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Seep City

At a time when urban development in San Francisco is more visible than it has been in generations, it's easy to forget nature. Yet the built environment, from building types and heights to locations and angles of streets, reflect physical constraints linked to the original natural conditions of our landscape.

The Seep City Map of Water Explorations, a trove of technical data disguised as an art poster, was installed in March in an eight-by-eight-foot display on Divisadero Street at McAllister. It’s been a magnet for explorers, especially those interested in water and history. The Green Earth food store has provided the exhibit space.

The purpose of the project, which is presented by Thinkwalks, is to provide a sense of the past. It maps out the bay fill, courses of hidden and buried creeks, and even paved-over dune regions prone to wet weather saturation. Since much of the map shows water and land that still exists today, it leaves the viewer with a craving for more specific information. What historic maps did this information come from? Where on today's street grid is that filled pond? What hill is that one with all the springs still flowing from it?

Joel Pomerantz (in blue cap), Seep City mapmaker, ran a successful crowd-funding campaign in April to fund a Seep City Water Log book, an illustrated guide that will become available in August. It will contain answers to the questions above and results of Joel’s decades of waterway research. For additional information, or to support the project, visit

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