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Additional Views 

Senator Pete V. Domenici

On Corps of Engineers and Levee Issues

Hurricane Katrina: A Nation Still Unprepared develops its conclusion based on available, 

albeit incomplete, data. Th e Army Corps of Engineers is continuing to collect and synthesize data on the storm. Th e Interagency Performance Evaluation Task Force (IPET) established by the Chief of Engineers to provide credible and objective scientifi c and engineering 

answers to fundamental questions about the performance of the hurricane protection and 

fl ood damage-reduction system in the New Orleans metropolitan area has not yet completed their analysis. Th eir report is scheduled for completion in June 2006. Th e IPET team 

consists of more than 150 experts from more than 50 federal, state, and local agencies, as 

well as international, academia and industry groups.

As this team was established by the Corps, outside oversight was considered essential to validate the team’s results. Th e oversight is set up as follows: the Corps IPET team will collect 

the facts, the National Research Council Committee on New Orleans Regional Hurricane 

Protection Projects will synthesize the facts, and the American Society of Civil Engineers is 

the external review panel to verify the data and develop conclusions.

Th e IPET Mission has fi ve focus areas. Th ey are:

Th e Flood Protection System – What were the design criteria for the pre-Katrina hurricane protection system, and did the design, as-built construction, 

and maintained condition meet these criteria?

Th e Storm – What were the storm surges and waves used as the basis of design, 

and how do those compare to the storm surges and waves generated by Hurricane Katrina?

Th e Performance – How did the fl oodwalls, levees, pumping stations, and 

drainage canals, individually and acting as an integrated system, perform in 

response to Hurricane Katrina, and why?

Th e Consequences – What have been the societal-related consequences of the 

Katrina-related damage?

Th e Risk – Following the immediate repairs, what will be the quantifi able risk 

to New Orleans and vicinity from future hurricanes and tropical storms?

Th e hurricane and fl ood damage-reduction projects in the New Orleans metropolitan area 

were designed for a compact, relatively fast-moving Category 3 storm. Th is was the socalled standard project hurricane.

Katrina was a huge, powerful, relatively slow-moving hurricane. Th e United States Geological Survey (USGS) says that the storm surge from Hurricane Katrina was the largest 

recorded storm surge ever to hit the United States. 

Some of the preliminary information from the report shows that levee subsidence had 

caused some levee segments to be lower than designed, and consequently did not provide 

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the protection level intended. For instance, the levees along the Industrial Canal were nearly 

three feet below the design elevation due solely to subsidence.

Unanticipated failure mechanisms in the I-wall design resulted in catastrophic failure of 

the I-walls along two of the interior drainage canals with water levels below the tops of the 

fl oodwalls. Th ese failure modes had been modeled, but had not been incorporated in the 

design as they were not anticipated to occur at these locations.

Earthen levees were subjected to long-period ocean waves. Th is type of wave is not usually 

associated with more compact hurricanes typical of the Gulf of Mexico. Th ese long-period 

waves carry tremendous energy and ripped huge chunks out of the levees as the waves 

overtopped the structures. Vivid images of this destruction were captured showing waves 

breaking over the levee along the Mississippi River Gulf Outlet during Hurricane Katrina as 

well as pictures created aft er the storm showing the same levee section and how it was damaged by these breaking waves. Th is type of wave action was not incorporated in the design 

of the earthen levees.

While these preliminary results from the IPET team do not absolve the Corps of Engineers, 

the State of Louisiana, or local offi cials from blame in design and maintenance of the levees, 

Katrina was a huge storm when it made landfall. It packed a Category 5 storm surge even 

though wind speed may have been as low as Category 3 when it made landfall. Th e storm 

surge was the devastating factor on the fl ood-control infrastructure. Further, the interior 

drainage system, developed over a 100-year period mostly by non-Federal interests, proved 

to be inadequate to deal with the fl ooding caused by the storm surge and attendant fl ooding. 

Th e preliminary information from the IPET study shows that the design assumptions that 

were made when the project was authorized and throughout the 40-year period of construction were likely faulty, in hindsight. However, as a storm like Katrina was not considered 

typical for Gulf hurricanes, the same design decisions may well have been repeated if we 

were building the project today, had this storm not occurred. 

Somewhat as a validation of the above statement is that FEMA was in the process of revising 

the 100-year fl ood plain maps for New Orleans prior to Katrina. Had Katrina not occurred, 

these maps would have, in all likelihood, validated existing, but faulty, conclusions. However, aft er Katrina occurred, FEMA reworked their analysis to incorporate the data from 

Katrina. Th e result was drastically altered 100-year fl ood plain maps for the New Orleans 

metro area. Th ese new maps indicate that the levees currently in place do not provide 

protection from a 100-year fl ooding event. Prior to Katrina, it was believed the same levees 

provided a 200-year level of protection. Th is revised analysis demonstrates the power and 

magnitude of Katrina by showing how drastically it altered the hydraulic assumptions in the 

metro area. 

Supplemental appropriations to date have provided the Corps necessary funding to respond 

to immediate disaster needs and restore the hurricane and fl ood-protection system to preKatrina conditions before the start of this year’s hurricane season on June 1st. Additionally, funding has been provided to complete the hurricane and fl ood-protection system as 

originally conceived and designed.

Th e latest supplemental proposal is intended to strengthen the obvious weaknesses in this 

system by closing off the interior drainage canals and the Industrial Canal to storm surge. 

Th is will provide increased protection to the central area of New Orleans. Proposed levee 

raisings will increase protection levels for the New Orleans metropolitan area. Armoring of 

the levees will protect many of the levees in St. Bernard and other hard-hit areas from the 

wave action that was so devastating during Katrina. Restoration of coastal areas will provide 

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protection by reducing storm surge, and storm-proofi ng the interior pump stations should 

allow this vital system to continue operating during hurricane events.

Studies by the Corps are on-going to determine the ultimate level of protection that should 

be provided for the greater New Orleans and south Louisiana area. Th ese studies will 

provide preliminary interim recommendations in June 2006, with a fi nal report scheduled 

for December 2007. Th ese studies are anticipated to provide the basis for additional investments in hurricane and fl ood-system improvements to the greater New Orleans and south 

Louisiana area.

Hurricane Katrina: A Nation Still Unprepared