Gary, IN Environmental Rules: Flood Elevation Requirements (2026)

Gary's floodplain division defines the regulatory flood at Sec. 123-247 as the flood with a one percent annual chance of being equaled or exceeded, also called the base flood, and Sec. 123-252 pins the actual elevation numbers to specific federal mapping products rather than a single citywide figure. For the Little Calumet River, Grand Calumet River, and the Southern Shore of Lake Michigan, the regulatory flood elevation and floodway limits come from the 100-year flood profiles in the Flood Insurance Study of the city dated September 16, 1980, matched to the Flood Boundary and Floodway Map/Flood Insurance Rate Map dated March 16, 1981, both prepared by FEMA.

Areas mapped as an AH or AO Zone instead use the elevation or depth shown directly on the city's flood insurance rate map, and any remaining A Zone areas without a mapped elevation use the best data available as provided by the department of natural resources, per Sec. 123-252(3). For land in unincorporated Lake County within Gary's extraterritorial jurisdiction, Sec. 123-252(4) instead uses the Lake County Flood Insurance Study dated March 2, 1981, and its FBFM/FIRM dated September 2, 1981. Sec. 123-283 makes the zoning administrator, described as the plan commission director, building inspector, clerk, treasurer, etc., responsible for maintaining these regulatory flood data and every project's as-built elevation records; where a party disagrees with the mapped data, Sec. 123-252 requires them to submit a detailed engineering study to the state department of natural resources for review.