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New flood maps will likely steer rebuilding

The new federal flood maps for New Orleans scheduled to be released this year will provide critical information for residents trying to decide whether -- or how high -- to rebuild their damaged homes, members of Mayor Ray Nagin's Bring New Orleans Back commission say.

The maps also could drive new building codes and standards that try to minimize future flood damage, should city leaders decide to adopt them quickly.

For those reasons, one of the key recommendations of the commission's land use panel was to urge the Federal Emergency Management Agency, which draws the maps, to release preliminary versions within 30 days.

But that's unlikely to occur, something Joe Canizaro, chairman of the BNOB's land use committee, conceded shortly after the panel issued its report Wednesday.

In fact, New Orleans area residents who are eager for guidance from FEMA as they decide how to go about rebuilding are likely to find themselves in a dilemma. If they rebuild now, all they have to go on is the current required elevations, which may -- or may not -- be substantially changed when the new maps are released. Yet even if they wanted to voluntarily use the latest elevation information and get started renovating their homes, they can't -- it's not available.

It likely will be about two months before FEMA can provide any new data to the city, according to Gary Zimmerer, FEMA's lead engineer for the mapping project. Even then, Zimmerer said, the agency likely will not release maps, but only provide "advisory information" about what the new maps are likely to show.

While there has been plenty of speculation that the new maps could change dramatically from the current ones, drawn in 1984, and thus slow the recovery process by requiring homeowners in heavily flooded areas to build much higher, Zimmerer said it is too soon to guess what the new maps will look like.

Preliminary maps probably won't be available until summer, Zimmerer said. Once those are released, city officials will be able to appeal them in part or in whole while FEMA works on the final versions. When the maps are finalized, the city must adopt them or be shut out of the National Flood Insurance Program, which is administered by FEMA.

So for now, and likely for the next year or so, the 1984 maps on the books are the law of the land. The upshot is that citizens looking to renovate may do so without raising their floor levels as long as they fall into one of two categories: Their homes already meet the "base flood elevation" required in the 1984 maps, or their homes did not receive "substantial" damage as defined by FEMA, meaning more than 50 percent of the structure's pre-Katrina market value.

Those who follow those rules cannot be dropped from the flood program, and their flood insurance premiums can rise no more than 10 percent a year.

However, some experts warn that, while rebuilding now under the old maps may be the cheapest option -- particularly for homes built on slabs -- it's not necessarily the smartest, nor the most cost-effective over the long run. The higher that homeowners build, the less likely they are to flood, so the lower their flood insurance rates will be.

Moreover, if owners of homes that were inundated during Katrina choose to rebuild and subsequently suffer another flood at a later date, FEMA may force them to raise their homes at that point by declaring them victims of repetitive flooding.

Marc Levitan, director of Louisiana State University's Hurricane Center, said rebuilding right at the 1984 base flood elevation means there's a 26 percent chance a home will flood at least once during the 30-year course of a typical mortgage.

"If you build to base flood elevation, there's an alarmingly large chance that you'll be flooded at some point," Levitan said. "You're just asking for problems. I strongly urge communities to seriously consider adopting local flood plain ordinances that take the FEMA maps as a minimum and add to that."

 

Residents in limbo?

How the delay in getting good data from FEMA will affect the ambitious four-month neighborhood planning timetable proposed by Nagin's land use committee is unclear.

The plan presented by Canizaro's committee calls for the teams that will steer the process for the city's 13 planning districts to begin meeting by Feb. 20. One of the main charges for those teams will be to identify which residents plan to return, and whether they plan to try to resettle in their old neighborhoods.

By March 20, according to the committee's report, the teams are to have completed that work, though the final plans for each of the 13 districts are not due until May 20.

Reed Kroloff, dean of Tulane University's School of Architecture, and architect Ray Manning, the two men Canizaro has charged with overseeing the planning process, said they wish the data could be made available sooner, but they don't believe the delay will significantly set back progress.

For now, the two said they will be focusing on devising a process to gather input from as many New Orleanians as possible, and amassing data and information to help those people make decisions about their future. That work can continue without the flood-plain data, they said.

Kroloff acknowledged that many displaced residents will have a difficult time determining their best course without the best flood information, but he said others are likely to have already made up their minds one way or another.

"There may need to be some adjustments" to the schedule, Kroloff said. "But it doesn't mean we can't be gathering information already. We can still start canvassing. There are some people who are going to return no matter what, and some who aren't.

"I believe we can still make important progress with the initial time frame, although it would be better if we had the information sooner. The intention is to keep (the process) as tightly focused an exercise as possible, to move through it with speed and care that works to the advantage of New Orleanians."

Kroloff, like Levitan, said he believes residents wishing to rebuild in flood-prone areas would be wise to wait for the new data -- even if they can legally rebuild now.

"If I were putting my lifetime savings in the single biggest investment I'll ever make, I'd want to make sure I had minimized every possible risk," he said. "And this isn't a small one. I'd want to get the data I need to make a decision if it were my money."

Manning agreed for the most part, but said he believes people who are renovating flooded homes that didn't receive catastrophic damage should not feel they have to wait.

"If I were making a decision about building a house from the ground up, I would certainly wait until March to make my plans," he said. "But if I'm gutting and renovating, I would go ahead."

