Army Corps Nears Completion of Levee Safety Inspections (USA)
The U.S. Army Corps of Engineers Galveston District is nearing completion of a comprehensive evaluation of seven federally-constructed levees in Alice, Freeport, Lynchburg, Matagorda, Port Arthur, Texas City and Three Rivers, Texas, as part of the Corps’ Levee Safety Program.
Using state-of-the-art technology and consistent risk methodologies, the inspections will allow Corps experts to properly “rate” the levee systems to determine compliance with operation and maintenance requirements, measures of performance, understand the overall levee condition, and establish eligibility for federal rehabilitation assistance under Public Law 84-99, which provides reimbursement for specific damages to levees that result from high-water events.
“Inspections are an engineering assessment of the levee system that involves a system wide field inspection along with reviewing the original design documents and comparing them to our current design criteria,” said USACE Galveston Levee Safety Program Manager Scott Leimer. “It is these methods of inspection that help identify areas where we can strengthen the levee system and help reduce flood risk.”
In response to the levee failures during Hurricane Katrina, Congress passed the National Levee Safety Act of 2007 mandating that all federal levees undergo a comprehensive evaluation to determine their condition. The program also evaluates the consequences to life and property safety if a levee fails.
“Levees are incredibly beneficial to communities as they guard against unpredictable flooding,” said Leimer. “The Corps’ Levee Safety Program works with a multidisciplinary team led by a professional engineer to assess, communicate and manage inundation risks to people, property and the environment resulting from breach or malfunction of components of our levee systems.”
While many levees are federally constructed, they are operated and maintained by local sponsors to a standard level acceptable to the Corps. This maintenance and proper operation of the levee prevents routine damages and reduces the possibility of levee failure. “Ratings given to a levee system as a result of Corps inspections are used to determine if a project is active in the Corps’ Rehabilitation and Inspection Program (RIP),” said Leimer. “Active levee systems are eligible for federal rehabilitation funds (authorized by Public Law 84-99) for damages as a result of a flood event.”
According to Leimer, the RIP is a partnered solution to flood damage reduction similar to hazard insurance that owners may purchase for their homes. A levee system must maintain an ‘acceptable’ or ‘minimally acceptable’ rating to remain active and eligible for future continuing eligibility inspections and repair assistance if damaged.
“The public sponsor must continue to ensure the levee is operated and maintained to minimum RIP standards that were developed to reduce the risk of levee failure,” said Leimer. “The Corps works closely with project sponsors if a levee system receives an overall rating of unacceptable, to explain the deficiencies and help devise a System Wide Improvement Framework plan (SWIF) to correct the deficiencies. The sponsor is placed in an inactive status until the SWIF is approved or corrections are made. The levee system remains eligible for flood fighting assistance.”
According to Leimer, levees reduce the risk of flooding but no levee system can eliminate all flood risk.
“Life safety is the program’s ultimate goal,” said Leimer. “There is always a chance that a flood will exceed the capacity of a levee, no matter how well built. Levees can work to provide critical time for local emergency management officials to safely evacuate residents during flooding events. The possibility exists that levees can be overtopped or breached by large floods; however, levees sometimes fail even when a flood is small.”
According to Leimer, re-evaluating the levee system based on current criteria helps the Corps look for troubled areas that might not be performing as originally intended. It also takes into account lessons learned and the further development of the science behind the analysis of soil structures and the interaction and stability of the floodwalls.
“Periodic inspections include evaluating routine inspection items; verifying proper operation and maintenance; and evaluating operational adequacy, structural stability and the safety of the system,” said Leimer. “Inspections help to identify deficiencies ranging from unsatisfactory culverts, non-compliant vegetation, encroachments and animal burrows.”
Evaluations are scheduled to be released upon completion of final reports in last quarter of 2012. All final inspection results will be provided to the local sponsor and the Federal Emergency Management Agency and state and local emergency management agencies.
“Living with levees is a shared responsibility,” said Leimer. “It’s important that the public knows there risk, and responsibilities and that they take action to reduce their risk.”
The USACE Levee Safety Program is an integral component of a broad, national flood risk management effort that employs a system-wide approach to flood risk management and embraces shared responsibility.
Press Release, September 11, 2012