Levee-Related Observations, Conclusions, and Recommendations from Previous Reports
Throughout the preparation of this report, the committee came across many previously published reports on the topic of levees and the National Flood Insurance Program that were of use. The observations, conclusions, recommendations put forth by selected works are listed below, in chronological order.
A Levee Policy for the National Flood Insurance Program (NRC, 1982)
Existing levees should be recognized for the purpose of reducing insurance rates where they provide protection against 25-year or larger floods and where they meet specified structural design criteria, including requisite freeboard.
New levees should be recognized for the purpose of reducing insurance rates where they provide protection against 100-year or larger floods and where they meet specified structural design criteria including, freeboard. All levees on which construction begins after a date to be determined by FEMA should be considered new levees.
All levees (existing and new) to be given credit for reducing flood risk in the NFIP must meet standard minimum engineering criteria with respect to geometric parameters, freeboard, soils and foundations, interior drainage, closure devices, and rights of way.
In its administration of design evaluations and construction conformance inspections, FEMA should first pursue the possibility of using the services of federal and state agencies having water resources experience. Where federal participation cannot be arranged, FEMA must use state and private sector capabilities.
Where responsible federal or state agencies have had continuous maintenance responsibilities on levees they designed and constructed, and will attest to their adequacy under FEMA standards, independent evaluations should not usually be required. Evaluations should be required, however, on levees that were designed and constructed by federal agencies but are currently being operated and maintained by others.
Where a federal or state agency does not evaluate a Levee, Levee evaluations should be done by “levee evaluation contractors” (LECs), private consulting firms designated by FEMA.
While FEMA should designate qualified private consulting firms to be LECs, the firms should work under contract to an applicant interested in having a levee evaluated for recognition by FEMA. All costs of the LECs work should be borne by the applicant.
Since recognition of 25-year levees for the purpose of reducing insurance rates would represent an important change in federal policy, FEMA should publicize the benefits, costs, and procedural details for levee recognition.
FEMA should inventory all levees previously credited as providing projection from the 100-year flood, set priorities, and schedule communities for restudy to reevaluate the levees.
FEMA should develop a short and simple checklist that can be used to make a quick assessment of whether a levee meets recommended criteria.
FEMA should confirm its interim policy that does not recognize sand bags on top of levees and other types of human intervention, except for structural closures which are legitimate parts of planned levee systems, as augmenting levee systems design level of protection.
Federal Code 208.10, Title 33, “Local flood protection works; maintenance and operation of facilities should be modified where not well suited, supplemented for interior drainage, and adopted by FEMA as a guideline for operation and maintenance of levee systems.
A specific operation and maintenance plan, tailored to the local needs, must be formally adopted by the levee owner for a levee to be credited and continue to be credited in the NFIP.
The operation and maintenance plan must, provide for periodic inspections. The plan should be completed within a designated time period, meet the requirements of, and be acceptable to FEMA. Each inspection must be by a professional engineer retained by the levee owner and registered in the state in which the levee is located. A written report to the levee owner should be promptly prepared and certified by the professional engineer making the inspection. The report must specifically describe items found deficient and emerging potential future problem areas. Copies of the certified report should be sent, by the certifying professional engineer to the regional FEMA office. Also, a copy should be provided the local political entities which have responsibilities to FEMA for the levee-protected area. FEMA should follow up to assure corrections are made within a reasonable length of time. In instances where corrections are not made to critical deficiencies, FEI4A should withdraw recognition.
FEMA should require the elevation of new residential structures and the flood-proofing of other new buildings in all areas protected by levees unable to contain the 100-year flood.
FEMA should require purchase of flood insurance in all areas where the ground is lower than the unconfined 100-year flood level except where protected by a levee built to contain the 500-year flood.
Communities should regulate the placement of critical facilities (not regulated by some higher level of government) in all leveed areas in accordance with the procedures of Executive Order 11988.
Owners, tenants, and lenders occupying areas designated as protected by levees should be notified periodically by responsible local officials that their land in the levee protected area is still subject to flooding in the event of levee failure.
Local officials of any NFIP participating community protected by a levee, regardless of its size and reliability, should prepare and promulgate an action plan for warning and evacuation in the event of levee failure.
FEMA should help make local governments and special districts aware of the possibility of liability for actions or nonactions that aggravate flood hazards.
FEMA should, in appropriate cases, seek to recoup federal flood-related costs (including flood insurance payments, disaster assistance, etc.) from levee owners/operators when such costs arise from improper operation and maintenance of levee and associated interior drainage facilities.
Regardless of the level of protection provided, the levee-protected area should be disaggregated into flood risk zones and an actuarial rate be established for each zone that reflects the degree of protection actually provided by the levees.
Consistent with the design levels of protection recommended in Chapter 3, NFIP policyholders in areas behind existing levees that offer more than 25-year protection or new levees affording 100-year protection or greater should pay lower rates that reflect the reduced risk of property damage.
The levee flood risk zones should match the existing flood risk zones established for the regular Flood Insurance programs
FEMA should continue its efforts to establish an actuarial rate basis for the Flood insurance program and, as far as practical, convert its present rate schedule to actuarial rates. The actuarial rates as is done by the private insurance industry would be updated annually to reflect experience, claims paid, and the cost of doing business.
FEMA should contract for the development of a list of key categories concerning tire physical condition of a levee that would be used to evaluate the levee’s ability to function effectively and concerning use of those factors to estimate geotechnical risk. An unsatisfactory rating would result in increased flood insurance premiums.
All levees, dikes, or floodwalls should be labeled as such on any new or revised FHBM. Also, the areas protected by levees providing 100-year or greater protection should be delineated on the new or revised FHBMs as Zone LP. Areas protected by Levees not meeting this standard would continue to be mapped as Zone A.
The location of all levees, dikes, or floodwalls credited as providing 100-year protection or more should be clearly denoted on all future FIRMs.
