Contact

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

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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Click on the poster image to download the full size PDF

If you clicked on the “Get the Poster” QR code during the AGU Ocean Sciences Meeting then you likely landed here. You can download or link to any of the three resources mentioned on my AGU OSM 2020 poster. Just follow the links below. Thank you for your interest in our work related to overwashing of Dauphin Island during Hurricane Nate.

 

If you did not jump here from the poster then you might be wondering what this is all about. Please read the “plain language abstract” text below for a non-technical (as non-technical as I can get) description of this work.

We put sensors on a barrier island before a hurricane in October 2017. Those sensors measured water levels and waves as the storm surge rose and washed over the low-lying barrier island. We also measured barrier island elevations before and after the storm event. The waves eroded sand from the beach face. Some of that sand was carried by the currents and deposited over large portions of the barrier island in features commonly called overwash fans. These measurements are unique. They allow us to describe the change in storm tide elevations and wave heights across the barrier island continuously throughout the storm event. This poster describes only basic characteristics of water levels, waves, and erosion across the island. Time-series analyses are ongoing.

 

Get the Poster: click here for the poster

 

Get the Paper: click here for the paper

 

Get the Data: click here to request the data

 

 

We recently completed a two-year collaboration with the USDOT Federal Highway Administration during which we developed a new resource that explains how transportation professionals can implement nature-based solutions to enhance the resilience of coastal highways. The complete implementation guide is available on the FHWA project website (or click on cover image at right). A brief summary is provided below. Additional project resources and reports are also described and linked from the project website, as are the reports from a number of pilot projects conducted around the US.

A webinar is scheduled for October 23, 2019 to assist in the rollout of this new resource. The webinar agenda includes presentations on the new Implementation Guide by Tina Hodges of USDOT FHWA and Bret Webb of the University of South Alabama; an overview of the US Army Corps of Engineers’ Engineering With Nature(R) initiative by Jeff King; and a summary of NOAA resources for nature-based solutions by Kim Penn. Click on this link for more information and to register for the webinar (required).

This Implementation Guide is designed to help transportation practitioners understand how and where nature-based and hybrid solutions can be used to improve the resilience of coastal roads and bridges. Upfront, it summarizes the potential flood-reduction benefits and co-benefits of these strategies. From there, the guide follows the steps in the project delivery process, providing guidance on how to consider nature-based solutions in the planning process, how to conduct a site assessment to determine whether nature-based solutions are appropriate, key engineering and ecological design considerations, permitting approaches, construction considerations, and monitoring and maintenance strategies. The guide also includes appendices with site characterization tools, decision support for selecting nature-based solutions, suggested performance metrics, and links to additional tools and resources.

 

 

I recently completed a document that introduces transportation professionals to coastal modeling. The guidance document, entitled A Primer on Modeling in the Coastal Environment, was written for the U.S. Department of Transportation Federal Highway Administration. It is now available for distribution. You can download a copy of the manual by clicking on the cover image at right. The document abstract/summary is provided below.

 

Document Summary

This manual provides an introduction to coastal hydrodynamic modeling for transportation engineering professionals. The information presented in this manual can be applied to better understand the use of numerical models in the planning and design of coastal highways.

Here, the term “coastal highways” is meant to generally capture the roads, bridges, and other transportation infrastructure that is exposed to, or occasionally exposed to, tides, storm surge, waves, erosion, and sea level rise near the coast. The hydrodynamic models that serve as the focus of this manual are used to describe these processes and their impacts on coastal highways through flooding, wave damage, and scour.

The primary audience for this manual is transportation professionals ranging across the spectrum of project delivery (e.g., planners, scientists, engineers, etc.). After reading this manual the audience will understand when, why, and at what level coastal models should be used in the planning and design of coastal highways and bridges; and when to solicit the expertise of a coastal engineer. This manual provides transportation professionals with the information needed to determine scopes of work, prepare requests for professional services, communicate with consultants, and evaluate modeling approaches and results.

