Eight years after Hurricane Katrina struck, the New Orleans region is

Transcription

D efending
N ew O rleans
Special
Report
ight years after Hurricane Katrina slammed into the
levees and floodwalls that were supposed to
protect the city of New Orleans, causing multiple breaches that flooded much of the region for days and even weeks, the U.S. Army
Corps of Engineers is completing a new line
of defense for New Orleans that features miles
of raised, reconstructed, and reinforced levees
and floodwalls, along with enormous sector
gates and surge barriers, including what is believed to be the world’s largest drainage pump
photocredit goes here
E
station and a nearly 2 mi long barrier structure
that was the largest civil works project ever undertaken by the Corps. The new physical infrastructure, together with changes in procedures
and other improvements, were designed to
make the city safer than it’s ever been.
But even with a budget of more than $14
billion—of which $10.4 billion had been
spent at press time—the Corps readily admits that this new system still does not actually protect New Orleans.
Instead, as its name implies, the new Hurricane and Storm Damage Risk Reduction
System (which goes by the unwieldy acronym
HSDRRS, pronounced “HIZ-ders” by some)
is designed primarily to reduce the risk that
the residents of New Orleans face from storm
surge and flooding if and when another major
hurricane strikes the region. Prior to Katrina,
the levees and floodwalls that surrounded New
Orleans were referred to as a hurricane protection system, but that designation created “a
false sense of security,” notes Colonel Edward
R. Fleming, the commander of the Corps’s
New Orleans District during the construction
of much of the HSDRRS. As he explains, “A
U.S. Army Corps of Engineers, all
Eight years after Hurricane Katrina struck, the New Orleans region is
being ringed by a more than $14-billion system of stronger and higher levees,
improved floodwalls, and new storm surge barriers that the U.S. Army
Corps of Engineers says provides the best defenses against hurricanes that the
region has ever known. This special report examines what was constructed,
how it is expected to work, and why various experts and groups have such
strong feelings pro and con about the new system. . . . . By Robert L. Reid
A crisscrossing array of crane booms, opposite, helped the
Corps to complete at least 2 mi of new T-wall floodwalls per
month along a 23 mi long section of levees in St. Bernard Parish.
The foundations of the new levee known as LPV-111 were
buttressed via a method known as deep soil mixing and involved
the installation of more than 18,000 stabilizing columns.
© 2013 american society of civil engineers all rights reserved
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levee doesn’t protect anybody or anything; a levee is just an additional feature that reduces risk” from storm surge.
In such a risk reduction system, however, there are measures
other than just federal flood projects to help reduce the risks,
some undertaken by state and local authorities, including the
elevation of buildings or critical equipment, the protection and
restoration of barrier islands and coastal wetlands, and even the
evacuation of populations that are in harm’s way, Fleming says.
Given the combined threats to New Orleans of increasingly
powerful storms that many climate scientists foresee, together
with predictions of rises in sea level and the ongoing subsidence
of the land in the region, “there will always be some residual
risk” for the people of the Big Easy, Fleming says. And this is
why, having learned critical lessons from Katrina, the Corps has
adopted “a whole different mind-set,” he stresses.
The change is more than a semantic switch away from
“protection.” For the Corps’s New Orleans District, at least,
it represents a tremendous change in the Corps’s approach to
the engineering, financing, construction, and even purpose
of major civil works.
Fleming declared the HSDRRS “complete” in May after a series of practice drills at several of the new system’s major facilities
in preparation for the 2013 hurricane season. He turned over
command of the New Orleans District to Colonel Richard L.
Hansen later that same month. Like “protection,” however, the
designation “complete” also must be explained because certain
critical construction projects for the system are still in the works.
Of prime importance, the levees are not yet armored and construction has just begun on a series of permanent pump stations
and closures to replace interim facilities at three outfall drainage
canals along Lake Pontchartrain. But the system is complete in
the sense that it is now capable of withstanding the surge from
a storm that has a 1 percent chance of being equaled or exceeded in any given year, also known as a 100-year storm. The ability to withstand a 100-year storm is the standard used by the
Federal Emergency Management Agency to certify the region
for participation in the National Flood Insurance Program; the
Corps has submitted a National Flood Insurance Program levee
system evaluation report on the new levees to the Federal Emergency Management Agency, as required, but at press time certification from the program had not yet been granted.
The new system will actually defend the New Orleans region today at a level above a strict 100-year standard, Fleming
notes, given that it was designed to accommodate the storm
surge of a 100-year event over the next 50 years. The design
took into account the expected rise in sea level as well as the subsidence of land over those five decades. Moreover, the planned
armoring of the new levees will be designed to offer the resilience necessary to survive the storm surge of a 500-year event.
The armoring of levees is key to the Corps’s efforts to provide
the resilience to withstand a 500-year storm, notes Fleming.
Although the levee and floodwall elevations are designed to the
100-year storm standard, “if we get a 500-year storm and get
overtopped, there will be flooding,” Fleming concedes, “but
you’re not going to get the catastrophic [levee and floodwall]
failure or the breaches like you would have seen before.”
That idea is critical to the Corps’s new approach to risk
reduction. New Orleans has often been flooded during ma[ 5 0 ] C i v i l E n g i n e e r i n g n o v em b e r 2 0 1 3
100-Year Risk Reduction System
jor storms, but the water was simply pumped out afterward.
Considerable damage resulted, but there was not the citywide devastation that occurred during Katrina when the
levees and floodwalls were breached, which meant there was
no way to stop the water or send it back out again.
The new system is also considered complete because for
the first time since work began in the aftermath of Katrina,
no temporary closures will be needed to secure construction
openings during future storms because those openings have
now all been closed, explained a May 30, 2013, issue of Task
Force Hope’s Status Report Newsletter. (Task Force Hope is the
name of the Corps office that is responsible for oversight of
the HSDRRS program.)
As the clarification of such terms as “protection” and
“complete” should indicate, however, little concerning the
HSDRRS and post-Katrina New Orleans has been simple
or easy. For example, the new system was tested in August
2012 by Hurricane Isaac and performed exactly as designed,
according to Mike Stack, Jr., P.E., the New Orleans District’s
chief of emergency management (see “New Orleans’ Defenses Weathered Isaac ‘Very Well,’” Civil Engineering online edition, September 25, 2012, http://www.asce.org/CEMagazine/Article.aspx?id=25769811641&terms=mike+stack+
hurricane+isaac). But instead of being able to breathe the
proverbial sigh of relief, the Corps faced criticism because
while the new defenses had protected people and property
within the perimeter system from Isaac’s surge-related flooding, it was contended that the HSDRRS might have worsened
the flooding in certain regions outside of that system, including portions of Plaquemines and St. John the Baptist parishes
that had not experienced flooding during Katrina.
And while many local stakeholders interviewed by Civil
Engineering for this special report did agree with a statement
by Fleming that “the system that’s in place right now is the
best system that New Orleans has ever seen, clearly better
than it was before Katrina,” they also expressed strong reservations about individual aspects of that system. In particular,
they questioned the adequacy of the 100-year standard itself, a standard that many have noted might not even prevent
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The 1.8 mi long Inner Harbor
Navigation Canal–Lake Borgne Surge Barrier,
considered the largest barrier of its kind in
the world, was designed to prevent storm surge
from Lake Borgne from rushing into the Inner Harbor
Navigation Canal and the Gulf Intracoastal Waterway.
the overtopping that the region experienced during Katrina,
which produced storm surges and waves equivalent to those
of a 400-year storm.
A 100-year storm standard was declared “inadequate for
flood protection structures in heavily populated areas such as
New Orleans, where the failure of the system would be catastrophic,” according to a 2009 report by the National Academy
of Engineering and the National Research Council entitled The
New Orleans Hurricane Protection System: Assessing Pre-Katrina Vulnerability and Improving Mitigation and Preparedness.
Likewise, ASCE’s Hurricane Katrina External Review
Panel (ERP) declared the 100-year standard “unacceptable”
in an April 15, 2008, letter to Lieutenant General Robert L.
Van Antwerp, Jr., P.E., then the Corps’s commander and chief
of engineers. The ERP conducted an independent technical
review of the findings of the Corps-sponsored Interagency
Performance Evaluation Task Force (IPET), which was established to assess the performance of the hurricane protection
facilities in New Orleans and southeastern Louisiana during
Katrina. Noting that the 100-year storm standard, even with
a 500-year flood standard, means that there is a 10 percent
chance every 50 years of Katrina-like catastrophic flooding
and “loss of property, life, and lifestyle,” the ERP’s letter concluded that “this level of risk in the New Orleans area [is] far
above that employed for other engineered structures.”
H
ow the Corps managed to construct the HSDRRS
despite numerous challenges and impediments, the technical details of the system’s major features and facilities,
and how these efforts have been perceived and received, as
well as what the Corps might have to do next in terms of
risk reduction in southeastern Louisiana, will be explored
in this special report, for which I visited several of the major
pieces of the new system, spoke with the Corps’s leaders and
project managers and with its critics, and pored over stacks
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of reports, letters, news articles, the minutes of government
agency meetings, and other documents.
The consensus among those interviewed is that the
HSDRRS should enable the residents of the Big Easy to rest
a little easier during future hurricane seasons. However, they
note that such an ambitious infrastructure project will never
really be finished. Even the new levees will need additional
lifts over time, and in fact work has already been done on one
section. Moreover, some feel strongly that critical aspects of
the new line of defense around New Orleans should be reconsidered and potentially even reworked.