Areas behind recognized 100-year levees that would be flooded (assuming no levee) by a 100-year flood should be designated as Zone ALP. Areas between the 100-year flood boundary and 500-year flood boundary should be designated as Zone BLP.
The locations of all credited levees, dikes, and floodwalls should be clearly denoted on all Floodway Maps. Areas behind credited levees providing 100-year protection that would be flooded during a 500 year flood should be shown on Floodway Maps.
FEMA should create an AL(No. ) Zone that would designate an area protected by a levee with a frequency of protection defined by the (No.). For example, if the levee had an elevation equal to the 40-year flood (plus required freeboard), then the Zone would be Al(40).
FEMA should not make it a mandatory requirement to include evacuation routes on maps If the information is available when the maps are being prepared and if it makes sense from a community-to-community mapping standpoint, then the evacuation routes could be included on the maps. In other cases, it may be expeditious for communities to develop their own special evacuation route maps.
Interior drainage situations in areas on the landside of levees should be analyzed in conjunction with the riverine flood analysis, and the areas flooded by interior drainage should be shown on FEMA maps in accordance with current practice. Appropriate consideration should be given to correlation of the event on the river and the event causing the interior drainage problem.
Assessing the Adequacy of the National Flood Insurance Program’s One Percent Flood Standard 2006 (Galloway et al., 2006)
If implementation of the standard can be improved, FEMA should retain the one percent annual chance flood as the Federal standard for regulation of activity in the SFHA. The Nation needs to have a common standard for Federally imposed land use restrictions.
FEMA should take action to improve the implementation of the one percent standard for regulation of land use. Such actions as enhancement of public understanding of hazards, use of future-conditions hydrology to account for urbanization and climate change, reduction in floodway infringements, and greater attention to enforcement of existing NFIP provisions would greatly improve the effectiveness of NFIP related land use decisions.
States and their communities should exercise their responsibility to impose higher standards, where the health and safety of the population merits a higher standard for land use regulation. Concurrently, FEMA should examine the use of incentives, possibly through use of the Community Rating System (CRS), to reward States that exercise these responsibilities. Imposition of higher standards is well within the purview of the States and the communities that lie within the States and receive their land use authority from the States.
FEMA should seek legislative authority to require mandatory purchase of flood insurance by those living in the 0.2 percent floodplain if they hold a Federally insured mortgage or if they are to receive any disaster assistance from the Federal government in the case of a flood. The cost of this insurance should be determined actuarially, based on the reduced risk of living at a specific elevation within the 0.2 percent floodplain.
FEMA should not recognize levees under the NFIP unless they provide protection to the 0.2 percent (500-year flood) level. Levees in non urban areas should protect against the 1 percent or larger flood, depending on the economic costs and benefits of the levee.
FEMA should seek legislative authority to require mandatory purchase of flood insurance by those living behind accredited levees to address the residual risks they face and to ensure they are aware of this risk. Structures behind levees are subject to residual risks and should be insured against that risk.
FEMA should ensure that NFIP guidance and program activities clearly indicate that critical facilities should be located outside the 0.2 percent floodplain.
FEMA should improve the collection of policy and claims data, to assist in ongoing evaluation efforts, and should actively support Federal funding of efforts by NOAA to upgrade precipitation frequency estimates and flood data collection, and the U.S. Geological Survey (USGS) efforts to upgrade its stream gaging program. The accuracy of the Federal flood data is no better than the baseline information from which it is derived.
FEMA should ensure that consideration of natural and beneficial functions is fully integrated into all aspects of FEMA and NFIP actions influencing floodplain activity.
GAO Hurricane Katrina: Strategic Planning Needed to Guide Future Enhancements Beyond Interim Levee Repairs (GAO, 2006)
The Army Corps of Engineers should develop (1) a comprehensive strategy that includes an integrated approach for all projects and plans for rebuilding and strengthening the system and (2) an implementation plan that will achieve the specific level of protection in a cost-effective manner, within a reasonable time frame.
The Army Corps of Engineers should establish an evaluative organization like the Interagency Performance Evaluation Task Force, to assist in its efforts in developing a strategic plan, monitoring progress, and providing expert advice for constructing a stronger and well-integrated hurricane protection system.
The National Levee Challenge; Levees and the FEMA Map Modernization Initiative - 2006 Interagency Committee (FEMA, 2006)
FEMA should define a new flood insurance zone (Zone XL) for areas behind levees that provide 100-year protection and meet other requirements for inclusion in the NFIP and, in coordination with other agencies, identify the level of risk to those structures behind those levees. The XL zone would include those areas behind the levee that are subject to inundation by the 100-year flood in the without-levee condition. The area between the 100- and 500-year floodplain lines would be shown as a shaded X zone.
Levees would also be identified under a scientifically based levee risk classification system (e.g., high, medium, or low). This classification system would be based on several factors, including the following:
• Potential depth of flooding in the event of failure or overtopping,
• Type and density of development in protected areas behind the levee,
• Steps taken to ensure that levee failure does not occur during levee capacity exceedance (overtopping),
• Warning times,
• The number and types of egress so that people who may be inundated may move out of harm’s way.
This levee risk classification would be designated on the Flood Insurance Rate Map (FIRM) and in the Flood Insurance Study report.
To ensure that levee systems maintain the conditions that qualified them for NFIP accreditation, FEMA should require as a condition of retaining FEMA recognition of levee status that sponsors:
• Conduct annual inspections of the levee system,
• Submit to FEMA biennially the results of the annual inspections, levee system operation and maintenance records, and an assessment of the levee system during any flood events that occurred within the reporting period,
• Submit to FEMA every 10 years a report, prepared by a registered Professional Engineer or Federal agency responsible for levee design, that recertifies the engineering and geotechnical conditions of the levee system,
• Certify levees as systems that include not only levees and floodwalls, but also the pumps, interior drainage systems, closures, penetrations, and transitions that provide systems integrity, and ensure that operation and maintenance plans cover all elements of the system.
