Starting February 10, SFPUC crews will begin minor construction work on the top of Lower Crystal Springs Dam. The space between the dam and the newly-constructed bridge on top of it is relatively small. So, crews need the help of a giant crane to ferry equipment and supplies to the top of the dam.
Crews will do some minor follow up work to the dam, including addressing the issue of water ponding on the dam and to fill a gap in the parapet wall. These projects will improve SFPUC operators access to the dam and will ensure the upgrades to the Dam’s parapet perform as they are designed to do.
The footings of the crane and the crane arm will take up most of the bridgeway. Therefore, the bridge must be closed to cars during the work.
The bridge will be closed to all car traffic Monday through Friday. There is no anticipated work on weekends and holidays. The Trail Portion of the Bridge will remain open, but hikers and cyclists could experience occasional delays of approximately 15 minutes during weekday work hours. Flaggers will temporarily halt trail traffic when the crane arm is in motion and it is not safe to be under it. The bridge will reopen to car traffic at sunrise on Saturdays, and will close at sunset on Sundays and holidays.
The SFPUC owns and operates the Hetch Hetchy Regional Water System, which delivers drinking water to 2.7 million people in four Bay Area Counties. The agency owns approximately 23,000 acres of watershed land on the Peninsula. The three reservoirs located there: Pilarcitos, Crystal Springs, and San Andreas, serve approximately one million people in northern San Mateo County and San Francisco county.
Lower Crystal Springs Dam impounds water at Crystal Springs Reservoir. The SFPUC performed upgrades to the dam (built in 1888) to allow it to accommodate revised evaluations for a maximum probable flood. At the end of 2018, a newly-constructed Bridge over Lower Crystal Springs Dam was constructed by San Mateo County.
The work is scheduled to take place February 10, 2020 through April 3, 2020.