By Chuck Chase, CFM and Mitch Paine, CFM
From December 2016 Floodplain Management Today
In floodplain management, the terms “building” and “structure” are used interchangeably. The floodplain management definition for a building/structure, which is in all local ordinances, mirrors the definition found in the state and federal minimum standards: “a walled and roofed building, including a gas or liquid storage tank, that is principally above ground, as well as a manufactured home.”
A house, for example, clearly meets this definition – there are at least four walls and a roof. A new house in the floodplain would be required to have its first floor elevated to at least 1 foot above the base flood elevation. A restaurant is also clearly a building, and, like all nonresidential structures, it must be elevated or floodproofed to at least 1 foot above the base flood elevation.
Similarly, these oil tanks on the right also meet the definition and would have to be elevated or floodproofed to the same standard as nonresidential structures.
However, the Gage County Roads Department’s equipment shed in Beatrice, shown below, may appear to be a building but is only walled on 3 of its 4 sides. Since one side is permanently open, it is not a structure by the definition in Beatrice’s local ordinance. A concrete privacy wall around a property, as another example, may have the same footprint as a structure and may obstruct floodwaters in a similar way, but since it is not roofed, it is not a structure.
Though a privacy fence or an open-sided equipment shed may not be structures, they are still development in a floodplain and require a floodplain development permit. Other standards may apply too, such as no-rise requirements.
The floodplain management definition of building is very clear and very inclusive. Grain bins and storage tanks are completely walled and roofed, as are multi-sided homes, and all are buildings according to the standard ordinance definition. Situations will certainly arise where the definition of a building is challenged, but comparing other buildings can help make a determination
A second definition that floodplain administrators should be familiar with is the flood insurance definition for a structure. The NFIP insurance definition from 44 CFR 59 is, “‘Structure’ means: A building with two or more outside rigid walls and a fully secured roof, that is affixed to a permanent site […].” A building can be a structure as defined for insurance purposes, but not as defined by floodplain management regulations. By flood insurance definition, the open equipment shed meets the definition of a building and may be expensive to insure if built below BFE in a floodplain. Community officials play a role in helping their residents and business owners understand these nuances.
Floodplain management can have some rather grey areas. Yet, the definition of a structure/building in local ordinances is rather clear and very inclusive. An apartment building, a garden shed, a grain bin, or manufactured home is a structure if completely walled and roofed. It will need a permit and Elevation Certificate if new or substantially improved.
If you encounter a situation that isn’t clear, feel free to contact Katie Ringland at Katie.Ringland@nebraska.gov or 402-471-2094 for help.