From the Southern end of Sweeny Ridge in San Bruno, to the eastern end of McNee Ranch in Pacifica, is an open space area that stretches all the way to highway 92 and then south past Filoli. This 23,000 acres property is not wilderness, it has in it an entire network of well-maintained service roads, some of which have a history of use all the way back to the 1860’s.
The dirt and gravel roads in the area wind their way through thick forests of redwood, cypress and oak trees. The roads go past a beautiful mountain lake, Lake Pilarcitos, which was the first reliable water source for the city of San Francisco. This is the SF Watershed, and you are forbidden to go there.
The SF Watershed land is managed by the SFPUC, otherwise known as the San Francisco Water Department. It is entirely closed to the public; it is only open to a few select SF water department employees and a few politicians from San Francisco.
The SF Watershed has some of the most important historical sites in the Bay Area, and because it has been closed for so long much of this history is forgotten from public consciousness. The untold history inside the watershed is as important as the Bay Area discovery site, Mission Dolores, the Barbary Coast Trail, or any of our historically important places.
Pilarcitos Dam was completed in 1867 right after the civil war. Designed by master engineer Herman Schussler it was a marvel of engineering for its time. The dam created the first reliable water source for San Francisco, Pilarcitos Lake. Water was shipped to the city via a redwood flume powered by gravity. Before this development water in San Francisco was sold by the barrel. Without water the city would not have grown, when you consider how much the San Francisco Bay Area has shaped the history of the world, it puts into perspective how important this dam is to our cultural history. There is at plaque at Pilarcitos Dam placed in 1967 at the one hundred year anniversary of the dams construction. It is a plaque paid for with public money, on public land, that no one in the public is allowed to see.
There are other significant historical sites in the watershed, including Stone Dam, pieces of the redwood flume that are still standing, homes dating back to the 1860’s and countless other artifacts left un accounted for left by the Spring Valley Water company before it was acquired by the San Francisco Water department in the 1930’s.