           
New Orleans
Flood risk maps that the Army Corps
unveiled Wednesday include the possibility of some levee overtopping and
failure -- but don't take pump capacity into account.
Related Link: 100-Year Risk Maps
The 1 percent maps detail the risk of flooding in the event of a
100-year storm, or a hurricane that is expected to occur just once in a
century.
For example, Hurricane Rita has been described as a 100-year storm,
whereas an event like Hurricane Katrina is predicted to occur far less
often.
The 2 percent maps show the risk of flooding in a 50-year storm, and the
0.2 percent maps outline the flood risk in a 500-year storm.
The Corps said New Orleanians can expect better flood protection by
2011, when new plans are in place.
But that protection is coming in at a price tag that's double what was
originally estimated. The Corps said it would need $7.6 billion to pay
for improvements, in addition to the $71 billion already appropriated.
About $1.5 billion would come from the state, while about $6.1 billion
would come from Congress.
Lower Plaquemines will not get 100-year flood protection, because,
officials said, it is just too difficult. However, $1 billion will be
spent in flood improvements in the parish.
Future risk maps will take pump capacity into account, the Corps said.
http://blog.nola.com/times-picayune/hurricane_risk_3.pdf
http://blog.nola.com/times-picayune/hurricane_risk_2.pdf
http://nolarisk.usace.army.mil/
New Orleans
Corps of Engineers Releases New Risk Maps for the New Orleans Area;
Powell Releases New Costs for 100-Year Hurricane Protection
Aug 22 2007
Administration to work with Congress for additional drainage measures
beyond 100-year commitment
NEW ORLEANS, Federal Coordinator for Gulf Coast Rebuilding Donald E.
Powell and U.S. Army Corps of Engineers Director of Civil Works Maj.
General Don T. Riley today detailed the improved hurricane protection
that will be provided to New Orleans area residents once the city's
levees are built to the 100-year level. In addition, Powell announced
$6.3 billion of further funding needed for improved protection for the
New Orleans area and the Administration's plan to secure necessary funds
to complete the work by 2011.
Powell also announced the Administration will work with Congress to fund
a $1.3 billion network of interior drainage projects to ensure the New
Orleans area has a more complete hurricane protection system. The
100-year protection, in addition to the drainage component, ensures the
greater New Orleans area has a hurricane and flood protection system
that far exceeds what existed before Hurricane Katrina.
"Today's announcement restates President Bush's continued commitment to
a Gulf Coast rebuilding effort that prioritizes the safety of the people
of this area," said Powell.
"The risk maps released today by the Corps show exactly how the new
100-year system will provide far superior hurricane protection for
greater New Orleans than at any time in the city's history. Safety is
the top priority for the Administration and one of the main roles for
the Federal government in long-term rebuilding."
As part of ongoing efforts, Corps officials also released information
compiled by the Interagency Performance Evaluation Taskforce (IPET), an
independent team of more than 150 international and national experts
from more than 50 different government organizations, universities, and
private industry, that shows maps of how this planned hurricane
protection will reduce the risk of flooding once the construction is
complete in 2011. This groundbreaking scientific and engineering study
demonstrates a significant reduction in flooding compared to the system
in place prior to Hurricane Katrina. This is the first time anyone has
had a model that could provide a system wide risk assessment. The use of
this model is a pioneer effort, demonstrating the state of the art risk
assessment technology the Corps is using to improve the hurricane
protection system in New Orleans.
"Increased public safety and communication of risk continue to be the
Corps' top priorities for the New Orleans metropolitan area," said Maj.
Gen. Don T. Riley, USACE Director of Civil Works. "The risk maps being
released today are another important piece of information the citizens
in the New Orleans area need to help them make well-informed decisions
about where and how they choose to live and work."
"The maps clearly show that the New Orleans metropolitan area will have
reduced risk of flooding in the future from major storm events as the
comprehensive system is constructed."
The Corps currently has sufficient funding to continue scheduled repairs
and improvements until Fiscal Year 2009. The request to Congress to
provide funding to complete 100-year protection and additional drainage
will be made by the Administration as part of the FY 2009 budget process
since the need for this additional funding will not arise until the
October 2008 timeframe.
Further, Powell stated that there would be a local sponsor cost share
component on the work to ensure that localities have a stake in the
decision-making process and incentives to keep costs down. The standard
cost-share for water projects nationally is 65 percent Federal and 35
percent local. Powell indicated the Administration will review the
historic cost-share arrangements and expressed a willingness to consider
options for the non-federal sponsors to meet their cost-share
obligations.
With this announcement of the additional cost estimate of $7.6 billion,
the total levee repair and enhancement costs for the New Orleans area
now totals almost $15 billion. Based on continued engineering analysis,
rigorous hydraulic modeling, design criteria and expected market
conditions, additional funds are necessary to complete the system.
One-hundred year flood protection is defined by the Federal Emergency
Management Agency (FEMA) as the flood elevation that has a 1 percent
chance of flooding in any given year. The 100-year level of flood
protection is a standard used by most Federal and state agencies,
including FEMA's National Flood Insurance Program (NFIP).
Corps releases risk assessment for New Orleans
"I’ve had this job for 18 months now, and this may be the most important
day since I’ve been on the job."