To ensure that all components of a levee system meet required standards, FEMA should exclude embankments, such as roads and railroads, from inclusion in accredited levee systems unless those embankments meet the engineering criteria required of levees and are maintained and operated in accordance with the provisions of 44 CFR 65.10.
FEMA should revise 44 CFR 65.10 to incorporate the above recommendations and to deal with other needed changes in the administrative requirements of 44 CFR 65.10 as noted in the appendices to this report.
FEMA and USACE should continue their efforts to develop a joint database structure that will meet the needs of both agencies and other Federal and State organizations to maintain an inventory and assessment of flood damage reduction structures, including levees.
While agency-specific components of such a database will be needed, the management and fiscal benefits that accrue from a common core and adherence to the national spatial data infrastructure (NSDI) will be significant.
Working with its Federal, State, and local partners and with levee sponsors, FEMA should develop and implement a public awareness and outreach strategy that will improve public awareness and understanding of the hazards and risks associated with levees. This audience includes the Administration and Congress, other public officials, and private citizens.
As part of this public outreach effort, levee sponsors should be required to notify annually property owners in areas behind a levee about the residual risk that exists and the risk classification of the levee.
The relationships among institutions and organizations dealing with levees are not clearly defined and vary by agency and region.
The Federal Government’s role in flood damage reduction through USACE, the Natural Resources Conservation Service (NRCS), the Bureau of Reclamation, the National Oceanic and Atmospheric Administration (NOAA), and the U.S. Geological Survey (USGS) is generally understood. FEMA’s role in floodplain management is evolving and is less understood by the public. Similarly, the role of State and local organizations in carrying out floodplain-related activities is evolving.
Success in Map Mod as well as flood damage reduction will depend on the development of close working relationships among representatives of the agencies involved.
Efforts should be made to closely coordinate the activities of relevant Federal agencies in floodplain management and related mapping programs.
FEMA and USACE should review existing authorities and funding available to assist communities in performing certification analysis and make recommendations to the Office of Management and Budget (OMB) if the funding and authorities are not available.
FEMA and USACE also should develop expedited processes to assist communities in remediation of publicly-owned levees and seek OMB and Congressional approval of these processes and the need for resource commitments to support them.
FEMA should consider seeking legislative action to permit use of A99 designation and procedures by communities that are able to self-fund levee upgrades
To ensure that the base data used to support the hydraulics and hydrology (H&H) analysis are up to date and reflect 21st-century computation technologies, FEMA, in coordination with other Federal agencies that use these data and techniques, should support funding of NOAA efforts to upgrade precipitation frequency estimates, upgrades to the USGS gaging program, and the Advisory Committee on Water Information Subcommittee on Hydrology revision of Bulletin 17B, which guides flood recurrence interval determinations.
Recognizing the national and international movement toward use of risk analysis in dealing with floods and their consequences, the significant strides that have been made in developing risk assignment techniques, and the current use of these techniques by USACE in levee design, FEMA should modify 44 CFR 65.10 to phase out, over the next 10 years, use of the freeboard-based approach and should substitute the risk analysis methodology for levee-height determination. During the transition period, FEMA should permit either approach to be used in levee design and recertification analysis
Strong consideration should be given to not recognizing, for NFIP purposes, levees that provide protection to highly urbanized areas unless they provide protection against floods greater than 100 years (e.g., the 500-year flood). There is a long history of recommendations and analyses to support protection to 500-year or greater levels. Given the large number of existing levees, the transition would not be quick or easy. Nevertheless, FEMA should take steps to immediately examine this issue in detail and determine if a change in the standard for recognition should take place.
Non-Federal levees exist at the sufferance of the States and counties in which they are located. Federal levees, for the most part, are passed to State and local sponsors following their completion for operation and maintenance.
State and local agencies must play a significant role in dealing with levee issues as they arise. Federal agencies should recognize the State and local roles and develop incentives and support mechanisms to ensure that State and local agencies can effectively carry out their responsibilities.
Property owners behind levees continue to face the residual risk of flooding, yet they are not required to share in the mitigation of this risk through insuring their property against the dangers of the residual risk. FEMA should address the challenge of the residual risk in the following ways:
• Seeking legislative change to require property owners to purchase some level of flood insurance for structures behind levees (new Zone XL).
• Requiring communities to establish special early warning systems and to develop flood warning - preparedness plans for those areas that are protected by levees.
The current H&H approach for calculation of the BFE ensures that structures being designed to comply with the BFE are out of date by the time they are constructed. Future H&H conditions are not directly addressed. FEMA, working closely with other Federal agencies, States and communities, should examine how best to deal with climate change, sea-level rise, and future development. Such efforts will require the commitment of significant resources. It also represents a conceptual shift from specifying the mapping criteria to reflect present conditions to establishing criteria based on possible, but not fully quantifiable, future conditions.
When communities are not able to document immediately the recertifiability of currently certified levees and the levees are not known to be at risk, FEMA should notify the communities of the need for a more detailed examination of the levees and provide a specific schedule for that activity. Communities should be required to notify all residents who are living in areas behind the levees of the re-examination and identify for them the residual risks and the need for information about the levees. This action would closely parallel ongoing FEMA efforts to permit completion and adoption of new countywide maps that contain levees needing further study.
A major challenge facing those responsible for levee certification is conduct of appropriate and rapid geotechnical assessments of levee integrity. These assessments are critical to providing assurances of levee safety. However, such assessments, depending on the nature of the material and the cross section of the levee, are very costly. The bulk of the costs are related to the number and depth of soil borings. No methods or technologies are currently available to replace soil borings, and little effort is underway in the Research and Development (R&D) community to deal with the challenge. FEMA, USACE and USGS should support R&D efforts focused on improvement of rapid assessment of levee geotechnical integrity and should jointly recommend to the National Science Foundation that attention be given to this area of research.
