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Little Dry Creek Flood Hazard Map
About this partner project:
This project is a collaborative effort between Mile High Flood District (MHFD) and the jurisdictions within the Little Dry Creek Basin, including the City of Westminster, City of Arvada, and Adams County.
Visit Mile High Flood District's project website
mhfd.org\little-dry-creek-study
to learn more
Who is Mile High Flood District (MHFD)?
MHFD was established by the Colorado Legislature in 1969, following the 1965 South Platte River flood, to support local governments in the Denver metropolitan region with complex, multi-jurisdictional drainage and flood control challenges. Today, MHFD focuses its resources on more than 1,600 miles of major streams and serves a population of approximately 2.8 million residents.
MHFD’s mission is to protect people, property, and the environment through floodplain preservation, flood mitigation, and public education.
Flooding as Public Health and Safety Concern
Flooding poses a serious risk to life, health, safety, and property. Even shallow floodwaters can be dangerous. As little as six inches of fast-moving water can knock down an adult,and twelve inches of moving water can carry away a small car. Driving or walking through floodwaters remains one of the leading causes of flood-related fatalities.
For these reasons, maintaining accurate and up-to-date flood risk information is essential for protecting communities and supporting responsible planning and development.
Upcoming Open House
Learn more at Mile HIgh Flood District's upcoming Open House for the City of Westminster and Adams County at:
The MAC (3295 West 72nd Avenue, Westminster)
Wednesday, April 29
5:30 to 7 pm
A Flood Hazard Area Delineation (FHAD) Study provides a revised evaluation of flood risks in the Little Dry Creek Basin and its associated streams. The study identifies updated floodplain boundaries and improves understanding of flood behavior based on current watershed conditions and modern technical methods.
The jurisdictions (City of Arvada, City of Westminster, and Adams County) and Mile High Flood District (MHFD) are responsible for maintaining accurate floodplain data to inform property owners, guide development, and support infrastructure planning.
Learn more about the FHAD on Mile High Flood District’s project page: www.mhfd.org/little-dry-creek-study
The Major Drainage Plan (MDP) recommends drainage improvements and best management practices to guide future public works projects and land development. The MDP serves as a planning tool to support coordinated infrastructure decisions and improve long-term flood resilience within the basin.
Project Resources
Frequently Asked Questions:
The most recent FHAD study for the Little Dry Creek Basin was completed in 1978, with some minor revisions since then where projects have been built. This study has found that flood risk within the basin is greater than previously understood.
Flood risk information is updated periodically for several reasons, including:
- Increased development within the basin
- Changes in watershed land use and surface conditions
- Climate variability and changing precipitation patterns
- Advances in hydraulic and hydrologic modeling technology
In general, flood risk increases over time as development expands, and watershed conditions evolve. This means that assumptions used in earlier studies may no longer accurately represent current or future conditions.
For example, the 1978 FHAD assumed impervious cover in the basin would grow to approximately 33%. Current analysis indicates that approximately 49% of the basin is currently impervious, and this value is estimated to increase to approximately 53% as growth continues. Increased impervious surface results in greater stormwater runoff, faster flow response, and higher flood peaks.
Additionally, previous flow assumptions are no longer valid. Earlier studies assumed that flood flows would enter the Croke Canal and the Farmers Highline Canal and be conveyed toward Standley Lake. These canals are not flood control facilities and cannot be relied upon for flood conveyance. As a result, updated modeling indicates that greater flood flows will reach the lower basin than previously estimated.
Modern modeling tools also provide improved accuracy through updated detention modeling and improved understanding of bypassing conditions at existing detention facilities.
Yes. Property owners in the Little Dry Creek FHAD boundaries will be notified via mailed postcards and public engagement events.
If a property is mapped into the floodplain, mortgage lenders may require flood insurance. FEMA floodplain adoption for this study may take five or more years to complete. Local floodplain regulations and requirements would be in effect as soon as the FHAD is complete.
Flood Insurance Policies are available through the National Flood Insurance Program (NFIP). More information can be found at www.floodsmart.gov. It is important to note that anybody anywhere can purchase flood insurance from FEMA, the property does not have to be within a floodplain to qualify.
Yes. However, floodplain regulations may affect new development or renovations. Homeowners should check with the City’s floodplain management office to understand any restrictions. Contact Andrew Hawthorn at ahawthorn@westminsterco.gov or call 303.658.2428.
No construction is currently planned, but the MDP provides a guide to future public works projects to manage flood risk in partnership with MHFD. If construction occurs in other areas in the future, the jurisdictions will work to notify residents and minimize disruption. Residents will receive advance notice regarding construction schedules, detours, and mitigation measures.