Kroloff believes the lack of current data is a powerful argument in favor of the land use panel's recommendation that Nagin impose a four-month moratorium on building permits in flooded areas. Nagin has so far indicated he's unlikely to support such a measure.

"New Orleans is not the first city to suffer a significant natural disaster," he said. In other places, he noted -- Kobe, Japan, and Grand Forks, N.D., among them -- "people have stepped back and given themselves time to rationally consider the best process for proceeding."

 

Complicated process

The slow pace in New Orleans' receipt of its new flood data -- communities along the Gulf Coast of Mississippi received preliminary maps months ago -- owes in part to the complexity of the city's flood-protection and drainage systems, Zimmerer said.

Models must take into account a complex system of levees, pumps and drainage canals, variables that aren't present in Mississippi, he said.

Zimmerer said the first question the modeling process seeks to answer is this: How high will storm surge push the levels in local waterways in a 100-year storm?

Once that question is answered, the models will attempt to determine whether the water will overtop any of the city's levees, Zimmerer said. If the models show water would overcome the levees, it could have a dramatic impact on the maps.

The 1984 maps assume that the levees hold back the surge, and are thus designed to calculate elevations based only on the amount of rainfall generated by a once-a-century storm.

It's standard procedure for FEMA's models to first analyze whether levees will hold back the storm surge, Zimmerer said, even though the Army Corps of Engineers says the levees are designed to hold back a 200-year storm.

"We look at what's the worst-case scenario; is it the storm surge or the rainfall?" Zimmerer said. "We're not saying that we're overtopping the levees at this time. We're doing an analysis."

The officials and agencies designing the model have not yet determined whether the levee system in its current form will be used, or whether the model will reflect ongoing and planned work on the levees, Zimmerer said. City officials are arguing that the $2.9 billion in levee improvements coming to south Louisiana must be considered, along with the plan to block Lake Pontchartrain storm surge from entering drainage canals.

The new maps also will factor the new elevations of various points in the city as measured by the National Geodetic Survey, which maintains a system of 85 "monuments" around southeastern Louisiana. The monuments -- brass disks implanted into public rights of way -- feed information to satellites that is converted into elevation.

Dave Zilkowski, acting director of the Geodetic Survey, said some parts of town may have fallen by as much as a foot since the 1984 flood maps went into effect due to steady subsidence of the land. But subsidence varies depending on the neighborhood, he said.

The new heights will be "as close to reality as you can get," Zilkowski said.

 

Time to debate

While Mississippi was in some ways lucky to get new FEMA maps quickly, New Orleanians might want to be careful what they wish for as well.

Douglas Otto, chief of hydrology and hydraulics for the corps' Mobile branch, said the new federal maps in Mississippi used tidal data from Katrina and Hurricane Camille, which struck Pass Christian in 1969. The results were drastic new elevation requirements, particularly in Hancock County, that will require buildings to be constructed much higher there.

Though Hancock County bore the brunt of both storms, Otto noted, the area is not necessarily more vulnerable than any nearby sections.

"Basically what they did is they took the observed high-water marks and did a statistical analysis," he said. "That's why it came out pretty quick. But it was based strictly on what has happened in the past. I'm not sure it's the best approach. To me, it's not a real great indicator of where these storms are going to hit in the future."

New Orleans, like the Mississippi Gulf Coast, has had substantial flooding from two hurricanes in the past 40 years: Katrina and Betsy, which struck in 1965. However, unlike the Mississippi coast, New Orleans has upgraded its flood protection system. But it's not clear how the New Orleans measures will affect the new maps.

The effects of the new maps in New Orleans will be determined not only by what the maps say, but how residents and politicians choose to use them.

Once preliminary maps are released this summer, officials here will have perhaps a year to debate the virtues and shortcomings of the maps before they become binding.

In the meantime, local officials will have to decide which flood maps to enforce. Do they want to stringently enforce the 1984 maps now on the books, adopt the new maps, or perhaps require that new construction meet an even higher standard?

Many of the homes in the city, because they were built decades ago, are well below the base levels required under the 1984 maps now in effect. To a large extent, it will be up to City Hall to require homeowners wishing to rebuild such structures -- if they are heavily damaged -- to raise their houses.

In terms of future development, city officials will likely find themselves under pressure to allow building right at the base flood elevation determined in the new maps. But Levitan thinks going further would benefit everyone in the long run. In his view, the city may want to encourage homes be built atop garages in flood-prone areas.

"Some of the buildings that were elevated survived without much problem," he said. "A lot of neighborhoods that saw 2 to 6 feet of water, well, what if you just had the garage under the house? OK, the tool bench and the junk you had stored down there got wet, so you clean that up and throw it away."

While crucial to New Orleans, levees shouldn't be seen as the only line of defense against storms, he said.

"You need a belt and suspenders; you need multiple lines of defense," Levitan said. "The first line is the wetlands, and we've got to restore them. The second is the levee system. Then if water gets past that, and the buildings are elevated, you've got another level beyond that.

"In some cases, levees can be our worst enemy, because what happens is that while they provide protection from more frequent storms, they don't protect us from the larger ones. And what happens is you've encouraged people to build lower."

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Gordon Russell can be reached at grussell@timespicayune.com or at (504) 826-3347. James Varney can be reached at jvarney@timespicayune.com or (504) 826-3386.