The draft risk assessment model will allow residents of New Orleans to
estimate the risk of where they live before storms like Hurricane
Katrina strike. (Photo by Don McClosky, Entergy Michoud Power Plant)
Donald Powell, chairman of the Gulf Coast Recovery (GCR) Office,
highlighted the significance of the U.S. Army Corps of Engineers’
release of the prototype draft risk assessment model results for the
hurricane protection system in the Greater New Orleans vicinity with
that statement on June 20. Powell’s comment was made as part of his
opening remarks at the New Orleans press conference conducted to
announce the release of the assessment.
The release of the draft risk assessment marks the first time a model
has enabled an analysis of an entire hurricane protection system. The
assessment provides supercomputer modeled information about the
vulnerability of the Greater New Orleans-area system as it existed both
pre-Hurricane Katrina and on June 1, the start of hurricane season 2007.
The draft risk products enable officials and the public to make better
risk-informed decisions about where and how to rebuild as the region
moves forward in its recovery from the devastating impacts of Hurricane
Katrina on Aug. 29, 2005.
Lt. Gen. Robert Van Antwerp, 52nd Chief of Engineers, said, "We’ve
conducted this world-class study so people will understand their risk.
We intend to communicate transparently, tell the public what we know,
when we know it."
Lt. Gen. Carl Strock, then the 51st Chief of Engineers, commissioned the
independent Interagency Performance Evaluation Task Force (IPET) after
Hurricane Katrina to study the performance of the hurricane protection
system during the storm. IPET developed the risk analysis as part of
their mission.
The released draft risk products show how post-Katrina repairs and
improvements to the protection system have reduced pre-Katrina risk and
vulnerability in most areas.
The publicly released products are the result of a concerted effort by
USACE, GCR, the Office of the Assistant Secretary of the Army (Civil
Works), and other agencies to ensure the highly technical IPET risk
information is translated into easily understood, useful information for
the public.
Lt. Col. David Berczek, USACE program manager for New Orleans risk and
reliability, said, "We have a highly technical assessment that we wanted
to make understandable and useful for the general public. So we
presented it to small community groups and asked for their feedback."
In the weeks leading to the official public release, USACE met with
numerous small groups to present the draft risk assessment and to
solicit comments on how to make the information most useful for the
public.
These sessions included the office of the Mayor of New Orleans, city
government, and local parish presidents and councils; the New Orleans
Business Council; the Louisiana Recovery Authority; local colleges and
universities; insurers and realtors; and many local community and
neighborhood organizations. The groups’ input was essential to the
success of the final products.
The public can now go to the Internet (http://NOLArisk.usace.army.mil)
to view and download annualized flood risk information for specific
locations around Greater New Orleans based on the hurricane protection
system’s status as of June 1. Flood depth information on the maps can
provide the public, businesses and community leaders with critically
needed information for decisions about where and how to build, and what
mitigation measures to adopt.
Risk products are updated from pre-Katrina conditions to show
improvements already made to the system’s 350 miles of levees, temporary
gates, pumps, and other improvements. These prototype risk products
required the development of an entirely new hurricane modeling method.
IPET worked with USACE, the Federal Emergency Management Agency, the
National Oceanographic and Atmospheric Administration, universities, and
private industry to develop the model.
The IPET risk analysis employs advanced physics, mathematics,
engineering, hydrological, geological, and meteorological knowledge. It
incorporates three main factors when determining risk -- hazard
(probability of hurricanes, their surge and waves), the protection
system (performance of levees, floodwalls, and other structures), and
consequences (loss of life or property).
Dr. Lewis Link, IPET director, noted that while past models were based
on actual storms, this model incorporates both historic and possible
future storms. The IPET fed 152 actual and hypothetical storms of
varying severity that might hit the Louisiana coast into the model. The
storms ranged from 50-year storms (two percent annual chance of
occurring) to 5,000-year storms (.02 percent annual chance of
occurring). Hurricane Katrina is considered a 400-year storm for the
Louisiana coast.
The hurricane modeling provides critical water levels (storm surge and
waves) for future storm. These water levels are applied to New Orleans’
350-mile hurricane protection system to determine reliability factors.
More than 135 reaches of floodwalls and levees, representative of
uniform areas of the system, and 350 specific structures (gates,
transition points, pump stations and other features) are profiled in the
protection system model. Information on elevation, design, construction,
maintenance, soil foundations, soil erosion, and other factors are
incorporated into the structural data to determine the overtopping,
overtopping and erosion breaching, foundation failure, and other
parameters of the protection system performance. These factors give the
reliability and potential flooding aspects of the protection system.
The data was applied to pre-Katrina population and property values to
determine risk for loss of life and economic losses for the entire
region by natural drainage basins in the area parishes. The model
assumed no population evacuation. Annualized risk for flooding (water
depths) was also computed for these areas based on hurricane hazard,
structural reliability, and ground elevation.
Link stated that in addition to the model’s ability to show where
vulnerabilities exist in the hurricane protection system, it is also
used to model which potential improvements to the system will provide
the greatest risk reduction and enhanced reliability.
The American Society of Civil Engineers and the National Academies’
National Research Council peer review panels are performing a technical
review of the risk assessment products. ASCE and the NRC have peer
reviewed all other previously released IPET analyses, reports, and
findings.
