Coal Creek Channel Improvements

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Last Updated December 30, 2015

The Town of Superior, in conjunction with the Urban Drainage and Flood Control District, will be making channel improvements to Coal Creek through Original Town Superior from 2nd Avenue upstream to the Town limits. The Town has been awarded federal grant funding project through FEMA's Hazard Mitigation Grant Program, which is designed to help communities pay for hazard prevention. This page will be periodically updated through the design and construction process.

Project Summary

This project will increase the flow capacity of the 2nd Avenue structure and sections of the channel in order to reduce the size of the mapped 100-year floodplain.  All habitable structures within Original Town Superior will no longer be within the limits of the mapped 100-year floodplain once this project is complete and FEMA has completed their final review.

The current bridge structure at 2nd Avenue is a three-sided concrete box culvert.  Flow capacity at the 2nd Avenue structure will be increased by adding a second "overbank culvert" on the north side of the existing structure.  The bottom of this overbank culvert will be approximately two feet higher than the existing channel.  Typical low flows will continue to flow through the existing structure while higher flood flows will spill out to the north and flow through the overbank culvert.

The creek will be slightly realigned at 3rd Avenue to mitigate a flow restriction at this location.  New slopes will be constructed and stabilized on each side of the creek.  Additional channel capacity increases will be constructed upstream of 3rd Avenue as well.  A new "interceptor channel" will be constructed on Town open space land to collect the remaining split flood flows approaching Original Town from the west.

To allow residents and emergency vehicles access to south Original Town during work on the bridge, a temporary "shoo-fly" bridge was constructed adjacent to the current 3rd Avenue bridge by Edge Contracting. This bridge has since been removed and the original bridge is open to traffic.

Frequently Asked Questions


Project Schedule

November - December 2014 - US Fish & Wildlife and Army Corps 404 permitting (complete)
January 2015 - Advertise for contractor (complete)
February - April 2015 - Finalize project design (complete)
January - May 2015 - Finalize all easement documents with private land owners (complete)
July - October 2015 - Construction of 2nd Avenue and 3rd Avenue portions of the project (complete)
November - December 2015 - Construction of improvements upstream of 3rd Avenue
2016 - Submit Letter of Map Revision (LOMR) to FEMA
2017 (approximate) - FEMA approval of LOMR and floodplain limits are finalized

Project Documents

Approximate Floodplain Impacts - June 2014
Preliminary Construction Drawings - January 2015 (8 MB pdf
Preliminary Landscape Plans - May 2015 (5 MB pdf)
Temporary 2nd Avenue Detour Routing - April 2015

Town Board Presentations

Town Board Work Session Presentation - 2/11/2013 (6 MB pdf)
Town Board Work Session Presentation - 4/22/2013 (8 MB pdf
Town Board Presentation - 2/10/2014 (3 MB pdf)
Town Board Presentation - 4/14/2014 (2 MB pdf
Town Board Presentation - 7/28/2014 (4 MB pdf)

Community Meetings

Community Meeting Presentation - 4/4/2013 (2 MB pdf)
Community Meeting Presentation - 10/1/2013 (6 MB pdf)

For further information, please contact Alex Gorsevki, Public Works Civil Engineer at 303-499-3675, ext. 114 or by email.


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