O'Shaughnessy Dam was completed in 1923 and raised in 1938. A Condition assessment of the dam outlet works revealed deficiencies. This rehabilitation project addresses deficiencies of the existing outlet works system at O'Shaughnessy Dam.
Seven projects were identified and have been prioritized. Phase 1 will include three of these projects: drum gate rehabilitation (upgrading the hinges and rivets, recoating the gate and existing seals, and repairing the spillway concrete), installation of a new bulkhead system, and rehabilitation of slide gates and installation of a diversion pipe butterfly valve.
The project is part of a larger Hetchy Capital Improvement Program (HCIP), a multi-year capital program to upgrade or improve water conveyance, water storage, and power generation facilities in the Sierra Nevada portion of the Hetch Hetchy Regional Water System.