Colsman Tunnel Rehabilitation Project

Our apologies in advance for the annoyances that come with construction and we thank you for your patience and cooperation while we rehabilitate critical infrastructure to protect health, safety, and the environment in your neighborhood!

Schedule Update (4/17/19)

The contractor has successfully pulled the new pipe into the tunnel. The process of grouting the tunnel is currently underway. Work on the tunnel portals as well as site improvements are also underway with the anticipation that all work will be completed by November, 2019.

Project Information:

Location E. Orchard Road, between S. Jackson Street and S. Cherrywood Circle
Greenwood Village/Centennial
Description Rehabilitate an existing 1.5 mile long sewer tunnel 
that serves the entirety of Southgate Sanitation District to protect public health, environment, and safety, and ensure its long-term adequacy, function, and reliability
Estimated Cost $15.5M
Owner Representative Burns & McDonnell Engineering Company, Inc.
Design/Build Team
Garney Companies, Inc.
Dewberry Engineers, Inc.
Shannon & Wilson, Inc.
Schedule April 2019 – May 2019 for grouting operations
May 2019 – November 2019 for portal and site improvements at the east and west portals.  The entrance at Cherrywood Circle and Orchard Road has been reopened.

Project Description:

We are rehabilitating an existing 1.5-mile long sewer tunnel by pulling a new, 48-inch diameter plastic pipe through the tunnel. The new pipe is made of high density polyethylene (HDPE) and the joints will be fused together, making it one solid piece of pipe through the entire length of the tunnel. The contractor must set-up work sites at two locations to pull the pipe in place – one at the entrance of the tunnel and the other at the exit of the tunnel. One work site (the "east portal") will be located at Southgate's offices near East Orchard Road and South Jackson Street. The second work site (the "west portal") will be located on the south side of East Orchard Road between South Ogden Court and South Humboldt Court.

The new pipe will be fused together and fed into the tunnel at the west portal. The pipe will be pulled through the tunnel by a machine located at the east portal. Once the new pipe is in place, grout will be pumped into the tunnel to fill the empty space between the new pipe and the tunnel wall. Thereafter, the contractor will reconstruct the portals and clean-up and restore the work sites.

We anticipate the areas located around the portals will experience noise, traffic, and odor impacts during the project. The anticipated traffic impacts are described below, and we will try to minimize noise and odor impacts as best we can.

Project Location Map

Traffic Impacts:

West Portal

  • Lane closures on East Orchard Road from South Ogden Court to South Humboldt Court will be required with approved traffic plans by City of Centennial and City of Greenwood Village
  • East Orchard Road will be temporarily re-striped to maintain 2-way traffic. Both directions of travel will be shifted to the north.
  • South Cherrywood Circle will be closed at East Orchard Road and traffic will be detoured to South Clarkson Street.
  • A traffic plan is below for reference.

East Portal

Significant impacts to traffic are not expected at the east portal since work will occur on Southgate's property and adjacent sewer easements. Traffic impacts at the east portal are expected to be minor, infrequent, and relating to equipment and material deliveries.

Emergencies (Sewer Spill or Back-up, or Safety Concern)

Call Southgate at (303) 779-0261 (select option 8 after hours to speak with a Field Operator)