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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. Local adoption of the Preliminary FIRMs into the Floodplain Overlay District allows the county to base floodplain regulations and permitting on the best available data, but it does not impact flood insurance requirements and rates.

What is happening in 2020 and 2021?

Although the county already adopted the CHAMP data at the local level, FEMA is also in the process of incorporating the CHAMP study into their effective Flood Insurance Rate Maps (FIRMs), which are used for flood insurance rating. In January 2020, the county held a series of community meetings at various locations around the county to review the FEMA adoption process and the flood insurance requirements related to the Preliminary FIRMs. Representatives from FEMA, the CHAMP team, and the county were present at each session. Visit the project’s How to Stay Informed Webpage for meeting materials.

In the spring of 2020, there was a 90-day appeal period offered by FEMA. Due to the pandemic and the need for most appellants to submit additional information, FEMA is running a second appeal period in 2021. During this period, anyone may work with Boulder County to submit an appeal to FEMA based on scientific and technical data. Learn more about the appeals process.

The county expects FEMA’s Preliminary FIRMs and any approved appeals to become the effective FEMA FIRMs in 2022. Until that time, the county will continue to regulate development in the Floodplain Overlay District using both the locally-adopted CHAMP data and the effective FEMA FIRMs.

Contact Us

Floodplain Administrator Contact

Floodplain Administrator


Floodplain Remapping Program Contact



2525 13th Street
Boulder, CO 80304

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