Floodplain Management

The Town  of Lyons joined the National Flood Insurance Program (NFIP) in 1980 and has been active in floodplain management since that time. Under the NFIP, residents of the Town of Lyons have access to flood insurance and the county can receive disaster assistance from the federal government. In exchange, the Town adopts and enforces FEMA-approved floodplain regulations. These regulations apply to land located in Town of Lyons that lies within the Special Flood Hazard Area (SFHA) as determined by latest FEMA Flood Insurance Rate Maps (FIRM).The goals of floodplain management are to reduce flood hazards and risk by:
•    Regulating floodplain uses and development;
•    Adopting floodplain policies;
•    Mapping floodplains; and,
•    Educating the public about floods and floodplains.
Property owners of buildings with any portion of the structure (including roof overhang, gutters, footings, decks, balconies, etc.) encroaching into the floodplain are required to obtain a Floodplain Development Permit before expanding a building or constructing any improvements, including grading, fences, hot tubs, etc.  See Floodplain Development below.

Floodplain Maps – Know Your Risk

Everyone has flood risks. Know Yours!

The Town of Lyons has three drainages with mapped floodplains. Floodplain maps identify areas at risk of inundation during the 1-percent-annual-chance (100-year) flood, also known as the regulatory floodplain. However, a property can still be at risk of flooding if it is mapped outside a regulatory floodplain.

Floodplain Maps

The FEMA floodplain be viewed on the FEMA Map Service Center. From within this link, you can generate a “FIRMette” which is a zoomed in FIRM map for your property and is often useful for building permit applications or insurance discussions.
These FIRM maps may be outdated, see FEMA site for latest FIRM maps

FEMA FIRM Maps (as of October 2024):

Central Lyons Area 

West Lyons Area

South Lyons Area

East Lyons Area


Flood Zone and Base Flood Elevation Determinations

For an official determination of the flood zones on your property, the Base Flood Elevation or to ask questions about the floodplain maps in your area, contact the Floodplain Administration team at (303) 823-6622 ext. 47 or email jdoles@townoflyons.com

Elevation Certificates on file with the Town are available upon request.

Base Flood Elevations can be approximated from the FIRM map or using the Colorado Hazard Mapping & Risk Portal as follows:

  1. Go to: https://coloradohazardmapping.com/
  2. Click on “Flood Hazard”, then “Boulder County”, hit the “Acknowledge & Proceed” popup, select “WSEL Grids”, then hover over your site.   

*Keep in mind, this is just an estimate and the Town’s Floodplain Administration Team will make final determination of BFE elevation for Floodplain Development Permits.

 

Updates to Floodplain Maps

The Town supports and participates in periodic updates to floodplain maps with neighboring communities and FEMA. These updates ensure that the floodplain maps reflect current conditions.

Individual homeowners may apply to the for a FEMA Letter of Map Amendment (LOMA) if they believe their property has been inadvertently mapped within the 100-year floodplain.

Flood Insurance

Town of Lyons participates in the National Flood Insurance Program (NFIP), which is administered by the Federal Emergency Management Agency (FEMA). The NFIP makes federally-backed flood insurance available for all buildings, whether they are in the floodplain or not. Flood insurance covers direct losses caused by surface flooding, including a river flowing over its banks, a lake or ocean storm, and local drainage problems. Communities that participate in the NFIP must adopt and enforce floodplain management regulations.

The NFIP insures buildings, including mobile homes, with two types of coverage: structural, and contents. Structural coverage is for the walls, floors, insulation, furnace, and other items permanently attached to the structure. Contents coverage may be purchased separately provided the contents are in an insurable building.

What you should know:

  • General homeowners insurance does NOT cover floods
  • Flood insurance is available to all homeowners, renters, and business owners in the Town of Lyons
  • There is a 30-day waiting period when purchasing flood insurance
  • Flood insurance is backed by the federal government, but can be purchased through a local agent
  • Contact your insurance agent today to ask about flood insurance!
  • Visit FEMA’s Flood Smart website for more information on why you might consider purchasing flood insurance and where to find an agent who can help.

 

The Mandatory Purchase Requirement:

Owners of property within the FEMA 100-year floodplain who hold a federally-regulated mortgage are required by law to have flood insurance. Even if not federally required, a lender can require flood insurance regardless of flood zone

 

Floodplain Development

Before beginning any design or construction (new development, addition, remodel, repair, filling, grading, etc.) in the regulatory floodplain, contact the Floodplain Administration team at (303) 823-6622 ext. 47 or email jdoles@townoflyons.com for specific requirements. A Floodplain Development Permit is required for all floodplain development.

 

Requirements for floodplain development can be found in the following regulations:

Floodplain Development Permit Application:

Elevation Certificates

All new buildings and most building modifications will require an Elevation Certificate after completion in order to close the Floodplain Development Permit.  Below are links to the FEMA forms. The forms must be completed by a Colorado licensed surveyor, engineer, or architect.  

Proposed Development in the Floodway:

The Floodway is the portion of the floodplain that is reserved to pass the base flood discharge without increasing the flood depth and is shown on FIRM map in a different color or shading.   Generally in Lyons, it is along the main channel of the river.    Any proposed development in the FEMA designated Floodway will either require one of the following in addition to a Floodplain Development Permit:

  • No-Rise Certification: This is for projects that will have a zero increase in BFE.   No-Rise Certification and analysis must be performed by a Colorado licensed engineer and will be reviewed by the Town Engineer for approval.
  • Conditional Letter of Map Revision CLOMR:  This is for projects where the proposed improvements would result in a BFE increase greater than 0.00 vertical feet and/or would relocate, shift or widen the Special Flood Hazard Area.  A CLOMR is submitted to FEMA for their review and approval and can often take 12 months or more to complete the process.

Floodproofing

Floodproofing is only allowed for non-residential buildings and non-residential portions of mixed-use buildings.  The Town highly recommends elevation instead of dry floodproofing whenever possible due to complex design considerations, cost implications, construction and testing difficulties, long term maintenance responsibilities, and potential flood insurance ramifications.   Due to flash flooding type events in this region, all floodproofing measures must be effective without human intervention. These are often referred to as “passive” or “automatic” systems.

Additional Resources:

  

Stay Informed During a Flood

Visit bocoalert.org to sign up for county emergency alerts.

The Mile High Flood District maintains real-time storm and flood data.

Emergency warning sirens may also be activated before or during a flood.   Move to higher ground, do NOT try to outrun a flood!