Faculty Explore the Complexities of Katrina's Devastation

September 10, 2005

Durham, N.C. -- Duke environmental experts and civil engineers have responded to Hurricane Katrina devastation with a broad range of insights. They are criticizing the failure to heed computer models that warned of disaster; pondering how to rebuild the city to avoid future catastrophe and examining 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 coastal Galveston, Tex. 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, is 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. "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."

Curtis Richardson, a professor of resource ecology at the Nicholas School and director of Duke's Wetland Center, offered insights into the potential impact of degraded wetlands in the region. He has intensively studied imperiled wetlands in Florida's Everglades and Iraq's Mesopotamian Marshes.

While some consider the Iraqi wetlands the site of the Garden of Eden, Richardson said the equally imperiled wetlands on the Gulf side of New Orleans New Orleans represent "our modern Garden of Eden.

"Both the Iraqi marshes and these marshes have sustained their nations with seafood and gas and oil, as well as protected the people who live there, Richardson said.. "But they are not given very much value."

Richardson said the wetland destruction has a variety of causes, including land subsidence from subterranean fossil fuel pumping, sea level rise, channelization for boat traffic, and massive flood control measures upsteam on the Mississippi that now deprives the region of needed silt and nutrients.