Joel spoke at the Exploratorium on July 15th, 2015 exploring in conversation and images “Seep City” – a catalog of water discoveries in the city of San Francisco.
Joel’s map of Seep City shows today’s landforms, but overlays the springs, water, and waterways of the past (I like how the map is a lacking in any streets — makes it funner to try and identify the places you know). Crissy field used to be much larger (the current marsh is a “sculpture of a marsh”), and there were large marshes on the eastern side of the city, a tidal waterway running up to the Mission District, and Islais creek wending it’s way into the peninsula. The sands also held many temporary lakes and water ways that would come and go with storms (and the shifting sands). They are barriers and dams, but could be blown away in a storm. Creeks flowing out of the dunes were often temporary or seasonal.
San Francisco — unlike a lot of cities — is not built on a river, and a question you might ask is why we have these seeps and springs at all. If you stripped all our human construction and put back features we’ve flattened or otherwise shaped, you’d find a lot of sand, as well as some serpentite and chert. Before all of our hardscape, rainwater would have been absorbed by sand and passed underneath it, but there is also water coming out of the tops of hills despite the drought. Joel still has yet to answer the question where this exactly comes from.
There were someplaces the water always flowed. The Ohlone, not a stone age people, but perhaps better described as people of the fabric age, made use of water based technology and had daily rituals washing in the creeks here. But there were only a few hundred there when the Spanish arrived.
The Spanish built their settlements in San Francisco around a couple of springs, in the Presidio and in the Mission. Captain Anza noted the spring that flowed out of the dunes near where the Mission was to be built was enough for a larger water wheel.
As the city developed, San Francisco used local water for laundries and for bottling, water was brought around the city through flumes built by private companies selling water to the more settled regions of the city. Lobos creek was one of the sources the flume running along the coast. Another had a water works that created stow lake. Safeway in the Mission/Castro area used to be a reservoir with water pumped over the hills from outside of San Francisco. Tank hill had a tank of water.
Water was also stored around the city for fighting the frequent fires of San Francisco’s early days. You may see the circle and square bricks circling intersections of San Francisco Streets. These continue to hold water for fighting fire.
Most of our water no comes from outside of San Francisco. The Presidio gets 80% of its water from its own springs. And lot of that water still flows, just mostly out of sight, channelized and covered over. There are of course many more water features now in the way of fountains and reservoirs, and some of that come from local water. The fountain in UN plaza (7 piles of stone representing the 7 continents apparently) actually runs on ground water that people refered to as Hayes Creek. BART has to pump water of its tunnels continually. Water runs under the Armory building in the Mission. There is a brewery at Haight and Steiner which hope to use the water underneath their store. The presidio has a creek you can shut it off in 3 places in case someone falls in.
This map is of course just a start, there are seeps and springs all over the city, and while this map holds many — Joel continues to hear of new possible springs and seeps. Keep up to date with this project at his website: seepcity.org
SF Natural History Series 