The NFIP only considers the 1% AEP. However, the designer should analyze the effect of a proposed structure on the full range of AEP water surface elevations (the 50%, 20%, 10%, 4%, and 2% as well as the 1% AEP). The proposed structure may not cause any problem at the design AEP flow, but may cause a problem at one of the other frequencies. Analyzing only for the 1% and design AEP flows may fail to reveal these problems. See above. Some FEMA models contain only the 1% AEP. The designer will need to develop the full range of flows (50%, 20%, 10%, 4%, and 2% AEP) using a suitable method.