Bret M. Webb, Ph.D., P.E., D.CE
University of South Alabama
150 Jaguar Drive, SH3142
Mobile, AL 36688 USA
Phone: (251) 460-6174
Fax: (251) 461-1400

Research Positions

Currently seeking multiple graduate students to fill positions at the MS, PhD, and Postdoc levels. Research topics include: living shorelines, beach and tidal inlet dynamics, barrier island response to extreme events, groundwater impacts to coastal lagoons, and infrastructure resilience. Research assistantships are available. Click here for more information.

Current Research Assistants

PhD Students
Garland Pennison


MS Students
Kelsey Carpenter
Sean McQuagge
Elizabeth Winter
Jackie Wittmann


Undergraduate Students
Ian Cox

Former Students

MSCE Students
Patrick Hautau (2018)
Marshall Hayden (2018)
Kate Haynes (2018)
Justin Lowlavar (2017)
Bryan Groza (2016)
Kari Servold (2015)
Chris Marr (2013)
Richard Allen (2013)
Miyuki Matthews (2012)


Post Docs
Jon Risinger
Jungwoo Lee

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A preliminary analysis of the data obtained during the wave basin testing of bagged oyster shell has been completed.  Forty-three experiments were conducted yielding unique combinations of structure height, structure length, and wave characteristics.  The ratio of incident and transmitted wave heights were compared to published methodologies for estimating wave transmission at low-crested rubble mound structures.  In general the equations, limits, and methodologies described in Van der Meer et al. (2005) tend to overestimate the transmission coefficients measured in the laboratory experiments, but a simple linear regression on a direct (one to one) comparison of predicted and measured values yields a coefficient of fit of 91%.

While the limited data suggests that existing methodologies for estimating wave transmission at rubble mound structures could potentially be used in the design of bagged oyster shell breakwaters, the following should be addressed through continued experimentation:

  • An expanded test matrix should be developed that includes analysis of additional monochromatic waves, as well as simulation of random waves.
  • The summative contributions of wave reflection and overtopping should somehow be segregated from actual transmission through the structure, and the overall contributions of each compared to one another.
  • The frequency attenuation of such structures, regardless of their material composition, should be explored in more detail for regular and irregular waves since wave period places an important role in sediment transport.

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