Floodplain Mapping Process
In June 2017, the county adopted the first phase of comprehensive zoning map amendments to the Floodplain Overlay Zoning District based on draft floodplain mapping developed in conjunction with the State of Colorado Hazard Mapping Program (CHAMP) for waterways throughout unincorporated Boulder County that were most affected by the 2013 flood. These maps included revised or new regulatory flood risk zones and helped to identify risk for property owners and enable proactive measures to protect people and property. Effective August 2018, the county adopted the second phase of comprehensive zoning map amendments to the Floodplain Overlay Zoning District based on draft CHAMP data.
In September 2019, FEMA released Preliminary Flood Insurance Rate Maps (FIRMs) that refined the previously adopted CHAMP mapping. Effective January 2020, the Preliminary FIRMs were adopted by the Board of County Commissioners (BOCC), replacing the draft map data. Six public meetings were held around the county in January 2020 to allow residents to review the map updates, the FEMA adoption process, and the flood insurance requirements related to the Preliminary FIRMs.
In 2020 and 2021, FEMA ran appeal periods, where anyone had the opportunity to appeal or comment on the Preliminary FIRMs. The appeals were resolved in 2021 and 2022, including a Scientific Resolution Panel for a portion of Lefthand Creek. In July 2023, FEMA released revised Preliminary Flood Insurance Rate Maps (Preliminary FIRMs), which differ from the already adopted draft CHAMP maps in eight areas where FEMA approved the changes submitted during the appeal periods.
What is happening in 2023 and 2024?
With the release of the revised Preliminary FIRMs, FEMA is in the final stages of incorporating the CHAMP study into the effective FIRMs. New FIRMs will become effective on October 24, 2024.
At the same time, the county will update and align the Boulder County Floodplain with the revised Preliminary FIRMs. Public meetings were held in 2023. Public hearings before the Planning Commission and Board of County Commissioners were held in January and March 2024. Visit the How to Stay Informed webpage for meeting details, and to sign up to receive updates. Until the new FIRM effective date, the County will continue to regulate development in the Floodplain Overlay District using both the locally-adopted CHAMP data and the effective FEMA FIRMs.