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 and/or doctoral level. 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. Contact me for more details.

Current Research Assistants

SE Students
Garland Pennison

 

MSCE Students
Kelsey Carpenter
Elizabeth Winter
Jackie Wittmann

 

Undergraduate Students
Evan Mazur
Ian Cox
Morgan Lassitter

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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drifters

A number of drifters were released in the Gulf of Mexico south of Mobile Bay on October 27, 2011. A total of 18 drifters were released in two clusters of nine each. One cluster was deployed on the 20-meter isobath and slightly west of Mobile Pass, while the other cluster was deployed on the 30-meter isobath south of Mobile Pass. The deployment occurred under favorable weather conditions: air and water temperatures were near 21oC, winds were out of the south at 2 – 3 m/s. The drifter deployment took place between 1000 – 1230 HRS CDT, just after low water during a tropic tide.

While previous drifter deployments in July and August occurred during a time of predominantly eastward flow on the inner shelf (upwelling favorable), the trajectories of this latest group of drifters suggest that conditions on the inner shelf have changed. The latest group of drifters are describing a predominantly westward flow on the inner shelf (downwelling favorable). The drifters moved westward toward the Chandeleur Islands, and then turned southward, heading toward the Mississippi River delta. Click {here} to see the tracking page for both clusters. Individual tracking maps for a drifter from each cluster are provided below.

 

20-meter Cluster (DISL 059)


To show more or less of the drifter trajectory, select the desired duration from the History dropdown menu. Click on the ballon or a green circle for location and speed data.

 

 

30-meter Cluster (DISL 058)


To show more or less of the drifter trajectory, select the desired duration from the History dropdown menu. Click on the ballon or a green circle for location and speed data.

Tropical Storm Lee has given our remaining drifters (DISL 002, DISL 007, and DISL 011) some interesting weather in the Northern Gulf of Mexico.  Most all of them got a large bump to the north over the past few days during the development of TS Lee. One of them {DISL 011} has run aground a few miles west of Navarre Beach Park in Florida. Another has not reported since 0200 HRS this morning {DISL 007}. And somehow, {DISL 002} snuck into Little Lagoon early this morning during some rather rough weather. Check out the photo at right and videos below.

 

Little Lagoon is located in Gulf Shores and has a very small tidal connection to the Gulf of Mexico. The inlet, or pass, goes directly through the beach and is only about 15 m wide in this area. The pass is stabilized by steel sheetpile on either side. The pass is frequently closed out at low tide by the longshore sand transport. The inside of the pass is dredged frequently to maintain water quality in the lagoon.

 

The first of two videos below shows the drifter caught on a dredge pipe near where the pass widens into the lagoon. The dredge pipe is being floated by the orange buoys, and is making a “U” shape with the sag very near where the drifter is hung up. The second video shows the mouth of the inlet with the Gulf of Mexico beyond. It’s hard to make out in the video, but the waves are breaking at about 4 – 5 ft across a pretty wide surfzone. Winds were out of the east at 20 – 25 knots.

 

While it was not possible to retrieve the drifter today, I contacted the dredge operator and left a message explaining what was caught on their dredge pipe. Hopefully, we will be able to get this one back at some point. I honestly don’t think it will find its way back out into the Gulf… I don’t even know how it got through the pass in the first place.

 

 

Part 1/2 – Video & Audio of DISL 002 in Little Lagoon Pass

Part 2/2 – Video & Audio of Little Lagoon Pass

 

To show more or less of the drifter trajectory, select the desired duration from the History dropdown menu.

Just wanted to provide a brief update on the status of drifters released during the last deployment (16 Aug 2011)… We have witnessed some interesting behavior over the past two weeks. Seven of the northernmost drifters deployed in water depths less than 20 m moved to the north and eventually ran aground on Dauphin Island after a number of days. Some trajectories were short lived while others took more than a few days to finally run aground. Interestingly, there was no significant net drift eastward or westward in this region.

 

The three drifters that were deployed in depths greater than 20 m experienced a net eastward drift similar to the pattern seen in the July release of DISL 003. These three drifters are still adrift and continue sending transmissions once every thirty minutes. Two drifters (DISL 002 and DISL 011) spent some time in shallower water south of Pensacola looping back toward the west, while one (DISL 007) has continued its eastward migration and is now southeast of Panama City Beach.

 

All ten of the drifter deployment synopsis pages are now available under Drifters -> Drifter Release – August 16, 2011. Hover over the menus to find submenus.

 

Another drifter deployment is coming soon… so stay tuned.

Ten drifters were released in the Gulf of Mexico, south of Dauphin Island, Alabama, on Tuesday, August 16, 2011. The drifters were spaced approximately 2.5-km apart along a constant longitude (88o 13′ W) starting in about 25 m of water and ending close to shore in 7 m of water. A CTD cast was taken at each release location to determine the corresponding vertical profile of hydrography to complement the initial conditions of the drifter trajectories. Click on the Google Earth image at right for an overview of the drifter release locations.  For more information about the release, please visit the drifter release synopsis for August 16, 2011 by {clicking here}.

 

You can see the current and previous drifter locations by {clicking here}. Use the arrows under the messages window to step back through the drifter trajectories. Visit each individual drifter page for an information capsule and live tracking map. Drifter pages can be accessed through the submenus of the “Drifters” tab in the horizontal link bar above.

A drifter prototype was released on Thursday, July 7, 2011 in about 20 m of water south of Dauphin Island, Alabama. The photo at right shows the drifter floating away as we obtained a CTD cast from the R/V Spinner. The embedded, interactive map below shows the trajectory of DISL 003. You can select the amount of data to show by setting the History to your desired duration. A link to a full shared page for DISL 003 can be found {here}. I’ll be creating some dedicated pages for this drifter project in the coming weeks, but in case you don’t feel like drilling down into those you can use the embedded tracking widget in the left sidebar.

 

We experienced some delays fabricating a reliable GPS unit for the drifter project, but they are functioning well now. A special thanks also to Gary Howell at {CivilTek} for helping us troubleshoot our GPS system. The expected life of the power supply is over 320 days based on some preliminary testing. Chances are the drifters will meet an untimely demise some time prior to this! Believe it or not, there is lots of stuff in the Gulf of Mexico for this drifter to get hung up on… or run over… or picked up… or eaten. You just never know what you’re going to get. We have 10 more drifters ready for deployment in the coming weeks, and fabrication of the remaining 40 drifters is slated to begin in the next two weeks. As a point of reference, it takes about on week to fabricate and prepare 10 drifters.