Blue Earth County, MN Environmental Rules: Flood Elevation Requirements (2026)

Under Sec. 8-41, the county defines the regulatory flood protection elevation (RFPE) as an elevation one and one-half feet above the base flood elevation (BFE), an 18-inch freeboard above FEMA's mapped one-percent annual chance flood. Sec. 8-63's minimum development standards apply that freeboard countywide: all new or substantially improved development must be designed and anchored against flotation and hydrodynamic loads, built with flood-resistant materials, and have heating, ventilation, ductwork and air conditioning equipment, along with water, sewage and electrical lines, elevated to or above the RFPE.

In the flood fringe district, Sec. 8-82 spells out how residential structures reach that elevation: fill must be no lower than one foot below the RFPE and must extend at least 15 feet beyond the structure, with elevations certified by a registered engineer or surveyor. Nonresidential buildings may instead use alternative elevation methods such as piers, filled stem walls, or dry floodproofing meeting FEMA Technical Bulletins 1 and 3. Materials that are buoyant, flammable, or hazardous if they float away during flooding must be stored at or above the RFPE or floodproofed and approved by the zoning administrator.

Critical facilities face a stricter standard under Sec. 8-63(3): their lowest floor must sit at least two feet above the base flood elevation, or above the two-tenths-percent annual chance flood elevation, whichever is higher. All these elevations are measured against the FEMA Flood Insurance Study and rate maps adopted by reference in Sec. 8-52.