Scientists will assess health of New York-Long Island barrier protection in wake of Sandy

January 9th, 2013 in Earth / Earth Sciences

A rapid response science team from the University of Texas at Austin's Institute for Geophysics will help map the impact of Hurricane Sandy on the beach/barrier systems off the south shore of Long Island.

The team will collaborate this month with researchers from Stony Brook University, Adelphi University, the City University of New York and other institutions from the New York metro area to assess the health of the offshore barrier system that protects the New York Harbor and southwestern Long Island region against damage from future storms.

The team will conduct marine geophysical surveys of the seafloor and shallow subsurface to map the sedimentary impact of the hurricane on the beach/barrier systems of selected bay, inlet and nearshore areas of the south shore of Long Island.

Sand and other coarse-grained sediments are vital to the naturally occurring barrier systems that dissipate storm surges, protect coastal residences and shelter biologically diverse estuaries and ecosystems.

Results of the survey will help environmental engineers plan future efforts to restore sand to the barrier system in the wake of Sandy's devastating, long-term damage.

The Texas team has unique experience with similar geophysical surveys of nearshore sediments after Hurricane Ike, the costliest storm in Texas history, which made landfall near Galveston on Sept. 13, 2008. Furthermore, the team has a rich collaborative history studying the continental shelf off New Jersey and New York.

"As with Ike, we will be looking at where the sand went as a result of the storm," said John Goff, a principal investigator for the project at The University of Texas at Austin. "With Ike, we found that the ebb of the storm surge moved a lot of beach barrier sand off shore."

Using a compressed high-intensity radar pulse (CHIRP) and an even higher frequency seafloor supplied by Stony Brook University, the scientists will use multiple research vessels to profile the seafloor and upper of the ocean bottom. Similar research after Ike found an "event layer" of sand that the storm deposited over a wide area of ocean floor.

The danger with any storm of Sandy's magnitude, added co-principal investigator Jamie Austin, is that "a lot of the sand gets pushed too far off shore, beyond the ability of normal processes to reincorporate it into the system that nourishes the barrier naturally."

When that happens, the only way to restore the sedimentary system may be to recover sand from new, offshore locations manually and deposit it where it was before the storm.

"The cost to society for these restoration projects can be huge," said Austin, "so we need to get the sediment budget details absolutely right."

Colleagues from Adelphi University and the City University of New York also expect to take sediment samples during these at-sea investigations to assess sediment budgets further.

"Our study of the sediments will allow us to better understand how the surge impacted the fragile estuarine system," said Beth Christensen, team leader from Adelphi University.

The U.S. Geological Survey is providing crucial seafloor mapping data for before-and-after comparisons.

Assessment of the seafloor is already under way. The geophysical survey will take place Jan. 7-28. Results will be prepared for distribution later this year.

Provided by University of Texas at Austin

"Scientists will assess health of New York-Long Island barrier protection in wake of Sandy." January 9th, 2013. http://phys.org/news/2013-01-scientists-health-york-long-island-barrier.html