In contrast, 286 bodies were recovered in the Lower Ninth Ward, New Orleans East, and neighboring St. Bernard Parish, where Katrina's storm surge poured over levees and flooded neighborhoods.
The role of the 17th Street and London Avenue Canals' floodwalls in the destruction of New Orleans has been hotly debated in the four months since the Aug. 29 storm. Engineers who are investigating the walls' collapse think that floodwaters generated by Katrina never rose high enough to pour over the walls, and they blame flawed design, construction or maintenance for the walls' failure and the resulting flooding.
Louisiana authorities are investigating whether laws were broken during construction of the floodwalls, but until now there has been no attempt to quantify how much their failure might have contributed to New Orleans' death toll.
Louisiana State University hurricane expert Ivor Van Heerden said there was no doubt that vast areas of the city would have remained dry, and residents relatively unscathed, had the walls of the 17th Street and London Avenue Canals not collapsed.
"A big yes," Van Heerden replied to e-mail asking whether the majority of the city would have stayed largely dry had those floodwalls held.
Peter Nicholson, an associate professor of civil and environmental engineering at the University of Hawaii, said that some flooding in central New Orleans came from breaches on the west side of the Industrial Canal, but that those breaches were above sea level and the flooding stopped as Katrina's surge died down Aug. 29.
"The big difference is, with 17th Street and London, the breaches opened gaps that were below sea level and continued to drain Lake Pontchartrain until they were closed," Nicholson said.
This confounded rescue efforts and stranded thousands in darkened hospitals, in attics, on freeway overpasses, or in the foul refuges of the Superdome and the Convention Center.