To understand the facilities that were constructed for the
HSDRRS and why and how the Corps’s work on this project
differed greatly from the many other efforts undertaken by
its engineers, it’s best to start with a reexamination of what
went wrong during Katrina, especially since many of the actions and decisions made before and even during that storm
helped to guide the decisions about the design, construction,
and funding of the new system.
First, it’s important to remember that much of the New
Orleans region is located below sea level and that flooding
during hurricanes is hardly a new problem there. But during Katrina the water could not simply be pumped out because of a series of failures that included breaches in the region’s flood protection defenses at about 50 distinct locations
and problems with the region’s pumping stations, according
to the ERP’s 2007 report, The New Orleans Hurricane Protection System: What Went Wrong and Why (see “The ERP Report:
What Went Wrong and Why,” Civil Engineering, June 2007,
pages 54–61, 73–76). Thus, the devastation during Katrina
was a “unique” natural disaster in which “much of the destruction was the result of engineering and engineering-related policy failures,” the ERP report concluded.
In particular, although many of the failed levees had been
overtopped by floodwaters that eroded the levee material, at
least seven of the major breaches were caused by the failure of the
concrete floodwalls known as I walls that had been constructed
atop levees that were not armored or otherwise protected against
erosion. These included I walls at two of the outfall canals on
Lake Pontchartrain—the 17th Street Canal and the London
Avenue Canal—which failed while the floodwaters were still
about 5 ft below the top of the walls, “well below the design
water level,” the ERP report noted. Moreover, at the 17th Street
site, the engineers “responsible for the design of the levee and I
wall overestimated the soil strength,” the ERP stated.
Potential problems with I walls in general had been discerned by the Corps as far back as 1985, when a field test under high-water conditions “revealed the potential for large
I-wall deflections,” the ERP said. But as “research and new
information evolved in the 1980s and 1990s, the design of
the existing I walls was not checked for safety and stability in
the light of new information,” the ERP explained.
Elsewhere in New Orleans, Katrina showed the city’s pumping stations to be inadequately designed. The pumps lacked the
capacity to handle the water levels that resulted, and the pump
station buildings lacked the structural strength to withstand
the wind and water forces of the hurricane, the ERP concluded. In Jefferson and St. Bernard parishes, for example, nearly
all of the pump station operators had to be evacuated during
the storm, which meant their pumps lay idle. The pumping
stations at the south end of the 17th Street, London Avenue,
and Orleans Avenue outfall canals were designed nearly a century ago to pump out rainfall but were “never strengthened or
retrofitted” to resist the hydrostatic loads of storm surge, even
though these facilities had come to be considered part of the region’s hurricane protection system, the ERP noted.
During the design of the pre-Katrina hurricane defenses, Congress had authorized the Corps to protect the region
against “the most severe combination of meteorological con-
ditions that are considered ‘reasonably characteristic’ of the
region,” which for the Corps has historically meant a hypothetical storm called the standard project hurricane, the ERP
noted. But “reasonably characteristic” implied a storm that
the ERP considered to be less extreme than, say, the probable
maximum hurricane as defined by the National Weather Service. As a result, the pre-Katrina New Orleans hurricane defenses were “underdesigned,” the ERP concluded.
In fact, when Katrina struck, the New Orleans region’s
hurricane protection system was actually “a system in name
only,” the ERP said, restating a conclusion reached by the
members of the IPET, as well as by Lieutenant General Carl
A. Strock, P.E., Dist.D.NE, M.ASCE, now retired, who served
as the Corps commander and chief of engineers during Katrina and is now employed by the international engineering
firm Bechtel. Originally designed to provide flood protection and remove rainfall from the city, the presumed system
was in reality “a disjointed agglomeration of many individual projects that were conceived and constructed in piecemeal fashion. Parts were then joined together in ‘make-do’
arrangements,” the ERP explained.
Moreover, because of the congressional budgeting process,
“the stream of funding for the New Orleans hurricane protection system was irregular, at best,” the ERP stated. “If a project was not sufficiently funded, the Corps was often required
to delay implementation or to scale the project back.”
As Fleming explains, the Corps does not receive an annual
budget from Congress; thus, he says, “we cannot just go out
and build things.” Instead, the Corps must receive authorizations and appropriations—permission and funding—for each
project on a case-by-case basis. In the New Orleans region that
approach was followed over the past six decades, the first hurricane protection project for the region being authorized in
the mid-1950s, Fleming notes. Unfortunately, it produced an
The Lake Borgne surge barrier’s 26 ft high wall is supported by an A-frame system that features more than 1,200 vertical
concrete piles, each 66 in. in diameter, and more than 600 inclined batter piles, each 248 ft long and 36 in. in diameter.
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unfinished line of defense that by August 2005 was roughly
60 percent complete for parts of the city on the east bank of the
Mississippi, which cuts a winding course through the New
Orleans region, and only about 40 percent complete for the
neighborhoods on the west bank, Fleming says.
Furthermore, even what had been constructed was not always adequate. The levees susceptible to overtopping had not
been armored, and the levees and floodwalls had not been designed with sufficient additional height to accommodate the
“well understood” subsidence in the region, the ERP noted.
A lack of coordination among the various federal, state,
and local agencies responsible for the construction, operation, and maintenance of segments of the hurricane protection system—including the pre-Katrina levee boards, some
of which also ran such non-flood-protection operations as airports, parks, and casinos—also meant that certain floodgates
“were out of service and left open during Hurricane Katrina
because of repairs, allowing water to flood through them unimpeded,” the ERP said.
In other locations, the openings into key waterways or
drainage canals had no protection at all against Katrina’s
storm surge. To the north of New Orleans, the Lake Pont
chartrain side, these openings included the mouths of the
outfall canals and the Inner Harbor Navigation Canal, a
5.5 mi long channel that links the lake to the Mississippi.
Likewise, there was nothing stopping storm surge from Lake
Borgne on the eastern side of the city at the confluence of
the Mississippi River–Gulf Outlet (MRGO)—designed as a
shortcut for navigation between the Gulf of Mexico and the
port of New Orleans—and part of the New Orleans portion
of the Gulf Intracoastal Waterway, a navigable inland waterway that stretches from Florida to Texas. These unobstructed openings, as well as nearby breaches, contributed to the
flooding that caused more than 1,100 deaths and sank the
Lower Ninth Ward, Chalmette, Gentilly, the part of the city
east of the Inner Harbor Navigation Canal and north of the
Gulf Intracoastal Waterway (“New Orleans East”), and other
sections of the city under as much as 10 ft or more of water.
A month after Katrina hit, a second hurricane, Rita,
struck the New Orleans region, causing some of the areas
flooded during Katrina to flood again as certain key levees
were breached for the second time.
“Clearly there were gaps in the physical construction of
the system that caused it not to really be a system,” concludes
Fleming.
O
The Lake Borgne surge
barrier features a 150
ft wide sector gate
with two steel-framed
segments that swing
open and closed to
provide navigation for
vessels of shallow draft.
n the basis of the extremely hard lessons learned from
hurricanes Katrina and Rita, the State of Louisiana decided
to consolidate many of the existing levee districts in the
New Orleans region under two so-called super levee boards. The
Southeast Louisiana Flood Protection Authority–East (SLFPA–
East) has jurisdiction over three levee districts—the East Jefferson Levee District, Orleans Levee District, and Lake Borgne Basin
Levee District—on the east bank of the Mississippi River, and
the Southeast Louisiana Flood Protection Authority–West
(SLFPA–West) has jurisdiction over the West Jefferson Levee
District and the Algiers Levee District on the west bank of the
Mississippi.
The Corps also set out to make fundamental changes, many
of which addressed the ideas outlined in the IPET and ERP reports, notes Robert G. Traver, Ph.D., P.E., D.WRE, M.ASCE, a
member of the ERP team, a professor in the civil and environmental engineering department at Villanova University, and
the director of the university’s Center for the Advancement of
Sustainability in Engineering. In particular, Traver commends
the Corps’s early efforts to install erosion protection on certain
new and existing levees, which improved the region’s defenses
during Hurricane Gustav, in August 2008, and applauds the
photocredit goes here
The Bayou Bienvenue
lift gate structure on
the Lake Borgne surge
barrier measures 56 ft
wide by roughly 80 ft tall.
It is designed primarily
for recreational boats.
extensive efforts that were undertaken by officials throughout
southeastern Louisiana and in New Orleans itself to evacuate
vulnerable populations prior to Gustav.
To correct one of the harshest assessments from the IPET
and ERP reports, the Corps sought to create an actual system
that would defend the New Orleans area against hurricanes.
This risk reduction system features a 133 mi perimeter of
new, strengthened, or raised levees, along with floodwalls,
gated structures, and pumps. The Corps’s efforts have been so
comprehensive, Fleming adds, that some sort of work—raising, strengthening, repairing, or replacing—has been done
to “every inch of this perimeter system.”
The scope of the HSDRRS increases to 350 mi when all of
the levees and floodwalls within the perimeter and in other
planned projects in the region are included, and the new system also features a different type of floodwall, known as a T
wall, to correct the problems caused by the earlier I walls. Existing structures, including gated barriers and pump stations,
were strengthened and new facilities were constructed, especially where there had been no defenses at all against storm
surge. And everything is tied into the existing levees on both
banks of the Mississippi so that, in combination with new operating procedures that have been adopted, “we’ve worked very
hard to make sure that it is in fact a system,” explains Fleming.
