I've been refreshing the beach monitoring page every hour or so and the dreaded blinking triangles have appeared. This means that a mixture of raw sewage and stormwater has been released due to the system being at capacity.
SF, as some of you know, has "combined sewerage", which means that stormwater gets processed in the same system that handles raw sewage, before being released to the ocean. By and large, this means that our beaches tend to be a lot cleaner, since runoff (which contains all sorts of filth) doesn't flow directly to the ocean; however, a large rain event like today's means that we end up with even grosser stuff in the water when the system overflows.
San Francisco has about 7 or 8 releases like this a year, down from 60 a few years ago. We've added a lot of capacity to the sewage system, but it would be prohibitively expensive to add more. The future is downspout disconnection and porous pavement!
Avoid.
