Public safety is the number one priority of the U.S. Army Corps of Engineers' Levee Safety Program.
Many levees were originally constructed to protect agricultural assets but subsequent unrestricted community and business development has drastically changed the risk and consequences the areas protected by levees.
The Rock Island District has many levees active in the inspection program. The construction of these levees dates back to the mid 1800s. Establishment of legislation in that time period allowed for the creation of drainage and levee districts in order to drain the wet lands and create tillable farmland. Many of the levees in the Rock Island District were initially built during this period.
There is no single agency with responsibility for levee oversight nationwide. The Corps has specific authorities for approximately 2,000 levees, or approximately 14,000 miles of levees across the country.
The misperception exists that the Corps has universal responsibility for the nation’s levees. The Corps serves as one of the nation’s largest infrastructure stewards with high visibility assisting emergency responders during catastrophic flood events. Regardless of levee ownership, the Corps works closely with state and local emergency managers to inspect, advise and assist communities with professional engineering expertise and materiel during flood fights.
The Corps shares responsibility among federal, state and local agencies, and private landowners for awareness and understanding of the risks associated with living and working behind levees. The responsibilities of local levee partners are broad and include levee safety; land use planning and development; building codes; and operations, maintenance, repair, rehabilitation and replacement of the levee. Levees do not eliminate risk, they reduce risk. In situations where levees are stressed, or may be overtopped, due to high water, they serve an added function of providing additional time for local emergency management officials to safely evacuate residents.
Operations and maintenance is important to levee safety, but it is not the only factor that affects risk and reliability of a levee, and should not be represented as such. It is important to note, there is still a large universe of private and other non-Corps jurisdiction levees that have not been inventoried or inspected/assessed. We don’t know the size of this universe, where the levees are located, their condition, or the consequences of failure, loss of life being of paramount concern.
Risk comprises the likelihood that natural events will take place; the performance of a particular levee during an event; and the consequences of failure, loss of life being of paramount concern.
It is important to understand that projects built to the 1% annual chance exceedance flood (or the 100-year flood event) do not entirely eliminate risk. The 1-percent flood event, as used in the National Flood Insurance Program, is not a safety standard for engineered works. There remains the risk that the levee could overtop, breach or fail or it could be overwhelmed by an event greater than its design.
Levees alone do not eliminate risk. Flood risk reduction includes a combination of local decisions about land use, zoning, and building codes; outreach and education; local emergency management planning and evacuation plans; and flood insurance.