ASFPM: National Flood Policy Challenges - Levees: The Double-Edged Sword (ASFPM, 2007)
The ASFPM urges FEMA and the U.S. Army Corps of Engineers, along with other federal water resources agencies, to revisit and revise the definition of levee so that it includes elements of function, risk, and vulnerability. This effort should include defining a levee, dam, or incidental work that modifies flood flows and the interrelationships among these definitions. The Federal Interagency Task Force on Floodplain Management is one potential vehicle to undertake this task.
The ASFPM believes that the Corps of Engineers should be tasked as the lead agency to develop and maintain a comprehensive inventory of current and future levees. This would start with federal levees and ultimately include non-federal and private levees.
Levees should be used as a structure of last resort and only after other measures, especially nonstructural ones, have been fully considered. Levees should not be used as a means to facilitate the development of currently undeveloped floodprone lands.
Federal investments in levees should not be made for a structure that provides less than 500-year protection, and the Corps of Engineers planning process of maximizing the NED should explicitly incorporate this public safety standard as a lower boundary for federal investment.
Levees should not be constructed in floodways and, to the maximum extent possible, when constructed or reconstructed levees should be set back from rivers to allow the river to function more naturally and to provide for the protection or restoration of riparian and wetland resources between the river bank and the levee.
The ASFPM urges Congress and the Administration to adopt a policy that the 500-year level of protection for levee design is the minimal standard for purposes of flood insurance and other federal investment.”
Current levees that provide less than 500-year protection but meet all the requirements for design, maintenance, and operation, and are recognized by federal programs as meeting the standards for 100-year protection, could be provided grandfathered status. Criteria should be developed to determine when and if protection provided by a specific levee would need to be upgraded and how that would be achieved.
Benefit/cost analysis is an appropriate tool with which to evaluate and contrast federal projects, but it should be bounded by a strong public safety design standard, which for federally supported levees should be the 500-year level of protection.
The design of levees should include improved methods of providing resiliency, most notably the inclusion of designed fail-resistant spillways built into many levees so that when the levee design is exceeded, excess flow spills through that area, preventing catastrophic overtopping or failure of the structure.
The impacts of any new, rehabilitated, or reconstructed levee that would result in the transfer of damage or in adverse economic, social, or environmental consequences must be mitigated.
The local sponsor must demonstrate the financial and staffing capability to provide operation and maintenance for the life of the structure—before the project is approved, constructed, re-constructed, or recognized as providing a certain level of flood protection.
Congress should fund the National Research Council to engage experts to evaluate and propose modifications to levee design, operation, and maintenance standards. These efforts should include review of previous National Academies reports, and the extent to which previous recommendations have been addressed.
Written guidance is needed on what constitutes a “proper” inspection, what is needed for certification to enable the NFIP to recognize the levee, and what the actual consequences are to the levee owner if the levee is not properly maintained to meet these requirements. Both the Corps of Engineers and FEMA have guidance for requirements of programs that come into play with these issues, and the guidance from each agency must be consistent and correlated with the other agency’s guidance.
A federal policy should be clearly articulated that the periodic certification and inspection of levees, including related operation and maintenance, is the responsibility of the levee owner and that transferring this responsibility to the federal government is inappropriate. Participation in federal programs of repair, insurance, and disaster relief must be contingent on levee owner compliance with these elements.
A federal policy should be clearly articulated that the periodic certification and inspection of levees, including related operation and maintenance, is the responsibility of the levee owner and that transferring this responsibility to the federal government is inappropriate. Participation in federal programs of repair, insurance, and disaster relief must be contingent on levee owner compliance with these elements.
A state-administered national levee safety program is needed to protect the federal interest in public health, safety, and fiscal responsibility, as well as to protect public safety and costs related to all levees not in the federal system. Such a program must be fully integrated with state and local programs of flood risk management, especially floodplain management and dam safety, and should use a state delegation model similar to that used to implement the Clean Water Act, rather than function as an independent program like the existing National Dam Safety Program. State capability in this area is critical and can be developed most effectively through federal legislation that provides incentives and disincentives for states to accept delegation for the development and implementation of effective state levee safety programs.
FEMA should require that all communities with an NFIP-recognized levee have a multihazard mitigation plan that considers how other hazards affect the safety of their levee (e.g., earthquake, subsidence, river sedimentation, erosion, etc.) and appropriate emergency action plans (EAPs) with action steps to account for any of these factors that affect the safety of the levee. FEMA should require that this plan be updated at least every five years, including accounting for any changes in flood flows caused by increased watershed development. The potential for catastrophic consequences of levee failure or overtopping should be included in levee planning, design, regulations, and insurance considerations.
The area that would be inundated when a levee fails or is overtopped, or when internal drainage systems are overwhelmed or incapacitated should be mapped as a residual risk flood hazard area and depicted on Flood Insurance Rate Maps.
Emergency action plans (EAPs) that address flood warning and evacuation should be required for all residual risk areas behind levees in order to protect lives and minimize property damage. These plans, and the periodic exercise of them, should be a requirement of any federal or state program that recognizes the levee as providing protection.
The purchase of flood insurance and implementation of appropriate development standards should be mandatory for all property protected by levees, to reflect the potential for the catastrophic consequences of levee failure.
Communication of the residual risk behind levees on a regular basis should be an explicit component of all aspects of proposed and current levee activities. It should include notification to all property owners of the risk (e.g., a notice in an annual water bill or tax bill) along with other measures such as posting signs in all land areas at risk behind the levees. All communication should state clearly that the area behind the levee is provided with some level of protection by levees, that the levees may fail or be overtopped, and that the area is a floodplain, with indications of the depth of flooding when the levee fails or is overtopped. Communication to the property owners should provide clear information on their role if an evacuation is ordered.
