GRA San Francisco Branch and Association of Engineering Geologists
Speaker: Joel Pomerantz, Author "Seep City - San Francisco Water History Atlas"
Water emerges from local springs throughout San Francisco, including in church courtyards, public spaces and in hidden concrete channels under thousands of private homes. Joel’s Seep City project has been tracking and mapping local natural water, but it turns out that a full understanding of water and its effect on our history is impossible. Why?
Early descriptions of San Francisco were filled with wonder, each person comparing to conditions they had observed in the lands they had just fled, or those they had experienced harrowingly on their way here. Reports before the Gold Rush era tended toward single examples and generalities, never a careful rundown of the land and water features.
The Seep City project uses every forensic device from core samples to the jaded familiarity of old timers to sleuth out the water history and dynamics of this very dry city. Cities are made through a chaotic layering of historic artifacts, patterns printed one upon another on natural fabric, each obscuring and sometimes eradicating tatters from the previous scheme. The earliest were responding to a natural environment. Each successive layer became more distant from and therefore beholden to fewer of those geologic features, what are considered to be “original” and “natural” conditions.
Seep City has tracked nearly two dozen major springs that still exist today, even in drought times. The project map was built from earliest available reliable sources consisting of both image and text. It debuts innovations addressing watery specifics such as the how to map past lakes that had no precise shoreline. (They shrank as they soaked into the dunes.) It acts as both a repository of information about San Francisco and an art piece incorporating significant calibrated data.
Come learn more about these many newly discovered elements of this beautiful city’s hydrologic story.
Joel Pomerantz focuses on exploring and encouraging exploration of San Francisco. As a former journalist, wilderness trip leader, mural organizer and bicycle transportation advocate, he has come to know the city’s underlayers along with a big picture overview. How did things get to be the way they are from the natural settings that existed before? And how do we know that? His study reinforces the realization of the conclusion that we really don’t know much, especially when so many myths are created through folk processes in this chaotic, ever creative town. Joel has put together a historical map and annotated atlas which together form a natural science educational resource. He did this as a citizen scientist simply pursuing his curiosity.