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Hetchy System Improvement Program (HSIP)


Moccasin penstocks

The Hetch Hetchy Water System delivers an average of 222 million gallons of high-quality drinking water per day to 2.6 million people in the San Francisco Bay Area. The system also generates enough clean, reliable hydropower annually for the Modesto and Turlock irrigation districts, City of San Francisco facilities and services, and newly constructed homes and businesses in the redeveloped San Francisco Shipyard.

The Hetchy Capital Improvement Projects (HCIP) are a $936 million, multi-year group of capital projects to upgrade numerous upcountry water transmission, hydroelectric generation and power transmission facilities essential to continued reliable delivery of both water and power. The approximately 30 projects, varying in scope and complexity, address necessary work on water transmission, hydroelectric generation and power transmission facilities in Tuolumne, Mariposa, Stanislaus, San Joaquin and Alameda counties. Construction of some HCIP projects began in 2012, with the entire set of projects scheduled for completion by 2026.

Current Projects

Mountain Tunnel Improvements

mountain tunnel outlet 

Mountain Tunnel outlet

The Mountain Tunnel in the Sierra foothills has transported water from Kirkwood Powerhouse to Priest Reservoir since 1925. It is a critical part of our Hetch Hetchy Regional Water System, and this winter we are undertaking two projects to ensure its continued operation. The tunnel will not be in service for approximately two months, and our local water reservoirs will provide continued supply.

Mountain Tunnel Adits and Access Improvements. To meet water delivery goals, the Mountain Tunnel must be capable of return to service within three months in the event that water service is interrupted. Since quick entry into the tunnel by construction crews and equipment would be essential, certain adits and access roads are being widened and improved to minimize the time required to return the tunnel to service. An emergency restoration plan will be established, and new monitoring instruments will be installed to enhance the existing system that continually assesses changed conditions in the tunnel.

Mountain Tunnel Inspection and Repairs. This project calls for a tunnel inspection in 2017 to update a previous 2008 condition assessment plus the repair of approximately 7500 linear feet of concrete lining.

Cherry Dam outlet works
Cherry Dam outlet works

Cherry Dam Outlet Works

The outlet facilities at Cherry Dam have reached the end of their service life at nearly 60 years old. The stream release assets must be in working conditions to meet U.S. Department of Interior’s stream flow requirements, but requirements cannot be met at low lake elevations. The 66-inch valves will be replaced in order to operate the dam safely during storm conditions and heavy inflows to Cherry Lake. The valves are critical for maintaining maximum carryover storage and meeting SFPUC water supply objectives. The scope of work includes replacement of the stream release valves and associated piping as well as the low level outlet 66-inch hollow jet valves. Construction began June 2016 and is expected to be complete on February 2018.

dam outlet works

Valve installation at O'Shaughnessy Dam

O’Shaughnessy Dam Outlet Works

The O’Shaughnessy Dam Outlet Works consists of several subprojects. The objective of the O’Shaughnessy Dam Outlet Works Project is to rehabilitate the drum gate and the release system from O’Shaughnessy Dam. The Outlet Works consists of six slide gates, seven needle valves and a single butterfly valve; valves are due for upgrades due to age and to meet safety compliance.

O’Shaughnessy Dam Drum Gate Automation is one of several subprojects, and we reached substantial completion of the construction phase for this subproject in December of 2016. The next subproject, the O’Shaughnessy Dam Outlet Works—Access & Drainage Improvements, is in the planning phase.

Moccasin Yard—New Shops/Office Buildings

The Hetch Hetchy Water and Power shops and buildings are original and vary from 45 to 80 years in age. The primary objective of this project is to build a 10,000-square-foot combined-function complex consisting of a plumbing shop, vegetation management shop, right-of-way shop, electronic technician shop, lockers, shower facilities, and break room. Construction began in July 2016, and we expect completion in January 2018.

moccasin yard projects

Site work at Moccasin Yard

Contact Information
Last updated: 3/28/2017 4:28:31 PM