Rather than relying on just that single “standard project hurricane” to determine the details of the new system, the Corps
also took a new approach in analyzing the potential hazards,
one based on IPET research that modeled 152 different possible
hurricanes of different intensities. The modeling also looked at
different tracks and explored how those storms might affect the
new perimeter system, explains Mike Park, the chief of Task
Force Hope. Using the best hydraulic modeling tools available
at the time, the IPET team studied storms that ranged from 50to 5,000-year events and considered such variables as water levels, maximum winds, storm size, speed, and direction. “It was a
much more comprehensive definition of the hazard than anyone
has ever had before to design a system like that,” notes Ed Link,
Ph.D., M.ASCE, a senior research engineer in the civil and environmental engineering department at the University of Maryland and the leader of the IPET team.
As with most civil works projects, the cost of the
HSDRRS, more than $14 billion, was split between the Corps
and the local sponsor—the State of Louisiana through its
Coastal Protection and Restoration Authority. Approximately $9.6 billion was funded completely through federal money, while approximately $4.9 billion was covered through a
cost-sharing arrangement, the federal government paying 65
percent and the local sponsor 35 percent. The Coastal Protection and Restoration Authority will also be the official owner
of the projects once they are all completed and turned over
to local control, although the operation and maintenance of
the facilities, as well as portions of the state’s share of the construction costs, will eventually be the responsibility of the
SLFPA–East and the SLFPA–West.
In the New Orleans region, the HSDRRS consists primarily
of two sets of projects that form distinct hydraulic units separated by the Mississippi—hydraulic units being developed portions of the region that require protection from storm surge.
On the west bank of the Mississippi, in the hydraulic unit
that the Corps formally refers to as the West Bank and Vicinity, the projects focused on risk reduction facilities and defenses
in portions of St. Charles, Jefferson, Orleans, and Plaquemines
parishes. The major civil works projects constructed here
include the Gulf Intracoastal Waterway–West Closure
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Complex, which features the nation’s largest sector gates and
drainage pump station to prevent storm surge from entering two stretches of the Gulf Intracoastal Waterway. One is
the Harvey Canal section (that canal, originally known as the
Destrehan Canal, becoming part of the Gulf Intracoastal Waterway in 1924), and the other is the Algiers Canal section.
Other major projects are the Bayou Segnette Complex, which
involved the construction of a sector gate, a pump station, new
floodwalls, and a levee, as well as the lowering of the existing
Company Canal floodwall to create a new storm-water detention basin, and the Western Tie-In and the Eastern Tie-In,
which, as their names imply, connect portions of the HSDRRS
defenses to the existing Mississippi levees at locations that are
actually to the southwest of the city, at Lake Cataouatche, and
to the southeast, at the Hero Canal, near the point that the
Corps designates river mile 70 (70 mi
from the Mississippi’s mouth).
In the second hydraulic unit, referred to formally as Lake Pontchartrain and Vicinity, the projects include
civil works on the east bank of the Mississippi in portions of St. Charles, Jefferson, Orleans, and St. Bernard parishes. Among the major new risk
reduction projects constructed in this
unit are the Inner Harbor Navigation
Canal–Lake Borgne Surge Barrier, a
1.8 mi long structure that is the largest
barrier of its kind in the world and is
designed to prevent storm surge from
Lake Borgne from rushing into the
Inner Harbor Navigation Canal and
the Gulf Intracoastal Waterway; the
Seabrook Floodgate Complex, adjacent
to New Orleans Lakefront Airport, on
the shore of Lake Pontchartrain, which
was designed to stop storm surge from coming south off the
lake and also to work together with the Inner Harbor Navigation Canal–Lake Borgne Surge Barrier; permanent closures
and pump stations on the outfall canals along Lake Pont
chartrain, now under construction; and a new floodwall and
ramp for the existing parallel spans of the Lake Pontchartrain
Causeway Bridge, which crosses the lake in a north–south
direction.
Although not technically part of the HSDRRS, the MRGO
has been closed by constructing a rock dam across its channel,
and the waterway has been “deauthorized as a federal navigation project,” explains Park, who adds that the Corps disputes whether the MRGO truly was the “conduit for storm
surges that some have claimed.”
The location of some of the new HSDRRS barriers helps to
shield as much as 70 mi of levees and floodwalls from direct exposure to storm surge, notes Park. That is because the region’s
perimeter defense previously followed the banks of those various canals and offered unobstructed openings. But now certain
features of the new system close off those openings and essentially remove the canal levees and floodwalls from harm’s way.
“So we’re defending on a much smaller front,” Park says, which
makes the new system more secure because “there are fewer
things that can go wrong in a shorter perimeter.”
Throughout the HSDRRS, the heights of floodwalls and
other hardened structures were raised to elevations designed
to accommodate storm surge, compaction, subsidence, settlement, and other possible changes over the next 50 years. These
heights vary on the basis of the “much better understanding of
storm surge potential” that the Corps has acquired since Katrina, says Park. So instead of constructing new levees or raising existing ones to a uniform elevation, the new system has
been designed to achieve a “uniform level of risk reduction
around the perimeter” to accommodate the 100-year storm
surge potential at different sites, Park explains.
To determine those individual levee heights, the overtopping rates at various elevations were analyzed, as were
the still-water levels—essentially the
storm surge without waves—for storms
up to a 500-year event, Park says. The
levee heights were then set at some
point above those measurements for
each particular location, he adds. In
different sections of the east bank of
the Mississippi, for instance, the levee
heights now range from 12 to 26 ft
above sea level because of the potential
differences in storm surge at each location, and new floodwalls can take the elevations to more than 30 ft. The levees
were also overbuilt where practicable to
accommodate future conditions. Thus,
a levee that needed to be only a certain
height today was actually constructed
somewhat higher to account for nearterm settlement and compaction, factors that the pre-Katrina levees did not
address, Park explains.
In St. Bernard Parish, a 23 mi section of levees that parallels the MRGO originally featured earthen levees approximately 14 to 15 ft high that during Katrina were battered by
a still-water surge of as much as 18 ft and waves that reached
23 ft, says Chris Gilmore, P.E., a senior project manager for
the Corps. Approximately 60 percent of the levees there were
destroyed, he adds. So as part of the Corps’s efforts immediately after Katrina to provide new defenses as quickly as possible and then as part of the HSDRRS itself, the Corps rebuilt
the remaining levees and constructed entirely new ones along
that 23 mi section, raising the levees themselves to a height of
20 ft and capping the new levees with floodwalls that reached
a maximum elevation of 32 ft, Gilmore says.
After Katrina the Corps also adopted stricter specifications for the earthen materials it uses to construct levees, a
change that sometimes made it “difficult to find the amount
of borrow material that we did,” says Gilmore. The Corps engaged in “an unprecedented search for clay material,” seeking some 93 million cu yd of borrow material to complete the
HSDRRS levees and floodwalls, explained a website created
by the Corps “to serve as a reference for all landowners interested in providing clay material for these projects.”
The location of some
of the new hsdrrss
barriers helps to
shield as much as
70 mi of levees and
floodwalls from
direct exposure
to storm surge.
The Seabrook Floodgate Complex, on the shore of Lake Pontchartrain
adjacent to New Orleans Lakefront Airport, was designed to stop
storm surge from coming south off the lake and also to work together
with the Inner Harbor Navigation Canal–Lake Borgne Surge Barrier.
The Corps is also in the process of raising and improving
certain riverine levees along the Mississippi between river
miles 70 and 85.5 as part of the 100-year risk reduction system, notes Fleming. The earthen levees and concrete floodwalls along this 15.5 mi section of the river could be improved
as part of the HSDRRS because hurricane storm surge is the
governing event in these locations. Levees improved in this
way are referred to by the Corps as colocated. That means the
height of a levee to reduce the risk from storm surge in a 100year event is higher at that location than the levee height required to protect people and property from riverine flooding.
Elsewhere, the Corps cannot perform HSDRRS work on levees
if riverine flooding is the governing event, one of the many
complicated restrictions governing the work of the Corps,
notes Fleming, who adds that the exact location of that distinction between riverine and storm surge flooding will probably move farther north on the Mississippi as sea levels rise.
In addition to being raised, the HSDRRS levees and floodwalls along the Mississippi will be designed to offer greater
resilience and longevity and easier maintenance, their slopes
chosen so as to reduce wave run-up, adds Garnet Hardin,
M.ASCE, a Corps project manager.
In one area, a roughly 5 mi long levee section in New Orleans East flanking the Gulf Intracoastal Waterway east of the
Inner Harbor Navigation Canal–Lake Borgne Surge Barrier
was reconstructed roughly 10 ft higher than it had been before Katrina and ultimately reached a height of approximately
28 ft. Known as the LPV-111 project (“LPV” denoting the Lake
Pontchartrain and Vicinity hydraulic unit), the new levee was so
large that the engineers were especially concerned about consolidation of the levee material and subsidence, Park says. So prior
to the construction of the larger levee section, the foundations
were buttressed via a method known as deep soil mixing, auger
drills being used to mix cement and water slurry into the soil to
form a stabilizing column. Believed to be the largest such project in the United States, the deep soil mixing at LPV-111 involved 1.7 million cu yd of mixed material in the construction
of more than 18,000 columns, each approximately 5 ft in diameter and 67 ft long on average, along the length of the levee.
Deep soil mixing techniques were also used at the levees along
the 17th Street and Orleans Avenue outfall canals.
Another subsurface stabilization project in New Orleans
East, where the soils are weak and marshy but the new levees
required extensive footprints, involved the construction of a
sand blanket several feet thick atop the footprint of the future
levee and the insertion through that sand layer of approximately 250,000 wick drains, notes Park. The corrugated
wick drains serve to preconsolidate the soil, creating “a pathway for groundwater to rise to the surface as we compress this
under the sand blanket load, essentially pressing the water
out,” Park explains. The wick drain system seems to be yielding benefits, Park adds, because little loss of elevation has
been observed in the levees at which that technique was used.
