Mesa County, CO Environmental Rules: Flood Zones (2026)

Section 4.07(A) makes a Floodplain Development Permit mandatory prior to any land disturbance and before construction or development begins within any area of special flood hazard established under Section 8.14, so the requirement attaches the moment a parcel falls inside the mapped floodplain rather than only when a building permit is sought. The permit process runs through the Floodplain Administrator: an applicant may request a pre-application meeting, then submits an application against the Administrator's checklist, the Administrator circulates it to review agencies, and issues a written decision approving, conditionally approving, or denying the request under the Section 4.07(C) approval criteria, which weigh flood height, velocity, duration and sediment transport at the site, the proposed use's susceptibility to flood damage, whether the use will be inhabited full time or seasonally, and the adequacy of proposed water and sanitation systems.

Section 8.14(D) extends the underlying floodplain regulations to all land adjacent to any watercourse that would be inundated by the 100-year flood or is shown to be flood prone by on-site evidence, and Section 8.14(J)(1) makes any land use in a designated floodplain that is not specifically allowed or conditionally allowed through a Floodplain Development Permit an outright prohibited use. Floodway and Flood Fringe subdistricts carry different permit-triggering activity lists and outright prohibitions, including bans on new habitable dwellings and any activity that would raise flood elevations, in the Floodway District under Section 8.14(J)(4)(b).

The boundaries themselves come from the October 16, 2012 FEMA Flood Insurance Study, incorporated into the Land Development Code and recorded with the Mesa County Clerk and Recorder.