Floodplain Maps and Updates

The City regulates three different mapped floodplains associated with the streams and other flood-prone areas within the City. 

Clear Creek

The largest floodplain is along Clear Creek, which enters the city from the west and flows east through the northern third of the city, paralleling I-70, then I-76, for much of the way until it exits the City in the northeast. Much of this floodplain is included within the naturally preserved Clear Creek Greenbelt. For more information on the benefits of preserving mapped floodplains as natural open space, visit: WEBPAGE LINK[MW1] 

Lena Gulch

A smaller floodplain occurs along Lena Gulch which enters the city from the southwest just downstream of the Maple Grove Dam. Lena Gulch flows northeast through the southwest quadrant of the City until it flows into Clear Creek just east of Kipling Street. While Lena Gulch has a few areas that have been preserved as natural open space, Lewis Meadows Park, much of it has more development immediately adjacent to the stream. As a result of the development, several mitigation projects have been done to reduce the flood risk to the nearby development. For more information on the mitigation projects, visit: WEBPAGE LINK[MW2] 

Sloan’s Lake

The smallest floodplain occurs along 26th Avenue between Wadsworth and Sheridan Boulevards. This floodplain is associated with tributaries upstream of Sloan’s Lake. Two of those tributaries extend into the City from 26th Avenue and have been adopted by the City as LFHAs[AH3]. Most of the floodplains associated with Sloan’s Lake are not obvious since most of the flows are conveyed by storm sewers and in the streets versus in open channels. But the higher risk of flooding still exists in the mapped floodplains.

Floodplain Map Updates

The City recently adopted the revised Jefferson County Digital Flood Insurance Rate Map (DFIRM) with an effective date of August 2, 2022. The mapped floodplains for Clear Creek and Lena Gulch adopted in 2014 did not change; however, the mapped floodplain along 26th Avenue associated with Sloan’s Lake had minor revisions. The Local Flood Hazard Area (LFHA) upstream of 26th Avenue, also associated with Sloan’s Lake, remained unchanged from what was previously adopted by the City in 2019. Properties within the LFHA are regulated by the City in the same way as the City’s other floodplains. However, flood insurance, while strongly encouraged, is not mandatory.

The floodplain maps for Clear Creek are still in the process of being redone with the new lower flows that were approved in late 2016. The maps are being finalized and are expected to be adopted by the State and submitted to FEMA by the end of 2022. Updates will be provided at the Annual Floodplain Meeting in late March 2023. For more information on the remapping process, including a comparison map with a slider that shows the current floodplain on one side and the proposed floodplain on the other side, visit: Clear Creek FHAD

A process to revise the floodplain maps for Lena Gulch is expected to start before the end of the year. Since the flows are not changing downstream of the Maple Grove Dam, only minor changes are expected to the floodplain boundaries within the City.

 [MW1]Link to Benefits of Preserving Natural Floodplains webpage

 [MW2]Link to Benefits of Floodplain Mitigation Projects webpage

 [AH3]Spell this out since you don’t have it spelled out earlier on this page.