Order Code RS22276
Updated January 24, 2007
Coastal Louisiana Ecosystem Restoration
After Hurricanes Katrina and Rita
Jeffrey A. Zinn
Specialist in Natural Resources Policy
Resources, Science, and Industry Division
Summary
Prior to Hurricanes Katrina and Rita, the U.S. Army Corps of Engineers had been
seeking congressional approval for a $1.1 billion program both to construct five projects
that would help restore specified sites in the coastal wetland ecosystem in Louisiana, and
to continue planning several other related projects. The state of Louisiana and several
federal agencies participated in the development of this program. This report introduces
the program and more extensive restoration options that are being discussed in the wake
of the hurricanes. It also discusses whether this program, if completed, might have
muted the impacts of the hurricanes. Congressional consideration will be informed by
new information about the extent of coastal wetland change that resulted from the
hurricanes and further changes since the hurricanes struck. This report will be updated.
Introduction
The widespread destruction caused by Hurricanes Katrina and Rita altered the 109th
Congress’s perspective on coastal Louisiana restoration as it considered provisions in
legislation (e.g., S. 728 and H.R. 2864) that would have authorized the U.S. Army Corps
of Engineers (Corps) to implement numerous activities to slow the rate of coastal
wetlands loss. No legislation was enacted in the 109th Congress, so it seems very likely
that the 110th Congress will again consider legislation to address this issue. Both bills,
developed before the hurricanes struck, would have authorized funding to implement a
program that the Corps had recommended in a November 2004 feasibility report. The
Corps recommended $1.1 billion for activities to be initiated immediately and completed
over the next decade, and estimated an additional cost of $0.9 billion for future work. As
a result of the hurricanes, more expansive options, costing up to $14 billion and requiring
three decades before they are fully implemented, are also being considered.
Of the initial $1.1 billion in the proposal Congress was considering when the
hurricanes struck, $828 million is to complete planning and construct five projects, called
“near-term features.” The remainder of this initial authorization would be spent on

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monitoring program performance; building small demonstration projects (a maximum
cost of $25 million per project); exploring options to use dredged materials to create
wetlands; and continued planning of 10 additional projects that would have to be
authorized at a future date. Finally, additional funding would be provided to study six
less defined possible program elements for the future, termed “large-scale, long-term
coastal restoration concepts.” H.R. 2864 was approved by the House on July 25, 2005,
while S. 728 was reported by the Senate Environment and Public Works Committee on
April 26, 2005. After the hurricanes struck, Congress provided $96 million in FY2006
Defense appropriations (P.L. 106-148) for activities that would reduce threats to New
Orleans by improving coastal wetlands, leaving open the potential for a wide range of
legislative actions in the future. (For more information on the proposed Corps program,
see CRS Report RS22110, Coastal Louisiana Ecosystem Restoration: The Recommended
Corps Plan, by Jeffrey Zinn; for information on authorizing legislation, see CRS Report
RL33504, Water Resources Development Act (WRDA): Army Corps of Engineers
Authorization Issues, coordinated by Nicole T. Carter.)
The National Research Council was asked to review the Corps’ recommended plan.
It recognized that these hurricanes, which struck after the report was largely completed,
will likely lead to reconsideration of some plan components. It concluded that while most
of the individual projects are sound, they are not a comprehensive response to wetlands
loss. It calls for the development of a detailed map showing the desired landscape of
coastal Louisiana that would serve as the basis for selecting future actions. The lack of
synergy among projects in this plan contrasts with another Corps large-scale ecosystem
construction and restoration program in the south Florida Everglades, where success
depends on completing all the interrelated program components.1
Background
The Corps recommendations for projects to restore some wetlands and slow wetland
losses in November 2004 is the most recent of many such proposals offered over the past
four decades, shortly after the rapid rate of coastal wetlands loss was first documented.
It is now estimated that more than 1.2 million acres of wetlands, an area approximately
the size of Delaware, has been converted to open water since the 1930s. The remaining
wetlands cover about 3.5 million acres, an area slightly larger than Connecticut. The U.S.
