Coolidge Dam Outlet Works Rehabilitation, Withdrawn Land, San Carlos Indian Reservation, Arizona, Gila and Pinal Counties

Coolidge Dam and all of its associated facilities, including a storage facility and dam tender quarters are within the San Carlos Apache Indian Reservation. The dam is on the outlet of the San Carlos Reservoir on the Gila River approximately 31 miles southeast of Globe, AZ. The dam is accessed via BIA Route 3 which runs south out of Peridot, AZ, which is approximately 20 miles east of Globe, AZ. The dam impounds water that serves as an irrigation water storage reservoir for approximately 100,000 acres of farmland in the vicinity of Florence, Casa Grande, and Sacaton, AZ. The Government is seeking qualified, experienced sources capable of performing the following work on the Coolidge Dam Low Level Outlet Works Rehabilitation Project: Rehabilitate and upgrade the East and West Low Level Outlet (LLO) Works isolation/maintenance and flow regulating gate equipment at the Coolidge Dam. The existing 150 ft. tall cylindrical, steel isolation gates in each outlet tower will be demolished and replaced with new isolation butterfly valves, added to the existing buried conduits. The existing downstream, dual high-pressure slide gates have suffered long term operation problems. The oil hydraulic operating machinery for these gates all require upgrades. A new control building will also be added to operate the gates as well as other monitoring functions. Dredging of the reservoir immediately in front of the intakes, to remove years of accumulated shotcrete debris from the dam domes, will be required to unblock the flow entrances to the towers. Design, supply and installation of two new, electrically operated isolation 96 in. diameter butterfly valves, fittings and couplings to connect them to the existing steel conduits. One new hydraulic power unit (HPU) system, complete to replace the two existing problematic HPU’s to operate the 4 existing hydraulically operated bonneted slide gates. New electrical local and remote control system for the four (4) existing hydraulically operated bonneted slide gates. Underwater installation and removal of a new, temporary isolation bulkhead to permit dewatering of the low level conduits in support of the construction. Dredging, removal and disposal of gunite debris (from old dam dome coating) now submerged in the reservoir and impinging on the outlet tower entrances. Will require underwater work. Demolition of two off-site wood framed house structures. Demolition of a section of the two existing low level conduits for the addition of the new butterfly isolation valves and modifications to the existing valve vaults to suit. Repainting of the full length of the two existing low level conduits. Selective modification to a section of each of the two existing 96 in. steel conduits to incorporate a new thrust block structure. Repair of existing reinforced concrete paving slab under central dome at the powerhouse. Demolition and removal of two existing 150 ft. high by 8.75 ft. diameter cylinder gates, hydraulic operating machinery and appurtenances which will require underwater work. Underwater removal, rehabilitation and re-installation of 16 existing intake trashracks sections. Removal of existing stilling well structure on the west outlet tower and supply and installation of a series of new stilling wells and water level sensor equipment. Will require limited underwater work.

Division 02 -	Existing Conditions, Subsurface Investigation.
Division 31 -	Earthwork, Site Clearing, Grading, Excavation and Fill, Subgrade Preparation, Excavation, Shoring, Tunneling and Mining, Tunnel Excavation.
Division 35 -	Waterway and Marine Construction, Dam Construction and Equipment.