First, a little bit of background:

Hurricane Katrina was the costliest and one of the five deadliest hurricanes in the history of the United States.

It was the sixth-strongest Atlantic hurricane ever recorded and the third-strongest hurricane on record that made landfall in the United States.

Katrina formed on August 23 during the 2005 Atlantic hurricane season and caused devastation along much of the north-central Gulf Coast.

The most severe loss of life and property damage occurred in New Orleans, Louisiana, which flooded as the levee system catastrophically failed, in many cases hours after the storm had moved inland.

In Louisiana, the federal flood protection system in New Orleans failed in more than fifty places.

Nearly every levee in metro New Orleans breached as Hurricane Katrina passed east of the city, subsequently flooding 80% of the city and many areas of neighboring parishes for weeks.

At least 1,836 people lost their lives in Hurricane Katrina and in the subsequent floods, making it the deadliest U.S. hurricane since the 1928 Okeechobee Hurricane. The storm is estimated to have been responsible for $81.2 billion (2005 U.S. dollars) in damage, making it the costliest natural disaster in U.S. history.

The catastrophic failure of the flood protection in New Orleans prompted immediate review of the Army Corps of Engineers, which has, by congressional mandate, sole responsibility for design and construction of the flood protection and levee systems. There was also widespread criticism of the federal, state and local governments' reaction to the storm, which resulted in an investigation by the U.S. Congress, and the resignation of Federal Emergency Management Agency director Michael D. Brown. Conversely, the National Hurricane Center and National Weather Service were widely commended for accurate forecasts and abundant lead time.

[Source: http://en.wikipedia.org/wiki/Hurricane_Katrina]

NOW FOR THE IMPORTANCE OF COMMUNICATION AND INFORMATION FLOW IN RISK MANAGEMENT!

ASCE urges corps to tell residents of continuing flooding risk
by Mark Schleifstein, The Times-Picayune, New Orleans, USA

Thursday April 17, 2008

Despite ongoing levee improvements, the New Orleans area still faces a life-threatening risk of flooding from hurricanes, and it's the responsibility of the Army Corps of Engineers to make that risk clear to the public, an American Society of Civil Engineers panel said.

"The message should not be sugar-coated, must be in clear, easy-to-understand language and, in our opinion, needs to come from the engineer who designed and is responsible for the hurricane system," members of the engineering group's External Review Panel said in a five-page letter sent Tuesday to Lt. Gen. Robert Van Antwerp, chief of the corps. [This and other highlighting mine. - NK]

The panel also recommended that the corps use its bully pulpit to ensure that local evacuation and emergency planning equals or exceeds similar planning elsewhere in the nation.

"No one understands, or should understand, the limitations of the hurricane protection system better than the Corps of Engineers," the letter said. "Evacuation and emergency planning appears to be the only means available in the near term to provide significant additional protection to human health and welfare in the New Orleans area."

The engineering group has been conducting a peer review of the corps-sponsored forensic study of the causes of levee failures during Hurricane Katrina, and its letter was part of its review of that study's chapter on risk.

Before completing the risk chapter, the corps released maps during two news conferences last year that explained the risk of flooding from so-called 100-year or 500-year hurricanes, those with a predicted 1 percent chance, or a 0.2 percent chance, respectively, of occurring in any year. The maps showed the potential of flooding if the levee system had been built as designed before Hurricane Katrina, with repairs to the levees that were completed by June 2007, and with completion of the new 100-year levee system, scheduled for 2011.

With the repairs in place last year, the maps indicated that almost all areas inside the levee system would experience catastrophic flooding during a 500-year event. With completion of the 100-year levee system, the maps showed only minimal flooding from a 100-year hurricane. Flooding from a 500-year event would be dramatically less than before Katrina in most areas, but still would cause significant damage, the maps showed.

Putting risk in perspective

The American Society of Civil Engineers panel is concerned that today's risk from a catastrophic storm might be lost on elected officials and the public because of the focus on the improvements in flooding risk promised by the expected 100-year levee improvements, said David Daniel, chairman of the panel and an engineering professor who is president of the University of Texas at Dallas.

"There's a natural human tendency to downplay risks and to think that things are better than they really are," Daniel said Thursday. "But in this case, the risk is potentially life-threatening."

The term "500-year storm" may make some people believe it can happen only once in 500 years, but that's not necessarily the case. To make its point, the team said the public should understand, for instance, that there is a 10 percent probability of a 500-year flood occurring one or more times in the next 50 years, a risk the American Society of Civil Engineers calls unacceptable.

In comparison, other structures are designed to withstand much greater risk:

• Major U.S. dams are designed so that the probability of a failure causing more than 1,000 fatalities is less than once    every 100,000 to 1 million years.

