Pratt Civil Engineers Respond to Hurricane Katrina

Duke civil engineers responded to Hurricane Katrina devastation with a broad range of insights. They criticized the failure to heed computer models that warned of disaster; pondered how to rebuild the city to avoid future catastrophe; and examined the potential for ecological damage in the storm's aftermath.

Pratt School of Engineering urban hydrologist Miguel Medina Jr. criticized the failure to heed the long history of engineering predictions and computer modeling that foretold what would happen in New Orleans.

“I don’t think we lack for computer simulation models," said Medina, a professor of civil and environmental engineering who develops and uses mathematical modeling to evaluate water quality and transport problems. "What we lack is for people to listen carefully to what the experts have been saying for years. It’s kind of inexcusable.

“New Orleans will never be the same," Medina said. "The question is, how much should they invest in fixing it. Should we consider that certain areas should be evacuated for good, or just considered as sites where there will be temporary flooding? It’s going to take, I think, a very comprehensive analysis."

Henry Petroski, Aleksandar S. Vesic Professor and Medina's colleague in Pratt's civil and environmental engineering department, noted that after past destructive hurricanes in coastal Galveston, Texas, officials opted for the enormous task of raising the entire city.

But Medina said that many parts of New Orleans not only start out below sea level, they're becoming even more so.

"New Orleans is built over mud and peat," Medina said. "And when you place a number of manmade structures on such a surface it compresses. Some parts of New Orleans have been sinking about one third to one half inch per year. How much fill would you need to raise the city of New Orleans?"

One possible solution would be to "rebuild those homes that were devastated with new foundations so they would float," Medina said. Dutch engineers are using that solution in parts of flooding-prone Holland by building foundations with large blocks of Styrofoam surrunded by concrete and steel that will "float vertically" while still being anchored in place "so they won't be carried downstream," he said.

A more immediate concern than rebuilding, said Karl Linden, an associate professor of civil and environmental engineering, was the potential environmental impact of pumping water from New Orleans' flooded streets back into Lake Pontchartrain.

"Water going into the lake from the city will certainly have with it some load of pollution that could have serious environmental consequences," Linden said while parts of the city were still flooded. "The extent of the pollution is not very clear because there is not much detailed information available at this point. But if we move forward too rapidly without knowing the extent of the pollution load, we could be leading to another environmental problem."