Shoring up the nation’s coastline
Coastal communities are experiencing unprecedented population growth, and, at the same time, the land on which they are built is disappearing. Sea levels are rising – some say because of global warming – storms are carving away at shorelines; and millions of homeowners are facing the possibility of watching their property wash out to sea. Consequently, it has become more important than ever for coastal communities to develop strategies for maintaining the beaches that attract so many of their residents.
A report prepared by the Washington, D.C.-based H. John Heinz III Center for Science, Economics and the Environment, a non-profit research institute, indicates the extent of the coastal erosion problem in the United States. The report, prepared for the Federal Emergency Management Agency and released in June, states that the Atlantic coast is losing an average of two to three feet per year, and some areas on the Gulf Coast are losing as much as six feet per year. The Heinz report predicts that one out of four homes within 500 feet of a coast will be lost to erosion during the next 60 years.
With 3,600 people moving to them every day, coastal communities are searching for effective methods of maintaining their beaches – their most valuable resource. “We have a moral responsibility to save our beaches,” says Reese Musgrave, mayor of Pine Knoll Shores, N.C. “[The alternative is to let things go], and, if we did that, half of our tax base would fall into the water.”
Arming the coast
Communities have a number of options to manage beach erosion, most of which fit into two categories: hard solutions and soft solutions. Hard solutions include groins, seawalls and breakwaters, and soft solutions include beach renourishment, dune construction and property retreat.
Groins are built perpendicular to the shoreline and are extended into the water to catch drifting sand. They have been used frequently, particularly on the New Jersey coast, but they are falling out of favor as primary solutions to erosion because they interrupt the flow of sand to neighboring beaches.
Seawalls, also known as revetments and bulkheads, are usually built vertically on beaches to protect property, but they have disadvantages also. “You almost always see a lowering of the beach profile next to a seawall, and you get scour and a whirlpool effect on the sides,” says Truman Henson, a Massachusetts Coastal Zone Management coordinator. “You may even see these results within one season [of building a wall].”
Alternatively, sloped stone revetments have been used and have shown fewer significant consequences, Henson says. The sloped surface resembles the natural slope of the beach but armors the sand with rocks, which do not wash away as easily as sand. The spaces between the stones in such structures also serve as habitats for small animals.
Breakwaters are structures built off shore, parallel to the beach, to catch waves before they break on the beach. The structures create calm waters on the shore. However, depending on the water depth and the size of the structures, breakwaters may not protect the beach at all, says Rebecca Haney, a Massachusetts Coastal Zone Management coordinator. “It’s hard to protect eight miles of beach with breakwaters,” says Susan Lucas, chief of coastal planning for the Philadelphia District of the U.S. Army Corps of Engineers. “And some people think they’re unsightly.”
Because of the problems associated with hard solutions, North Carolina banned them all in 1986. The state encourages homeowners to move their homes away from the shore rather than build solid structures to stop erosion. However, most of the communities on the North Carolina coast are old towns, and residents are reluctant to move, says Tony Caudel, Wrights-ville Beach town manager. As a result, towns on North Carolina’s coast are trying to implement renourishment solutions.
Economic ebb and flow
The U.S. Army Corps of Engineers conducts most large beach renourishment projects because of the cost and the amount of work involved in each project. In 1996, Congress passed the Shore Protection Act and charged the Corps with helping coastal communities rebuild their beaches. The Act established rules for local governments to follow to get federal support from the Corps, and it pledged that the Corps would maintain the beach renourishment projects for 50 years.
Currently, the Corps spends $80 million a year to maintain the nation’s coastline. “That’s only half of what’s needed,” says Howard Marlowe, president of the Washington, D.C.-based American Coastal Coalition, a non-profit coastal advocacy group. “The demand for federal money is increasing.”
Once the Corps approves a renourishment project, it covers 65 percent of the project’s cost; local governments are responsible for remaining costs. Wrightsville Beach, N.C., has participated in federal renourishment projects designed to protect the town against storms since the 1960s, following damage by Hurricane Hazel in 1954. The Corps has recently committed to return to the town every four years – at a cost of $2.5 million per visit – to refill the beaches with sand.
