Category: Watershed

“Nothing in the world is more flexible and yielding than water. Yet when it attacks the firm and the strong, none can withstand it, because they have no way to change it.” –Lao Tzu

There’s something about San Francisco’s bodies of water that people just can’t resist. We abuse them, we bury them, we fill them in with rubble and toxins – and then finally when we realize the error of our ways, if we’re lucky we can pull them back from the brink.

Consider Yosemite Creek, a small but crucial part of the city’s watershed. The creek’s entire trip, from McLaren Park to Bayview, takes place in aging underground pipes. But it may not always be that way: the Public Utilities Commission is exploring nifty new ways to “daylight” the creek, ranging from creating new parks to placing watery channels alongside city streets.

The Marsh

Poor McLaren Park. It has a name, but sometimes it seems to lack an identity. Way out in the Excelsior – or is it Portola? – it boasts a head-spinning array of amenities: tennis and basketball courts, a pool, dog run areas galore, barbecue pits and an amphitheater, woodsy trails, and possibly soon a disc-golf course.

But among the Park’s distinguishing features, a spot called Yosemite Marsh may be the most unique. Unlike two nearby asphalt-contained bodies of water – one a reservoir, the other McNab Lake – Yosemite Marsh is a naturally-occurring wetland.

You could be forgiven for walking right by without noticing it. It’s small, and hidden by a thicket of trees. A wooden footbridge crosses through the thicket, spanning a thin gully. Nearby, and for no discernable reason, a concrete sculpture of a dolphin sits across from an always-empty park bench.

At this time of year, the creek is nearly completely dry; but during the rainy season, a steady stream of water emerges from the hillside to feed the marsh. The marsh, in turn, provides habitat to herons, quail, ducks, bullfrogs, lizards, and (thrillingly) wrentits.

Formerly a bit run-down, the Marsh enjoyed an extreme makeover in 2006 [PDF]. The most prominent upgrades are a nice footpath and seating, but there are more infrastructural improvements under the hood: erosion control, enlarged banks, and enhanced wetland plantings, thanks to a $150,000 grant and $150,000 in Rec & Park Department Funds. With riparian rehab projects such as this, it can take five to ten years for plants to mature; the hillside above the marsh still looks a bit scraggly, but you can definitely see where it’s growing in.

Hal Phillips put together this very “electric” edit of footage we shot recently at the marsh:

There’s still lots of work to be done elsewhere in the park. McLaren is currently in the running for a $30,000 grant from Sears (yes, Sears) to improve a particularly unkempt northern entrance to the park.

Of course, the marsh isn’t the only moisture in the area. Various trickles of water can be found throughout the park. (And in fact, I carelessly stepped into one up to my ankle when I visited after a rainstorm.) Why is McLaren so wet? Bedrock. Soil is slow to discharge moisture, so water tends to hang around a bit.

And when the water finally does trickle out of the park, it has quite a trip ahead of it. From McLaren, it winds its way underground past University Mound Reservoir under Portola and the Phillip Burton Academic School, under the 101 and the 3rd Street light rail, and then finally aligning itself with Yosemite Ave – its namesake – before emptying into the South Basin in an area known as Yosemite Slough.

The Slough

The most complicated step in Yosemite Creek’s journey lies at the very end, in Yosemite Slough. It’s a highly sensitive ecological area, decimated by decades of heavy industry. But there’s reason for hope: a massive environmental restoration is underway [PDF], featuring the planting of thousands of native species, soil remediation, and habitat construction.

But it is only hope at this point. As the video below shows, the area is currently an industrial dumping area. (The song is “33” by David Molina’s Ghosts and Strings.)

It’s not exactly an easy spot to access, and lord knows it’s toxic in several different ways; we’ve done the exploring so you don’t have to.

The Slough is part of Candlestick Point State Recreation Area, which in general is well worth a visit. Don’t let the unseemly history scare you off. Yes, legend has it that it got its name because of all the burning abandoned ships nearby. And yes, for years it was used as a landfill. Okay, and the Navy didn’t exactly take great care of it during WWII.

But! You can’t beat that view. And apparently the birds agree: there’s no better place in San Francisco for spotting herons, loons, egrets, and avocet than nearby Heron’s Head Park. Environmental cleanup – much of it led by students – is gradually turning the area from a garbade dump to prime real estate.

With Yosemite Marsh stronger than ever, Yosemite Slough on the mend, and Yosemite Creek facing a new lease on life, there’s never been a better time to thank San Francisco’s watershed for sticking with us through thick and thin.

Matt Baume is a San Francisco writer and photographer covering transit, ecology, and the science of cities.

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