Coastal and Floodplain Construction Inspector's Practice Exam

According to elevation requirements, where should the lowest supporting horizontal structural member of a building with a III structure category be located?

1. At least BFE + 2 ft or DFE, whichever is lower.

2. At least BFE + 2 ft or DFE, whichever is higher.

3. At the same level as the adjacent ground.

4. At least 1 foot above the wave approach.

The correct answer is: At least BFE + 2 ft or DFE, whichever is higher.

The correct answer indicates that for a building categorized as III, the lowest supporting horizontal structural member should be located at least the Base Flood Elevation (BFE) plus 2 feet, or the Design Flood Elevation (DFE), whichever is higher. This ensures that the structure is elevated sufficiently to avoid flood damage and to comply with various building codes and floodplain management regulations. The rationale behind using the higher of the two elevations is to provide an extra margin of safety. The BFE represents the elevation determined to be the base flood level, which is the height of a flood that has a one percent chance of being equaled or exceeded in any given year. The DFE may incorporate additional factors like future conditions, climate change, and freeboard requirements to further enhance the structure's resilience against flooding. When the lowest structural member is situated at these specified elevations, it minimizes the risk of structural damage during significant flood events. Thus, securing the building from the potential impact of water levels is critical for safety and durability. The other options do not appropriately account for the necessary elevations relative to flood risks and structural safety requirements. Some may provide insufficient elevation that does not comply with regulatory standards and flood mitigation practices.