To address the problem of unarmored levees that were overtopped and failed during Katrina, the Corps plans to armor
“virtually every point around the perimeter...in some fashion,”
n o v em b e r 2 0 1 3
Navigation Canal–Lake Borgne Surge Barrier, for example,
fall into this category. In areas that did not lend themselves
to major construction work, the Corps left the I walls in place
but buttressed them with, say, “a support every six feet on center—sort of like studding a wall,” notes Fleming. However, he
adds, “in the vast majority of cases we did switch to T walls.”
A
The West Closure Complex features the nation’s largest sector gates
and drainage pump station and was the site of a carefully planned and
constructed floodwall along an environmentally protected area.
explained René Poché, a public affairs specialist for the Corps,
who responded in writing to Civil Engineering questions. This
armoring will be installed especially in such critical areas of the
HSDRRS as the protected sides of levees, the transition points
between levees and structures, and the points at which pipelines
and utilities cross levee alignments, Poché explained.
Although the final decisions on exactly which sections of
levees will be armored and which methods will be used have
not been made, the Corps has been testing different approaches and materials over the past several years with assistance
from the U.S. Army Engineer Research and Development
Center, Texas A&M University, and Colorado State University,
which is equipped with a full-scale, computer-controlled wave
overtopping simulator. The Corps and Louisiana State University have also conducted field tests on a section of levee in
St. Charles Parish involving high-performance turf reinforcement mats through which grass was grown; various methods
of mowing the grass also were tested during the experiment,
which was carried out in the fall of 2011.
More recently, the Corps conducted additional pilot tests involving five manufacturers of high-performance turf mats on
two 5,000 ft long levee sections, one on an east-bank levee in
St. Charles Parish and the other on a west-bank levee in the area
encompassing Westwego and Harvey. At press time, additional
armoring tests were under way. The armoring construction contracts are not expected to be awarded until June 2014, and construction is not expected to be completed until the fall of 2016.
In contrast to the cost-sharing agreements governing most of
the civil works projects carried out by the Corps, the cost of the
armoring project, estimated at more than $300 million, will be
borne entirely by the federal government, according to Park.
The problems associated with I walls were resolved by
replacing most of those structures with more robust T-wall
systems, so named because they resemble an inverted letter
T, the horizontal section being at or below the ground. Angled steel beams formed from H-piles and reaching depths of
165 ft also were used to further brace the new T walls, and
steel sheet piles were used to prevent water seepage. In one
section of existing levees, for instance, more than 10,000 sheet
piles were driven into the levees to depths reaching 70 ft, according to an article in the November 30, 2011, issue of Status Report Newsletter entitled “HSDRRS...What Lies Beneath?”
In addition to providing greater robustness to the HSDRRS,
the use of T walls in a 23 mi long section of levees in St. Bernard
Parish also obviated the need to construct an impossibly large
levee in that area, notes Park. If the levees there had simply been
constructed to the heights deemed necessary, they would have
required a footprint roughly 900 ft wide and therefore would
have encroached on the nearby canals and marshland, Park explains. Instead, the T walls and their deep piles kept the levee
footprints at a more manageable size and facilitated the fastpaced construction schedule, which involved the “extraordinary
effort” of completing at least 2 mi of floodwalls per month in
the lead-up to the 2011 hurricane season, Park says. He recalls
an iconic construction photo taken during the project (see the
image on page 48) that depicts something like 80 crane booms
silhouetted against an orange sky at dusk. As he explains, when
people ask him how 2 mi of floodwalls could be constructed
each month, “I show them that picture and say, ‘This is how
you do that.’”
Some I walls remain within the HSDRRS, including walls
that have been rendered redundant because newer defenses
have been constructed between them and the path of potential
storm surge. I walls on the protected side of the Inner Harbor
lthough the HSDRRS involved hundreds of construc-
tion projects, several stand out because of their size and
importance and because they represent new lines of defense in areas that previously were wide open to storm surge.
The Inner Harbor Navigation Canal–Lake Borgne Surge
Barrier features a concrete wall approximately 10,000 ft long
and 26 ft high that stretches roughly north to south across an
area known as the Golden Triangle Marsh. The wall runs from
the LPV-111 levee section in New Orleans East and crosses the
now-closed channel of the MRGO before connecting to the
St. Bernard Parish levees. Prior to Katrina the Corps believed
that New Orleans was more in danger of flooding from Lake
Pontchartrain than from Lake Borgne, notes Park. This was
largely because of the flooding in 1965 from Hurricane Betsy,
which pushed surge from Lake Pontchartrain into the Gulf
Intracoastal Waterway, the Inner Harbor Navigation Canal,
St. Bernard Parish, and the Lower Ninth Ward, he explains.
During Katrina, however, “surge came in from the Gulf
of Mexico, through Lake Borgne, and into this marsh area,”
producing up to 15.5 ft of surge and waves of more than
20 ft, explains Jason Ragolia, P.E., the Corps’s deputy resident
engineer for the Inner Harbor Navigation Canal–Lake Borgne Surge Barrier. The water “came through this area into the
city...and put 20 feet of surge over the existing floodwalls,
causing scour behind the floodwalls that caused the walls
to fail,” Ragolia says. A 4,000 ft long section of I walls and
levees collapsed and caused devastating flooding in St. Bernard Parish and the Lower Ninth Ward.
Newly constructed T walls now stand where the I walls
failed, Ragolia says. Although a few I walls remain, they are
“no longer in use because we fight the flood here,” he explains
in referring to the new surge barrier.
At its northern end, the barrier’s crenellated parapet wall
features two openings that can be sealed off in the event of a
storm. One is a 150 ft wide sector gate with two steel-framed
segments shaped like pie slices in plan that swing open and
closed; the other is a barge gate in the form of a large floating block of concrete 150 ft wide and 42 ft tall that can be
swung closed on a large hinge and then flooded so that it will
sink and lock into position, retaining a 26 ft tall barrier above
the water. Roughly in the middle of the barrier, at a location
called Bayou Bienvenue, is a 56 ft wide vertical lift gate structure roughly 80 ft tall that, when closed, also provides a 26 ft
tall storm surge defense, says Ragolia.
The sector gate provides navigation for vessels of shallow
draft, the lift gate is designed primarily for recreational boats,
and the barge gate serves primarily as an alternative navigation route when the sector gate is under maintenance.
The surge barrier facility also features a concrete-framed
“safe house” for its staff of roughly four operators; the house
is 32 ft above water and has enough fuel in storage to power
generators that can operate the system for about two weeks,
notes Ragolia.
The towering, blocklike West Closure Complex pump
building is approximately 80 ft tall and 480 ft long and has
a total pumping capacity of more than 19,000 cfs.
n o v em b e r 2 0 1 3
The barrier wall itself and the gates are supported by an
A-frame system that consists of more than 1,200 vertical concrete piles, each 66 in. in diameter, and more than 600 batter piles, each 248 ft long and 36 in. in diameter. The vertical
piles were driven into the marshland to a depth 130 ft below
the water level, the inclined piles were driven in at an angle
of 40 degrees to a depth of 190 ft, and the two types of piles
were connected by concrete caps that were precast or cast in
place, according to Ragolia and information in the paper
“Design and Construction of the Lake Borgne Surge Barrier
in Response to Hurricane Katrina,” by Scott R. Huntsman,
Ph.D., P.E., G.E., D.GE, F.ASCE, an engineer for Shaw Environmental & Infrastructure Group, of Concord, California.
Huntsman presented his paper at the 2011 Conference on
Coastal Engineering Practice, which was organized by ASCE’s
Coasts, Oceans, Ports, and Rivers Institute.
Shaw Environmental was the design/build contractor
for the Inner Harbor Navigation Canal–Lake Borgne Surge
Barrier, which was designed by a joint venture of Tetra Tech
INCA, headquartered in Bellevue, Washington, and Ben C.
Gerwick, Inc., of Oakland, California. The approximately
$1.1-billion project was the largest design/build contract
ever let by the Corps. The design/build approach, says Ragolia, was essential to the scale and 15-month construction time
frame of the barrier, which had to be in place by June 1, 2011,
for the start of the hurricane season. “If we’d done the typical
design/bid/build, we’d still be looking at a marsh,” he says.
The Seabrook Floodgate Complex is located to the west
and north of the Inner Harbor Navigation Canal–Lake Borgne
Surge Barrier. Designed to act in tandem with that barrier, the
Seabrook complex was constructed at the Lake Pontchartrain
end of the Inner Harbor Navigation Canal just south of a railroad bridge and a highway bridge. During Katrina the roughly 350 ft wide channel here was wholly open and experienced
storm surge in two directions, notes Gilmore. First, Katrina
pushed storm surge northward from Lake Borgne “through
this channel into Lake Pontchartrain,” he explains. “Then Katrina got past us, a little north of us, then flipped around and
the storm surge came back from north to south.”
This doubling back contributed to flooding in the area the
Corps refers to as New Orleans Metro, which encompasses the
east bank of Orleans Parish west of the Inner Harbor Navigation Canal and a small portion of Jefferson Parish near the Mississippi River. Flooding was also experienced in New Orleans
East, Gentilly, the Ninth Ward—which includes
the Lower Ninth—and St. Bernard Parish.
In the HSDRRS, the Lake Borgne surge barrier
is designed to prevent an east–west storm surge,
whereas the Seabrook complex is designed to prevent the north–south surge, Gilmore says. The
Seabrook complex features a 95 ft wide sector gate
with two steel-framed segments shaped like pie
slices in plan that are flanked by two 50 ft tall vertical lift gates. When I visited the site toward the
end of the 2012 hurricane season, the air was filled
with the sound of birds courtesy of a recording
designed to keep birds away so they do not roost
on top of the structure, where nests would “cause
maintenance nightmares,” Gilmore explains.
