Joel Pomerantz and Greg Braswell came out to talk to us May 15th about creeks and sewers. One particular creek in fact, Precita Creek, and how this creek was developed to the sewers that are there today.
Joel walked us through the natural flow of this creek and early history. The name Precita comes from a Spanish word meaning dam or weir. Native Americans would use weirs which were funnels with a basket in the middle into which they would drive the fish. The creek flows down from under where Market Street is today (from the Mission Mountains according to early maps), down along the north side of Bernal Heights and through the gap between Bernal and Potrero into Islais Creek. The creek has left it’s traces in odd little bends in streets (Joel was hoping to have Burrito Justice join us, but alas!).
The creek ended in the wetlands that pushed up through this gap, and the water joined Islais creek. For early San Franciscans this swampy area ended up in the late 1800s a perfect dumping ground for fill, effluents from tanneries and soap factories, and their sewers. The word fetid probably does not do it justice.
The first master sewer plan was in 1875, and many more have since followed. Before that there was a lot of add hoc sewers that did not really go anywhere (This talk almost cured me of my nostalgia for seeing San Francisco back in the day!). The first houses in this area were built in the 1860s and some had wooden sewers bringing waste down the hill.
The 1875 Humphrey plan had to get the state legislature to redraw streets for the plan to go forward. And it wasn’t til 1881 that a sewer was complete under (now) Cesar Chavez. The brick arch of this sewer was 11.5′ wide and 8′ tall. It’s had work done it since, but it is in essence still in use today.
The sewers extended out into the Marsh becoming the bones in a sense of later fill. The earthquake and fire of 1906 provided a lot of that fill.
The city didn’t see its first treatment plants to around the ’30s. Plants in Golden Gate Park and Fort Point. The SW treatment plant wasn’t built until the 40s. The city treats both sewer and storm water in one system — and for good reason — the water that falls onto San Francisco takes with it a lot of nasty crap, which we wouldn’t want pouring back into the oceans.
One could sense that Greg could tell amazing stories about just about any piece of our sewer system. Whether its current state, or how it came to be the way it is today.
SF Natural History Series 