Levees , dams and other flood control structures are designed to protect against a certain level of flooding . In more serious flood events , levees can fail or overtop . And , as levees age , their level of protection can change . When levees overtop or fail , the flooding that follows can be catastrophic . Because of these unique risks , if you live near a levee , dam , or in areas reliant on other flood control structures , purchasing flood insurance is highly recommended .