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UNDERSTANDING PREDICTING RESILIENCY
OF BARRIER ISLANDS
Research by Dr. George Voulgaris
Department of Geological Sciences Marine Science Program
 The
impact of Hurricane Katrina on the Gulf Coast created a
rare opportunity to investigate the bathymetric change
and erosion resulting from an extreme hurricane event on
coastal environments similar to those found along the
coast of South Carolina. University of South Carolina
researchers set out to examine the effect of hurricanes
on the nearshore and the inner shelf of a transgressive
shoreline.
The study area was the 21 kilometer-long Caminada-Moreau
headland located along the south-central Louisiana
coastal zone, consisting of uniform fine to medium
quartz sand. Along part of the headland, detached
breakwaters protect highly erosional areas of the
shoreline. As part of the CRISIS program USC researchers
collected onshore (beach morphology) and offshore
(bathymetric and shallow geophysical survey) data after
the 2005 hurricane season documenting the combined
effect of Hurricanes Katrina and Rita.
USC researchers analyzing the data from these surveys
are focused on answering four questions: 1) Do
hurricanes create return flows during the recess of the
storm surge that create morphological features such as
Scoured Rippled Depressions? 2) What is the expected
maximum landward retreat of a shoreline in response to a
major hurricane? 3) What volume and what type of
sediment are transported offshore during a major storm
impact? and 4) What morphological changes occurred along
the unprotected versus the protected zones of the
headland?
Researcher data attempted to answer these questions with
beach topographic profiles and offshore bathymetric,
seismic and side-scan sonar images. Researchers have
concluded that extreme erosion of the sea bed in
response to the hurricanes occurred in areas where the
bed had been disturbed previously. There are indications
that more sediment was transported by strong alongshore
flows in response to the strong winds during the
hurricane period than during the recess of the storm
surge waters. Further, researchers determined that oil
and gas pipelines on the sea floor are subject to damage
during the passage of extreme hurricanes. Finally,
researchers concluded that undeveloped barrier islands
respond much better to hurricane forces than developed
ones.
Comparison of these data to surveys conducted before the
2005 hurricane season provided an ideal opportunity for
researchers to assess the morphological evolution
associated with tropical cyclone impacts and will help
researchers predict the impact of hurricanes. The
results will also benefit on-going USC research to
understand the origin of sea bed features called Rippled
Scoured Depressions that have been associated with beach
erosion off barrier islands. Outcomes will also
contribute to understanding the resiliency of the
coastal zone and assist in designing the policies needed
in the case of an extreme hurricane impact on South
Carolina's developed barrier islands. Moreover, the
study offers insight into improving methods of securing
underwater oil and gas pipelines so that no disruption
to supply or spills occur due to failures associated
with hurricanes.
USC researchers have also established new research
collaborations with scientists from the University of
New Orleans that will lead to new scientific endeavors.
A female undergraduate student has been involved in
analyzing the data, an experience that has led her to a
decision to become further involved in science by
seeking a Master’s degree at USC. USC researchers are
presenting findings at Ocean Sciences 2006.
Biography
Dr. George Voulgaris is an associate professor at the
Marine Science Program and the Department of Geological
Sciences. He is a coastal geologist with a Ph.D. in
Oceanography from the University of Southampton, United
Kingdom, where he studied the response of beaches and
inner-shelf to wave dynamics. He is the director of the
Coastal Processes and Sediment Dynamics Laboratory that
consists of two post-doctoral research associates, one
technician and four Ph.D.-seeking students. He is
leading a real-time coastal wave-monitoring program
funded by ONR and has a number of active research
projects funded by NOAA, NSF, ONR and the South Carolina
Sea Grant Consortium. His publication record includes
more than 50 peer-reviewed papers in journals and
conference proceeding volumes, 60 published abstracts,
and 24 technical reports.
Research Team/Collaborators:
Scott White, Department of Geological Sciences, as
well as Dr. Mark Kulp from the University of New
Orleans. Part of the data collection was completed with
the assistance of RPI Louisiana Inc., a small
environmental company based in New Orleans. Historical
data were provided by the Louisiana Department of
Natural resources. |
