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E-Newsletter | October 2022 |
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 Once on site, the 25,000-pound, steel wye was loaded onto a flatbed trailer and pulled up the hill by a D-10 bulldozer, the largest on site.
Colorado-Big Thompson Project Tie-In Started at the Bald Mountain Interconnect
One of the most time-sensitive aspects of the Chimney Hollow Reservoir Project is currently in progress – the Bald Mountain Interconnect. To complete this portion of construction, a shutdown of the Colorado-Big Thompson (C-BT) Project is in place as crews cut into the existing infrastructure to tie in a 126-inch steel pipe with a 72-inch steel offtake (known as a wye) to add the capacity to deliver water into Chimney Hollow Reservoir from the C-BT Project. This interconnect requires coordination, planning and communication between the U.S. Bureau of Reclamation, Northern Water, Barnard Construction and on-site subcontractors.
To keep water from flowing to Flatiron Reservoir, the first step was to install a bulkhead at the outlet of Pinewood Reservoir. The U.S. Bureau of Reclamation then partially refilled Pinewood Reservoir. Once the bulkhead was in place, crews cut into the existing concrete-encased tunnel connecting the two reservoirs to place the wye. This was the first time the tunnel has been excavated and exposed since it was built 70 years ago.
Once at the site, the 25,000-pound, steel wye was loaded onto a flatbed trailer and pulled up the hill by a D-10 bulldozer, the largest on site. The intricate process took nearly four hours before the wye was lifted in place by a crane and sealed into the existing C-BT infrastructure.
Crews will continue to work double shifts to complete this project phase by the end of November. Additionally, the U.S. Bureau of Reclamation is conducting maintenance during this time at the Adams Tunnel’s East Portal before C-BT Project water resumes flowing in mid-December.
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 Project Engineer Jeremy Deuto takes you on a virtual tour.
Chimney Hollow Virtual Tour Created as In-Person Tours Take Seasonal Break
After a successful tour season with more than 1,000 people who were able to view the Chimney Hollow Reservoir construction progress, tours concluded early for much-needed repairs on the access road to the project overlook. Staff will use the winter season to prepare for 2023 tours, anticipated to begin sometime in the spring.
In lieu of an in-person tour, the Chimney Hollow team has created an 18-minute virtual tour that gives an up-close look at key project components. This virtual tour follows Project Engineer Jeremy Deuto around the site to see the tunnel, main dam, cofferdam, saddle dam and more. You’ll feel like you’re riding shotgun with Jeremy and see just how big this project is.
This new virtual tour has been added to the Chimney Hollow website, so please feel free to share with family and friends. To stay up to date on construction progress, be sure to follow us on Facebook or Twitter, and sign up for our Chimney Hollow Project e-newsletter.
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 Project Engineer Jeremy Deuto shows Northern Water crews the main dam test section.
Northern Water Operations and Maintenance Crews See Reservoir Come to Life Through Chimney Hollow University
After construction is complete, the “key” to Chimney Hollow Reservoir will be passed from Barnard Construction to Northern Water operations and maintenance (O&M) staff. To better educate and train our O&M staff, ongoing training is conducted through Chimney Hollow University.
Northern Water’s three O&M crews (mechanical, electrical and civil) visit the site monthly for a half-day training. Some sessions are in a classroom setting while others are in the field. By regularly bringing the crews on site, they are gaining first-hand experience of the reservoir components they will maintain once it is built.
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 View facing east shows the Flatiron Penstocks close proximity to Chimney Hollow Reservoir construction.
How Will Water Get into Chimney Hollow Reservoir and Delivered to Participants?
Chimney Hollow Reservoir’s location adjacent to C-BT Project infrastructure will enable water to easily be moved in and out of the reservoir when C-BT Project capacity is available per an agreement with the U.S. Bureau of Reclamation.
The process of getting water to Chimney Hollow Reservoir begins on the West Slope. Just west of Granby sits Windy Gap Reservoir, where water is collected and pumped six miles via pipeline to Lake Granby. From there, existing C-BT infrastructure conveys Windy Gap water through Shadow Mountain Reservoir and Grand Lake to the Adams Tunnel, which flows beneath Rocky Mountain National Park.
After traveling 13.1 miles through the tunnel to the East Slope and then through four reservoirs and three power plants, water will make its way in and out of the Chimney Hollow Reservoir through the inlet/outlet works, which includes C-BT Project interconnections, the conduit, valve house, the inlet/outlet tunnel and the inlet/outlet tower located within the right (east) abutment. From Chimney Hollow Reservoir, water is released into Flatiron Reservoir where it can be delivered to the 13 participants using the existing C-BT distribution system that spans across Northern Colorado.
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 Project Engineer Jeremy Deuto presents to students at Big Thompson Elementary.
Project Outreach Reaches Elementary and Graduate Level Students
Due to Chimney Hollow Reservoir’s remote location, public outreach and education are key components of the project’s success. During the 2022 tour season, the Chimney Hollow team hosted over 500 tour attendees including participants and water industry professionals, with an additional 500 people who took part in the first Chimney Hollow Community Day for the reservoir’s neighbors.
In mid-September, Project Engineer Jeremy Deuto presented reservoir details to a Colorado State University graduate level civil engineering class. He shared design elements of the project’s three dams, the engineering behind the inlet/outlet works and construction progress to date. Two days later, he brought the class on site to see the construction up close.
Later that month, Deuto presented the project to fourth- and fifth-grade students at a local elementary school. Many of the students live around Chimney Hollow Reservoir and were excited to learn about the large project happening right in their neighborhood. Deuto said this was more challenging than presenting to the graduate level engineering class.
 Night work on the right (east) abutment of the main dam.
Night Work at Chimney Hollow To Temporarily Increase
Next week, night work activities at Chimney Hollow will temporarily increase for about three weeks as the asphalt core installation begins and the rockfill embankment expands to keep up with the core installation. Our Construction webpage will be updated as needed.
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Stay Connected
Visit the Chimney Hollow Reservoir Project website for the latest news and project highlights.
Also, connect with us on Facebook and Twitter!
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About Chimney Hollow Reservoir
The Chimney Hollow Reservoir Project is a collaboration between 12 Northeastern Colorado water providers to improve the reliability of, or make firm, water supplies from the Windy Gap Project. Chimney Hollow Reservoir will be located just west of Carter Lake in Larimer County to provide dedicated storage to supply a reliable 30,000 acre-feet of water each year for future generations.
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