Correction to This Article
A Sept. 14 photo caption erroneously described the Mississippi River Gulf Outlet in a photo of a different canal in New Orleans.
Mississippi River Gulf Outlet

Canal May Have Worsened City's Flooding

Years before Katrina hit New Orleans, critics of the Mississippi River Gulf Outlet, left, said it was a
Years before Katrina hit New Orleans, critics of the Mississippi River Gulf Outlet, left, said it was a "hurricane highway" that would strengthen storm surges. (By Mannie Garcia -- Reuters)

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By Michael Grunwald
Washington Post Staff Writer
Wednesday, September 14, 2005

On May 19, Hassan Mashriqui addressed a roomful of emergency planners and warned of a "critical and fundamental flaw" in the coastal defenses for New Orleans. Mashriqui, a computer modeler at Louisiana State University's Hurricane Center, singled out the Mississippi River Gulf Outlet, a 40-year-old shipping canal aimed at the city's gut.

For years, local residents had decried the little-used canal as a "hurricane highway" that would deliver massive storm surges into their neighborhoods.

But now Mashriqui was offering proof. His hydrodynamic modeling showed that a "funnel" created by the Gulf Outlet and a nearby waterway would amplify storm surges by 20 to 40 percent. He described the funnel as "Crescent City's Trojan Horse," carrying the Gulf of Mexico's waters into the city.

"I showed how dangerous that outlet was -- there was no ambiguity," says Mashriqui, who came to the United States after a tropical cyclone devastated his native Bangladesh. "And now it's all come true."

Authorities have not yet concluded what caused the drowning of New Orleans, and most attention has focused on two breached floodwalls near Lake Pontchartrain, to the city's north. But now experts believe that the initial flooding that overwhelmed St. Bernard Parish and the Lower Ninth Ward of New Orleans came from the Gulf Outlet, a channel that was an ecological and economic disappointment long before Hurricane Katrina.

Satellite images show that levees along the outlet were severely damaged by storm surges. Flyovers by the Army Corps of Engineers have revealed a path of destruction consistent with Mashriqui's theory that the Outlet provided a pathway for storm surges from the Gulf and neighboring Lake Borgne.

Mashriqui had warned that the confluence of the MRGO and the Gulf Intracoastal Waterway created a funnel that would direct storm surges into the New Orleans Industrial Canal and on into St. Bernard Parish. On the Friday before Katrina made landfall, the parish's state senator, Walter Boasso, complained at a congressional hearing that the federal government was "playing Russian roulette" with his constituents.

Katrina's first storm surges apparently shot up the Gulf Outlet and neighboring Lake Borgne from the southeast, then overtopped levees along the Outlet and the Industrial Canal. The floodwaters eventually breached the Industrial Canal's levees, and officials believe a large portion of the Outlet's levees have been destroyed as well.

"That funnel was a back door into New Orleans," said G. Paul Kemp, an oceanographer at the LSU Hurricane Center. "I don't think there's much doubt that was the initial cause of the disaster."

In 1965, the Corps of Engineers completed the MRGO -- pronounced "Mr. Go" locally -- which was a larger dirt-moving project than the Panama Canal. It was designed as a 76-mile shipping shortcut from the Gulf of Mexico to the Port of New Orleans that would give cargo ships an alternative to the sinuous Mississippi River.

But less than 3 percent of the port's cargo -- fewer than one ship per day -- passes through it. MRGO's freight totals had dropped by half since 1994, while the port's had increased overall. But the Corps still spent $13 million dredging the canal last year.

Critics have calculated the cost to taxpayers at more than $12,000 per vessel per day, and the Outlet has destroyed or damaged more than 20,000 acres of adjacent wetlands.


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© 2005 The Washington Post Company

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