Weighing Best Ways to Fight Beach Erosion

July 21, 2000 -- Every summer, thousands of people flock to the coasts to hear the soothing sound of lapping waves. But Gerrard Stoddard has witnessed the destructive side of water’s perpetual motion against the shore.

“I’ve seen severe storms come up to houses and eat the bottom out from underneath them,” says Stoddard, a Fire Island, N.Y., homeowner and vice president of the American Beach and Shore Association. “Some of that sand is replaced, but there’s no question that the island as a whole has eroded significantly.”

The gradual corroding of Fire Island’s shoreline is worrisome for Stoddard, who believes the erosion threatens beaches and homes on Fire Island as well as the mainland that the barrier island is intended to protect.

Fire Island’s shores aren’t the only ones at risk.

Constant Corrosion

Across the country, rising water levels, coupled with a series of intense El Niño-related storms in recent years, have eaten away at the nation’s beaches. A survey released last month by the Federal Emergency Management Agency estimated that erosion will corrode an average of 3 to 4 feet of beachfront every year for the next 60 years.

For districts across the United States, threatened beaches means threatened economies. In California alone, it’s estimated that beaches generate about $12 billion in annual revenue from recreation and tourism.

That’s why a number of regions have spent millions of dollars to scoop up sand from offshore locations and pump it onto existing beaches in a process called beach nourishment.

Among projects pending this summer, New York is considering a $5.6 million beach nourishment project for its barrier islands, including Fire Island. And the state of Delaware has proposed a $7 million beach nourishment project that would be the largest in the state’s history.

But beach nourishment and other, older beach rebuilding measures have come under fire in recent years by geologists, who claim they are ineffective, expensive and sometimes even destructive.

“We simply cannot engineer our way out of this problem even though we seem think we can,” says Orrin Pilkey, a geologist at Duke University who has been an outspoken critic of beach rebuilding programs.

Patching Up the Problem

Pilkey and others argue that pumping sand onto an eroding beach is like sticking a Band-Aid on a gushing wound. Sand transported to a beach is often smaller-grained since it is processed through grinders and pumps, he says, and it can erode at a faster rate than the original beach sand.

Depending on the energy of waves at a beach, a nourished beach can erode in less than two years.

“The only way to save the beach is if you keep nourishing and that’s expensive,” Pilkey says.

But at some sites, such as Miami Beach in Florida, the effects of beach nourishment can be longer lasting. Beaches in Miami are still stable after sand was transported to the region in the early 1980s. And Wendy Carey, a coastal adviser at the University of Delaware, argues the cost of such programs is all relative.

“Some people say that’s a lot of money, but if you think about what we spend on the national infrastructure — like roads that people use to get to beaches — it’s really not a lot,” she says.

Problematic Solutions

In an effort to design longer-term solutions to beach erosion, the Army Corps of Engineers installed structures in the past that were intended to protect the shores. In the 1940s and ’50s, devices known as groins were built at several beaches across the United States, including New York’s Coney Island. These structures extend at a perpendicular angle from the shore and trap sand carried by parallel currents.

Engineers have also installed devices called offshore breakwaters, which sit about 200 to 300 feet from the shore in the water. These barriers, made of concrete, wire-meshed stones and even old, sunken ships are designed to slow oncoming waves that erode the shore.

Now scientists claim both of these devices have done more harm than good.

“Basically they rob Peter to pay Paul,” says Stephen Leatherman, director of the Lab for Coastal Research at Florida International University. “Other areas are always being sacrificed in the process.”

Groins, Leatherman explains, tend to trap and prevent sand from flowing to beaches downstream. And offshore breakwaters, he says, can trap sand in front of them and divert wave energy to their flanks, causing more severe erosion at their edges.

“Engineers have been looking at the symptoms rather that the causes,” says Dick Holmberg, a Florida-based coastal management contractor. “If you create a secondary erosion problem, you haven’t solved the problem.”

Textiles and Spinning Snowflakes

Holmberg has developed alternative approaches to combating shore erosion that have been applied at approximately 100 sites along Great Lakes and ocean shorelines. His company, Holmberg Technologies, installs underwater stabilizers made of tough textiles that elevate a beach area and slow down incoming currents. By slowing the currents as they approach the shore, more sand is deposited. At the same time the stabilizers do not block sand from migrating downstream since currents can travel over them.

Other engineers have taken a more high-tech approach to fighting erosion. Dennis Smith secured a patent last year for a device he dubs the WhisprWave. These snowflake-shaped plastic barriers are strung together and anchored offshore. Smith says that unlike traditional offshore breakwaters which reflect wave energy, the WhisprWave absorbs the energy as the oversized snowflakes rotate with the waves, and then spin back against oncoming waves.

“It’s as if it was a punching bag,” he says. “You hit the bag and it goes away and when it comes back it has a lot of energy.”

New ideas like Holmberg’s and Smith’s are still relatively underused now as federal and state projects rely mainly on beach nourishment to fight erosion.

Harry Shoudy, a senior adviser at the Army Corps of Engineers, says that structural approaches to fighting beach erosion tend to be more expensive and they also pose more environmental risks than simply adding sand.

But change could be under way.

Deciding When to Act

A bill known as the Water Resources Development Act of 2000 is now in review in Congress. It would call for a complete re-evaluation of erosion policies.

“There’s no restriction to looking for new solutions,” says Shroudy. “We’re looking for whatever works best to solve the problem.”

In some places, new solutions can’t come fast enough. In California, about one-quarter of the shoreline between the Golden Gate Bridge and Mexico is now fortified with sea walls, according to the California Coastal Commission. The walls have been erected as a last resort to protect properties and land from thrashing waves. Geologists point out the seawalls lead to the disappearance of beaches since the structures bounce back the energy of waves at the shore and cause beachfront to erode even faster.

Pilkey argues the country’s beaches can’t wait for new solutions and that it’s time homeowners and businesses retreat from coastlines. By abandoning the coasts, he argues, people can allow nature to take its own natural course. Erosion, he says, usually doesn’t erase a beach, it simply shifts it further inland.

“We can retreat now and save our beaches or we can retreat later and probably ruin the beaches in the process,” he says.

Leatherman is less pessimistic. He believes adding sand to beaches is a reasonable way of combating erosion, even if it isn’t permanent. As he says, “That’s like saying it’s a losing battle to pave streets because some day grass is going to poke through.”

Meanwhile, on the shores of Fire Island, Stoddard is anxious for something to be done to stop the effects of the gnawing waters, even if it is only a temporary solution.

“We can’t just abandon property and beaches and not pay for it,” he says. “It’s about protecting our assets.”

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