New sections of T walls, each roughly 900 ft
long, were also constructed to tie the floodgate
complex into the existing levees that line the lake
to the east and west. A new gate on land also was
constructed to accommodate an existing railroad
line that passes the Seabrook complex.
When the new gates are closed, they and the
new floodwalls provide a 16 ft tall barrier against
storm surge; some of the preexisting floodwalls
also were raised to match that 16 ft elevation.
Although the sector gates are designed to accommodate boats on the Inner Harbor Navigation Canal, the nonnavigable lift gates are designed primarily to ensure that water flow in the
channel remains the same as before the complex
was constructed, Gilmore explains.
Enormous angled rakes on the northern side of
the West Closure Complex pump station slide up
and down in front of the intake screens to clear
away debris that might block the flow of water.
A roughly 50 ft tall space within the West
Closure Complex structure houses 11 giant
pumps that weigh 70 tons apiece. The
pumps were designed primarily to handle
the heavy rainfalls that accompany storms.
To construct the Seabrook complex, the Corps first filled
the existing scour holes in the channel, which were roughly
90 ft deep, with sand and then introduced piles, sheet piles,
and cofferdams to dewater the site, Gilmore explains. The
concrete structures that support the steel gates were then constructed, and the gates were brought to the site via barge. The
bottom of the channel was lined with new rock for erosion
control, and riprap was installed along the banks. Although
the earthen levees around the floodgate complex will definitely need additional lifts periodically to ensure that the proper
elevation is maintained, the concrete and steel gate structures
cannot be raised easily. Thus, they were designed to provide
the full 50-year design life right from the start. “So in 50 years,
Seabrook should still provide that 100-year level of risk reduction,” Gilmore notes.
The $165-million Seabrook complex was designed by the
New Orleans office of Bioengineering Group and the international engineering firms Arcadis, based in Amsterdam, the
Netherlands, and HNTB, based in New York City. St. Louis–
based Alberici Constructors, Inc., served as the general contractor under a so-called early contractor involvement arrangement.
In contracts of this type the general contractor provides certain
preconstruction services concurrent with the design effort. To the west of the Seabrook complex are the three outfall
canals (17th Street, Orleans Avenue, and London Avenue) on
Lake Pontchartrain for which permanent canal closures and
pump stations are now under construction. Ground was bro-
ken in June, and the three facilities are expected to be completed by early 2017, explains Dan Bradley, an engineer and
senior project manager for the Corps. The three outfall canals
run south–north from internal pump stations within New
Orleans. The canals are between 11,000 and 15,000 ft long
and serve as critical elements in the city’s flood control system, especially for rainfall. Because the lake ends of the canals
were unobstructed during Katrina, storm surge rushed into
them, breaching the levees and floodwalls that lined the 17th
Street and London Avenue canals and flooding much of the
central portions of New Orleans.
In recognition of the threat presented by the wide-open
outfall canals, which have widths reaching 300 ft at their
mouths, the Corps moved quickly in 2006 and 2007 to construct interim closure structures with gates and pumps that
would block the mouths without impairing the drainage
functions of the canals. Those interim facilities, however, had
a limited life span and were not powerful enough to handle
major hurricanes over the long term, Bradley says. They were
also subject to extensive corrosion and required considerable
maintenance. Robust and powerful permanent canal closures
and pumps were therefore always envisioned to achieve the
100-year level of risk reduction at the canals, Bradley says.
The $615-million design/build project is being designed
and constructed by a joint venture known as PCCP Constructors, comprising Kiewit Louisiana Co., of Metairie, Louisiana; Traylor Bros., Inc., of Evansville, Indiana; and M.R.
n o v em b e r 2 0 1 3
Pittman Group, LLC, of St. Rose, Louisiana. Although still
under design at press time, the new system is expected to feature permanent facilities with T walls, generator buildings,
and gated structures that reach up to 18 ft above water—
2 ft higher than actually required to ensure that the facilities would have the “structural superiority” to withstand the
expected storm surge, Bradley notes. The pumping capacities will vary, being 2,700 cfs at the Orleans Avenue Canal,
9,000 cfs at the London Avenue Canal, and 12,600 cfs at the
17th Street Canal, which means that the 17th Street facility
could fill an Olympic-size swimming pool in just seven seconds, according to a July 2013 document prepared by the
Corps entitled “Permanent Canal Closures & Pumps.”
The new barriers will be closer to the lakefront than the
interim facilities had been. Those facilities were kept back
from the lake’s edge by as much as 1,000 ft as a safety measure so that storm surge waves would dissipate somewhat as
they entered the canals, says Bradley. But the permanent closures and pump stations can be located right at the lakefront
because they will be designed to better withstand both storm
surge and wave impact, he says.
The new facilities will also be designed to accommodate
a disagreement that exists between the SLFPA–East and the
Corps over how exactly water should be removed from the canals. The SLFPA–East is in favor of deepening the three canals
and adapting them so that water would flow by gravity to the
new drainage pump stations at Lake Pontchartrain, thus obviating the need for interior pump stations. This approach is
referred to as Options 2/2a, explains Tim Doody, who serves
as the SLFPA–East’s president.
Through PCCP Constructors, the Corps is designing a
system that will operate the new pump stations together
with the existing interior pump stations; the Corps argues
that it has the authority, but not the funding, from Congress
to study Options 2/2a, explained Poché. The new facilities,
however, are being designed with deeper foundations and intake basins than are currently required to accommodate Options 2/2a in case that approach is ever adopted and funded,
notes Bradley. The superstructures are also being designed to
be large enough to accommodate the larger motors and generators that would be necessary to operate the permanent facility pumps if the canals were ever deepened by as much as
15 ft, as envisioned under Options 2/2a, Bradley says.
Unlike the surge barrier facilities at Lake Borgne and
along the shore of Lake Pontchartrain, the new sector gate
and pump station facility known as the Gulf Intracoastal
Waterway–West Closure Complex was designed as a proactive rather than reactive element of the HSDRRS. Located on
the southern side of the HSDRRS within the West Bank and
Vicinity hydraulic unit, the West Closure Complex was constructed approximately half a mile south of the confluence of
the Harvey Canal and Algiers Canal sections of the Gulf Intracoastal Waterway. Stretching east–west across the roughly 1,000 ft wide channel at this location, the West Closure
Complex will use floodwalls, gates, and the pump station itself to block surge heading northward.
The West Closure Complex, however, does not close off any
of the storm surge routes that contributed to flooding during
Katrina. Instead, it draws on the lessons learned from Katrina to
deal with potential flooding from future storms, says Tim Connell, the Corps’s project manager for the West Closure Complex.
“Katrina basically brought an awareness that the whole
area needed a higher level of risk reduction,” explains Connell. Moreover, if Katrina had struck the New Orleans region
just 40 mi farther to the west, “it would have been a completely different story on this side of the river—this whole
area would have been inundated,” Connell says.
Although the West Closure Complex now provides a
method of blocking storm surge from some 26 mi of levees
and floodwalls along the Harvey Canal and Algiers Canal
sections of the Gulf Intracoastal Waterway, the Mississippi
River itself, just a few miles to the east, is not closed off in a
similar way. But the riverine levees there, including the approximately 15 mi of colocated levees and floodwalls that are
being raised as part of the HSDRRS, will provide the 100-year
level of risk reduction in that area, Connell explains.
Constructed at a cost of approximately $1 billion, the
West Closure Complex features a 225 ft wide sector gate
structure that is believed to be the largest in the United
States, says Connell, as well as what has been called the
world’s largest drainage pumping station. This towering,
blocklike structure is approximately 80 ft tall and 480 ft
long and features steel moment-resisting frames and 8 in.
thick concrete panel walls, making it a “heavy, heavy concrete
structure designed to withstand surge” and hurricane winds
up to 140 mph, notes Connell. The pump station structure
is founded on more than 1,100 steel pipe piles driven more
than 160 ft into the soil and is topped by blinking navigation
lights to warn away jets from a nearby naval air station. The
sector gate segments weigh 750 tons each and are founded on
a 10 ft thick concrete slab and more than 400 steel pipe piles.
The pump station and the sector gates feature sheet-pile cutoff walls that reach depths of respectively 46 and 53 ft.
Within the West Closure Complex, a roughly 50 ft tall
space houses 11 giant pumps that weigh 70 tons apiece and
have a total pumping capacity of more than 19,000 cfs. The
pumping station was designed primarily to handle the heavy
rainfalls that accompany storms now that this previously
open end of the Gulf Intracoastal Waterway channel has been
cut off by the sector gate system. Because of the surge potential, however, the facility has also been designed with a socalled nonsiphonic discharge, which means that the pumps
will continue to operate at full capacity even as the level of
water outside the complex rises as a result of storm surge.
This feature sets the facility apart from the internal pumping stations in the canals elsewhere in the system, which lose
capacity under the same conditions, Connell says. Enormous
angled rakes on the northern side of the pump station slide
up and down in front of the intake screens to clear away debris that might block the flow of water.
The West Closure Complex was designed by Arcadis and
constructed under an early contractor involvement arrangement
by Gulf Intracoastal Constructors, a joint venture of Kiewit
Corporation, of Omaha, Nebraska, and Traylor Bros.