The next step in the risk analysis work is to model 100-year storm
elevations for the New Orleans-area system. New Orleans District is
using the IPET risk model to produce the 100-year risk products, planned
for release later this summer.
The prototype risk model is drawing interest elsewhere in the U.S. and
internationally as a tool to assist other communities understand and
evaluate the potential risk and reliability of their protection systems.
Karen Durham-Aguilera, director of the Corps’ Task Force Hope, noted the
significance of the risk modeling for New Orleans, saying, "We’re really
fortunate in New Orleans. We’re the only city in the country right now
that has a scientific analysis that tells us what our risk is."
On-line maps of the 37 sub-basins in the New Orleans area with
downloadable maps for use on Google Earth are available at http://NOLArisk.usace.army.mil
or at https://IPET.wes.army.mil. An interactive map and 100-year level
of protection maps will be available on the same Web sites in the coming
weeks.
Rebuilding Metro New Orleans After Katrina: Louisiana's New Statewide
Building Code
by Norma Jean Mattei, Ph.D., P.E., M. ASCE
Associate Professor, Department of Civil and Environmental Engineering
University of New Orleans
New Orleans, Louisiana
Hurricane Katrina
Hurricane Katrina first made landfall as a Category 1 hurricane on
August 25, 2005 just north of Miami, Florida. It traveled through the
Florida peninsula back into the Gulf of Mexico, where it strengthened
into a formidable Category 5 hurricane with maximum winds of 175 mph and
a minimum central pressure of 902 mbar. Katrina’s second landfall was
near Buras, Louisiana on the morning of August 29th. At that time, it
had just weakened to a strong Category 3 with winds of 125 mph and a 920
mbar central pressure. In physical size, Katrina was possibly the
largest hurricane of its strength ever recorded. The damage due to
Katrina along coasts of Louisiana, Mississippi, and Alabama make the
storm the most destructive and the most costly natural disaster in the
history of the United States. Table 1 gives the ranking of hurricanes as
a function of damage caused by each hurricane.
Table 1: Hurricane ranking as a function of value of damage (Source:
National Hurricane Center)
Rank
Hurricane
Year
Cost (billions)
1
Katrina
2005
~$150
2
Andrew
1992
$44.9
3
Charley
2004
$15.4
4
Ivan
2004
$14.6
5
Wilma
2005
$14.4
Homeland Security Secretary Michael Chertoff described the aftermath of
Hurricane Katrina as “probably the worst catastrophe, or set of
catastrophes” in the country’s history. Chertoff was not only referring
to the natural disaster caused by Katrina, but also of the man-made
disaster: the failures of portions of the hurricane protection levee
system of the city of New Orleans, causing long term flooding of the
city.
Katrina’s storm surge devastated the coastal communities along the Gulf
Coast from New Orleans, Louisiana to Mobile, Alabama. Storm surge also
caused the aforementioned breaches in the levee system protecting the
city of New Orleans. Subsequently, 80% of the city was inundated with
flood waters that remained for three weeks or more until the U.S. Army
Corps of Engineers could repair the breaches and pump the city dry.
Protecting New Orleans From Future Storms
In the recovery from Katrina, improved protection of life and property
is an overriding concern. Katrina proved New Orleans’s vulnerability to
Category 4 and 5 storms. The current Mississippi River and Lake
Pontchartrain levee system was built after Hurricane Betsy in 1965 and
is only designed to protect against a Category 3 storm (Betsy was a
Category 3). The National Hurricane Center predicts that the Gulf of
Mexico will see more frequent and stronger hurricanes for the next
decade. Higher flood protection standards are needed in order to protect
the coastal population from storm surge driven by these stronger storms.
The U.S. Army Corps of Engineers is presently repairing the levee system
to its pre-Katrina level of protection. It is hoped that the system will
be repaired prior to the 2006 hurricane season. The Corps is also
investigating improvements to the system. Structural options such as
raising the levees and building flood gates similar to those used to
protect The Netherlands from 1,000-year events are being studied.
Building in New Orleans, most of which is below sea level, is inherently
risky. One hundred percent protection against coastal hazards such as
hurricanes and flooding is not possible. One way to mitigate storm
damage is to rehabilitate coastal wetlands and barrier islands.
Louisiana has lost an alarming amount of coastal wetlands in the last
several decades due to subsidence and salt water intrusion. Coastal
wetlands provide the first arm of defense in combating damage due to
storm surge and can be looked upon as an apron of protection around
critical infrastructure such as levees.
Wind damages can be mitigated by development and enforcement of a
unified building code. Florida’s code was motivated by damage from
Hurricane Andrew in 1992. Florida adopted its enhanced building code in
2001. In 2004, Hurricane Charley, a very intense Category 4 storm,
provided a true test of Florida’s new code. One only had to compare the
conditions of homes built pre-code and post-code in the same vicinity to
see the dramatic difference building codes can make. Newer structures
that were built and inspected properly fared much better than
pre-building code structures.
Building requirements for flood protection are primarily driven by the
National Flood Insurance Program (NIFP) administered by the Federal
Emergency Management Agency (FEMA). In order to participate in the flood
insurance program, communities must adopt land use and construction
regulations that mitigate or eliminate flood damage in high-risk areas.
