Georgia
Assessing Shoreline Change and Coastal Hazards for the Georgia Coast
Principal Investigators: Clark Alexander, Skidaway Institute of Technology; David
Bush, University of West Georgia
ABSTRACT
Over the past few decades, a number of published studies have suggested that
shoreline erosion will likely intensify in response to rising global sea-levels.
Furthermore, as coastal populations continue to grow, there is an increasing
need to identify the potential impacts of not only shoreline erosion, but also of a
number of other coastal hazards. High resolution studies, conducted within a
Geographic Information System (GIS) framework and in the field, can help both
coastal scientists and managers better understand shoreline erosion and other
coastal hazards as well as facilitate better planning and management of select
areas and/or resources threatened by such hazards. Unfortunately, when
compared to many coastal states in the U.S., the record of historical shoreline
change and coastal hazards assessment for Georgia is incomplete. Given that
eustatic sea-level is rising, a long-time frame, detailed study of historical
shoreline movements of Georgia’s barrier islands is needed to ascertain the
spatial extent and magnitude of shoreline change and identify areas prone to
erosion hazards. Moreover, a coast-wide database of coastal hazards is needed
for Georgia to identify areas that may be at high risk from potential impacts of
other geohazards such as hurricanes. This research addresses Sea Grant’s
Coastal Hazards theme, specifically item a) identifying coastal hazards that
threaten the Georgia coast and b) develop predictors for Georgia coastal
hazards.
Ultimately, methodologies and geospatial tools developed for analyzing shoreline
changes and coastal geohazards within this study can be used by researchers,
policymakers, planners, and managers. The major objectives of the proposed
project are to: 1) quantify and characterize shoreline changes along Georgia’s
barrier islands; 2) identify coastal hazards within each coastal county; and 3)
provide outreach activities that include educating both scientists, managers and
non-science-oriented stakeholders concerned with coastal issues. A primary aim
of the project is to improve upon previous investigations by developing new GISbased tools and methods for obtaining and analyzing data from various sources
such as aerial photography, satellite imagery and coastal survey maps (NOS Tsheets). Moreover, the project also aims to provide lowcost methods of building
and maintaining a coastal hazards database using techniques that do not require
a high level of technical expertise.
Shoreline data sources, such as aerial photos and historic maps, will be obtained
and converted into a georectified, digital image format compatible with a GIS.
Shoreline position data will be extracted from these data sources through
manually digitizing features in the GIS. Analyses of shoreline position changes
through time will be performed utilizing GIS tools and the results will be groundtruthed through field observations to verify erosion and accretion trends. GIS
tools for shoreline assessments currently in use, developed in the 1990’s, have
not evolved to keep up with advances in technology or raw processing power.
This proposal will fund the development of updated GIS tools that will
significantly advance this field forward. Funds requested here will support
Chester Jackson, a PhD student in the Department of Geology at UGA, who is
developing these more powerful tools to update his earlier shoreline mapping
software to provide new analysis, data display and processing capabilities.
Mapping coastal hazards will involve employing lower cost, scientifically sound,
techniques such as photo documentation, simple beach profiling, and
geoindicator evaluations. The strengths of such approaches are that they are
low-cost, field-oriented, conducted by local stakeholders (as opposed to
commercial, disinterested entities) and provide immediate results and
applications that may be rapidly incorporated into decision-making than methods
relying on sophisticated instrumentation and complex data bases. Additionally,
GIS-based techniques utilizing geospatial datasets that include parameters such
as elevation, vegetation, and storm surge risk, will be combined with these
fundamental, community-based datasets to produce hazard maps. Although
these GIS-based techniques are a higher-cost approach, they can often provide
an enhanced assessment of coastal hazards, especially when coupled with data
derived from low-cost techniques.