A two-level safe room within the West Closure Complex
was constructed at an elevation of 26 ft above the normal
water level. Shielded by 16 in. thick reinforced-concrete walls
and designed to withstand winds of up to 250 mph, the safe
room can accommodate approximately 10 people, providing bunks and even showers. Outside the facility, large diesel
tanks store enough fuel to operate the pumps and generators
for the complex’s electrical systems for more than three days,
making the complex completely self-sufficient. The at-grade,
external site of the fuel tanks, however, is going to be improved, Connell adds. Although the fuel tanks are considered
secure “for all normal events...we are looking at measures to
further harden and further secure those tanks because they are
the lifeblood of the station,” he says.
During the fast-paced design of the pump station, the
elevation of the tanks, which originally were to be higher
to accommodate the most powerful
storms, was lowered to expedite construction, Connell explains. “But now
we’re taking measures to ensure their
survivability in these extreme events,”
he says.
As part of the West Closure Complex project, the Algiers Canal section
was also dredged, a nearby road was
realigned, and large intake and discharge basins were dug out on respectively the northern and southern sides
of the complex, says Connell. As a secondary line of defense against storm
surge in the West Closure Complex
region, a new floodwall also was constructed along the Harvey Canal section. Approximately 3.5 mi long, this
new T-wall section is 14 ft high and is
founded on 130 ft deep H-piles. During major storms, the Harvey Canal and Algiers Canal sections will now provide approximately 12.5 mi of detention
basins for the interior pump stations, notes Connell.
One of the most challenging projects in the West Closure
Complex vicinity, however, involved a 4,200 ft long T-wall
structure that was constructed on a narrow strip of land just
100 ft wide along the western side of the channel just north
of the sector gate floodwall. The work site was restricted because it bordered the Bayou aux Carpes wetlands area, which
is protected by the U.S. Environmental Protection Agency
under section 404 (c) of the Clean Water Act.
Unfortunately, during the risk analysis phase of the design of the HSDRRS, it was determined that a structure to
block surge would be necessary in the Bayou aux Carpes,
notes Connell. The Corps initially proposed the construction
of a barrier directly across the area covered by section 404 (c)
but encountered opposition from both the Environmental
Protection Agency and local environmental groups, Connell
notes. Working with the agency and other groups, however,
the Corps developed a compromise solution: it would construct the floodwall in a 100 ft wide band along the edge of
the 404 (c) area, and that floodwall would tie into other floodwalls outside of the protected wetlands, Connell explains.
To ensure compliance with the 404 (c) restrictions, a fence
was erected to delineate the boundaries of the approved work
site, and anyone working in that area had to be specially
trained. Upon completing the training, each person would
receive a 404 (c) sticker to place on his or her hard hat. The
sticker designated that the person had been trained and thus
could work in the designated area, and it also served as a reminder of the work site limitations, says Connell. “You understood that you didn’t go past the border fence for any reason—that’s the limit. You didn’t clear over there, you didn’t
throw anything over there,” he explains.
To the east of the West Closure Complex, the Corps constructed a series of levees and structures that form the Eastern Tie-In. The work included a new pump station, two
53 ft wide steel swing gates across a highway used for hurricane evacuations, and a swing gate for
an adjoining railroad line. These projects tie the HSDRRS into the existing
Hero Canal levees and the colocated
levees on the Mississippi on the southeastern side of the new system.
The corresponding Western TieIn was constructed at the southwestern end of the HSDRRS. It includes
approximately 4.5 mi of new levees
and floodwalls, a navigable closure
structure across an area known as Bayou Verret, an elevated crossing at one
highway, two railroad gates, and a second highway crossing before it connects to the Mississippi River levees
near river mile 118.
The Corps spent approximately $123 million repairing the existing
pump stations in the New Orleans metropolitan region and an estimated $340 million in making
those facilities stormproof. This work included the construction
of new, elevated safe rooms, the hardening of the building structures, the installation of new generators and additional fuel capacity, the construction of perimeter floodwalls and berms, and
other measures designed to prevent the conditions that forced
many pump station operators to abandon their facilities during Katrina.
Because evacuation is now seen as a major part of the new
emphasis on risk reduction, the HSDRRS also features a new
floodwall, as well as an elevated road and bridge over that
floodwall, at the southern entrance to the Lake Pontchartrain Causeway Bridge. During storms the southern entrance
to the bridge used to be closed off with sandbags that were
piled up against the surrounding, taller I walls, explains Brett
Herr, P.E., an engineer and branch chief in the Corps’s protection and restoration office. While this method seemed to
prevent severe overtopping, even during Katrina, it was not
considered adequate in the aftermath of that storm, says Herr.
A floodgate had first been considered, he adds, but that
idea was rejected because the causeway, which features twin
parallel structures, each carrying two lanes across the lake, is a
major evacuation route. Therefore the goal was to find a solution that would keep the causeway open as long as possible.
Shielded by 16 in. thick
reinforced-concrete
walls and designed to
withstand winds of up
to 250 mph, the safe
room can accommodate
approximately 10
people, providing bunks
and even showers.
n o v em b e r 2 0 1 3
In the end, the answer involved not shutting the bridge at
all. Instead, the causeway project involved the replacement
of the original I walls with taller T walls in 40 ft sections and
the construction of new, longer bridge ramps that pass over
the new floodwall. The new ramps are supported on a series
of concrete piers founded on piles driven to depths reaching
120 ft, explains Justin Smith, a project manager for the Corps.
The causeway project was especially challenging because
of the confined area on which the work was conducted and
because the numerous underground utilities, some of which
had to be relocated, were not well documented, says Herr. Furthermore, complicated detours and lane openings and closings
were necessary to keep the causeway in operation throughout
the construction phase, and a canopy arch bearing the name of
the causeway had to be preserved and then reinstalled, along
with new cameras to monitor the traffic flow, says Herr.
Designed by Gulf Engineers & Consultants, of Baton Rouge,
Louisiana, the $43-million causeway project was constructed by
New Orleans–based Boh Bros. Construction Co., L.L.C.
D
uring the more than seven
Weakest Link in Post-Katrina Flood Defense.” Complicating
matters, the bearings on several of the pumps at the West Closure Complex repeatedly cracked during the installation phase.
The 4,000 ft levee that had to be raised was not a surprise,
explained Poché, because it was in an area that was expected
to “experience significant settlement in a relatively short period of time,” in part because it was constructed above an old
slough. Thus, the Corps had always anticipated that the area
would have to be monitored regularly and that additional
lifts would be needed, he noted.
The malfunctioning barge gate in the Inner Harbor Navigation Canal–Lake Borgne Surge Barrier was finally closed successfully during the practice drills in May and has been opened
and closed several times since then, Poché said. A special training program was implemented for the barge gate operators,
he added, noting that each time “our crews operated the gate,
they became more experienced and more familiar with its operation.” Although certain sensors and gauges failed during the
recent drills, those faulty systems have been replaced, and none
of these problems prevented the successful operation of the barge gate,
Poché stressed.
Robert A. Turner, Jr., P.E., CFM,
M.ASCE, the SLFPA–East’s regional
director, says that while he is now
somewhat reassured about the barge
gate, he still has concerns. In particular, he describes the barge gate
as “an extremely complex mechanism” that relies on pumps, chains,
chain drives, and other equipment.
Since none of the equipment is automated, he says, it “needs constant
human monitoring and intervention in order to effect a successful
closure.” Heavily influenced by the
wind and the currents in the channel, the barge gate is closed by an
operator standing on the deck manipulating a pair of toggle switches controlling separate windlasses that function at different speeds, which means that
“every time you close it, it’s a different experience,” Turner
explains. Moreover, the Corps recommends that closure of the
barge gate begin as much as 96 hours in advance of a storm—
something that Turner says does not anticipate fast-moving
events that come in quickly off the coast.
In the case of the West Closure Complex pump bearings
that failed during installation, the incident does not represent
a problem so much as “a pretty incredible story of the determination of the contractors to meet the goal,” explains Connell.
The goal was to have at least 8 of the 11 pumps operational by
June 2011, the start of that year’s hurricane season, he notes.
But as the contractors—M.R. Pittman Group, Gulf Intracoastal Constructors, and various subcontractors—started to
test the pumps in April 2011, there was an indication that the
shafts were overheating. The test was stopped, but not before
an upper bearing had cracked. When the same thing happened
on both the second and the third pump as they were tested, the
The malfunctioning
barge gate in the Inner
Harbor Navigation
Canal–Lake Borgne Surge
Barrier was finally closed
years and more than 400 construction contracts that were involved in the creation of the new risk
reduction system, the Corps faced
numerous challenges, many of them
highlighted in an article in the January 28, 2013, issue of Status Report
Newsletter entitled “Construction
of HSDRRS: A Sometimes Bumpy
Road.” These bumps included the
need to rework schedules to accommodate both the nesting season of
egrets, a protected bird species, and
the comings and goings of freight
trains that operated throughout
the construction phase. In addition
to installing new track in the areas
that were to receive railroad gates,
the Corps had to cope with historic levels of Mississippi River
flooding in 2011, the complexities of raising and widening a
levee at the foot of the only runway at Louis Armstrong New
Orleans International Airport that can accommodate instrument landings, and other complications.
Additional problems included a series of back-and-forth legal challenges by the losing parties when contracts for certain
projects were awarded. A 4,000 ft long section of a new earthen
levee in the northeastern part of New Orleans “subsided so low
it wouldn’t be able to withstand a storm surge caused by a socalled 100-year hurricane,” according to a July 16, 2013, article
in the Times-Picayune entitled “Sinking Sections of Eastern New
Orleans Hurricane Levee Prompt $1.3 Million Repair.” Moreover, the barge gate in the Inner Harbor Navigation Canal–
Lake Borgne Surge Barrier was damaged in an early test. This
problem and others caused considerable concern to officials in
the SLFPA–East, according to a March 21, 2013, article in the
Lens, the Web publication of a nonprofit group that focuses on
the New Orleans area, entitled “Local Officials Losing Sleep over
successfully during the
practice drills in May and
has been opened and closed
several times since then.