The effects of 100-year events are predicted and base flood elevation (BFE)
maps, known as Flood Insurance Rate Maps (FIRMs), define high risk
areas. A community can use these elevations as part of its building code
requirements. In order to obtain flood insurance, a new structure must
be built at or above its BFE. However, building at the BFE is not a
guarantee that the structure will never flood. The flood level in the
majority of flooded homes in the New Orleans area was well above their
BFEs. The flooding of New Orleans from Katrina was an extreme event,
well beyond a 100-year occurrence level.
A Statewide Building Code
Mississippi and Alabama currently do not have a statewide building code
for residential structures. In 2004, the Louisiana legislature voted to
adopt a State Uniform Construction Code (SUCC), based on the 2000
International Building Code, for commercial buildings. Many Louisiana
cities such as New Orleans, Baton Rouge, and Shreveport, as well as the
unincorporated portion of Jefferson Parish, did have fairly stringent
building codes and inspection requirements for residential structures in
place. However, outside of major metropolitan areas, building codes to
protect against wind damage of homes were essentially nonexistent.
Louisiana did not have a statewide uniform building code for one- or
two-family residential structures—until now.
In November 2005, Governor Kathleen Blanco signed Senate Bill 44 into
law. This bill called for a statewide building code in Louisiana. The
bill created a 19-member, governor-appointed Uniform Construction Code
Council. The makeup of the council includes two state legislators, as
well as representatives from the fields of architecture, engineering,
plumbing, and real estate; from the Louisiana Home Builders Association;
from the insurance industry; and from the state fire marshal’s office.
It is tentatively proposed that the Louisiana Section of the American
Society of Civil Engineers be responsible for nomination of the
engineering representative. The new law requires that all new
residential homes have hurricane straps at roof and wall connections.
The structure must also be tied to the foundation. Laminated windows or
shutters and steel-reinforced garage doors are also required to protect
the residence from damage by wind-blown debris.
The impact of the new building code on residential construction costs
will vary from jurisdiction to jurisdiction, depending on the building
code currently in effect in each area. Homebuilder associations opposed
the new law, stating that the code would drive up the cost of
construction, especially in rural areas that did not have a residential
building code in place. Some planners estimate that the new requirements
have added $4,000 to $6,000 to the price of a new three-bedroom,
two-bath, 1,500 square foot home. David Williams, Jefferson Parish
Department of Inspection and Code Enforcement, said parish ordinances
already call for building standards that meet or exceed the new
statewide code. Accordingly, Williams does not expect the new state code
to have much of an impact on home construction costs in suburban
Jefferson Parish. Just how will the new code impact the rebuilding of
New Orleans?
Damage in Katrina-Affected New Orleans
Over 1.5 million people were evacuated from their homes along the Gulf
Coast because of Hurricane Katrina. Table 2 gives a breakdown of the
population (pre- and post-storm) of metropolitan New Orleans by parish
(county). Please note that the data for the current population and the
percentage of change are rounded numbers. Also note that Orleans Parish
encompasses and is the city of New Orleans. The other six parishes
comprise suburban communities surrounding New Orleans proper.
Table 2: Pre-Katrina and Current Population of Metropolitan New Orleans
by Parish
(Source: U.S. Census Bureau and the Times Picayune)
Parish
Pre-Katrina Population
Current Population
Change
Orleans
462,269
134,400
-71%
Jefferson
453,590
375,000
-17%
St. Charles
50,073
69,073
+38%
St. John
45,581
48,581
+7%
St. Bernard
65,554
8,000
-88%
St. Tammany
213,553
280,000
+31%
Plaquemines
28,969
14,500
-50%
Metro area
1,319,589
929,554
-30%
Some of the net gain in population of parishes such as St. Tammany may
be permanent. Much of it is due to displaced residents living with
friends and family while repairs are made to their homes or until they
can purchase a new home in the area. Over 300,000 area residents were
evacuated to other Louisiana cities, such as Baton Rouge, Lafayette, and
Shreveport, or to cities outside of the state, such as Houston, San
Antonio, Dallas, Atlanta, and Memphis. Some New Orleanians, especially
those that are not home owners, will eventually settle in the location
to which they were evacuated. The question plaguing many city planners
is: “Just how many will return?”
Roughly 80% of the homes on the eastbank of Orleans Parish flooded. The
westbank of New Orleans, the neighborhood of Algiers, did not flood.
Homes near the edge of the Mississippi River and Lake Pontchartrain were
less likely to flood, as these areas are higher in elevation. Homes
along natural ridges, such as Gentilly Ridge, also escaped flooding.
Inspections of the roughly 128,000 homes on the eastbank by the City of
New Orleans and the Corps of Engineers were completed in late December
2005. The houses were tagged with red, yellow, or green stickers. Table
3 lists the results of these inspections.