The liability of owners of structural flood control projects, such as levees and dams should be communicated to the owners of those structures on a periodic basis.
FEMA and the Corps of Engineers should evaluate and eliminate practices that cause increased flood damage or that lead to induced flooding (the transfer of flooding to other property that is primarily open space) unless property owners agree to a permanent flooding easement in return for this intrusion of flooding on their property.
The cumulative impacts of levees within a system or watershed should be evaluated before any levees are permitted, so those impacts are considered and mitigated, including increasing the design height to account for increased flood levels.
Levee construction, repair, and reconstruction should account for the protection of existing natural functions to avoid adverse impacts to the natural system. In addition, during repair or reconstruction of the levee, these natural functions should be restored to the maximum extent that is practical to account for past adverse impacts.
A California Challenge—Flooding in the Central Valley (State of California DWR, 2007)
Provide the highest level of risk reduction feasible to existing urban areas where thousands of people are at unacceptably high risk. The Panel believes that this level of protection should be equivalent to protection against the Standard Project Flood, which represents a flood that can be expected from the most severe combination of meteorologic and hydrologic conditions that are considered reasonably characteristic of the region. Providing this level of protection does not, by itself, prevent the failure of the system or of individual levees; nor does it guarantee that the Standard Project Flood cannot be exceeded in rare circumstances. One hundred year protection is not an acceptable level of protection for urban areas.
Develop an implementation plan for providing this reasonably high level of protection for all urban areas. The needed level of flood protection should be phased in with at least a 200-year level of flood protection to be achieved by 2020, and Standard Project Flood protection by 2030. Priority should be given to urban areas in deep floodplains.
In less populated areas, provide for protection against less severe floods (e.g. less than 200-year protection) as economically and environmentally justified, and maintain that lower level of protection into the future.
Ensure that any flood protection provided is sustainable fiscally and physically over time.
Manage the floodplain by focusing new development outside of the floodplain or in low-risk locations within protected areas of the floodplain, supporting the use of undeveloped and unprotected land for agriculture and other low-intensity land uses.8 Floodplain management should be accompanied by requirements for local governments to adopt and enforce needed land-use controls, financial and technical support to enable them to do so, and appropriate penalties if local governments fail to manage development to reduce flood risk. The state should continue to support the Federal Emergency Management Agency’s levee policy and assist them in accelerating completion and adoption of updated flood maps. This would ensure that any new development in areas behind inadequate levees takes place under the land-use provisions mandated by the National Flood Insurance Program, as a minimum.
Site, where feasible, new levees or major rehabilitation of levees at a distance from the river and from existing levees. This would provide a degree of redundancy in the system, increase the land available for habitat and flood storage, reduce operation and maintenance costs, and help to ensure the integrity of the structures. Levees built this decade will be in place for decades to come, and now is the time to begin building structures that will last. Where re-siting is not feasible, the existing flood system should be modified to mitigate the impacts of floods that exceed the design level of the system.
Mitigate potential financial losses to those behind levees and to those in the non-leveed 500-year floodplain shown on Federal Emergency Management Agency flood maps through institution of mandatory purchase of flood insurance, or through inclusion of flood insurance in homeowners’ policies of those within these areas.
Share the liability for flood damages among state and local governments. This would ensure that any local governments making land-use decisions that could increase potential flood damages share not only the benefits of that development, but also any liability incurred from potential flood consequences should those decisions prove to have been unwise.
Communicate to the public and each property owner in the floodplain the specific risks of occupying areas at risk of flooding, and provide steps property owners can take to reduce their exposure to flood damages.
Communicate to the public and each property owner in the floodplain the specific risks of occupying areas at risk of flooding, and provide steps property owners can take to reduce their exposure to flood damages.
Supplement the structural protection provided with floodproofing, elevation of homes and businesses, land-use regulations, and other non-structural approaches to reduce the residual risk that will continue to exist. Support
this with emergency response systems including the development of post-disaster sheltering and redevelopment plans and the exercising of floodplain evacuation plans on a regular basis. Dealing with flooding in the Central Valley will require a close examination of existing governmental institutions and how they work together. The lessons learned from the New Orleans disaster point out the disconnects that develop when too many agencies are involved in the decision-making process and no one agency has overall direction. Large flood events exploit those disconnects. California must address this difficult issue, especially in terms of the large number of overlapping roles, responsibilities and accountabilities of reclamation districts, and state and local governments. Without reforming the institutions that manage flood protection, large investments in infrastructure are likely to be wasted.
Hurricane Protection System Peer Review (Battelle, 2007)
USACE should seek Administration support for and Congressional approval to:
• Develop a single authorization for the HPS similar to that provided for the Mississippi River and Tributaries (MR&T) project.
• Authorize flexibility for reprogramming.
• Ensure multi-year or timely appropriations; recognize the consequences of delays.
• Provide expedited review of issues.
• Ensure close cooperation with local governments and understanding of the problems associated with lack of cooperation
Nonstructural elements should become an equal partner in completion of the HPS. USACE should receive increased funding to carry out programs of nonstructural technical assistance for communities and proactively provide technical assistance to FEMA and local authorities with respect to elevating structures, floodproofing, planning for interior drainage, and other flood management considerations. This is especially the case for interior polderization of protected areas which could reduce the spatial extent of flood risk.
TFH should work closely with local officials on full implementation of effective floodplain management and enforce that provision of Section 402 of the Water Resources Development Act (WRDA) of 1986 requiring development of local floodplain management plans. There is a clear opportunity for USACE to provide needed technical assistance, so that rebuilding occurs in a manner that minimizes the potential for future flood dam-age to public buildings and infrastructure and private homes and businesses.