The interim closure and pump station at the Orleans
Canal and facilities at the 17th Street and London Avenue
canals were kept back from the edge of Lake Pontchartrain so that the storm surge waves would
dissipate somewhat before
striking them.
contractors realized there was a definite problem, notes Connell. So they got together, disassembled the pumps within the
station, removed all the shafts and gears, and ultimately determined that the tolerance on the gears was too tight. The tolerance had been tightened to avoid vibration issues, Connell
notes, but it ended up being too tight, which caused friction.
So the contractors remachined the bearings to accommodate
additional tolerance, addressed some alignment issues that had
come to light, and then reassembled the pumps.
The 45-day period between April and June was originally
intended to provide a cushion that would enable the contractors to resolve minor problems. Instead, it was used to solve a
major problem so that on June 1, 2011, declares Connell, “we
had 8 of the 11 pumps pumping water—a phenomenal event!”
W
hile overcoming these and other bumps, the con-
struction of the HSDRRS benefited from at least three
critical developments, says Fleming.
First and perhaps most important, the HSDRRS projects
were not limited by the usual short-term, incremental funding that affects so many other major civil works efforts, he
explains. Instead, from late 2005 through 2008 Congress
passed seven supplemental appropriation bills that totaled
more than $14 billion—roughly three times the Corps’s usual annual civil works budget, notes Fleming—to fund the
new system for the New Orleans area. Other Corps projects,
including the ongoing dredging of the Mississippi, still had
to cope with the uncertainty of not knowing from year to year
how much money would be available, but this was not the
case with the HSDRRS program. Even as the budget battles
in Washington raised the possibility of federal government
shutdowns over the years, Fleming knew he had the money
he needed to proceed with the HSDRRS efforts.
In addition to the certainty it afforded those working on the
HSDRRS, the guaranteed funding enabled the Corps to benefit from economies of scale and award contracts more easily,
Fleming says. “”We even got into the steel business,” he notes,
explaining that the incremental approach would have meant
awarding different contracts to various contractors, and those
firms would then have had to “wait in line at steel mills” to obtain the necessary products, essentially competing with one another and driving up the cost of the steel or causing delays. But
because the Corps knew how much money it had to work with,
as well as what sort of steel it would need, “we bought a lot of
steel in advance, put it in storage yards, and told the contractors
not to worry about steel—just come get it from us,” Fleming
says. It was the first time the Corps had tried such an approach,
he says, and it definitely saved both time and money.
A second major development that enabled the Corps to
complete the HSDRRS faster than other civil works projects
involved an expedited environmental review process to meet
the requirements of the National Environmental Policy Act
(NEPA). If the Corps had been required to follow the typical
requirements set forth in that law, especially the completion
of several detailed reports that analyzed the HSDRRS projects
in their entirety, it would have taken “a significant amount
of time,” perhaps as much as three years, before any construction could have begun, according to the final version of the
Corps’s “Comprehensive Environmental Document: Greater
New Orleans Area Hurricane and Storm Damage Risk Reduction System,” which was published in May.
Typically, the Corps would have had to prepare a
n o v em b e r 2 0 1 3
separate environmental impact statement for each of the
more than 400 projects within the HSDRRS, explains Fleming. But if that had been the case “we’d still be doing [environmental impact statements] at this point,” he says. Instead, the Corps was allowed to use so-called emergency
alternative arrangements approved by the White House’s
Council on Environmental Quality. “We still had to do the
full NEPA process,” says Fleming, “still had to disclose all of
the impacts to the environment, to people, to air, traffic, pollution, et cetera.” And there were still public meetings and
public comment periods, he adds. But the use of the alternative arrangements did permit the environmental evaluation “of numerous smaller construction projects as the engineering design for each segment was developed, rather than
waiting to complete the NEPA evaluation once the designs
for the entire system were complete,” explained the final
version of the “Comprehensive Environmental Document:
Greater New Orleans Area Hurricane and Storm Damage
Risk Reduction System.”
The alternative arrangements cut through a lot of red tape
and allowed the Corps to start construction on the HSDRRS
projects much earlier than is typically the case, Fleming says.
Fleming also praised the various state and local organizations in southeastern Louisiana that passed new laws and implemented other measures that enabled the Corps to acquire
the land needed for the HSDRRS in an expedited fashion. Indeed, he considers this the third major development that enabled the Corps to complete the new system so quickly.
T
he new system underwent a baptism by storm surge last
year when Hurricane Isaac, a large, slow-moving storm of
low intensity, stalled over the region for roughly 45 hours. In
preparation, all of the major new features of the HSDRRS were
either closed or utilized for the first time in an actual storm, including the first closure of the sector gates at the West Closure
Complex—where the site’s massive pumps also were put into
action—the Seabrook Floodgate Complex, and the Inner Harbor Navigation Canal–Lake Borgne Surge Barrier. (The barrier’s barge gate was already in its closed position, but it was still
under construction at the time.)
Some 300 of the more than 500 openings in the perimeter system that provide access for railroads and motor vehicles and serve other purposes as well were closed for Isaac;
the remaining openings along the Mississippi did not have to
close because the water levels there were not considered high
enough to create a storm surge risk, as explained by Stack
and recounted in the Civil Engineering online article “New
Orleans’ Defenses Weathered Isaac ‘Very Well.’” Temporary
closures also had to be erected in several locations at which
construction work was still under way, including two sites
that had to be kept open as long as possible because, as Stack
explained and as was reported in the above article, once closed
they would have blocked major evacuation routes.
During Isaac there were several locations, especially at the
Inner Harbor Navigation Canal–Lake Borgne Surge Barrier,
at which “had we not had this system in place, the old system
would have been overtopped,” says Fleming. Senator David
Vitter (R-Louisiana) concurs, noting in written responses to
Civil Engineering’s questions that even if Isaac “didn’t fully test
the system,” the new HSDRRS defenses definitely prevented
significant flooding within its perimeter.
But Vitter also cited the “tragic flooding” that occurred
in areas outside of the HSDRRS and joined others in asking
whether the new system caused that flooding, especially because some of the neighborhoods had not experienced flooding during Katrina or Rita. The result was a reexamination
of the new system by the Corps and a call from Vitter for an
independent peer review.
The Corps’s analysis, Hurricane Isaac with and without 2012
100-Year HSDRRS Evaluation, was released in February of this
year and peer-reviewed by Battelle Memorial Institute, of Columbus, Ohio, and the Water Institute of the Gulf, based in
Baton Rouge, Louisiana. Although Isaac’s “nearly 45 hour duration of tropical force winds, track, size and slow forward motion, and considerable rainfall resulted in significant volume
of water delivered onshore,” the Corps concluded that “the
HSDRRS could not have significantly influenced inundation
at communities external to the system.” Instead, the flooding
of communities outside of the HSDRRS “was caused by intense and long duration storm surge due to the long duration
of tropical force winds, which in some cases were aggravated
by extreme local rainfall.”
In response, Vitter emphasized that there is “more important work to do” with regard to flood protection in southeastern Louisiana. Many of the areas flooded during Isaac
“have little to no flood protection,” Vitter stated, adding that
“many of these areas were promised protection through other Army Corps projects” that have since been “dramatically
slowed or cancelled.” Stressing “the need for critical flood
protection in areas outside the 100-year system,” Vitter called
on the Corps to “expedite ongoing projects to protect those
areas that were heavily flooded because of Isaac.”
Vitter has also called for reforms to the Corps designed to
eliminate “unnecessary bureaucracy” and cost overruns, reduce red tape, and “streamline and complete” other Corps
projects in the region. The senator’s proposed reforms are included in the Water Resources Development Act of 2013,
which passed the Senate in May and at press time was still being considered by the House.
L
ike Vitter, a number of local stakeholders, as well as
other engineers who have studied the new system, have
both praise and misgivings regarding the HSDRRS. For
example, Thomas L. Jackson, P.E., D.WRE, Pres.03.ASCE, a
former president of the SLFPA–East and a regular member
of that body until the summer of 2012, asks, “When you
look at the system that was built around New Orleans, are
we better off today than we were pre-Katrina? Absolutely—
no doubt about it!” However, he also asks, “Do I have differences about some of the things that were done? Yes, I do!”
Jackson notes that the SLFPA–East “fought tooth and nail
on a number of issues” with the Corps, including the decision by the Corps to use H-piles that had not been coated
with a corrosion-resistant paint in constructing the T walls
in St. Bernard Parish; instead, the Corps used larger piles than
necessary “to add a level of thickness to act as the corrosion
surface,” according to a written response to a follow-up question submitted by Civil Engineering to the Corps’s Gilmore.
The use of additional steel thickness “is a widely accepted
practice that is used all over the world,” especially by the marine industry, Gilmore explained. Both Louisiana’s Coastal
Protection and Restoration Authority and the Corps have
been conducting corrosion tests. Although Gilmore noted
that the authority’s tests are reported to have revealed “excessive corrosion,” the Corps’s tests, which included excavations
to expose the H-piles for a visual inspection and instrument
measurements, were still being evaluated at press time.
Jackson also points to the SLFPA–East’s disagreement
with the Corps over the Options 2/2a gravity flow proposal
for the three outfall canals on Lake Pontchartrain. The Corps
warns that this approach might take up to 10 years to complete and involve “significant construction impacts to the
residents” and that large expanses of
real estate would have to be acquired,
noted Poché.