Geological Survey estimated that an additional 448,000 acres could be lost by 2050 if no
additional restoration projects are initiated. If the Corps’ program is implemented, it
estimated that net wetland losses would be reduced to 170,000 acres by 2050. These
estimates do not appear to account for major but unpredictable hurricane events.
These losses have been caused by a combination of human activities and natural
factors that have been documented in many reports by the Corps and others. Proposals
to respond to these losses have centered on rebuilding the region’s coastal wetlands in
ways that could reduce the ecological, economic, and social costs. One cost receiving far
more attention today is the role that wetlands can play in absorbing storm surges and
thereby decreasing flood elevations and muting the force of wave energy.
1 The full report, titled Drawing Louisiana’s New Map: Addressing Land Loss in Coastal
Louisiana, can be downloaded at [http://www.fermat.nap.edu/catalog/11476.html].

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The Corps’ current recommended program includes projects centered in the wetlands
south and southwest of New Orleans. No projects are in the western portion of state
where Rita struck, and few are east of New Orleans, where Katrina’s damage to coastal
development and the environment was most concentrated. In the Corps analysis of the
selected set of options and the alternative proposals included in the November 2004 final
report, there is almost no mention of hurricanes, nor an analysis comparing how these
proposals might mitigate the effects of a major hurricane. The District Engineer for New
Orleans did not mention hurricanes when he made his recommendations, stating: “I am
convinced that the LCA [Louisiana Coastal Area] Plan would begin to reverse the current
trend of degradation of Louisiana’s coastal ecosystem, support Nationally significant
living resources, provide a sustainable and diverse array of fish and wildlife habitats,
reduce nitrogen delivery to offshore gulf waters, provide infrastructure protection, and
make progress towards a more sustainable ecosystem.”2
While Congress has not yet authorized any restoration program, two prototype
restoration projects — Davis Pond and Caernarvon Diversions (opened in 2005 and 1991,
respectively) — had been initiated under existing authorities. The primary purpose of
both diversions is to introduce fresh water (bearing sediment) into the wetland areas, and
thereby reduce the salinity. Both restorations are located in the greater New Orleans area
along the main channel of the Mississippi River. River water is periodically introduced
into these sites, which are large receptacle areas bounded by low levees. As the water
sinks into the ground or evaporates, it leaves sediments and raises land elevation, which,
in turn, provides an environment in which wetland habitat can be reestablished. These two
diversions are planned to add about 50,000 acres of wetlands over 50 years.
Effects of Recent Hurricanes on Restoration Planning
In the wake of the 2005 hurricane season, some supporters of restoration, especially
from within the state, are calling for a more substantial program than in the current
legislation. Supporters emphasize that the hurricanes caused nationally significant
disruptions, especially to energy supplies and bulk transportation, and therefore the
restoration would have significant national benefits. They are seeking consideration of
a $14 billion restoration effort that had been laid out in the Coast 2050 Plan, released in
1998. This Corps-led planning effort resulted in recommendations for 77 “restoration
strategies” to be completed over 50 years. The strategies would be distributed along the
entire length of the Louisiana’s coastal area, but concentrated in the central coast south
and southwest of New Orleans. The anticipated result from fully implementing these
strategies would be to protect or restore almost 450,000 acres of wetlands.
Congress has not considered legislation authorizing the Coast 2050 Plan. Instead,
in 2000, the Corps and the state began to develop a more modest set of proposals for
projects that could be initiated over a 10-year time period. A draft was completed in
October 2003 but never officially released. It included several options for implementation
with estimated costs that reportedly ranged between $4.3 billion and $14.7 billion.
However, the Administration, represented by the Office of Management and Budget,
reviewed these options, then reportedly directed the Corps to come up with a less costly
2 U.S. Army Corps of Engineers, Louisiana Coastal Area (LCA) Ecosystem Restoration Study,
Final Report, New Orleans, November 2004, p. MR 6-1.

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package of proposals in late 2003; that package is what Congress was considering when
the hurricanes struck.
