BoCo Alert System

Level 2 Fire Restrictions in effect for western Boulder County (more). See flyer and map for details.

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.


Floodplain Remapping Project Area Map for Phases I and II

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 Fourmile Canyon Creek

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
  • Little Thompson River
  • Lower Boulder Creek Floodway
  • St. Vrain Creek Floodway


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.

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