturally. This process is called “sand starvation.” The News-Press concluded, “When that happens, people on the sand-starved beach put in their own groin, which starves the next section of beach and prompts another groin, and then another, until miles of beach become a vast and unattractive groin field.” Scott L. Douglass, author of Saving America’s Beaches and a professor at the University of South Alabama, adds, “If you want to make a beach disappear, build jetties and seawalls [which are horizontal to the shoreline].”

To learn more, there"s an extensive section on beach erosion and sand replenishment in E"s new book, Feeling the Heat: Dispatches from the Frontlines of Climate Change (Routledge), which is available online.

So what are concerned beachgoers and private property owners to do when they see their favorite shores under siege from wind and waves? Douglass suggests replenishment, in which truckloads of sand are brought in from another location. The procedure can be expensive, however. Another technique is to move buildings farther back from the water’s edge. Some forward-thinking places in the U.S. already have regulations that mandate a sensible distance between the shoreline and new construction.

Of course, in many cases people may need to advocate for removal of offending structures, such as excessive inlets or unnecessary dams that block river sediments from entering the coastal zone in the first place. Further, protecting and restoring natural barriers to erosion, such as dunes, wetlands and vegetation close to shore, should always be a high priority, because it is a cost-effective way to protect beaches. Such measures provide other benefits as well, especially to wildlife and sightseers.

As the sun sets in a spectacular display of orange and red, brown sandpipers run briskly up and down the shoreline, their wet feet glinting in the fading light. A small white jellyfish, stranded earlier on the beach, is lifted back out to sea. Beachgoers pack up their belongings and head back inland. Perhaps the ultimate solution to erosion and sea level rise will be to begin to truly accept nature as a dynamic, changing environment, and to learn better how to live in harmony with the air, land and sea.