Table 3: Assessment of Homes on the Eastbank of New Orleans (Source:
Corps of Engineers)
Category
# of Homes
Description
Green
35,475
Safe to enter, occupancy is permitted, may have minor, repairable damage
Yellow
86,934
Some structural damage or hazard, areas may be able to be occupied,
owner may demolish or repair
Red
5,534
Unsafe to enter, danger of imminent collapse, occupancy is prohibited
Of the 5,534 homes that were deemed structurally unsound, about 2,500
pose a public health hazard. The other 3,000 will be inspected again,
for verification purposes. Owners of red-tagged historic properties may
want to rehabilitate or salvage parts of these buildings, if feasible,
but most of these residences will ultimately be demolished. The fate of
the yellow-tagged homes is not so cut-and-dry. Many owners of homes with
yellow stickers have not yet decided to sell as-is, demolish and build
new, or rehabilitate. Many factors are involved in this decision. The
percentage that the home is damaged is a critical number. Under the
“fifty percent” rule, if the home’s top of lowest floor elevation is
below the BFE on current FEMA flood maps (see figure 1) and the repairs
costs more than 50% of the pre-Katrina value, the home owner must
elevate the property to at least match the BFE. Homeowners whose
structures are damaged more than 50% and elevation is required are
eligible for a FEMA grant of up to $30,000, to cover the costs of
raising the home.
The Impact of the Building Code on Rebuilding New Orleans
Most green tagged homes are located on high ground found along the
Mississippi River in the French Quarter, Garden District, and Uptown
neighborhoods. Many are 100 years old or older, predate the levees, and
are timber structures built on piers. As the high ground became built
up, homes were built in areas reclaimed from swamp. Home construction
after 1950 was primarily on pile-supported slabs in these lower lying
areas. Red and yellow tagged homes in New Orleans are more often located
further from the river, making them more likely to be lower in elevation
and newer (thus perhaps having a slab foundation and not easily
elevated). Because New Orleans is such an old city—it predates the
United States by over 60 years—most homes in New Orleans were built
before any code was in effect.
THE LIE: N.O. IS TEN (10) FEET BELOW SEA LEVEL!
the truth (from the same page): only a bit over half of NO is below sea
level. 70.6% was flooded (storm surge is well above normal sea level.)
That's fine. Punt the part that floods, rebuild the part that isn't
going to be underwater after the category 6 that's coming this year.
"Minneapolis is destroyed by tornadoes"
Tornadoes are very destructive but they don't take out entire cities.
The damage is amazingly selective.
turbodog writes "New Orleans wasn't flooded with sea water either. If
the lakeside levees hadn't failed, the city would have weathered the
storm pretty well (except for the torn off roofs and fallen trees). If
the MS river hadn't topped the levees around St. Louis, no flood. Sea
level has nothing to do with it."
Difference is when the Mississippi receeds St. Louis drains, not so much
for New Orleans. In fact one of the fears in a Cat 4/5 is the storm
surge over topping the levees thereby filling the bowl and causing more
damage than flooding from the lake side.
posted by Mitheral at 6:31 PM on April 7
You know, Minneapolis really doesn't have very many tornadoes at all.
It's not even in what is generally referred to as "Tornado Alley." It
doesn't even have more tornadoes than places like Boston, New York City
or DC.
So why is Minneapolis suddenly the tornado city referred to here? Surely
we mefites have more knowledge of geography than this.
posted by JekPorkins at 8:00 PM on April 7
I work for the company that created the flood map that Nola linked to
above.
In case anyone's curious, this is my understanding of how the flood map
was created (it is not perfectly accurate):
NO consists of several natural and man-made "bowls". The level of the
water should be the same elevation throughout the bowl (for the most
part). So, if we have evidence of a particular bowl having water at 1ft
above sea level, for example, we can apply that throughout the bowl. If
someone's home is on land 2 ft under sea level, the water level in that
location will be three feet (roughly).
Water depths were collected from various sources including charts given
to us by a few government agencies (almost daily). Also, we do a lot of
work offshore, so we have satellite phones. These were loaned (to the
national guard, I believe) to help out in NO. So those guys called us
every so often and gave us the water depths at known locations (street
intersections, for example).
I'm sympathetic to the broader point. The idea has been bruited about
that NOLA doesn't deserve to be rebuilt because it's in a stupid
location -- despite that the flooding was largely subject to man-made
factors such as poor design and construction of floodwalls (not to
mention the use of floodwalls instead of levees; they're different
animals), the lack of maintenance and upkeep and monitoring of said
floodwalls, the failure to implement long-obvious recommendations such
as a storm surge barrier for Lake Pontchartrain, lousy pre-disaster
planning at various levels, malcompetent management of post-disaster
rescue and recovery efforts -- which all make such a judgement
particularly obscene. Especially when you consider the investment in
rebuilding that coastal residents chipped into for years and years, on
top of the taxes they all pay.
It's also stupid because NOLA wasn't always at such risk. The Army
Corps, by walling the Mississippi, has prevented the silt that comes
down from the Midwest from helping to maintain the delta (now it's shot
straight out into the bottom of the Gulf). The wetlands have been
destroyed by other man-made factors, further reducing the natural
protection that the city used to have. And pumping the city to keep the
floor dry, as it were, has helped parts of it sink further. Then, as if
that all weren't bad enough, global warming comes along and helps sea
levels inch upward, and supercharges the hurricane season so that we get
more, and worse, storms each year.
