EW ORLEANS, May 21 (Reuters) - The last two Atlantic hurricane seasons passed with barely a stir in south Louisiana, sparing New Orleans another disaster. But some local officials fear the respite may have contributed to a false sense of safety in parts of the city that still face great danger.

Hurricane Katrina decimated New Orleans and killed 1,500 people on the U.S. Gulf of Mexico Coast in August 2005, but no other hurricanes have struck the city since.

The government is shoring up levees and floodwalls, but completion of some of that work is years away and local officials say little has been done to protect the Mississippi River delta from a tidal surge like the one that devastated Myanmar this month.

Post-Katrina New Orleans remains two separate communities as another hurricane season begins on June 1.

One sustained heavy damage during the flood that followed Katrina and is still bears the storm's scars.

The other, which includes the historic French Quarter, shows few signs of a brush with Katrina, a Category 3 storm on the five-step Saffir-Simpson scale of hurricane intensity.

On the city's East Bank, the U.S. Army Corps of Engineers is raising levees and installing steel-reinforced gates on three drainage canals to block a surge in Lake Pontchartrain from pushing into the canals, as occurred in 2005.

Lt. Col. Murray Starkel, the Corp's deputy commander in New Orleans, said the reinforced gates will protect the canals against a surge during a Katrina-like storm that might occur once every 100 years.

That once-in-100-year-event has become the Corps' minimum standard for New Orleans' flood protection.

"I think the inner portion of the city of New Orleans is better protected than it has been in many, many years," said Jerry Sneed of Louisiana's Office of Homeland Security and Emergency Preparedness. "Is it at the 100-year storm level? Not yet, but it will be in the near future."

FLOODWALL, LEVEE IMPROVEMENTS INCOMPLETE

The other side of the river is a different story.

About $285 million in improvements on West Bank levees and floodwalls won't be completed for another year.

That system will only meet standards set more than two decades ago, said Gerald Spohrer, executive director of the West Jefferson Levee District. Reaching 100-year storm protection will take at least three more years, he said.

The West Bank, much of which lies south of downtown New Orleans, is at greater risk than the rest of the city because it is more exposed to the Gulf. It came through Katrina relatively unscathed only because the storm jogged eastward just before landfall.

"The West Bank is still vulnerable," Sneed said. "Our biggest fear is that people who live on the West Bank of New Orleans and didn't get flooded think that they are home free in the event of a storm."

Also still facing danger from a direct hit is St. Bernard Parish, downriver from New Orleans, which suffered massive damage from Katrina's storm surge.

Many St. Bernard residents blame their woes on a shipping channel called the Mississippi River-Gulf Outlet. Water surging through that outlet contributed to a canal wall breach that flooded much of the city's Lower 9th Ward and St. Bernard.

In April, the Corps awarded a $695 million contract for construction of barriers to block the canal by 2011.

All this work could be for naught if the authorities do not address a problem, which parallels one of the vulnerabilities in Myanmar, where Cyclone Nargis pushed a wall of water 25 miles (40 km) inland, killing tens of thousands.

The Irrawaddy Delta and New Orleans have dwindling vegetation buffers that could reduce the force of a storm surge. Myanmar's delta sacrificed its coastal mangrove forests to shrimp and rice farming. Louisiana has lost hundreds of miles (km) of wetlands to erosion.

Studies are under way on rebuilding Louisiana's wetlands, but significant action is years away, said Robert Twilley, a coastal researcher at Louisiana State University.

"A valid flood protection system has to include a very aggressive coastal restoration program," he said.
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 By Kathy Finn

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