By Stephen Leahy
02:00 AM Jun, 02, 2006 WIRED NEWS
Beach cities around the country are fighting to save their coastlines by dredging and dumping millions of cubic feet of sand on their shores. But environmentalists say it’s a futile endeavor.
San Diego, for example, dumped 54 million cubic feet of dredged sand on 12 badly eroded beaches in 2001 — the biggest beach-replenishment project ever attempted on the West Coast. Most of the sand was gone in two years.
“Dredging sand from someplace else for beach replenishment is a temporary fix because the waves will simply wash it away again,” said Rick Wilson, coastal management coordinator for The Surfrider Foundation, a nonprofit environmental organization.
Some San Diego beaches will be worse this year than they were before the project began, said Rob Rundle, project manager of the San Diego Regional Beach Sand Project. “That’s because there hasn’t been any additional replenishment since 2001. It has to be an ongoing effort.”
That would mean dumping another 54 million cubic feet of sand every other year, at a cost of about $15 million, he said. But there’s no funding to do it. “People expect beaches to be there but they don’t want to pay for them,” he said.
As global warming raises sea levels and powerful storms sweep sand from shores, pumping and dumping sand onto beaches has become a billion-dollar fix — temporary though it may be — along both coasts. Virginia Beach completed a $120 million beach-replenishment and sea wall project in 2002. Between 1995 and 2006, 17 states spent $1.25 billion in federal taxes on beach nourishment, according to Marlowe and Company, which lobbies Congress for sand money on behalf of communities. States and local municipalities spend hundreds of millions more.
“Beaches are America’s top tourist destinations and buffer shoreline properties from storms,” said Paul Ordal, vice president of Marlowe & Company. “For every dollar invested in beach nourishment, you get another three to four dollars back,” Ordal said.
More-powerful ocean storms will pound beaches in the future, according to study results reported by Purdue University’s Climate Change Research Center. The study found that warmer oceans due to global warming are producing more tropical cyclone activity, including hurricanes. In another study, researchers at Pennsylvania State University and Massachusetts Institute of Technology found that warmer waters are largely responsible for the recent strengthening of Atlantic hurricanes into superstorms like last year’s Katrina, Rita and Wilma.
The costs of protecting beaches and shoreline property will rise dramatically, scientists say. As sea levels rise, erosion rates in the greater New York City and Long Island region are projected to double by 2020 and increase six times by 2050 (.pdf), making it impossible to dredge up enough sand to keep pace, scientists say.
More than 75 percent of Florida’s shoreline, 47 percent of New York’s shoreline and 26 percent of New Jersey’s and Virginia’s shorelines are critically eroding, according to Surfrider’s State of the Beach 2005 Report.
About 62 percent of the Texas coastline is actively eroding, the report said, with some areas losing five to 10 feet every year.
The generally low-lying East and Gulf Coasts will be hardest hit, while the West Coast is somewhat protected by the Coast Range mountains — but beach deterioration is increasing there as well, Wilson said.
Sea levels have already risen four to 10 inches depending on the location over the past 100 years.
“Another foot to 18 inches of sea-level rise and we’re in real trouble,” said Orrin Pilkey, professor emeritus of geology at Duke University in North Carolina and author of numerous books on beaches and shorelines.
Levels will likely rise even higher as warmer global temperatures melt the Arctic, Greenland and Antarctic ice sheets and mountain glaciers. That could mean sea levels three to five feet higher by 2100, putting major coastal cities like New York and Miami at serious risk, Pilkey said.
Beaches have their own mechanisms for maintaining sandy shores, but sea walls and jetties have blocked those processes. As bluffs and shorelines erode, they become a natural source of new sand. But by preventing erosion, sea walls and jetties cut off this source, Wilson said.
Natural erosion also dumps millions of tons of sand into rivers that eventually carry it to the sea. But dams, particularly in Southern California, have cut off this flow of sand, he said.
And while building sea walls or revetments save shoreline property temporarily, they ultimately accelerate erosion by reflecting wave energy back to the sea, said Gary Griggs of the Institute of Marine Sciences at the University of California at Santa Cruz.
“Shorelines are dynamic, and without a chance to retreat there will be a lot fewer beaches in the future,” Griggs said.
With more than half the population of the United States living in coastal states, the sea-walling of America is well under way. There are 30 miles of armored shoreline in North Carolina, 110 miles in California and more than that in Florida.
Shorelines have been slowly retreating from the sea since the last ice age, but global warming has accelerated the retreat. Powerful storms that move a shoreline back up to 20 feet in a day also seem to be increasing, he said. “It’s hard to be optimistic about America’s beaches.”