A levee is a structure designed to prevent or control flooding. These man-made structures are made to divert water from a flood-prone area so that communities can be protected from a relatively small amount of flooding. Levees are often built with the potential for flooding in mind. Many are embankments, but other materials can be used to create water diversions in the case of a flood. Often, when a levee breaks, it is because the type of flood is more than the levee was designed to hold.
In addition, the Federal Emergency Management Agency (FEMA) will certify levees as "accredited" if they meet a set of rigorous inspections showing that they are capable of holding back flood waters. There are thousands of miles of levees, often very old ones, in the United States. Some of these levees can offer a false sense of protection to those that live behind them. Although the levee may have been built with flooding in mind, the conditions in, near, or under the levee can change. Other environmental factors can also increase the possibility of levee failure. To understand your risk of flooding, regardless of your proximity to a levee, you should learn how to read Flood Insurance Risk Maps (FIRMs).