Commerce City, CO Environmental Rules: Flood Zones (2026)

Sec. 21-4400 creates the FP Floodplain Overlay District covering all special flood hazard areas identified by FEMA's Flood Insurance Study for Adams County and its accompanying Flood Insurance Rate Maps, along with areas removed from the floodplain by a FEMA Letter of Map Revision Based on Fill. The district's purpose is to promote public health and minimize flood losses. Agricultural uses that don't require structures, such as general farming and raising livestock or nursery stock, are allowed by right in the floodway fringe if the underlying zoning permits them.

A short list of other uses, including public and private recreational facilities, utility lines and pipelines, wildlife and nature preserves, regional detention or water quality facilities, and certain flood-resistant fencing, can occur in the floodway fringe only with a floodplain development permit issued under Sec. 21-3213 by the city's floodplain administrator. Sec. 21-4400(4) flatly prohibits both residential buildings and structures and commercial buildings and structures anywhere in the floodplain overlay district. Within the floodway itself, Sec. 21-4400(8) bars essentially all encroachments, fill, construction, and substantial improvements unless the applicant demonstrates through hydrologic and hydraulic engineering analysis that the work will not raise flood levels anywhere in the city during a base flood event.

The floodplain administrator reviews permit applications against criteria in Sec. 21-3213(3), including whether the applicant has obtained all other federal, state, and local permits and whether the proposed use minimizes disturbance to the floodplain's natural topography.