Thornton Transitional Reservoir CSA Decommissioning

Installation of concrete tunnel plugs; installation of mass concrete fill; tunnel lining and contact grouting in the Diversion Tunnel from approximately Station; removal of the rock plug in the upper Thorn Creek Connection Tunnel; tunnel lining and contact grouting; and removal of concrete and metal components, loose rock, sediment, and vegetation at the Thornton Transitional Reservoir, removal of the existing concrete haul tunnel plug. Work also includes demolition inside the cone valve dewatering chamber, including the removal of four (4) 42” diameter knife gate valves, two (2) 42” cone valves and spool pieces, and the hydraulic power unit and its appurtenances, along with removal of all conduits, cables and other live utilities from the control to the valve chamber; sealing a 42” dewatering pipe with a DIP blind flange and replacing a cone valve with a 42” DIP pipe; The Dewatering Chamber and Valve Shaft shall be sealed shut at the access point in the control building; installation of backflow preventer on the 42” dewatering outlet pipe inside the Construction Shaft; removal of two (2) electrical cabinets along Vincennes Road; removal of existing swing gate at northwest corner of the Thornton Composite Reservoir (TCR) and replacement with new chain link fencing and posts; Repairs to rockfall netting at approximately nine (9) locations along the TCR north highwall access ramp; Removal of rock and sediment debris at the bubbler intake adjacent to toe of TCR north highwall; Installation of reservoir level measurement equipment at the TCR; Work at the 30-ft diameter TCR Construction Shaft includes concrete liner repairs.