Geotechnical engineer talks flooding, infrastructure in Louisiana in wake of Tropical Storm Barry

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As a geotechnical engineer who studies foundation engineering, soil mechanics and earth retaining structures, Brian Anderson offered his expertise on the impact on Louisiana’s infrastructure since Tropical Storm Barry made landfall this weekend. Anderson is an associate professor in the Department of Civil Engineering in Auburn’s Samuel Ginn College of Engineering. He earned his bachelor’s degree in civil engineering from North Carolina State, and his master’s and doctorate degrees in the same discipline from the University of Florida. Anderson surveyed flood related damage after Hurricane Florence in North and South Carolina last September as part of a Geotechnical Extreme Events Reconnaissance team deployed by the National Science Foundation.

Will widespread flooding cause roads and bridges to be wiped out?

I do not anticipate roads and bridges to be wiped out. I would expect water to be over roads in places, which happens even with smaller storm events in New Orleans. Within the city, the pump system will move the water out, albeit at a likely slower rate than the rainfall. 

How long after the flooding will it be before engineers can evaluate damages?

I would say as soon as it is safe, engineers will begin to assess damage. There are lifeline routes that will carry emergency and relief traffic that are built to be more resilient. Those will be the first evaluated; once deemed safe, then engineers can move to assess further. Of course, the entire picture gets clearer as flood waters recede.

What is the recovery time for something like this as far as repairing infrastructure?

Of course that depends on the severity of damage. Simple culvert washouts can be repaired within days. Power line restoration will begin as soon as it is safe to move repair equipment in place. Larger infrastructure failures, such as bridges, if they occur, require an engineering design. All depending, repairs could be complete in six weeks or up to six months or more.

Storm waters could have surged above the levees along the Mississippi River. Is there still a threat of that happening as rainfall continues?

I would say, at this point, the threat of surging water has passed. The Mississippi is already handling large amounts of water and is experiencing record breaking flooding upstream of New Orleans in Baton Rouge. The Bonnet Carré Spillway remains open to alleviate stress on the levee system by allowing water flow into Lake Pontchartrain, and will remain open until the flooding eases.  

What effect, if any, will a storm like this have on the levees? Is there concern for their sustainability for future storms this hurricane season?

A levee, just like any infrastructure facility, has a useful life and requires maintenance to achieve or extend that life. The ability of the levees to continue to function throughout historic floods and an active hurricane season requires thoughtful engineering and maintenance along with public support. There were changes made in the wake of Hurricane Katrina that spurred evaluation and fortification of the Mississippi Levees System. Today, the system is much more resilient than what was in existence before Katrina, but improvements are ongoing.

What are the residential consequences facing cities after flooding?

High water has the potential to enter homes. The floodwaters carry contaminants into structures. After the water recedes, there is a high likelihood of dangerous mold growing inside residences and on furnishings. The homes will be uninhabitable until, at a minimum, the contaminated furnishings, carpets, drywall, etc. are removed and proper treatment of mold is completed. Many residents in the area do not have flood insurance and may lose their homes due to the impact of high water.

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