Poudre Canyon Flooding |COVID-19 Info | Data | Testing | Vaccine | Guidance

Traducir al español
Flood After Fire - Fire Recovery Resources

Recovery Resources for Residents Impacted by 2020 Larimer County Wildfires.


CR 70 (Owl Canyon) & CR 9 Roadway Improvements (PN 339)


CR 70 (Owl Canyon) & CR 9 Roadway Improvements (PN 339)

The Larimer County Engineering Department and the Larimer Coun

More about CR 70 (Owl Canyon) & CR 9 Roadway Improvements (PN 339)


County Transportation Impact Fees and Building Permit Fees to Rise by 2.4 % Effective: July 1, 2021

Larimer County's Transportation Capital Expansion Fees will increase July 1st by 2.4% on July 1, 2021.

More about County Transportation Impact Fees and Building Permit Fees to Rise by 2.4 % Effective: July 1, 2021


2020 Traffic Safety Report

The 2020 Safety Report was presented to the Larimer County Commissioners on May 11, 2021.

More about 2020 Traffic Safety Report

Larimer County joined the National Flood Insurance Program in 1974 and has been active in floodplain management since that time. Floodplains are regulated as an overlay zone in Larimer County. The floodplain regulations and the floodplain maps provide the foundation for Larimer County's Floodplain Management Program.

The links to the maps below can be used to determine the limits of the regulatory floodplains in Larimer County. The Larimer County Engineering Department can also be contacted to determine if a property is within a regulatory floodplain. It should be noted that there are many areas in Larimer County that are not shown within a regulated floodplain and have undetermined flood hazards. A property can still be at risk of flooding even if the property is not shown in a regulatory floodplain.

The 2013 flood event caused widespread damage and changes along waterways throughout the County and in 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.  Information on CHAMP is available at the Colorado Hazard Mapping and Risk MAP Portal.

Draft floodplain boundaries within Larimer County for CHAMP Year 1 (Little Thompson River, Buckhorn Creek and portions of the Big Thompson River) and Year 2 (Estes Valley and portions of the Big Thompson River) are now available on the Larimer County Flood Information Locator

CHAMP Years 1 & 2 Stream Reaches 

PowerPoint presentations from Open Houses are available which provide additional information on CHAMP, floodplain mapping and the National Flood Insurance Program.

Estes Valley Open House Powerpoint

Portions of Big Thompson River Open House Powerpoint

Fact Sheet on CHAMP from the Colorado Water Conservation Board (CWCB)

Flood Risk Fact Sheet - Colorado Risk MAP Projects (CWCB)Technical comments or questions can also be submitted to the Larimer County Engineering Department using the Technical Comments or Questions Card


  1. To determine if your property is within a FEMA or locally designated floodplain, you can contact the Larimer County Engineering Department or view the flood zone information through the County’s interactive map. Floodplain areas designated by FEMA on the Flood Insurance Rate Maps (FIRMS) are also available online through FEMA’s Map Service Center.

    To view the floodplain information for your property using the County's interactive map, follow the steps below:

    1. Navigate to the Larimer County Engineering Department website at www.larimer.org/engineering/floodplains
    2. Click the “Online Floodplain Map - Larimer County Land Information Locator” button near the top of the screen
    3. Type your address in the search bar at the top right of the screen, click the search icon. The search results will appear on the left side of the screen. Click the appropriate parcel from the list and the map will zoom into your property.
    4. Click the “Flood” button near the top of the screen if floodplain information is not already displayed
    5. Click the “Layer List” icon near the top left of the screen. A list of map layers will appear below.
    6. Scroll down to the “Floodplain” layer. Check the box next to “2021 FEMA (Preliminary)” to see the preliminary floodplain layer for your area. You can compare this to the current floodplain for your property by checking the “FEMA Floodplain (Current Effective)” on or off.

    There are several flood zones which may apply for your property. Click Flood Zone Descriptions for a list.

    Keep in mind that even if your property is not shown in a regulatory floodplain, it does not mean that there is no risk of flooding. There are many areas in Larimer County that are not shown within a regulated floodplain but have undetermined flood hazards.

  2. Structures in a floodplain may be damaged when flooding occurs. Some structures flood frequently, while others get damaged only by the more severe events.

