CEE professor Smith saw threat to New Orleans

When the muddy waters of Lake Pontchartrain filled the streets of New Orleans in the wake of Hurricane Katrina, Princeton professor James Smith was not surprised.

Smith, a flood expert in the Department of Civil and Environmental Engineering, has told his students for years that the lower Mississippi River — and New Orleans in particular — were vulnerable to catastrophic flooding.

"We teach a course on 'Rivers and the Regional Environment,' and we always give two lectures on the lower Mississippi, which is one of the most controlled rivers in the world," said Smith, who co-teaches CEE 263 with Professor David Billington. "As we finished last year, Ivan looked threatening. Katrina brought graphic evidence of how accurate those predictions were."

Smith said decades of man-made alterations in the course of the river had weakened Louisiana's natural defenses against flooding. Although the Mississippi's natural path runs through New Orleans and south into the Gulf of Mexico, Congress passed legislation in the aftermath of a 1927 flood to divert 31 percent of the Mississippi's water into the Atchafalaya River.

Smith said the Atchafalaya channel, along with the extensive levee system surrounding New Orleans and the damming of the Missouri River, prevented sediment from flowing into the Mississippi River delta below New Orleans.

"By [making these alterations], you've shut off much of the sediment that feeds the delta. So Louisiana has been losing land extremely rapidly, and this is the protection from the storm surge, and the storm surge was what was responsible for breaking the levees," Smith said.

Partly as a result of that coastal erosion, he added, the possibility of a hurricane striking New Orleans had been "broadly recognized as the top natural disaster in the U.S."

Although Smith devoted significant class time to the lower Mississippi, the geographic focus of his research lies elsewhere: the Appalachian Mountains of the eastern United States.

In the aftermath of Katrina, Smith was prepared to investigate the effects of the storm in the Northeast. But the most severe damage was confined to the Gulf Coast, which he said lies outside his area of research interest.

"Rain had virtually nothing to do with what happened," Smith said. Instead, the flooding in New Orleans resulted from Katrina's storm surge, particularly in Lake Pontchartrain.

After Hurricane Isabel struck the eastern United States in 2003, Smith and his research team traveled to Baltimore and Philadelphia to reconstruct the flooding that occurred in those areas.

"When a tornado happens, you go out and you look at all of the debris, and you reconstruct some aspects of the tornado," Smith said. "You can do the same with floods, and you go look at the damage, where rivers flow over their banks, how high the water goes."

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As far as the reconstruction of New Orleans is concerned, Smith warned against the temptation of easy solutions. He said planners should consider the environmental impact of potential changes on areas far from Louisiana.

"It is a very complicated system that we have created," he said. As the history of the Mississippi shows, if "you do one thing here, it can have impacts on some remote locations."