That said, I'm also pragmatic, and NOLA should have its lowest-lying
areas redlined, the racial and economic composition of those areas
pre-Katrina be damned. In the wake of the disaster, those areas will be
forever ghettoized. NOLA is never, as Astro points out, going to get
some of those people back, but they didn't have jobs before the
hurricane. Yes, NOLA is an important port still, but many of the jobs
have been automated or moved out of the city proper (there is a major
seaport facility west of the city). Without jobs for people, there's no
way I can recommend they all return.
I do think NOLA can be a viable city at a majority or even plurality
fraction of its pre-storm size. Maybe 250,000 people. So even if people
can't rebuild where their old house was they will certainly be able to
rebuild somewhere in the city -- there's gonna be plenty of room. And
yes, especially if the main industry continues to be tourism, a lot of
people are going to be poor. I think to a very large degree the people
that want to come back to NOLA will be able to do so.
But we have to be smarter about the next time. I'm pretty sure that my
major idea here will never be implemented so I may as well be tooting
out my ass, but I think the Japanese super-size levee -- basically a
levee with a minuscule grade that becomes the land on which people build
-- should ring the city. The trouble is, you can't easily build such a
project when people are living there, but you can build it when they're
not. In other words, this is the golden opportunity to build these
levees, when there's nobody living in the houses because they aren't
there anymore.
Then the city needs to address its Titanic problem -- floodwalls that
don't completely insulate parts of the city from one another. Those
walls (and floodwalls inside don't bother me as much) should be complete
barriers, and they should probably break up the city into smaller
chunks, so that a flood won't be as catastrophic.
Residents, meanwhile, need to start thinking like they're below or near
sea level, and any new construction should be full of barrier island
features such as the first living floor on stilts and the ground level
utility rooms such as garages (just think -- more back yard). If the
lowest areas are redlined, that reduces the number of houses that need
such treatment.
And the Dutch learned from us, more or less, how to build their
seawalls, which they were prompted to build by the awful North Sea
"hurricane" of the 1950s -- now it's time for us to learn back from
them. A storm surge barrier like the Thames Barrier may well have
prevented much of the flooding (no guarantees, of course).
So that's my plan in a nutshell. NOLA gets rebuilt, but sensibly. The
money isn't spent on making inadequate floodwalls higher, it's spent on
a more forgiving and less reactionary theory of flood management. The
idea is no longer How do we keep the sea out? but How do we manage
inevitable flooding? So we put money into rebuilding the city, but we
also protect our investment, by doing it smarter.
This could all be done if we had visionary leadership and transparent
government. But we don't, so it's not gonna happen. Twenty years after
the Chicago fire, Chicago was the nation's second largest city and
hosting a world's fair. There's no reason, if we wanted to, that we
couldn't make New Orleans a world-class showcase of American spirit and
values.
Preservationists: "Don't tear down New Orleans." I really hope people
like this can make a difference ... from today's Times-Picayune:
In the aftermath of a natural disaster, the first instinct of local and
federal officials is to tear down devastated structures -- an "instinct
that is almost always wrong," said the president of the National Trust
for Historic Preservation, who urged officials at the group's annual
symposium here to lobby for the preservation of New Orleans' historic
buildings.
"There are new technologies, new building practices that can be brought
to bear that were not available even 15 years ago," said Richard Moe,
president of the trust, which spearheads preservation efforts in all 50
states. To thunderous applause from the packed auditorium in downtown
Portland, he stressed that: "No historical building" in New Orleans
"should be torn down without a survey."
The trust's president is attempting to place his organization at the
forefront of the debate over whether the low-lying areas of the
hurricane-ravaged city should be rebuilt.
[...] According to the trust, there are 20 neighborhoods within New
Orleans designated on the National Register of Historic Places,
containing 37,000 historic structures.
"There's a lot of talk about mold," Moe said. "But there are measures
that can be taken" to mitigate its effect and save the historic core of
New Orleans from demolition.
[...] "You can't save New Orleans without rebuilding what's there," Moe
said. "It has this unique character.
"No other city in the country or in the world has these layers of
cultures, traditions, histories...It's the Creole home, the corner shop,
the shotgun structure that makes up the vernacular architecture."
There was a terrific article in the New York Times the other day about
83-year-old New Orleans master plasterer Earl A. Barthé, from a family
who for the last 150 years have provided artisanal plaster to homes and
buildings, and are among the dwindling number who are part of the city's
"architectural soul."
We need people like him now, more than ever. What's more, we need some
home folks to come back and be his apprentices.
Short Term: Levees
Many challenging factors had to be taken into account for our plan. The
loss of the wetlands over the years and the rising Mississippi River are
two of the biggest threats, but subsidence and the fact that much of New
Orleans is already below sea level also affected our solution. Our
figures also had to be readjusted to account for global warming. In the
future, global warming will cause sea levels to rise, which means more
land loss, and it will also cause increasingly powerful hurricanes from
the Atlantic, which means more powerful storm surges and flood waters.
We also looked at the possible environmental effects of our plan because
we didn’t want to greatly imbalance any ecosystem.
Many of the levee failures were human error and bad engineering design,
which can be fixed by careful design, construction, and maintenance. The
New Orleans flood protection system was not built cohesively as one
uniform system. It was built in phases and stages by many different
groups. We emphasize the importance of standardizing the construction,
monitoring, and maintenance of the system.
