Hearings - Testimony
 
Full Committee
Evaluate the Degree to which the Preliminary Findings on the Failure of the Levees are Being Incorporated into the Restoration of Hurricane Protection
Thursday, November 17, 2005
 
Mr. Joseph Suhayda, PhD
Emeritus Engineering Professor, Louisiana State University

My name is Joe Suhayda and I pleased to appear before you today to testify about incorporating the preliminary findings about the failures of the levees protecting New Orleans and adjacent areas into a plan for restoring hurricane flood protection to the area. This is certainly a critical and timely issue since, while there is a need for immediate action to rebuild the now non-functional system, recreating the vulnerabilities of the past only guarantees future disasters.

I would like to describe some of the suggestions I have been making to provide interim flood protection for the city that will bridge the gap between the current condition of the flood protection system and the future improved conditions that may be decades away. These suggestions result from my having been involved with hurricane flood prediction and flooding issues in Louisiana for several years. I worked for 30 years as a faculty member at Louisiana State University including 20 years in the Civil and Environmental Engineering Department teaching hydraulics, coastal engineering and marine geotechnology. I was a senior consultant to the Hydrology and Hydraulics Branch of the New Orleans District of the Corps of Engineers for 4 years in the late 1990s and I have also worked under contract to the FEMA, the Louisiana Office of Emergency Preparedness and several individual parishes concerning hurricane flood preparedness.

I would first like to review a few significant points about the preliminary findings concerning the levee failures. These findings have been presented in testimony before Congress and in a recent report prepared by the American Society of Civil Engineers, to which I refer you for details. What I want to emphasize are three the major findings which I feel have particular relevance to the restoration of hurricane flood protection for the City of New Orleans and the surrounding area. These significant findings are:

1. The hurricane flooding protection system protecting the city and the adjacent areas consisted of a complex array of canals, levees and floodwalls that were geographically and administratively distinct. Subcomponents of this system, the levee districts, existed for the Jefferson Parish Lakefront, the Orleans Parish Lakefront, Orleans Parish (New Orleans East), St. Bernard Parish and Plaquemines Parish. The levee system was designed to provide variously 100 year and Category 3 flood protection. The Lake Pontchartrain and Vicinity Project was initially authorized by Congress in 1965 and had not been completed prior to Kartrina.

2. The hurricane surge and waves produced by Katrina varied considerably over southeastern Louisiana, so that no two levee districts were subject to the same hurricane conditions. In locations south of the city the hurricane conditions exceeded the project design capabilities, while along the Lake Pontchartrain the hurricane conditions appeared to be at or lower than the project design conditions.

3. There were dozens of breaches of levees and floodwalls throughout the system resulting from overtopping, seepage, soil failure and piping causing miles of levees and floodwalls to be either severely damaged or destroyed.

4. It is currently not certain that all of the levee and floodwall breaches requiring rebuilding can be repaired to the pre-Katrina Category 3 protection before the start of the hurricane season in 2006. Furthermore, raising all floodwalls and levees to a greater level of protection greater than Category 3 will take many years, perhaps decades, to accomplish.

Reviewing these findings raises two issues. The first issue is the appropriateness of the current authorization by Congress limiting the city to Category 3 flood protection. This authorization has been repeatedly cited by the Corps of Engineers as the primary factor limiting their future actions. However, this level of protection has been looked at for some time as being inadequate. A higher level of hurricane flood protection can be justified on a consistency argument alone. The river levee system in the city is designed to protect from a 1 in 800 year flood, while the current hurricane protection system was designed to protect from a 1 in 200 year flood, or about 4 times the riverine risk. The current authorization for hurricane protection projects is now out of date because the City of New Orleans and the surrounding areas have undergone major changes. The landscape surrounding the city has been extensively altered due to continuing wetland loss and accelerated by Katrina. Also, the demographics and economy of the city have been changed considerably due to Katrina. A commitment by Congress now to authorize the Corps to begin to develop Category 5 flood protection for the City of New Orleans and adjacent areas would show that we have truly learned that the Category 3 protection was inadequate. It would also eliminate the current uncertainty about what the long term federal commitment is to providing hurricane flood protection to the city.

Because of the time delays in providing either Category 3 or higher flood protection, the second issue I want to raise is the consideration of some form of immediate interim flood protection. Interim flood protection would supplement the long term plans for rebuilding of the levee/floodwall system. This interim protection could act as an incentive to bring people back into the protected areas and establish the physical basis for economic and cultural recovery. Interim flood protection would be done to give us time to carefully develop a long term plan and would not interfere with the implementation of the long term plan. The interim flood protection approach is based upon the fact that flood protection can be achieved by augmenting the traditional levee and floodwall system with new approaches. These approaches include:

1. Recognizing the fact that the various levee districts comprising the hurricane flood protection system now have different problems, needs and opportunities for rebuilding and should be treated separately rather than as one big system.

2. Additional flood protection needs to be added existing levees and floodwalls that were not extensively damaged to minimize future damage to these structures.

3. Internal flood control barriers need to be created that would take advantage of existing roadways and natural ridges to compartmentalize areas within a levee district and prevent flood waters from a single overtopping or breach from flooding the entire district.

4. Flood proofing of critical individual infrastructure facilities needs to be accomplished with flood barriers in areas where district wide protection cannot be achieved. These flood proofing activities would concentrate on those facilities critical to recovery including governmental buildings, hospitals, schools, businesses and densely populated residential areas.

These approaches could be implemented selectively to meet the specific needs of the various levee districts. For example, the Jefferson Parish Lakefront levee district received little flooding and the floodwalls, levees and pumps survived essentially intact. To increase the protection of this undamaged area, flood barriers could be placed atop the lake shore levees to immediately increase the flood protection to Category 3 or higher. The flood water passing through the canal breaches in Orleans Parish did not flood Jefferson Parish because it was prevented by the 17th Street Canal floodwall and by a topographic feature called the Metairie Ridge. A flood barrier should be placed on the ridge to provide increased protection from flooding originating in the Orleans Parish.

In the Orleans Parish Lakefront district the emergency action taken by the Corps to close the canals at the lake with sheet piling should be continued. This would eliminate the currently suspect floodwalls in the district as a part of the hurricane protection system. Additional pumps could be placed at the lake shore to reduce to loss of drainage capacity during the summer months. The height of lakeside levees could be increased using flood barriers to obtain Category 3 or greater flood protection. Barriers could also be used along the natural Metairie and Gentilly Ridges to protect the Central Business District and French Quarter from any from flooding coming from Lake Pontchartrain. The floodwalls along the Industrial Canal can be protected from scouring that would result from overtopping by armoring the landward side of the floodwalls. For the New Orleans District, St. Bernard Parish and Plaquemines Parish, where extensive levee damage occurred, interior flood protection barriers could be deployed to establish flood free areas and protect critical infrastructure.

The designs and structures needed to achieve interim protection are readily available. Flood barriers that could be used for interior flood protection and flood proofing have been recently tested by the Corps of Engineers in both field and laboratory settings. These flood barriers are rapidly deployable and removable and are being developed as a replacement for sand bags. This same technology is already been used in repairing floodwalls along the London Avenue and Industrial Canals to make them less prone to erosion. These barriers have also been used at a variety of location nationwide and have been deployed in Louisiana prior to Hurricane Katrina along the East Jefferson Levee District levees at the lakeshore and in Slidell.

This concludes my testimony and I will be pleased to answer any questions you have.

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