Effects of Recent Hurricanes on Coastal Louisiana
Documenting the full effect of the 2005 hurricane season on coastal Louisiana will
be a long process. Coastal Louisiana is an extremely flat and dynamic physical
environment where major storm events can greatly alter the surface features, especially
wetlands, beaches, and barrier islands. Some portion of the losses caused by both storms
were only be temporary, as wetland vegetation was flattened by storm surge and strong
wind, and coastal beach sand and sediment was redistributed by these same forces. In
addition, in some locations where the storm deposited sediment, wetlands and beaches
may emerge or expand. A U.S. Geological Survey summary of wetland changes, released
in October 2006, estimates that almost 140,000 acres of wetlands were converted to open
water throughout the state’s coastal areas. Losses were most extensive in Breton Sound,
southeast of New Orleans. This summary also points out that this loss is about 42% of
the total losses previously predicted to take place between 2000 and 2050 (which included
periodic storms in making the calculation).
The wetlands were partially protected from ocean storms in central and eastern
portions of coastal Louisiana by a thin ribbon of coastal sand barriers and beaches along
the shoreline. These barrier systems were heavily damaged. These barrier systems have
been deteriorating for many of the same reasons, human and natural, as the wetlands.
Stabilization and restoration of them is critical to successfully restoring the wetlands that
they protect. It may be particularly challenging to reestablish wetlands landward of where
barriers were overtopped, flattened, or bisected by new inlets that allow an influx of salt
water. Over time, some of these barriers may stabilize or rebuild in new locations; others
will require extensive restoration.
What If the Restoration Program Had Been Completed
Before the Hurricanes Made Landfall?
If the entire first phase of the restoration program had been completed, that is, if
Congress had authorized and the Corps had completed the five initial projects
recommended in the November 2004 Corps report, it may be that these investments would
have had little effect on the pattern or extent of flooding or other storm damage around
the city of New Orleans, with the possible exception of modifications to the Mississippi
River Gulf Outlet (MRGO). These projects likely would have had some mitigating
effects on flood elevations and water flow velocities close to the projects sites, but the
magnitude of the effect would decline quickly as one moved away. The stability of the
levees and floodwalls around the city would not have been directly enhanced by any
component of the restoration program, so none of these projects would have reduced the
flooding in the city. Where the most severe damage occurred to the east of the city from
Hurricane Katrina and in the western portion of the state from Hurricane Rita, the
restoration program would have had little activity. Relationships between the hurricane
impacts on New Orleans and coastal communities and the proposed restoration may help
decision makers identify future restoration priorities, if they choose to follow the
recommendations in the 2005 NRC report.

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The potential damage from any storm event, and the role the restoration would play
in muting those damages, depends on specific characteristics of the storm event (e.g., the
storm’s intensity, its precise track, and the speed at which it is moving), the components
of the restoration effort, and the status of each component. Damage generally is most
extensive along the east side of a hurricane storm track in the Gulf of Mexico, where the
wind blows from south to north and the storm surge is most pronounced. In the case of
Katrina, the storm track was just east of New Orleans, and the highest storm surge and
greatest damage was documented to the east of that track. By contrast, within 100 miles
of New Orleans west and northwest — for example, in the nearby Baton Rouge area —
the damage was far less extensive.
Some scientists have offered generic support for the restoration effort by pointing out
that coastal wetlands cause friction to dampen storm surge, and estimate that for every 2.7
miles of marsh this surge passes over, its elevation is reduced by a foot. They also
estimate that storm surge is reduced by a foot in adjacent inland areas for every square
mile (640 acres) of wetlands that are restored. Other scientists caution that these general
relationships mask a wide variability, based on site-specific and storm characteristics. A
possible conclusion is that some restoration projects could have a great beneficial effect
in mitigating the damage to coastal Louisiana from storm events with certain
characteristics, and these benefits would be greatest near the projects. However, for
hurricanes with many combinations of characteristics, this specific set of projects may
have done little to reduce the storm’s impacts in much of the greater New Orleans area.