When Lisa and Peter Burk moved from St. Bernard Parish to New Orleans
last summer, they were acutely aware that they were going from one
disaster area to another.
Hurricane Katrina's massive storm surge devastated their Meraux
subdivision, washing away some houses, concrete slabs and all, while
inundating their two-story home with 14 feet of water.
Things weren't much better at the Lakeview home they would later buy in
the 6500 block of Marshal Foch Street, where floodwaters surged to about
10 feet in the street.
But Lisa Burk said they figured the relatively isolated levee failures
that caused the Lakeview flooding could be fixed faster than the miles
and miles of damaged and insufficient levees protecting St. Bernard.
"We knew it was still a bit of a gamble, though," she said.
And so she was relieved to learn that a team of more than 150 scientists
and engineers who spent 18 months studying 152 computerized hurricanes
has determined the couple's kitchen-table analysis was dead-on accurate.
Nearly two years after Katrina, the risk of flooding in Lakeview has
been substantially reduced, while St. Bernard is only slightly less
vulnerable, according to exhaustively researched flood-risk maps
released last week by the Army Corps of Engineers.
The maps compare the flood risk from a 100-year hurricane on the day
Katrina struck with that on June 1, after repairs and some improvements
had been made to 220 miles of the 350-mile hurricane protection system
in the New Orleans area. A 100-year hurricane is one that has a 1-in-100
chance of hitting the area each year.
Floodgates added to three outfall canals in Lakeview will block surge
entering from Lake Pontchartrain, reducing projected flooding in the
neighborhood by an average of 5.5 feet, according to the maps. But in
St. Bernard, the maps show a much more modest 2-foot reduction in
flooding, with vast areas still expected to be inundated by more than 8
feet of water in a 100-year storm.
"We thought the corps would be able to do more in Lakeview, and it looks
like we were right," Lisa Burk said. "It was hard for me to leave St.
Bernard, but I do feel safer from flooding here."
The release of the highly anticipated maps could add more fuel to a
recent uptick in rebuilding activity in Lakeview and boost the real
estate market in other areas, such as Old Metairie and Old Jefferson,
where the flood risk also is significantly lower than when Katrina hit.
In areas to the east where the maps show little or no reduction in the
flood risk, including Gentilly, eastern New Orleans, the Lower 9th Ward
and St. Bernard, residents and local officials said they will be
watching closely in a few weeks when the corps is expected to release
maps showing risk levels in 2011 after the hurricane protection system
is upgraded to guard against a 100-year storm.
"We fully expect to see some significant improvements when those maps
are released," said Joey DiFatta, St. Bernard Parish Council chairman.
St. Tammany, St. John and St. Charles parishes were not included in the
risk assessment.
Meanwhile, insurance experts said the maps released Wednesday could
prompt insurance companies to begin writing new homeowners' policies in
areas where the flood risk has been significantly reduced, although a
break in skyrocketing premiums seems unlikely.
The maps also could serve as a guide for flood-weary residents looking
to buy homes in areas less prone to flooding, real estate experts said.
A reassuring monstrosity
Connie Uddo, site manager for St. Paul's Homecoming Center in Lakeview,
said the maps won't help residents who are waiting for Road Home grants,
but they could give wavering Lakeview residents the confidence to
rebuild.
A survey done in February showed that just 17 percent of the 7,000 homes
in Lakeview were occupied, Uddo said. But a forthcoming survey likely
will show that figure is closer to 30 percent thanks to continued
renovations, she said.
"What's keeping a lot of people from coming back is a sort of crisis in
confidence. They don't know whether they can go through another
Katrina," she said. "These maps are very encouraging, because they show
we are significantly better off than before Katrina. That eliminates a
huge question mark for a lot of people."
However, she acknowledged some residents likely will dismiss the maps
because they don't trust the corps.
"Some people who are angry at the corps are going to say, 'Oh, right.
They told us we were safe before Katrina and look at what happened,'¤"
she said. "But the corps is under a huge microscope now. They know they
are going to be held accountable, and you can see it in how they have
been working 24/7 on the floodgates and pumps."
Lakeview resident Tim Keogh, who said he is as jaded about the corps as
anyone, said the flood-risk maps have confirmed his cautious faith in
the new 17th Street Canal floodgate.
"It's a massive, ugly, disgusting monstrosity that ruins the whole
ambiance of the lakefront, but you can't help but be reassured by its
presence," he said.
Vulnerabilities to the east
Despite the significantly lower flood risk in Lakeview, the corps' maps
show a mere 6-inch reduction in flooding on the other side of Bayou St.
John in Gentilly.
"Six lousy inches?! Is that the best they could do after nearly two
years?" said Tom Canfield, who lives in a FEMA trailer outside his
mother's flood-damaged Gentilly home in the 2700 block of Odin Street.
"It's mind-boggling. Why has so much been accomplished in Lakeview and
so little in Gentilly?"
Corps officials say the problem is to the east. Low floodwalls and the
potential for breaches along the Industrial Canal leave Gentilly's
eastern flank vulnerable to storm surge, they say. The corps plans to
spend hundreds of millions of dollars on floodgates to block surge into
the Industrial Canal at the Seabrook Bridge on Lake Pontchartrain and in
the Gulf Intracoastal Waterway.
