Mighty Dunes Do Their Job Print E-mail

The Hunt Website
May 2013

When hurricane Sandy slammed into the Jersey coast in late October, three factors -- astronomical high tide, direct hurricane impact, and fully developed seas -- set the stage for historic flooding. It was a worst-case scenario that came true.SH003

In the wake of devastation rendered by the super-storm the lesson learned should be: start building those living, mini-mountains of sand.

In north Jersey entire beaches and towns are gone. A sea of debris remains. Further south it is a different story. Summer destinations such as Long Beach Island, Ship Bottoms, Surf City, Avalon and Stone Harbor had instituted beach replenishment for years and sand dunes were built high and wide. Those communities were spared the worst damage.

Humans cannot control the sea, but they can adjust to it.

“It was painfully obvious, the dunes worked,” noted Stewart Farrell, director of the Richard Stockton Coastal Research Center which has been studying New Jersey’s shore for more than a quarter of a century.

SH002“You look at where the dunes were wider and higher, no damage from the waves. Where they were low and thin and narrow, wipeout time.”  

Geologists define barrier islands as long, narrow bodies of sand, running parallel to the shoreline, separated from one another by inlets and from the mainland by marshland, a shallow sound, bay or lagoon. The word barrier identifies them as buffers, protecting the mainland from storm and surf.

Drifting on the whims of sea and sand, barrier islands by the hundreds rim the Atlantic and Gulf coasts. A bit over two percent of the world’s coastlines are framed by barrier island chains. The longest stretch wraps around 2,000 miles along the coasts of the U. S. in an irregular chain from New York to Texas.

It is thought that barrier islands were formed about 18,000 years ago when the Ice Age ended. As glaciers melted and receded, sea levels began to rise, and flooded the areas behind the beach ridges. The rising waters carried sediments from those beach ridges and deposited them along shallow areas just off the new coastlines.

Sculpted by wind and waves, barrier islands, when left in their natural state, tend to lengthen with prevailing currents and migrate toward land. Human development may impede this migration but can never bring it to a halt.

Vanishing sand has long been a worry of coastal Jersey residents. As sea levels rises and beaches narrow, replenished sand is lost to waves, currents and storms. Farrell and his team cite studies where sea-level rise could reach three feet by the end of the century, and projections call for storms to increase in both number and intensity.

Still, the battle of the beaches rages. Homeowners and other opponents of larger sand dunes often complain about a loss of ocean views and breezes, the loss of coastal ambience and threat of increased public use of “their” beach.MightyDunes 5

Over the years the Army Corp of Engineers has mounted an ambitious program to combat the loss of beach sand along the Jersey coastline by nourishing the beaches: taking sand from “borrow” areas far off shore and piping it onto the beaches.

Sand dunes have always been the first line of defense against hurricanes and other coastal storms-- helping to keep the sand blowing away or washing out to sea, holding the sand in place. In 2012 a sum of $27 million was spent on Jersey beach replenishment, a reported 36 percent of the national total, to combat beach erosion. That is a fraction of the $38 billion generated by shore tourism.

The beach-fill projects don’t faze Mother Nature. The storms keep coming and the sand keeps moving. In the aftermath of Sandy huge amounts of sand washed into northern Jersey barrier island communities from their beaches, and homes were torn from their foundations by the storm surge that lasted hours.

Avalon and Stone Harbor comprise the Seven Mile Beach barrier island in South Jersey which stretches from Townsends Inlet to the north, and south to Hereford Inlet. Avalon suffered more damage than its sister, Stone Harbor. The flooding was deeper. Debris was stacked higher.  Dump trucks and dumpsters abounded during the clean-up operation.

“Flooding in Avalon came over the sea wall on the inlet side,” Farrell said. “The dunes worked. There was no sand in their streets. The dunes from 32th through 58th Streets have an elevation of 55 feet, the highest dunes on the east coast. I’ll tell you the December 1992 nor’easter did far more damage than Sandy.  Building those dunes was a lesson learned.  Dunes are cheap. The expense is the beach fill the dunes sit on. Both Avalon and Stone Harbor got a big payback.”

Stone Harbor dodged a bullet.  Its stretch of dunes preserved in its natural state negated Sandy’s powerful storm surge. It experienced moderate damage mostly from back-flooding from the bay that was enhanced by all the rain.

SH004Both Stone Harbor and Avalon have healthy, living sand dune systems full of trees, shrubs, and plentiful dune grass with roots that fan out beneath the dunes.  The dunes are dynamic systems that grow and shrink, with an average height around 10 to 12 feet in the back dune, which rises to more than 40 feet in places in Stone Harbor.

Bob Rich has been a Stone Harbor resident of over four decades. He is the owner of the local Coldwell-Banker realty business.  

“The dune restoration program was a methodical plan of replenishing the beach, building dunes wider and higher, planting grasses and putting in snow fences as barriers as well,” Rich remarked. “But, we’re not kidding ourselves. If Sandy had come up the Delaware Bay we would have experienced destruction like Asbury Park of Seabright. You can’t protect against the full impact of a monster hurricane.  But through all of the major storms we’ve experienced since the late ‘90s, the dune system has held up remarkably well.”

Local officials pushed for beach replenishment and building wider and higher sand dunes after the Halloween nor’easter of 1991 and additional nor’easters in 1992 and 1993. Massive waves broke over the bulkhead in many spots in Stone Harbor and Avalon causing extensive damage.

Prior to Sandy, both Avalon and Stone Harbor were awarded beach fill projects that will be fully funded by the Army Corp of Engineers. It was to address the beaches eroded during the Hurricane Irene storm event in 2011.  Slated to begin in mid-December, it will be one of the largest beach fill projects in the borough’s history.

The dredge “Charleston” will be work¬ing 24 hours a day, seven days a week.  When work is com¬pleted in one com-mu¬nity, it will take approx¬i¬mately seven days to mobi¬lize the dredge, equip¬ment, and pipes to the neigh¬bor¬ing community.  The total cost of the project, without options, is $4.59 million. In the aftermath of Sandy some of Stone Harbor’s dunes were lost, but most still stand, as do the houses behind them.SH005

“Our wonderful beaches are the key attraction for people coming here on vacation each summer,” Rich noted. “This beach fill project is an economic engine for Stone Harbor and Avalon. With the beach replenishment our visitors will have a large recreational beach to enjoy in 2013, and beyond.”          

Rich points out that with regular beach re-nourishment walks down to the beach may be longer as vegetation takes up more of the back-beach, and beaches may even become smaller as space is given over to builder even wider and higher dunes and planting dune grass.

“Yes, more oceanfront views could be lost,” he said. “But after Sandy, I’m sure the beachfront homeowners are all happy they have their homes today.”    

 

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