Since 1964, Dillon Reservoir has provided water storage for Denver Water customers and recreational opportunities for Colorado residents and visitors. Denver Water is responsible for maintaining a safe and reliable facility. To meet this responsibility, Denver Water must perform important maintenance on the dam’s outlet works facility — the gates that control the flow of water released from the reservoir into the Blue River — beginning in April 2012.
What is the project?
A Denver Water contractor is performing maintenance on the control gates within the outlet works facility. In order to work on the gates, Denver Water will need to reroute the normal flow of water around the construction in the outlet works. To do that, the contractor will use a bypass system that will redirect water into the Blue River while the gates are out of service.
What is the time frame of the work?
Construction activities are slated to begin in April 2012 and end by February 2013. The operation of the bypass system will begin in October 2012 and end in December 2012.
What are the project benefits?
The improvements will allow Denver Water to maintain a safe and reliable control point between the reservoir and downstream residents on the Blue River.
Why is the work necessary?
The gates are more than 50 years old and need maintenance because of normal wear and tear. The focus of the work will be to restore the gates to near original condition. The gates prevent water from passing unintentionally to the Blue River from the reservoir. If Denver Water does not complete this necessary maintenance, the gates will continue to degrade, reducing our ability to control releases between the reservoir and Blue River downstream of the dam.
Who will be performing the work?
Denver Water hired Gracon Corporation as the general contractor following a competitive selection and qualification process.
What should I expect to see during construction?
The majority of the work will take place inside the fenced-in area near the morning glory spillway at the west side of the dam. During construction, the contractor will be moving heavy equipment, such as cranes, loaders, excavators and trucks, around the dam area. A barge and/or temporary structure may be placed on the reservoir within the buoy lines near the spillway as part of the bypass system.
How will traffic on Dillon Dam Road be impacted by the project?
Daily construction traffic should not impact the traffic around Dillon Reservoir. However, there may be limited traffic impacts when the contractor transports large equipment at the start and end of construction.
How will the project impact the Blue River?
The bypass system will operate from October through December. During that time, the flows in the Blue River are expected to range between 80 cubic-feet per second (cfs) and 110 cfs, which corresponds with the 10-year average flows that time of year. The release rates during those months over the past 10 years have ranged between 78 cfs and 98 cfs (see Table 1). The historical lowest flows in the Blue River occurred in 2010, averaging 54 cfs.
Table 1: Blue River Flows
Month 2010 average flow (cfs) 10-year average flow (cfs) October 54 98 November 53 99 December 54 78
What happens in the bypass system fails to operate during the project?
The bypass system will have a secondary system ready for use if an outage of the primary bypass system occurs. The time needed to activate the secondary system will not significantly impact the flows in the Blue River.
Will the project impact the aquatic life?
No. Denver Water will maintain adequate flows in the Blue River for aquatic life.
Will fishing be impacted?
No impacts are expected. Fishing will be allowed during this period on the reservoir and the Blue River.
Is Denver Water working with Summit County officials and other agencies?
Yes. Denver Water is working with county officials and other local agencies, and will keep them updated on the project as it progresses.
Who can be contacted for more information on the project?
Phone: 970-278-9650, ext. 205