John M. Barry, a New Orleans–
based writer and the vice president of
the SLFPA–East, adds two more major areas of contention: the planned
armoring of the levees and a study
sponsored by the SLFPA–East suggesting that the Corps’s analysis of
the hurricane surge hazards for the
New Orleans region might already be
outdated.
According to the minutes of a May
16, 2013, meeting, the SLFPA–East is
concerned that the Corps “is reviewing revised (reduced) overtopping rates
which could significantly reduce the
amount of armoring anticipated and
planned in New Orleans East and along
the lakefront in Orleans and Jefferson
parishes.” The authority is also worried that the Corps might eliminate “the use of a risk analysis
in determining how much of the HSDRRS should be armored
for resiliency.”
As a result, the SLFPA–East unanimously voted to request that an independent external peer review group “be assembled to examine and comment on both the sufficiency of
overtopping rate calculations and the necessity for making
risk assessment an integral part of determining the armoring
footprint,” according to the May 16 resolution.
The SLFPA–East is particularly concerned about armoring because the Corps did not initially plan to armor most of
the authority’s levees with anything other than regular grass,
notes Turner. The SLFPA–East does not consider grass alone
to be adequate armoring, he says. But at press time he was encouraged that the Corps was reevaluating that plan and seeking additional input from the authority.
Although no one from the SLFPA–West responded to Civil Engineering’s requests for an interview, officials from that authority have suggested that the Corps consider either raising
the levees in the west-bank projects several feet now rather
than installing the turf mat armoring or delaying the installation of the armoring until after the levees have been raised
anyway because of local subsidence, according to an August
16, 2013, article in the Times-Picayune.
Barry also points to a recent study, Hurricane Surge Hazard Analysis: The State of the Practice and Recent Applications for
Southeast Louisiana, which was prepared for the SLFPA–East
by Bob Jacobsen, P.E., M.ASCE, a private engineering consultant in Baton Rouge, Louisiana, and the new president of
ASCE’s Louisiana Section.
According to Jacobsen’s report, between 2005 and 2009
the Corps conducted “a ground-breaking analysis” of the
100-year surge hazard in support of the regional Federal
Emergency Management Agency flood insurance study and
the HSDRRS design. This analysis “employed considerable
professional, academic, and other technical resources and
greatly advanced the state of scientific
knowledge and engineering practice,”
Jacobsen wrote.
However, as Jacobsen told me,
“surge hazard analysis methodologies
are evolving rapidly.” For example, it
is now recognized that the 100-year
hazard must also account for the probabilities of “large, slow-moving, lowintensity storms,” in addition to those
associated with major hurricanes, Jacobsen said. Moreover, exponential increases in computational power mean
that engineers can now greatly expand
both the number of storms and the hydrodynamic model resolution to better
capture surge responses. Jacobsen’s report indicated that the Corps’s storm set
of 152 events and the computer modeling can now be improved to better characterize important surge effects in such
large, sheltered water bodies as Lake
Pontchartrain. Such analyses are critical to estimating 500year storm surges.
Richard A. Luettich, Jr., Sc.D., a professor of marine sciences at the University of North Carolina, the director of the
Institute of Marine Sciences there, and a recent member of the
SLFPA–East, stresses that “a system of this significance and
magnitude should be reviewed on a periodic basis.” Every 5
years would be good, he says, but at the very least a system such
as the HSDRRS should be examined every 10 years “to simply
reevaluate, based on current knowledge and practice, whether
it continues to provide the protection that we thought it did
when it was designed.” Luettich, who also served on National Academy of Engineering and National Research Council
teams that examined the response of the hurricane defenses
during Katrina and the design of the new HSDrRS, would
like to see the development of sensors to monitor the integrity
of the new HSDRRS over time. There are a few such sensors in
place, he notes, but he recommends the use of many more to
measure ground or slope movement of the levees, settlement,
seepage, gaps, or “any of those things (Continued on Page 83)
Exponential increases
in computational
power mean that
engineers can now
greatly expand both
the number of storms
and the hydrodynamic
model resolution
to better capture
surge responses.
n o v em b e r 2 0 1 3
Defending New Orleans
(Continued from Page 67) that may be
occurring on a very slow and routine basis that have the potential to undermine
the performance of the system when impacted by a major storm event,” he explains. The long-term maintenance of
the HSDrRS “presents a tremendous
engineering challenge,” Luettich notes,
“but also a tremendous engineering opportunity to really develop a system that
can monitor the performance and the
robustness of the system as it goes forward and gets ready to meet the next
major event.”
A
lthough the Corps has started to hand over control of certain
aspects of the HSDRRS to the local authorities that will be responsible for the operation and maintenance
of the new system, this has mainly involved sections of levees and floodwalls
so far, notes Turner. Most of the large
infrastructure facilities, especially the
West Closure Complex and the Inner
Harbor Navigation Canal–Lake Borgne Surge Barrier, are still being operated by the Corps because they are only
about 99 percent complete rather than
100 percent, explained Poché. These
facilities will probably be turned over
to the local authorities by the end of the
year, says Turner, who commends the
Corps for its commitment not to turn
over any of these major facilities in the
midst of the current hurricane season.
Of course, once such organizations
as the SLFPA–East do assume responsibility for the HSDRRS features within their jurisdictions, they will have to
find a way to pay for the new defenses
year after year. Doody estimates that
operating and maintaining the risk reduction facilities will cost the SLFPA–
East roughly $16 million annually and
that perhaps another $20 million annually will have to be expended over
the next several decades to help pay the
local share of the construction cost.
Both Doody and Barry contend that
many of the hurricane defenses constructed in the New Orleans region, including aspects of the HSDRRS, involve
projects that provide benefits to the rest
of the United States, for example, protecting navigation channels for com-
merce throughout the region. Yet the considering whether people should be
local residents end up bearing the costs living in certain parts of New Orleans.
that arise both in operating and main- As O’Rourke notes in voicing a sentitaining the systems and in recovering ment expressed by many, “Nature’s gofrom the losses that are sustained when ing to control, ultimately, and bring
the levees and floodwalls along those up some event that exceeds the capacity of the system.” At that point, he
navigation routes fail, they explain.
concludes, “we’ll have to
A prime example insee how the human side
volves the gated structures
ce
responds.”
that have been constructed
along the Gulf Intracoastal
Robert L. Reid is the senior ediWaterway. “The Corps says
tor of Civil Engineering.
that is flood protection,”
Doody muses, “but we say
it’s a hole in our flood protecReid
Project Credits
tion.” Such systems should,
Hurricane and Storm Damlike the Corps-operated
locks along the Mississippi, be owned age Risk Reduction System owner
and operated by the Corps, Doody says. and local sponsor: Coastal Protection
The costs of operating and maintain- and Restoration Authority of Louisiing a large system like the HSDRRS be- ana Oversight of Hurricane and Storm
come “a kind of unfunded mandate” for Damage Risk Reduction System dethe local authorities, notes Thomas D. sign and construction: U.S. Army
O’Rourke, Ph.D., M.ASCE, who holds Corps of Engineers and numerous conthe Thomas R. Briggs Professorship tractors Inner Harbor Navigation Cain Engineering at Cornell University nal–Lake Borgne Surge Barrier designand also served on the National Acad- er: Joint venture of Tetra Tech INCA,
emy of Engineering and National Re- Bellevue, Washington, and Ben C. Gersearch Council team that produced the wick, Inc., Oakland, California Inner
2009 report. Levees, in particular, are a Harbor Navigation Canal–Lake Borgne
“wasting asset” in the New Orleans re- Surge Barrier design/build contractor:
gion because of the ongoing local settle- Shaw Environmental & Infrastructure
ment, regional subsidence, and erosion Group, Concord, California Seabrook
and thus require expensive maintenance Floodgate Complex designer: Bioenand improvements over time, O’Rourke gineering Group, New Orleans; Arsays. New Orleans, which still has not cadis, Amsterdam, the Netherlands;
returned to its pre-Katrina population and HNTB, New York City Seabrook
levels, faces the additional challenge of Floodgate Complex contractor: Alfinding the tax base to fund the costs of berici Constructors, Inc., St. Louis Gulf
such maintenance, he adds. O’Rourke Intracoastal Waterway–West Closure
predicts that some sort of financial assis- Complex design: Arcadis, Amstertance from the state or federal govern- dam, the Netherlands Gulf Intracoastal Waterway–West Closure Complex
ment may be necessary.
O’Rourke praises the Corps’s efforts contractor: Gulf Intracoastal Conin the construction of the HSDRRS, but structors—a joint venture of Kiewit
he also stresses that “we have residual Corporation, Omaha, Nebraska, and
risks here that we just don’t fully un- Traylor Bros., Inc., Evansville, Indiana
derstand...so I always call this a work Outfall canal permanent closure and
pump station design/build contractor:
in progress.”
Indeed, many of the experts inter- PCCP Constructors—a joint venture of
viewed for this special report say that Kiewit Louisiana Co., Metairie, Louisimuch work remains to be done to im- ana; Traylor Bros., Inc., Evansville, Inprove hurricane defenses in the entire diana; and M.R. Pittman Group, LLC,
southeastern Louisiana region. The ef- St. Rose, Louisiana Causeway project
forts will include restoring wetlands designer: Gulf Engineers & Consuland barrier islands, elevating houses tants, Baton Rouge, Louisiana Causeand other structures, adopting new ap- way project contractor: Boh Bros.
proaches to land use planning, and even Construction Co., L.L.C., New Orleans
n o v em b e r 2 0 1 3

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