Despite the efforts of federal, state, tribal, and local interests to reduce flood damages, flooding still accounts for 90 percent of all natural disaster damage in the United States. Flooding forces hundreds of thousands of people to flee their homes and places or work annually. The purpose of flood risk management is to help reduce the risk of flood damage through the use of structural or non-structural methods or a combination of both.
Structural measures are physical modifications designed to reduce the frequency of damaging levels of flood inundation. Structural flood risk management measures include levees, flood walls, channel modifications, or dams and reservoirs.
Non-structural measures reduce flood damage risks without significantly altering the nature or extent of the flooding by changing the use of floodplains or by accommodating existing uses to the flood hazard. Non-structural measures include modifying homes and business by elevating structures out of the floodplain or flood warning systems.
The cost-share for flood risk management projects authorized by Congress during construction is 65 percent federal and 35 percent non-federal. The sponsor may wish to implement elements of the project not authorized by Congress at a 100 percent cost to the sponsor. Any locally preferred measures to be implemented must still be reviewed and approved by the Corps of Engineers, have complete environmental compliance documentation and permits, and be contracted and built through the Corps of Engineers contracting policies.