    Flood insurance may be required. If you receive a mortgage or loan from a federally regulated or insured lender, you are required to have flood insurance if the structure is located in a floodplain. Generally, flood insurance can be purchased by contacting your regular homeowner's insurance agent. Even if you are not required to have flood insurance, it can still be a good investment if you live in or near a floodplain.

    Structures in the floodplain must comply with floodplain regulations. Larimer County requires permits for remodeling, improving, expanding or rebuilding any structure in a floodplain. In order to reduce long-term flood damage, structures that are substantially improved or substantially damaged are required to become compliant with current floodplain regulations. Substantially damaged structures in a floodway cannot be repaired or replaced within the floodway if the damage was due to flooding. In Larimer County, the cost of improvements is tracked over a 10-year rolling period. Certain items defined under Routine Maintenance or Minor Work can be excluded. Please see the separate sections regarding Routine Maintenance, Minor Work, and Substantial Damage for detailed descriptions of these definitions.

  3. You must submit a Floodplain Development Permit and required plans and documentation to Larimer County Engineering Department. Some projects within the floodplain will require approval from the Flood Review Board and/or the Board of County Commissioners. Formal Map changes will also require approval from FEMA. The application includes a checklist that outlines all required documentation and approval steps. The Floodplain Manager will review your application for compliance with the Flood Hazard Overlay Zone Districts. For information on the floodplain development permit, contact our Floodplain staff at (970) 498-5729 or send email.

  4. The floodplain is any area that is susceptible to being inundated by surface water from any source. Mostly, this is the area adjacent to a river, creek, lake, stream, or other waterway that is subject to flooding when there is a significant run-off event.

    The floodplain is typically divided into a floodway zone and a flood fringe zone. The floodway is the channel of a river and adjacent land areas that must be reserved in order to discharge the base flood without cumulatively increasing the water surface elevation more than a designated height. These areas are expected to have the fastest and deepest flows during a flood. The flood fringe areas are the outer edges of the floodplain where flows are shallower and slower moving. 

    More about Floodplain, Flood Fringe and Floodways

  5. Certain uses are limited or even prohibited within the floodplain. In general, new structures, or substantial modifications or improvements to existing structures within the floodway overlay zone are difficult. The floodway is highly restricted for development purposes since this area should be reserved in order to convey the expected flows within these limits. There are fewer restrictions within the flood fringe areas and new structures and development is generally allowed as long as the development meets the County floodplain regulations including proper elevation requirements.

    You must be issued a Floodplain Development Permit from Larimer County before you start any work, including grading, excavation or filling, in any portion of the floodplain.

  6. Floodplains are an overlay zone in Larimer County. The most current floodplain regulations can be found in the Larimer County Land Use Code Section 4.2.2.

  7. In the 1960’s, the United States government decided to use the 1-percent annual exceedance probability (AEP) flood as the basis for the National Flood Insurance Program. The 1-percent AEP flood was thought to be a fair balance between protecting the public and overly stringent regulation. Because the 1-percent AEP flood has a 1 in 100 chance of being equaled or exceeded in any 1 year, it is also referred to as the “100-year flood.”

  8. Floods happen irregularly. The “100-year flood” is an estimate of the long-term average recurrence interval, which does not mean that we really have 100 years between each flood of greater or equal magnitude. The “100-year flood” is also known as the 1-percent annual chance flood, which means that a flood of this magnitude has a 1- percent chance of occurring in any given year. A home in the 1-percent (100-year) floodplain has a 26-percent chance of being flooded at least once during the span of a 30-year mortgage.



Attn Floodplain
Larimer County Engineering Department
200 West Oak Street, Suite 3000
P.O. Box 1190
Fort Collins, CO 80522-1190

(970) 498-5731 or (970) 498-5732

I Want To

Larimer County, Colorado

200 W. Oak Street
Fort Collins, CO 80521
Map of Facilities

Connect with Us

Larimer County on Facebook Larimer County on Twitter Larimer County on YouTube Larimer County on LinkedIn Instagram Email subscription
Transparency | Accessibility | Security
Legal Disclaimers
Website Feedback Website Feedback
Flag Status:   US FlagHalfColorado FlagHalf
Top of Page