Following the 2013 flood, the Colorado Water Conservation Board (CWCB) initiated a program to re-map the predicted 1% chance regulatory floodplain (100-year flood zone) of the most affected waterways. The program was named the “Colorado Hazard Mapping Program” or “CHAMP.” Learn more here and below
Phase I data was submitted to FEMA in the spring of 2017 and Phase II data was submitted in the spring of 2018. We anticipate that FEMA will produce Preliminary Flood Insurance Rate Maps (FIRMs) in late 2019 or early 2020. The process after receiving Preliminary FIRMs includes a formal public comment and appeal period, further analysis, and the release of final effective FIRMs. This phase of the map development process can last 18 months or longer and is dependent upon FEMA timelines and budgets.
Maps are generated by combining ground surveying information and topographical data, anticipated rainfall and river flows, and then using modeling software to develop flood profiles and flood inundation maps. The process of developing floodplain maps is a technical undertaking by well-qualified professionals.
The CWCB draft floodplain maps and associated data will be more accurate and ultimately replace the regulatory floodplain maps currently in use. Both the flood elevations and the floodplain boundaries are likely to change. Any resident or property owner within or near a current regulatory mapped floodplain may be affected by the new maps in terms of development regulations and eventually flood insurance requirements.
In addition, some waterways (including Gold Run, Upper Boulder Creek, and others) that were not previously mapped are now being included. Residents and property owners in these areas may find that their property is located within the CWCB draft floodplain after maps are published.
Draft maps for waterways in Phase II will be available by early 2018. Once public, you will be able to view the maps and provide comments via the interactive web map. In 2018, Boulder County will conduct several community meetings to show the maps, answer questions, and record comments that provide site-specific corrections or updates that could improve map accuracy. Boulder County staff will then pass this information along to the CWCB.
Boulder County locally adopted the new maps developed from the CHAMP study for regulatory purposes shortly after they were submitted to FEMA for initial review. The Phase I maps were adopted for regulatory use by the Board of County Commissioners in May 2017 and the change became effective June 1, 2017. The Phase II maps were adopted for regulator use by the Board of County Commissioners (BOCC) in July 2018 and the changes became effective on August 1 and October 1, 2018.
FEMA adoption is anticipated by 2021 for both Phase I and Phase II area. Formal public comment will be collected as part of the FEMA adoption process. Once adopted by FEMA, the maps become the effective Flood Insurance Rate Maps (FIRMs) and will then be used for both insurance and regulatory purposes.
FEMA is involved throughout the entire project. FEMA will manage the process to turn the draft maps into new Flood Insurance Rate Maps (FIRMs).