The manual also provides guidance on when and where hydraulic and hydrodynamic models are used, and how they are used to determine the dependence of bridge hydraulics on the riverine or coastal design flood event.

The manual also gives recommendations for the use of models in coastal vulnerability assessments.

FHWA GI Pilot title slide... click for animation

We are wrapping up a one-year collaborative project between USA, the Mississippi Department of Transportation (MDOT), and the US Department of Transportation Federal Highway Administration (USDOT FHWA).  This was one of five pilot projects funded by USDOT FHWA to evaluate the use of green infrastructure for improving the resilience of coastal transportation systems. The pilot projects are an initial step in a more comprehensive effort by USDOT FHWA to develop an implementation guide for nature-based solutions that improve resilience. More information about that project is found at the following link {click here}.

 

Our pilot project with MDOT was focused on improving the resilience of a coastal bridge in Mississippi to hurricane hazards and future sea level rise. More specifically, our green infrastructure approach was designed to address the vulnerability of bridge approaches and low-elevation bridge spans. The causes of damage to the bridge during Katrina were determined through the use of hydrodynamic models. A hindcast simulation of Katrina was performed using the coupled ADCIRC+SWAN models. Those results were extracted and used to force a high-resolution, two-dimensional simulation using the XBeach model. An animation of some of those results is provided below.

 

To that end, a pair of vegetated berms were designed in order to mitigate storm damage now and in the future during extreme events.

 

An overview of the entire pilot project is available in a recorded webinar at the following link {click here for webinar}. Ours is the second presentation in the webinar recording (at about the 25-minute mark). Webinar recordings for all five pilot projects, as well as other presentations in an ongoing USDOT FHWA resilience series, can be found at the following link {click here for all webinars}. A brief animation of our presentation slides is available by clicking on the title slide image in this post.

 

Katrina Hindcast using XBeach, forced with ADCIRC+SWAN output…

XBeach animation

Hindcast of Katrina using XBeach: Terrain elevation contour colors correspond to the lower blue-green-brown-white color scale. Selected bathymetric contours are shown as dashed white lines on the surface. The animated water surface is contoured by significant wave height using the blue-white-red scale. Vectors represent the depth-averaged flow magnitude and direction, but only at every 1/10th grid cell for clarity.

 

Title slide image for ASBPA 2017 presentation

I recently presented the results of a year-long research project on synthesizing the capacity of natural and nature-based features (NNBF) to reduce coastal storm hazards. The presentation was given in the Living Shorelines session at ASPA 2017 in Fort Lauderdale, Florida in October. The project, and presentation, were a collaboration between researchers at USA, the Dauphin Island Sea Lab, Northeastern University, the City College of New York, and the US Army Corps of Engineers Engineer Research and Development Center who funded the project.

 

More than 200 published research papers were identified, evaluated, and synthesized in this work. The synthesis focuses on the ability of marshes, mangroves, maritime forests, seagrasses, reefs, beaches, and dunes to attenuate waves, storm surge, flooding, and erosion. With very few exceptions, the literature does not contain unified methods for analyzing and describing these capabilities, and the range of values describing their performance is broad. Regardless of the uncertainty in published values, there is literature that supports the capacity of each of the NNBF considered to provide some measurable reduction of coastal storm hazards. A logical next step is to perform a detailed meta-analysis on values reported in these publications in order to determine average performance values and characterizations of their uncertainty.

 

A short animation of the presentation can be viewed by clicking on the title slide shown here. Please contact me for a full copy of the presentation.

 

Suggested citation below…

Webb, B. M., Scyphers, S., Cebrian, J., Gittman, R., Sharma, S., Rosati, J. 2017. Evaluating the capacity of natural and nature-based features to reduce coatal storm hazards. American Shore & Beach Preservation Association National Coastal Conference. Fort Lauderdale, FL Oct. 24-27.