USACE should provide maps of residual risk for early distribution to residents and officials. Risk communication maps should be accompanied with information on personal mitigation measures to include flood avoidance, financial protection, and life-safety concerns. USACE must ensure that residents and officials understand the residual risk and the level of protection that is actually being provided.
Given the experience and the strategies the Japanese and Dutch use for protection, TFH should consider establishment of a centralized planning and inspection capability for O&M. Fragmented planning efforts provide significant opportunities for system disconnects and potential failures.
USACE should include high-tech monitoring systems for key elements of the completed HPS. Technology now makes it possible to remotely sense levees, floodwalls and other protective system problems as they occur. Some systems are currently under consideration by TFH.
Given the tight schedule for completion of the 100-year system, TFH should not divert human and physical resources from the principal task of finishing the HPS to the 100-year level to provide interim improvements. Since the HPS will not be at a 100-year level until the 2011 hurricane season at the earliest, some have expressed concern over the need for interim protection in components of IHNC and West Bank areas. While these concerns are important, completion of the system should have priority.
USACE should seek an accelerated decision on MRGO to allow early movement forward on dealing with hurricane protection in the area of the MRGO-GIWW and improving protection to the IHNC. Such a decision will save time, eliminate the need to plan against alternatives, and speed completion of the HPS.
TFH, in current construction activities, should take into account the potential footprints of subsequent construction under LaCPR so as to minimize repeat disruptions, multiple right-of-way acquisition, etc. Major long-term cost savings can be generated and significant public push back can be avoided by dealing with real estate issues only once.
Observations:
Provision of risk reduction (protection) against the 100-year annual chance (100-year) event is not sufficient to prevent possible loss of life and social disruption in a major urban area. For example, there is a 26% chance of the occurrence of such an event with the life of a 30-year mortgage. Urban areas need a higher level of protection. Providing 100-year protection may make it difficult to subsequently provide this higher level of protection.
It is not clear that there is agreement that the HPS being built reflects the understanding of all stakeholders and Congress as to what level of protection is supposed to be provided. TFH indicated that its first priority was to provide 100-year certified levees for all areas rather than 100-year or ‘as originally authorized,’ whichever is higher. This is a sound decision, but USACE should take action to obtain written agreement from stakeholders and the Congress that the 100-year first path it is following is in fact the path expected.
Many USACE technical manuals are badly out of date. Manuals being used in levee design are Dutch, because appropriate USACE manuals did not exist or had not been revised in many years. USACE O&M programs must include adequate funding to support continuous maintenance and upgrade of the documents and the necessary research and development (R&D) that maintains currency.
The New Orleans Hurricane Protection: What Went Wrong and Why (ASCE, 2007)
Keep safety at the forefront of public priorities by having all responsible agencies re-evaluate their policies and practices to ensure that protection of public safety, health, and welfare is the top priority for infrequent but potentially devastating impacts from hurricanes and flooding. Also, encourage Congress to establish and fund a mechanism for a nationwide levee safety program, similar to that which is in place for dams.
Quantify and periodically update the assessment of risk. This approach should be extended to all areas in the United States that are vulnerable to major losses from hurricanes and flooding.
Determine the level of acceptable risk in the community through quality interactive public risk communication programs in New Orleans and other areas threatened by hurricanes and flooding. Once determined, manage the risks accordingly.
Correct the system’s deficiencies by establishing mechanisms to incorporate changing information, making the levees survivable if overtopped, strengthening the I-walls and levees, and upgrading the pumping stations.
Assign to a single entity or individual (a licensed engineer) the responsibility of managing critical hurricane and flood protection systems such as the one in New Orleans.
Implement more effective mechanisms for coordination and cooperation. (For example, those responsible for maintenance of the system must collaborate with system designers and must upgrade their inspection, repair, and operations processes to ensure that the system is hurricane- and flood-ready.
Upgrade engineering design procedures and practice to place greater emphasis on safety.
Engage independent experts in high-level reviews of all critical life safety structures, including hurricane and flood-protection systems
Hurricane Protection Decision Chronology - 2008 (USACE, 2008) Reflections on Project Decision-Making:
1. Concerns about project cost growth, constrained federal and local budgets, delays in project completion, and the possible need for reauthorization if major changes were proposed, help to explain District decisions to construct the project according to original designs and datum benchmarks.
2. There was no Corps organizational process that required and provided funding for a continuing assessment of project performance capability during the postauthorization implementation period.
3. There is no evidence in the project record indicating that project engineers believed that the decisions made would threaten engineering reliability.
4. The only recurring organizational provision for systematically reporting the expected performance capability of the project was the annual Budget Justification Sheet.
Reflections on the Future:
1. The importance of sharing knowledge
2. Need for flexibility and adaptation in planning, design, and implementation
National Committee on Levee Safety (NCLS, 2009)
Establish a National Levee Safety Commission to provide national leadership and comprehensive and consistent approaches to levee safety including standards, research and development, technical materials and assistance, training, public involvement and education, facilitation of the alignment of federal programs and design, delegation and oversight of a delegated program to states.
Expand and Maintain the National Levee Database to include a one-time US Army Corps of Engineers inventory and inspection of all non-federal levees. Baseline information will be included and maintained in an expanded National Levee Database (NLD) in order that critical safety issues, true costs of good levee stewardship, and the state of individual levees can inform priorities and provide data for needed risk-informed assessments and decision-making.
Adopt a Hazard Potential Classification System as a first step in identifying and prioritizing hazard in leveed areas. Due to a lack of data regarding probability of failure, initial classifications should be based solely on consequences in order to assist in setting priorities, criteria, and requirements as the NSLP is being established.
Develop and Adopt National Levee Safety Standards that will assist in ensuring that the best engineering practices are available and implemented throughout the nation at all levels of government.
