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5 REQUIREMENTS OF LEVEE OWNERS GENERAL Most riverine levees are operated by a levee district or some other special or general local government. Often levees protect two or more communities and are the responsibility of jurisdictions other than the protected communities. This chapter recommends operation and maintenance criteria that FEMA should require of levee owners for continued NFIP levee recognition. These requirements are aimed at assuring that the levees continue to provide their credited level of protection by having a top elevation higher than the crest of the flood of credited exceedance frequency (plus the required freeboard) and by being able to structurally withstand that flood. OPERATION AND MAINTENANCE GOALS In formulating operation and maintenance (O&M) recommendations, the committee considered inspection procedures and intervals, operating plans, maintenance plans, assignment of responsibilities, and the nature and frequency of reporting on compliance and testing. The starting points were FEMA's interim policy on O&M and a detailed critique and evaluation of the appropriateness of Federal Code 208.10, Title 33, "Local flood protection works; maintenance and operation of structures and facilities," as a guide for NFIP requirements on this subject. Quality operation and maintenance are as necessary to good performance as proper design and construction. In the case of flood protection projects, maintenance is particularly important, because these structures are subject to deterioration between flood events and may go many years without experiencing floods anywhere near the magnitude of that for which they are designed. In floodplain areas protected by levees, two possibly independent causes of flooding existâ(1) external or riverine flooding and (2) flooding from interior drainage behind the levee. Typically, a levee system has, in addition to its distinctive earth embankment or concrete floodwall, street-gate closures, pumping and gravity drainage facilities, subsurface pressure relief well systems, and internal ponding areas. The earth embankment and all its design features require maintenance to minimize settlement and deterioration and to assure the integrity -24-
of its mass, internal materials, its foundation, and vegetated and/or rock-protected surfaces against the forces of seepage or flowing water. Closure and drainage facilities require service, testing, and competent operating personnel to assure their proper operation in flood situations. Well-documented operating plans and frequent operating practice drills are of great importance, considering personnel turnovers that occur over the years between major floods and the fact that real operations will occur during periods of adverse weather fraught with poor communication and transportation situations. The failure of a single street-gate mechanism or pumping station or a single weak, eroded, or gullied spot in an embankment may render an entire levee system ineffective. Engineers and managers of public works programs are generally conscious of the importance of proper operation and maintenance. Budget officials responsible for public works appropriations must be kept continually aware of the importance of proper levee system operation and maintenance for levee design levels to be realized in flood situations. FEMA's interim policy on levees (Appendix B) addresses maintenance in general terms, in that a credited levee must be adequately maintained. The interim policy is quite specific on the subject of human intervention and operation of closures. FEMA does not and should not recognize human intervention (sandbagging, emergency earth fill, etc.) during a flood event for the purpose of increasing a levee's design level of protection. Human intervention is recognized where closure structures, such as street gates and stop logs, are integral parts of the system design, where locally mandated by a formal operating plan, and where flood warning times are sufficient to permit placement. FEMA further requires annual testing of closure structures and regular training of operating personnel. Finally, compliance with these requirements must be demonstrated and accepted by FEMA. The committee recommends: ⢠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 a levee system's design level of protection. This recommendation should not, of course, be interpreted to mean that human intervention should not be encouraged in fighting floods that exceed a levee's design level of protection. RECOMMENDED OPERATION AND MAINTENANCE GUIDELINES Construction of levee systems has been a significant component of the Corps of Engineers Civil Works Program for many years. The Corps has constructed about 10,500 miles of levees and floodwalls, most of which have been assigned to nonfederal sponsors following construction -25-
for operation and maintenance. A few of these systems have failed during floodsâmostly from overtopping. Failures of Corps-built levees attributable to operation and maintenance deficiencies have been minimal. Communities responsible for Corps-constructed levee systems use Federal Code 208.10, Title 33, as a guideline for operation and maintenance; and, owing to the apparent successful results of its application, the committee began by reviewing this document but recommends modifications of those regulations for NFIP application. These guidelines, as modified by the committee, are presented as Appendix C. The committee recommends: ⢠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 local needs, must be formally adopted by the levee owner for a levee to be credited and continue to be credited in the NFIP. OPERATION AND MAINTENANCE INSPECTION Both property owners and the federal government, if it is insuring the property, have the right to assurance from the levee owners that the structural systems protecting flood-prone property will be inspected, maintained, and operated in the way intended at the time they were accepted into the National Flood Insurance Program. The committee recommends: ⢠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 must be promptly prepared and certified by the professional engineer making the inspection. The report should 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 to the local political entities which -26-
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, FEMA should withdraw recognition of the levee. -27-