Nearby Carolina Beach and Kure Beach undergo federal renourishment projects every three years, at a cost of $3.2 million and $4.5 million respectively. The state contributes approximately 75 percent of the non-federal share of the costs, and New Hanover County pays the remaining costs with money raised by a county-levied 3 percent room occupancy tax on rental properties. The room occupancy tax is used in many coastal communities, including popular Hilton Head, S.C., so that “the tourists who use the resource most pay to have it maintained,” says Clark Alexander, an associate professor at the Skidaway Institute of Oceanography in Savannah, Ga.
For many cities, beaches serve as economic engines. No beaches, no tourists. A 1997 survey conducted by San Francisco State University estimates that beach visits in California generate more than $10 billion in direct spending annually. The study reports that visits to California beaches reached 565 million in 1996 while visits to all of the state’s theme parks totaled 26 million. “We really can’t afford [to ignore beach erosion],” Marlowe says. “There’s an economic loss if we [do]. People will go somewhere else, and regions will lose money to other regions.”
Stop gap measures
All beaches cannot raise enough money through tourism to pay for renourishment projects. For example, Holden Beach, N.C., a barrier island in Brunswick County, has 990 permanent residents and approximately 10,000 rental property occupants in the summer. Holden Beach raises only $700,000 each year from its 6 percent accommodations tax.
Although the town has saved $1.5 million to pay for beach renourishment, Mike Morgan, town manager of Holden Beach, estimates that it costs $1 million to renourish one mile of sand. The town has five miles of beach that need renourishment, so it has applied for federal aid to support such a project.
Until Holden Beach is approved for federal assistance, which may not happen for another nine or 10 years, it must do whatever it can to maintain its beaches. The town most recently constructed five miles of dunes in 1997 by hauling in 200,000 cubic yards of sand by truck. The dunes were stabilized with plants and sand fencing, but they will have to be rebuilt in a few years.
The town also takes advantage of the Corps allowing communities to use dredged materials for beach reconstruction. The Corps routinely dredges the harbor in Wilmington and deposits the dredged sand on two miles of Holden Beach and neighboring beaches.
Just as hard solutions have critics, so does beach renourishment as an erosion control method. Florida beaches have had problems finding enough sand to maintain renourishment projects, says Robert Dean, professor of coastal engineering at the University of Florida. In fact, the Corps is finding that it has to go farther off shore to find sand for beaches than it used to.
For example, Miami Beach, which began renourishing its beaches in 1979, is finding that less sand is available locally to continue its renourishment. The Corps is searching for alternative sources of sand for Miami, and some geologists and coastal engineers have suggested using sand from the Bahamas to maintain the project, says Bruce Henderson, environmental specialist for Miami Beach. The Miami Beach tourism industry, which attracts more than three million visitors to the beach each year, supports that idea.
Others say that renourishment is only a temporary solution to a permanent problem. “Essentially, beach renourishment is treating the symptoms, not curing the disease,” said Steven Leatherman, director of the Laboratory for Coastal Research at the International Hurricane Center in Miami during a live online chat on USA Today’s web site in July. “It is not a general panacea for beach erosion problems, but it can work in some areas where the erosion rate is low.”
Some communities have tried to compensate for the disadvantages of hard and soft solutions by using many of them together in one project. For example, Virginia Beach, Va., with help from the Corps, has constructed a seawall, strengthened its boardwalk and dune system, and renourished its beach every three years. The city began planning the $115 million project in 1970. Scheduled for completion next year, the combined measures are intended to protect Virginia Beach from hurricane damage.
Although coastal communities are finding some success combining erosion control methods, they may soon have more effective alternatives. The Corps has organized the National Shoreline Erosion Control Development and Demonstration Program, a six-year effort to study new shore protection devices, designs and methods. The Coastal Engineering Research Board, an appointed advisory board, is selecting seven sites where it will evaluate test structures for stability, long-term performance and ability to withstand extreme events.
Beach erosion control methods have not changed much in recent years, but the importance of implementing the methods has increased dramatically. In 15 years, 27 million more people will be living on the coast, and coastal communities still will be grappling with disappearing shorelines.
Until new solutions are devised, communities will continue using groins, seawalls and breakwaters to fight erosion, and they will continue rebuilding dunes, dredging sand and moving their homes away from the shore. “Unfortunately, man has altered the natural resources by moving to the coast in droves,” Morgan says. “If we didn’t like it, we should have stopped it 50 years ago.”