Develop Tolerable Risk Guidelines in order to facilitate an understanding of the options to reduce identified risks, how uncertainty affects this understanding, and to better inform levee construction/enhancement decisions and weigh nonstructural alternatives to flood risk management in a risk-informed context. Change “Levee Certification” to “Compliance Determination” to better articulate the intent that “certification” under the National Flood Insurance Program (NFIP) requirements does not constitute a safety guarantee or warranty. The purpose of this change is to more clearly communicate residual risks of living and working in leveed areas.
Change “Levee Certification” to “Compliance Determination” to better articulate the intent that “certification” under the National Flood Insurance Program (NFIP) requirements does not constitute a safety guarantee or war-
ranty. The purpose of this change is to more clearly communicate residual risks of living and working in leveed areas.
Subject Levee Certifications (Compliance Determinations) under FEMA’s National Flood Insurance Program to Peer Review in order to increase confidence in technical determinations of compliance.
Swiftly Address Growing Concerns Regarding Liability for Damages Resulting from Levee Failures through exploration of a range of measures aimed at reducing the potential liability of engineering firms and/or government agencies that perform engineering services for levee systems (e.g. inspections, evaluations, design, construction administration, certification, or flood fighting). Congress should address this liability concern as a first priority in order to help ensure state and local interest in developing levee safety programs, and to prevent much needed levee repairs, rehabilitation and certification from coming to a halt.
Develop a Comprehensive National Public Involvement and Education/Awareness Campaign to Communicate Risk and Change Behavior in Leveed Areas as an essential element of levee safety by improving public understanding of the role of levees, associated risks, and individual responsibilities to empower people to make risk-informed choices.
Provide Comprehensive Technical Materials and Direct Technical Assistance crucial to the successful implementation of consistent national standards to states, local communities and owner/operators.
Develop a National Levee Safety Training Program including a combination of courses, materials, curricula, conferences, and direct assistance resulting in an increase in the level of expertise and knowledge in all aspects of levee safety. This would include the development of curricula and certification requirements for a Certified Levee Professional program.
Develop and Implement Measures to More Closely Harmonize Levee Safety Activities with Environmental Protection Requirements to ensure that critical levee operations and maintenance is not delayed and that, where possible without compromising human safety, environmentally-friendly practices and techniques are developed and used.
Conduct a Research and Development Program that will continually advance state-of-the-art technologies and practices for levee safety and conduct critical operations and maintenance activities in as cost-effective and environmentally-friendly manner as possible.
Design and Delegate Program Responsibilities to States to assist states and local governments develop effective levee safety programs focused on continual and periodic inspections, emergency evacuation, mitigation, public involvement and risk communication/awareness, etc.
Establish a Levee Safety Grant Program to assist states and local communities develop and maintain the institutional capacity, necessary expertise, and program framework to quickly initiate and maintain levee safety program activities and requirements.
Establish the National Levee Rehabilitation, Improvement, and Flood Mitigation Fund to aid in the rehabilitation, improvement or removal of aging or deficient national levee infrastructure. Investment (cost-shared) is recommended to be applied to the combination of activities, both structural and non-structural, that combined, would maximize overall risk reduction and initially be focused in areas with the greatest risk to human safety.
Explore Potential Incentives and Disincentives for good levee behavior through alignment of existing federal programs.
Mandate Purchase of Risk-Based Flood Insurance in Leveed Areas to reduce financial flood damages and increase understanding of communities and individuals that levees do not eliminate risk from flooding.
Augment FEMA’s Mapping Program to improve risk identification and communication in leveed areas and consolidate critical information about flood risk.
Align FEMA’s Community Rating System (CRS) to Reward Development of State Levee Safety Programs by providing further incentives to communities to exceed minimum program requirements and benefit from lower risk-based flood insurance rates to individuals who live in leveed areas.
The New Orleans Hurricane Protection System: Assessing Pre-Katrina Vulnerability and Improving Mitigation and Preparedness (NRC, 2009)
Hydrologic Realities and the Limits of Protective Structures:
• There are many inherent hydrologic vulnerabilities of living in the greater New Orleans metropolitan region, especially in areas below sea level. Post-Katrina repairs and strengthening have reduced some of these vulnerabilities. Nevertheless, because of the possibility of levee/floodwall overtopping—or more importantly, levee/floodwall failure—the risks of inundation and flooding never can be fully eliminated by protective structures no matter how large or sturdy those structures may be.
Future Footprint of the Hurricane Protection System:
• The pre-Katrina footprint of the New Orleans HPS consisted of roughly 350 miles of protective structures including levees, I-walls, and T-walls. There was undue optimism about the ability of this extensive network of protective structures to provide reliable flood protection. Future construction of protective structures for the region should proceed with this point firmly in mind and in the context of a more comprehensive and resilient hurricane protection plan.
Nonstructural Aspects and Options:
• Comprehensive flood planning and risk management for the New Orleans metro region will be based on a combination of structural and nonstructural measures, the latter including relocation options, floodproofing and elevation of structures, and evacuation studies and plans. Better risk communication also must be part of more effective mitigation and an improved state of preparedness. Structural measures such as levees and floodwalls should not be viewed as substitutes or replacements for nonstructural measures, but rather as complementary parts to a multi-tiered hurricane protection solution.
• Relocation: the planning and design for upgrading the current hurricane protection system should discourage settlement in areas that are most vulnerable to flooding due to hurricane storm surge. The voluntary relocation of people and neighborhoods out of particularly vulnerable areas—with adequate resources designed to improve their safety in less vulnerable areas—should be considered as a viable public policy option.
Floodproofing Measures:
• When voluntary relocations are not viable, floodproofing measures will be an essential complement to protective structures—such as levees and floodwalls—in improving public safety in the New Orleans region from hurricanes and induced storm surge. This committee especially endorses the practice of elevating the first floor of buildings to at least the 100-year flood level, and preferably to a more conservative elevation. The more conservative elevation reflects a subsequent finding in this report regarding the inadequacy of the 100-year flood as a flood protection standard for a large urban center such as New Orleans.