Possible Effect of the Hurricanes on Restoration Efforts
Katrina had greater adverse effects on the wetlands being created at the diversion at
Caernarvon than at Davis Pond. The Caernarvon area is estimated to have lost about
25,000 wetland acres. As the diversion is currently operated, it would take many decades
to offset the lost acres. If the diversion was enlarged or its operation modified to increase
the inflow of sediments, the restoration period could be shortened. Some are talking
about a goal of restoring 1,000 to 2,000 acres a year.
The impact from the hurricanes has greatly expanded the range of thinking about
restoration options. One aspect of that expansion is that while all past restoration planning
has been in response to wetland losses and coastal degradation within Louisiana, neither
hurricane respected political boundaries. Katrina caused extensive damage in coastal
Mississippi and Alabama, and Rita caused less extensive damage in eastern Texas. These
distributions of impact may create interest in considering a restoration program that would
provide benefits across the central Gulf Coast. A second aspect is renewed discussion of
projects that would result in larger changes across coastal Louisiana. The National
Research Council report, for example, discusses both the third delta and the abandonment
of the current delta in the context of providing more sediment for restoration. A third
aspect is a renewed interest in determining which projects would be most effective. A
January 2006 report by a group of recognized experts, primarily from academia, states that
project priorities should be based on storm damage reduction and ecosystem restoration

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to develop a “sustainable coastal landscape.”3 This report endorses the development of
a detailed project map that had been recommended in the NRC report.
Even if the 110th Congress authorizes a substantial restoration effort, such as the one
called for in Coast 2050, many of the physical changes on the ground will not be in place
for decades. Construction of the five projects for which authorization is currently pending
is not anticipated to be completed for about a decade after it is fully funded. For diversion
projects, actual reestablishment of wetlands requires many additional years after the
diversion starts to operate. Beyond the initial five projects, most of the others are much
earlier in the planning process, and therefore completion will be even further into the
future. If it is decided to follow the recommendation of the NRC, the timeline for this
effort could be further extended.
Ecosystem restoration goals may be in competition with other demands for federal
resources generally, and Corps resources specifically, in coastal Louisiana. These
demands include flood protection, economic development associated with navigation, and
housing. It may be too expensive to fully support all these goals at the same time. For
example, how will policy and program responses to the flooding in New Orleans be
viewed in relation to the restoration effort? It appears that little that was proposed in the
water resources legislation in the 109th Congress would have had much effect on
alleviating the causes behind the levee failures or moderating the rate or pattern at which
the city was subsequently flooded, nor would the many additional projects that were in
the Coast 2050 Plan be likely to have had a significant mitigating effect on the flooding
associated with Hurricane Katrina.
If Congress makes the protection or “fortification” of New Orleans its highest
priority, then some financial and agency resources may be drawn away from other
projects, such as those in the restoration efforts, that would contribute only indirectly to
protecting the city. Such a decision could reduce restoration efforts that could have a
more significant moderating effect on hurricane-related threats to communities and
resources south of the city and closer to the Gulf. If Congress wishes to address both
goals at the same time, then it may also want to consider setting priorities among the
protection activities it authorizes and funds. At a minimum, Congress might consider
asking the Corps to examine how each of the restoration projects might mute future storm
damage, and whether there are some modifications that could be made to pending projects
that would further protect the city or other south Louisiana communities.
Congress directed the Corps to develop options for a post-hurricane rebuilding plan
called the Louisiana Coastal Protection and Restoration Plan. In this plan, announced in
the March 3, 2006, Federal Register, the Corps identifies four combinations of structural
and nonstructural measures that would protect coastal Louisiana against a category 5
storm. Central issues include (1) what role(s) restoration projects would play in such a
plan, (2) how restoration projects would be integrated with structural measures, and (3)
how projects to protect the New Orleans urban area and to restore coastal Louisiana could
be most effectively integrated to minimize damage from future storm events.
3 Working Group for Post-Hurricane Planning for the Louisiana Coast, A New Framework for
Planning the Future of Coastal Louisiana after the Hurricanes of 2005 (Final Draft).

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