Jul 28, 2014

Beach Replenishment: How Does It Work?

A massive project creates a spectacle as it moves toward downtown Ocean City beaches.

At the same time Ocean City received some long-awaited spring weather, an Army Corps of Engineers sand-pumping project moved toward the downtown beaches.

The spectacle of pipelines, gushing mud and heavy equipment leaves many onlookers wondering what exactly they're witnessing.

Ed Voigt of the Public Affairs Office for the Army Corps of Engineers' Philadelphia Division, took some time Friday to explain how it all works (see photo gallery above for each stage of the process).

Ocean City is in the midst of a $15 million "renourishment and repair" project that will restore eroded and storm-damaged beaches between the north end of the island and 14th Street. Major work is expected by be complete by Memorial Day.

Voigt said the process is as follows:

  • The Army Corps identifies an underwater "borrow area" offshore, where the grain size of the sand matches the beaches of Ocean City. Voigt said the choice is not only for aesthetics, but for stability — matching grains are less prone to erosion.
  • A massive dredge (in this case clearly visible off the north end of Ocean City near the Great Egg Harbor Inlet) is the source where a giant "vacuum" pulls up sand and water.
  • The intake travels through grating that filters out debris. A 2006 project in Surf City on Long Beach Island infamously transported some long-submerged World War II military ordnance, and since then, the intake filters have been standard, Voigt said.
  • The sand and water travels through an underwater pipeline to the beach (in this case, it lands just north of North Street Beach).
  • The dredged material continues through a pipeline that runs down the beach to a work area that is proceeding southward to 14th Street.
  • The material gushes out the end of the pipeline into a "basket" that serves as a second filter (with a finer screen) to eliminate any sort of debris.
  • Any debris is hauled to dumpsters on the beach.
  • Conventional earth-moving equipment then moves the sand to the optimal shape and slope.

Voigt said much of the work is designed to elevate the "towel area" of the beach, which the Army Corps refers to as the "berm."

"The berm protects the dune, and the dune protects the community," he said.

As of Friday, the project had reached the Fifth Street jetty.

Read more: Ocean City Beach Update and Summer Countdown


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