Alexander Lab Group Activities at the ACRL

The Alexander lab group, led by Dr. Clark Alexander (adjunct full professor, Department of Geology and Geography), has worked out of the ACRL since 1991.  Our group works on a diverse range of research projects related to coastal geology, coastal and estuarine processes, and habitat mapping. Our research products provide basic scientific discovery as well as data and tools to assist coastal stakeholders in the development of sound management and policy decisions.  We also lead field trips to nearby barrier islands for undergraduate and graduate student groups to expose them to coastal and estuarine geology and environments.

Sea floor mapping

Our lab group acquires and processes high-resolution bathymetry and side-scan imagery of the seafloor in sounds, estuaries and the ocean, using a range of sonar systems deployed on various platforms.  The acquisition of this data is critical for developing updated charts, delineating habitats, and interpreting active processes. Comparing modern data with historic records allows us to evaluate areas of significant change or stability over time.  Several projects focus on Georgia’s sound inlets which exhibit a wide range of habitats and complex networks of channels and shoals. Other projects investigate offshore sand resources and both natural and artificial reefs.

Shoreline mapping

Our group conducts mapping projects which require high-accuracy positioning and characterization of shoreline types.  We also analyze modern and historic shoreline position as a critical data set for evaluating the land/water interface and its response to long-term natural processes, storm events, and climate-related change.  Using mapping-grade or survey-level Real Time Kinematic (RTK) GPS equipment, we collect detailed shoreline position data in the field. Processed data is incorporated in a GIS environment for analysis and comparison with digitized historic shoreline positions.  These tools and methods allow us to quantify rates of shoreline erosion or accretion at a given location. Geo-referenced videography is used in many projects to provide detailed information for classifying the type and composition of the shoreline.

Drone mapping

Drone acquired aerial imagery allows our group’s pilots to deploy rapidly to a research site and capture time sensitive data related to landform conditions.  This capability is extremely useful in documenting pre- or post-storm effects. Currently, we are conducting monthly aerial surveys to evaluate the geomorphology and changing structure of an artificially placed sand berm at Fort Pulaski National Monument along the Savannah River.  We simultaneously collect RTK-GPS data points to merge with drone imagery to generate three-dimensional elevation models for more detailed analysis of landforms.

GIS processing and analysis is a key component in each of our research projects.  Using a suite of various software platforms we often generate primary spatial datasets from both field-collected data as well as digitized historic records.  The Alexander lab group created and continues to maintain a historic archive of over 6,000 scanned aerial photographs of the Georgia coastal region. We also maintain a web-based Arcserver application, the Georgia Coastal Hazards Portal (, which provides a platform to disseminate our research products to the public, coastal managers and other research groups.

Last updated: 8/30/2019