Average Annual Damage by Flood Frequency Zone

Abstract

Average annual flood damage can be calculated individually for each flood‐plain property, but a less time‐consuming approach is to estimate average annual damage using a set of typical values for buildings in specific locations. By defining a range of depth‐frequency relationships and calculating average annual damage for hypothetical structures located at fixed frequency levels, it is possible to construct a graph showing the variation of typical average annual damage for structures in specified frequency zones with the degree of flood hazard. Although damage estimates based on zonal annual damage may not be particularly accurate for individual properties, the sum of a number of estimates will more closely approximate aggregate flood damage. The method can, therefore, be used to make initial estimates of flood damage in a floodplain, and can also be used as the basis for flood insurance premiums.