• Critical public and private infrastructure—electric power, water, gas, telecommunications, and flood water
collection and pumping facilities—should be strengthened through reliable construction, and ensuring reliable interdependencies among critical infrastructure systems.
Evacuation:
• The disaster response plan for New Orleans, although extensive and instrumental in successfully evacuating a very large portion of the New Orleans metropolitan area population, was inadequate for the Katrina event. Thus, there is a need for more extensive and systematic evacuation studies, plans, and communication of evacuation plans. A comprehensive evacuation program should include not only well designed and tested evacuation plans, protocols, and criteria for evacuation warnings, but also alternatives such as improved local and regional shelters that could make evacuations less imposing. It also should consider longer-term strategies that can enhance the efficiency of evacuations, such as locating facilities for the ill and elderly away from more vulnerable areas that may be subject to frequent evacuations.
Risk Communication:
• Before Katrina, there was a limited understanding and appreciation of the residual risks of living behind levees. Improvements in future hurricane preparedness and response will depend partly upon improved public understanding of these risks. In order to enhance the communication and appreciation of these risks, it will be important to extend the efforts of the IPET and to refine, simplify, and communicate consistently the risks of hurricanes and storm surge to the region’s residents, including how those risks vary across the region. Effective communication of the risk-based findings from the entire IPET report will be enhanced by creating a professional summary and compilation of the entire IPET draft report with layman’s terminology (see earlier recommendation in this report).
The 100-Year Level of Flood Protection:
• The 100-year level of flood protection is a crucial flood insurance standard. It has been applied widely across the nation and it is being used in some circumstances in reconstruction and planning activities in the New Orleans region. For areas in which catastrophic levee failure is not a major public safety concern, and where large floods would not imperil evacuation routes, the 100-year standard may be appropriate. For heavily-populated urban areas, where the failure of protective structures would be catastrophic—such as New Orleans—this standard is inadequate.
Independent Review for Engineering and Design:
• It is important to enlist periodic external review in the design, construction and maintenance of large, complex civil engineering projects such as the New Orleans hurricane protection system. A “second opinion” allows an opportunity to ensure that calculations are reliable, methods employed are credible and appropriate, designs are adequate and safe, potential blind spots are minimized, and so on. An outside external review group also may be able to state politically sensitive findings or facts that a government agency may be reluctant to. Such a review team should be adequately independent of the authority that identified.
Periodic Assessments and Updates of Concepts, Methods, and Data:
• Changing environmental conditions can affect the performance and operation of large hurricane and flood protection projects. Advances in scientific and engineering theories and methods may render assumptions on which these projects were based partly or fully obsolete. Because of these changes and the important implications they may have for expected performance of protective structures, a process should be implemented to ensure periodic review of underlying environmental, scientific, and engineering factors that affect New Orleans hurricane protection system performance. The process for incorporating new scientific information into large flood protection projects, like the New Orleans hurricane protection system, can be affected by congressional reauthorization requirements. Changes or clarifications to congressional policies and reauthorizations as they relate to large construction projects may be necessary to effectively implement findings of periodic scientific reviews.
The Future of Hurricane Risk Analysis for New Orleans and the Gulf Coast Region:
• The IPET has conducted a landmark assessment of the New Orleans HPS that could serve as a platform for future and ongoing assessments of vulnerability, levels of protection, subsidence rates, geological studies, risk assessments, and so on. As the IPET investigations come to an end, many of the external experts that participated in the studies will return to their respective careers outside the Corps of Engineers. Much of the IPET “institutional memory” therefore may not be infused into Corps of Engineers New Orleans District office, the State of Louisiana, or the City of New Orleans. It is essential that these analyses be extended and subsequently built upon by the Corps of Engineers and others, including the FEMA, NOAA, the State of Louisiana, New Orleans regional municipalities, and the region’s universities, engineers, and scientists. To facilitate future work that builds on the IPET studies, a publicly accessible archive of all data, models, model results, and model products from the IPET project should be created.
REFERENCES
ASCE (American Society of Civil Engineers). 2007. The New Orleans Hurricane Protection System: What Went Wrong and Why. Reston, VA: ASCE.
ASFPM (Association of State Floodplain Managers). 2007. National Flood Policy Challenges Levees: The Double-Edged Sword. Madison, WI: ASFPM.
FEMA (Federal Emergency Management Agency). 2006. The National Levee Challenge: Levees and the FEMA Flood Map Modernization Initiative. Washington, DC: FEMA.
Galloway, G. E., G. B. Baecher, D. Plasencia, K. G. Coulton, J. Louthain, M. Bagha, and A. R. Levy. 2006. Assessing the Adequacy of the National Flood Insurance Program’s One Percent Flood Standard. Washington, DC: American Institutes for Research. Available online at http://www.fema.gov/library/viewRecord.do?id=2595.
GAO (U.S. Government Accountability Office). 2006. Hurricane Katrina: Strategic Planning Needed to Guide Future Enhancements Beyond Interim Levee Repairs. Washington, DC: GAO.
NCLS (National Committee on Levee Safety). 2009. Recommendations for a National Levee Safety Program. Washington, DC: NCLS.
NRC (National Research Council). 1982. A Levee Policy for the National Flood Insurance Program. Washington, DC: National Academy Press.
NRC. 2009. The New Orleans Hurricane Protection System: Assessing Pre-Katrina Vulnerability and Improving Mitigation and Preparedness. Washington, DC: The National Academies Press.
State of California, Department of Water Resources. 2007. A California Challenge: Flooding in the Central Valley. Sacramento, CA: Department of Water Resources.
USACE (U.S. Army Corps of Engineers). 2008. Decision-Making Chronology for the Lake Pontchartrain and Vicinity Hurricane Protection Project. Washington, DC: USACE.
