501 Stanyan St
San Francisco
CA 94117
Thinkwalks presents an exploration walk:
Panhandle Water History
My most recent water research turned up an amazing fact: In 1869 there was an established creek that popped up out of a sand dune and then disappeared back into it—near Masonic Ave!
The source of that creek was Cole Valley and its upper slopes. The mouth was at Folsom Street, where Rainbow Grocery is today. Twice in that long run it soaked in and reëmerged. We’ll examine evidence and also the landscape to understand how things have changed and how the sandy ground is infused with groundwater flows. We’ll check the 1869 map that marks a creek and also the first good survey published of the Panhandle, by William Hammond Hall, that indicates hills where it’s now all flat.
Topics: Dune hydrology, bedrock springs, reservoirs, extreme weather, old maps & pictures.
☆ RSVP required (RSVP below…or you can email me)
↪ Rain or shine
↪ No hills! Lots of standing discussion, so you may get chilled if you forget your extra layers. It may be windy.
↪ Ending near Waller & Cole
↪ Maximum 12 people