Floodplain Remapping Project

Floodplain Remapping Project



The interactive webmap (use the button above) is meant to show detailed flood risk zones and related FEMA map amendments or revisions that are currently regulated throughout unincorporated Boulder County. (Data updated on June 1, 2017 to reflect adopted changes to the Floodplain Overlay Zoning District).

  • This map will update as new FEMA maps become effective throughout Boulder County and as the Boulder County Board of County Commissioners (BOCC) adopts Best Available Data (see information on maps below)


DRAFT floodplain maps are now available for stream reaches in Phase II of the Colorado Hazard Mapping Program (CHAMP) study. Visit the interactive webmap (by using the button above) to review and provide comments on the draft flood risk zones that are currently under review by Boulder County.



The data available online via our DRAFT Floodplain Map Webmap is available to allow the public to be aware of and provide input on the floodplain remapping project from the beginning. Draft map data from Phase I of the CHAMP and related flood studies was adopted June 1, 2017 and map layers in these reaches have been updated to reflect this regulatory change. An exception to this adoption is the data for the Little Thompson reaches within Boulder County – because these data sets were received later, the mapping for the Little Thompson River will be adopted at a later date.

Concerns or questions about these changes should be addressed to the Floodplain Management Team (contact info at the bottom of this page).


The 2013 flood event caused widespread damage and changes along waterways throughout the county and other areas of the state. In response, the State of Colorado is taking steps towards bolstering long-term planning and resiliency efforts by funding the Colorado Hazard Mapping Program (CHAMP) that will update local hazard information including regulatory floodplain maps for the most affected waterways.

Boulder County is supporting this initiative because accurate floodplain maps provide detailed information for property owners on their own flood risks and enable proactive measures to protect people and property before the next significant flood event.

Floodplain maps are under revision for the following waterways (or reaches therein) under the CHAMP study.

Phase I Waterways (2017)

  • Cabin Creek
  • North-South-Middle St. Vrain Creek(s)
  • St. Vrain Creek
  • Boulder Creek
  • North Boulder Creek
  • Middle Boulder Creek
  • South Boulder Creek
  • Dry Creek #2
  • Two Mile Canyon Creek
  • Coal Creek
  • Rock Creek
  • New Dry Creek Ditch
  • Upper Four Mile Canyon Creek
  • Little Thompson River

Phase II Waterways (2018)

  • North St. Vrain (Longmont Dam Road)
  • Little James Creek
  • Geer Canyon
  • James Creek
  • Left Hand Creek
  • Lower Fourmile Canyon Creek
  • Gold Run

Floodplain Remapping Program Stream Reaches in Study

Phase II floodplain maps are being released in early 2018. The floodplain mapping will be recommended for local adoption as it is reviewed and approved by the county. This will allow the county to base floodplain regulations on the best available data. Later, upon final FEMA approval and adoption, the floodplain mapping will become effective for both regulatory and flood insurance purposes. Read more about these components of the floodplain remapping process on the Floodplain Mapping and Code Amendments page and the National Flood Insurance (NFIP) page.

To educate and engage residents, Boulder County will provide information and updates throughout the state’s process via this website and a variety of other platforms. Use the links on the right side of this page to learn more about this effort.

Contact Us

Floodplain Administrator Contact

Floodplain Administrator


Floodplain Remapping Program Contact



2525 13th Street
Boulder, CO 80304

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Hours: 8 a.m. - 4:30 p.m. M-F

Mailing Address

P.O. Box 471
Boulder, CO 80306