Those improvements are expected to show a major reduction in the flood
risk for Gentilly in the 2011 maps to be released in the coming weeks.
"If it's going to be good news, I guess I can wait a few weeks,"
Canfield said Thursday. "But this is already Day 446 for me living in a
trailer. I keep a calendar like a convict serving time in prison."
Community leaders in eastern New Orleans said maps showing no reduction
in the flood risk there won't slow their recovery efforts.
"The maps made me question why the government hasn't done more to fix
the problem, but it won't stop us from rebuilding," said the Rev. Luke
Nguyen, associate pastor at Mary Queen of Vietnam in the predominantly
Vietnamese-American neighborhood of Village de l'Est.
More than 90 percent of the neighborhood's residents have returned since
Katrina, he said.
"Where else would we go? Most of our grandparents are buried here," he
said. "It is like a second homeland to us."
In St. Bernard Parish, the maps show post-Katrina repairs and
improvements to the levees along the Mississippi River-Gulf Outlet would
reduce fatalities in a 100-year storm by up to 90 percent in some areas
but would have an almost negligible effect on property damage.
"It's better than what we had, but it's far from being enough," said
DiFatta, the Parish Council chairman.
He said St. Bernard officials are anxious to see the 2011 flood-risk
maps, which will factor in several planned improvements, including
raising levees and floodwalls along the MR-GO from 20 feet to 28 feet
and adding gates to keep storm surge out of the Gulf Intracoastal
Waterway.
"We're going to hold their feet to the fire to make sure that all gets
done by 2011," he said. "We've waited 45 years for better levees and to
get the MR-GO closed. We can wait a few more years as long as they're
making steady progress on it."
Lower Old Metairie risk
For residents of Hoey's Basin, a depression that encompasses most of Old
Metairie in Jefferson Parish, the corps' new flood-risk evaluation is a
matter of degrees.
The new floodgate at the mouth of the 17th Street Canal, bolstered levee
walls near Airline Drive and two new retention ponds have done much to
lower the chances of flooding there during hurricanes.
Had all those measures been in place two years ago, Debbie McLanahan's
home on Atherton Drive would have been dry. She stopped short of
criticizing the corps Thursday, instead handing plaudits to parish
administrators for vigilance against flooding.
"I really do feel that Jefferson Parish has done everything that it can
do or could have done in the past 20 months to make things better," she
said. "It's our choice to live here. We know the risk. If it happens
again, we won't be coming back. Not many people we know will."
Joe Rault's home on Northline Drive sits a block away from the lowest
part of the basin at Nassau Drive and the Metairie Country Club. News of
the diminished flood risk meant little to him Thursday.
"Well, I'll still flood," he said with a laugh. "I think they're
spoon-feeding us. I think it's nice to get this, but it's not the whole
picture."
The only measure that will comfort him, he said, would be if the corps
built pumps to carry floodwater to the Mississippi River.
Wind versus water
Arthur Sterbcow, president of Latter & Blum Realtors Inc., said
prospective home buyers will undoubtedly take note of the flood-risk
maps.
"It's obviously good news for the Lakeview and Old Metairie real estate
markets," he said.
But he said the maps will have little or no effect on the region's
overall recovery unless the reduced flood risk helps mitigate the
insurance crisis.
"It's one thing for the corps to pat us on the head and use these maps
to try to show us that it wasn't a mistake to rebuild our homes," he
said. "But unless they can convince insurance underwriters to lower
premiums, the corps didn't get the job done."
Although the maps likely would have the greatest impact on federal flood
insurance, there could be a trickle-down effect on homeowner policies
covering wind, fire and liability, said Jeff Albright, chief executive
officer for the Independent Insurance Agents and Brokers of Louisiana.
As Katrina has demonstrated, people often don't have enough flood
insurance to cover their losses, so they tend to be more aggressive in
making claims on their homeowners' policies by saying damage was caused
by wind and not water, Albright said.
"To the extent that the maps show improvements in flood protection, it
should increase the appetite for insurance companies to write new
homeowners' policies in those areas because there's less of a chance
they will have to deal with wind-versus-water disputes," he said.
However, homeowners are unlikely to see significant reductions in
insurance premiums, he said.
"Because the homeowners' policies don't cover water damage, it's hard to
see how they would reduce premiums in areas with a lower flood risk," he
said. "But if we get more companies writing new policies, it could
reduce pricing because of the increased competition."
Canfield, the Gentilly resident, said the daily struggle to find
affordable insurance and secure a Road Home grant while making basic
repairs to his mother's house is taking a toll.
"Sometimes I don't know if I'm seeing the light at the end of the tunnel
or an oncoming train," he said.
But he said he found a bit of comic relief in the disappointing
flood-risk maps.
Noting that the projected reductions in flooding have a margin of error
of plus or minus 1.5 feet, Canfield wryly pointed out that Gentilly's
anticipated 6-inch reduction could actually be a 1-foot increase in
flooding.
"I had to laugh when I saw that things could be getting worse," he said.
"Are we living in the twilight zone?"
http://blog.nola.com/times-picayune/hurricane_risk_1.pdf
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