Flower Creek Dam Improvements

Owner: City of Libby

Location: Libby, MT

Major Components of Work: Demolition of the existing dam structure and construction of a new mass concrete dam. Work included bypass of Flower Creek around work area with 48-inch HDPE pipe and dewatering of dam foundation. Excavation of 15,000 CY of rock foundation, demolition of existing concrete dam, installation of a grout curtain along new dam alignment with pressure grouting to seal all voids in the foundation. Onsite batching of 11,000 CY of mass concrete and 1,000 CY of cast-in-place structural concrete, new 36-inch low level steel outlet pipe encased in concrete dam, new 42-inch knife gate and new valve house. Unstable slopes were covered with shotcrete. Johnson-Wilson Constructors self-performed 95% of the work and subcontracted 5%.