• Dams and coastal protection systems for densely populated areas of the Netherlands are designed for 10,000-year    storm surges.

• Improved flood protection on the Red River in Grand Forks, N.D., and neighboring Minnesota was designed to have    a 90 percent probability of withstanding a 250-year storm.

• Major buildings and bridges in California are designed to withstand earthquakes that occur less than once in 2,500    years.

The letter also urges the Interagency Performance Evaluation Task Force, the team that is writing the Hurricane Katrina levee report, to make its summary readable by the general public, including its explanation of risk.

That's already under way, said Ed Link, a civil engineering research professor at the University of Maryland who chairs the Interagency Performance Evaluation Task Force team. A third version of the public risk summary already is under peer review, he said.

Staying on the case

A spokesman for the corps' headquarters in Washington, D.C., said the agency remains committed to communicating risk to the public.

"We've certainly been engaged with trying to provide input with local communities about our structures and the work that's being done, and on evacuations and evacuation routes," corps spokesman Gene Pawlick said.

Meanwhile, New Orleans and state emergency preparedness officials said dramatic improvements in evacuation plans already are in place, and more are on the way.

New Orleans has plans for people without transportation and their pets, as well as for residents with medical needs, said Terry Ebbert, director of the New Orleans Office of Homeland Security.

State officials were meeting Thursday with their counterparts from Texas and Mississippi in a meeting in Biloxi with Federal Emergency Management Agency officials from two regions on just such improvements, said Louisiana Office of Homeland Security and Emergency Preparedness Director Mark Cooper.

"We'll have a more comprehensive and coordinated public information campaign this year, at the governor's direction," he said.

TOP     Mark Schleifstein can be reached at mschleifstein@timespicayune.com or (504) 826-3327.

FOOTNOTE ON NEW AND ADDITIONAL RISKS 

High water, construction could prove dangerous to levee stability
Posted by By Sheila Grissett, East Jefferson bureau (New Orleans, Lousisiana, USA) April 14, 2008

With the Mississippi River again creeping up its banks, authorities are scrambling to stop nearby construction and demolition because the work could undermine levees during this vulnerable period of high water.

Pile driving, excavation and other dirt-moving procedures are never allowed within 1,500 feet of a river levee unless the Army Corps of Engineers determines it's no threat to levee stability. Even then it must be permitted by the appropriate levee district, officials said. [1 foot = 0.305m]

But enforcement of these restrictions is more critical than ever when the river is high and levee damage could result, said Fran Campbell, executive director of the East Jefferson Levee District.

"It's all about not creating a path for the water to come through a levee," she said.

"I think most people assume the river levees can't fail, just like they didn't think that the hurricane protection levees could fail. But these rules are serious. They're in place for a reason."

The river stood at 16-1/2 feet at the Carrollton gauge in New Orleans on Monday, down from almost 17 feet on Thursday, the day before the Army Corps of Engineers opened the Bonnet Carre Spillway to divert some of the surge to Lake Pontchartrain. But the National Weather Service predicts it will climb back to 17 feet by Thursday and will stay there through April 22.

Campbell said levee district police officers and inspectors are checking multiple work sites daily and have shut down about a dozen of them. They have halted home building, swimming pool construction, a house raising, apartment renovations, fence removal and other activities.

Police also are driving side streets within the 1,500-foot zone grid in search of violators.

Some of the halted activities have permits that the levee district issued before the Mississippi River hit an elevation of 11 feet at the Carrollton gauge last month, the point at which invasive work must stop. But a permit still doesn't allow work during periods of high water, Campbell said. The paperwork simply makes it more efficient for authorities to visit each site to ensure work has stopped.

"We're also seeing a rash of people right now who're doing work without levee district permits, and that makes stopping it more difficult," she said.

Orleans Levee District Executive Director Stevan Spencer said he doesn't see as many violations because there are few residential structures along the river in New Orleans and the Port of New Orleans helps watch for business activities in the area.

But Spencer said the levee district has stopped work on two sites this week where piles were being driven, in one case only 700 feet from the levee. Neither violator had a permit, he said.

Spencer and Campbell said they are again appealing to the governments of New Orleans and Jefferson Parish not to issue building permits until applicants have levee permits in hand.

Campbell and Spencer said they've not cited any violators.

"We're trying to be nice and help people understand what's at stake here," Campbell said. "And we know people lose money when they have to stop work. That's another reason why we all need to be on the same page."

[Source: http://blog.nola.com/updates/]

TOP                                      Sheila Grissett can be reached at sgrissett@timespicayune.com