Located on the San Carlos Apache Indian Reservation, in Peridot, Arizona, the Coolidge Dam is impressive in its unique design, which includes three vast domes and a crest length of 580 feet. The massive dam, once a source of hydroelectric power, now solely provides irrigation water for approximately 100,000 acres of farmland in nearby communities. Due to aging and deteriorating conditions, operations at the Coolidge Dam became inhibited, requiring refurbishment of the outlet gate trash racks, removal of two 8’ x 150’ cylinder gates, and demolition of two concrete vaults and penstocks in preparation for new 96” butterfly valves.
As part of our Outlet Rehabilitation project, McMillen Jacobs, serving as General Contractor, successfully and safely removed the two 150’ long x 8’ diameter, 50 Ton, steel isolation gates contained in each outlet tower by utilizing a specialty and custom designed bridge crane system. This work also included dredging of over 2000 cubic yards of mud and concrete gunite that surrounded the outlet towers. McMillen Jacobs had to overcome unprecedented fluctuating reservoir levels to successfully complete the work. Following gates demolition, McMillen Jacobs procured and installed two new 96-inch butterfly isolation valves to new penstock spools. Additionally, a brand new HPU system was designed, fabricated, and installed to regulate the new valves and existing regulating gates. The new system can operate remotely from a new master control building that is connected to the powerhouse with a mile of underground conduit and fiber-optic that was self-performed by McMillen Jacobs Electrical crews.