CISTERNS_SFFD

[MFDPhoto1]

Sept. 10, 2014:

Ever notice a brick-lined circle embedded into a street intersection? Keep an eye out and you'll see them throughout San Francisco. As part of the San Francisco Fire Department's Auxiliary Water Supply System, these brick circles indicate a cistern full of water. Join SFFD's Chief Ken Lombardi and Firefighter Hashim Anderson as they discuss the history and function of these cisterns, and demonstrate the drafting procedures used to access the water.

http://www.exploratorium.edu/tv/index.php?project=104&program=1524&type=clip

-----------------------------------------------------------------------------------------------------------------
In the simplest terms, the AWSS is a gravity flow system with the highest point being a ten million gallon reservoir atop Twin Peaks.  The AWSS flows through two additional water tanks, the upper Asbury Tank, and the lower Jones Street Tank, on Jones Street at Washington. The systems special hydrants are on a grid system with gates so that various sections can be closed, if necessary, in case of water main breaks like those that happened in the 1989 Earthquake.  At the lowest end of the system, two pumping stations were built near the waterfront in case it should become necessary to add more water into the system.  Pumping Station No.1 is located on the south side of the City, at 698 2nd Street, which is now also Department Headquarters.  The other, Pumping Station No. 2, this building, is on the north side of the City.  Both pumping stations are an integral part of the system. In addition, intake manifolds were placed along the waterfront so that the two new fireboats could pump saltwater to the system.


http://guardiansofthecity.org/sffd/firehouses/vintage/pumping_station_no2.html

[Box 2565]

I really enjoyed the video.  Cincinnati still had cisterns and a high pressure system when I started buffing.  I saw the high pressure system used twice, but I never saw a company working from a cistern.

[MFDPhoto1]

Mar. 13, 2014:

"The five-alarm fire that destroyed a San Francisco apartment building this week put the city's municipal water supply to the test: When water pressure began to dwindle, firefighters tapped an emergency system that was built below the city—all the way back in 1913."

"The six-story building under construction in the city's Mission Bay neighborhood caught fire Tuesday and raged into the night, creating a mushroom cloud that billowed above the city. Over 90 fire vehicles were called to the scene, which quickly overwhelmed the water system and diminished firefighters' capabilities to pump water out of the city's hydrants."

http://www.sfgate.com/bayarea/article/Emergency-water-supply-used-to-fight-San-5312636.php#photo-6011761

[SixbyFire]

They use the high pressure system for major fires up in San Francisco somewhat regularly, and can run hand lines right off a hydrant, provided they have the pressure reducing valve attached. I don't have any pictures of the high pressure hydrants, but they are obvious once you see them. They're a lot larger and in addition to having a valve for each outlet (like the normal "low pressure" hydrants have) they have one valve that charges the outlets. It should be noted that most hydrants in the San Francisco bay area are "wet" hydrants, that is, they have water in them all the way to the top, instead of the hydrants back east with a single valve that pressurizes the hydrant and flows water out any outlet you take the cap off. Here most "low pressure" hydrants with two or three outlets, only have individual valves for each outlet, not one master valve for all outlets. That's why when a hydrant gets sheared off out here, it usually sends a plume of water up into the air.

The cisterns are pretty obvious too once you start looking for them, though I don't know how often they're used. I think the "low pressure" hydrants have a specially colored painted top when a cistern is nearby.

Jeff

[MFDPhoto1]

The cisterns are pretty obvious too once you start looking for them, though I don't know how often they're used. I think the "low pressure" hydrants have a specially colored painted top when a cistern is nearby.

Jeff

Here are a few photos (not mine) showing:
 
1 - Twin Peaks 10.5 Mil/gal reservoir
2 - AWS Diagram
3 - AWS Map and a hydrant
4 - street view on one of the 172 Cisterns, that hold 75,00 gals. each

photos courtesy SFGATE