EVENT DETAIL

Branch members toured the Chimney Hollow Construction Site on April 17, 2024.  Project Manager Joe Donnelly told us about the project, and was on hand to answer questions, along with Kevin Lock, Acting Branch President, and Stephanie Cecil, Government Affairs Co-Chair and a Past President as well.  It was really something to see the construction of a 350-ft tall dam!  

We took a couple of little busses from the Northern Water headquarters in Berthoud, up a winding road to the Chimney Hollow construction site. We went to an overlook with a full view of the valley, where we could see the construction, including the main dam, coffer dam, quarry, concrete plant and the operations in progress.  They had dump trucks taking material from the quarry, which is where the reservoir will be, up onto the dam.  They would dump the rock there, and D-9's would spread it.  Even with the large size of the pieces, they have to hold a certain grade.  We could see the asphalt core of the dam clearly.  Asphalt cored dams are common in Europe, but not in the US.  Clay cores are more common, but there was not enough clay available in the rock that is to be removed from the reservoir, and they would have needed to import massive amounts of clay to make the core.  

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.  Construction started on the 350-ft tall dam in August 2021 and is projected to be completed in 2025.