Macon-Bibb County, GA Environmental Rules: Flood Elevation Requirements (2026)

1 governs Zone AE areas of special flood hazard where FEMA has established base flood elevations but has not mapped a regulatory floodway. In these zones, the code bars "encroachments, including fill material, new structures or substantial improvements" from areas of special flood hazard unless a registered professional engineer certifies that the cumulative effect of the proposed development, combined with all other existing and reasonably anticipated development, will not raise the base flood's water surface elevation by more than one foot anywhere in the community; that certification must rest on technical data following standard hydraulic engineering principles.

1(2) still requires new construction or substantial improvements to be elevated or flood-proofed to the elevations set under Article IV, cross-referencing the two-foot freeboard and equipment-elevation standards spelled out in Section 11-21 and Section 11-30. This section sits alongside a parallel rule in Section 11-22 for A-zone streams where no base flood elevation data exists at all, which instead bars encroachment within the width of the stream or 20 feet, whichever is greater, unless an engineer certifies no more than a one-foot rise, and sets a flat three-foot-above-grade minimum lowest-floor elevation absent FEMA data.

1 give the Authority a technical, engineer-certified path to permit development in flood-prone AE and A zones lacking a mapped floodway, while Section 11-21 covers zones where the floodway has been fully delineated.