From where should beach replenishment sand come?

After years of beach replenishment, Delmarva is looking outside of its state borders and into federal waters for new sand reserves.

Delaware, Maryland and Virginia have each partnered with the Bureau of Ocean Energy Management to find new sand sources using existing mapping data. As part of the federal Disaster Relief Appropriations Act of 2013, which allocated $13.6 million to the bureau, all three states will each receive $200,000 for the two-year project.

The groups will consolidate old data into updated formats, to better understand where sand deposits could be used for future beach replenishment projects. Once geologists have examined the old data, they can identify which areas need to be studied further.

As the states’ own sand resources have diminished, they’ve eyed sand in federal waters, more than 3 miles off the coast, said Robert Conkwright, a geologist with the Maryland Geological Survey. Geologists are hoping to find the Goldilocks-type sand dredging projects need that is coarse enough to stay on shores during storms but fine enough to comfort beachgoers, he said.

Delaware’s project will comb the state’s entire coast with a focus on the beaches between Rehoboth and Fenwick Island, said Kelvin Ramsey, a University of Delaware geologist and principal investigator. During the latest dredging project in Rehoboth, crews were forced to haul sand from the south, near the Indian River Inlet.

“The farther you transport sand, the more costly the program is,” he said. “So we’re finding the most suitable sand is as close to the beach as possible.”

Delaware’s current borrow site lies about 2 miles offshore, with state waters, according to the U.S. Army Corps of Engineers spokesman Steve Rochette. Sites near Rehoboth and Dewey were used until 2005, when dredging was discontinued due to gravel and pebbles found in the sand. Since then, reserves near Fenwick Island have been used for construction at Dewey, Bethany, Rehoboth, South Bethany and Fenwick Island beaches. An area north of the Indian River Inlet is being evaluated as a new source, Rochette said.

Sediment samples may also give geologists clues to areas where heavy rare-earth minerals, such as titanium and zirconium, exist. The sought-after minerals can be used to manufacture everyday products including paper and paint. In 1988, a study by the Virginia Institute of Marine Science found a substantial number of mineral’s in the state’s continental shelf, according to the College of William & Mary.

In the 1980s, Maryland never found enough mineral deposits for further mining to be economically feasible, Conkwright said. Still, further analysis of sediments in Maryland, Delaware and Virginia could prove valuable, Waldner said.

“These (dredging) projects are very expensive and these heavy minerals could serve as a cost offset for nourishment activities,” he said. “But that is currently speculative, it’s not critically important to obtain those findings soon.”

Sediment data will also provide a map of important biological communities of shellfish, worms and bottom-dwelling fish, Conkwright said. The habitat map would point to areas of substrate which shouldn’t be disturbed for offshore projects such as wind farms.

The bureau will work with the University of Delaware’s Geological Survey, the Maryland Geological Survey of the Department of Natural Resources and the Virginia Department of Mines, Minerals and Energy Division of Geology and Mineral Resources, with assistance from the College of William & Mary’s Virginia Institute of Marine Science.


• Delaware, Maryland and Virginia will each receive $200,000 for the project, as part of the federal Disaster Relief Appropriations Act of 2013, which allocated $13.6 million to Bureau of Ocean Energy Management.

• The mid-Atlantic states have been using their own sand resources, which lie within 3 miles of the coast, for beach replenishment.

• As states’ own sand resources have diminished, they’ve eyed federal waters farther away.

• Geologist will consolidate old data into updated forms, to better understand where sand deposits could be used for future beach replenishment projects.

• Sediment data will also be used to identify rare-earth mineral deposits and maps of important biological communities.


Originally published in Delmarva Now:…

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