Construction of the Chimney Hollow Reservoir Project’s 355-foot-tall main rockfill structure and asphalt core dam is underway just west of Carter Lake in Larimer County. This major undertaking by Northern Water’s Municipal Subdistrict and the 12 Windy Gap Firming Project participants will take four years to complete.  

As the primary component of Chimney Hollow Reservoir, the main dam requires protection from water entering the dam site during construction. To accomplish this, project contractor Barnard Construction is building a 50-foot-tall cofferdam just upstream of the main dam. The cofferdam serves as a temporary barrier to prevent water from entering the main dam’s construction zone.  

In the video, Project Manager Jeremy Deuto discusses the purpose and role of a cofferdam in the Chimney Hollow Reservoir Project.