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Restore Hetch Hetchy
Guest Speaker: Spreck Resekrans
7:30pm, Thursday, August 21st, 2014
FREE at the Randall Museum, 199 Museum Way, San Francisco, CA 

Restore Hetch Hetchy is a grassroots non-profit organization seeking to restore the Hetch Hetchy Valley in Yosemite National Park to its original condition.

Constance Taylor on June 19th, 2014 show us that the estuary Lake Merritt — sitting in the middle of a now dense Oakland — was once much more. It’s muddy tidal flats used to extend to where three of Oakland’s theaters sit, the Paramount, the Grand Lake, and the old parkway. It’s tidal channel was huge. The edges of the estuary were thick with grasses, tule, pickle weed, willows, and oak. Salmon, grizzlies, and elk could be found there, ducks could blacken the sky. The Ohlone, hunted there.

In the 200+ years since the Spanish came, the lakes edges have been gradually swallowed up by our streets, the mud flats covered. The “lake” is still connected to the bay and is influenced by its tides, but the waters are now regulated by a flood control station, so the tidal flushing is much less than it once was. The inflows are still there, but rains and our water systems bring down everything we leave on the street, trash and more.

And yet, life still seems to thrive here. Part of this is due to the protection the lake received early on. Mayor Merritt in the 1860s had a house built nearby and (so the story goes) got fed up with hunters when a cow of his was shot. It was declared a wildlife refuge in 1870, the first of its kind (at least in the West), and became a model for protections placed on other parts of the country. Bird islands were constructed at various times to allow for nesting habitat, and the islands, and parts of the waters remain off limits to people and their boats. Recent renovations thanks to a ballot measure are working on the tidal channel, exposing more mud flats, and making the channel more channel like (most prominently reworking where water flows under streets).

A recent bioblitz species survey done by the volunteers turned up 236 species in 5.5 hours of looking. Cormorants nest there most prominently, but you can also find black crowned night herons, snowy egrets, great blue herons, brown & white pelicans, caspian terns, cooper’s hawks, red tailed hawks, hummingbirds, grebes, crows, ravens, canadian geese, and all manner of gulls, ducks, and song birds.  Some of these like pelicans, egrets, and night herons weren’t seen here 30 years ago — they’ve come back from the brink after DDT did in their numbers.

You might also find things like the white line sphinx moth, the hummingbird moth, pseudoscorpions, a species of sand hopper crustacean that only lives in a small stretch of sand in Lake Merritt and in Chile.

There’s raccoons, squirrels (brought in by homesick easterners), skunks, and feral cats. There has also been and an otter which showed up one day in 2013.

In the water (which at its deepest is 10′) holds smelt, herring, moon jellies, bat rays, and leopard sharks. Come at the right time and you’ll find brown pelicans patrolling the shores diving, or at other times white pelicans floating scooping wide swathes of water. You can watch cormorants, coots, and eared grebes swimming through the water chasing small fish with astonishing agility.

There are also our invertebrates like spaghetti worms, crabs, snails, zooplankton, tintinnids, and phytoplankton. Much of the plants around the lake have been cultivated and planted there, but in the water there grows widgeon grass (which periodically gets mowed), and pickleweed still appears around the lake (both planted and volunteered). The oak trees that are on the north side of the lake would have been there, though those too were cultivated — by the Ohlone. The Ohlone also made use of the California buckeye fruit  as a fish poison (interestingly it is also toxic to European honey bees).

There’s also plenty of fungus — death’s caps, honey mushrooms, jack o’lanterns, and lattice stinkhorns can be found in the wetter parts of the year.

There’s slime algae & diatoms, sea lettuce. Bacteria mostly harmless, but occasionally the birds are still affected by avian botulism causing limp ducks. There hasn’t been an outbreak since 1971 — perhaps because of improved tidal flushing that has been managed over the years since.

Archaea are also found in Lake Merritt once thought only to be found in extreme environments — they are also common in mudflats where there is low oxygen. They help produce the methane which is responsible for some of what you might smell near Lake Merritt.

With all these things – all these representatives of all our kingdoms of flora and fauna – Lake Merritt is a fun place to visit and look for things.

We hope that we can see even more improvements to the environment over the years — the estuary though is a popular destination for all sorts of activities. Keeping it nice and making it better is not just the responsibility of our government, but you and me. The Lake Merritt Institute (http://www.lakemerrittinstitute.org) has long been helping to make it a cleaner and better place, but there is always plenty of trash to pick up, and they have self cleaning stations around the lake. You can also explore the wild side of Oakland at the Rotary Nature Center and with Constance’s organization Wild Oakland (http://wildoakland.org).

How Earthquakes Are Measured
Guest Speaker: Julian Lozos
7:30pm, Thursday, July 17th, 2014
FREE at the Randall Museum, 199 Museum Way, San Francisco, CA 

Let’s say you feel an earthquake of moderate size. Once the shaking stops, you think, “Wow, was that the big one far off or a small one close by? How big was it?” The answer isn’t simply one number. Magnitude is certainly one way to describe an earthquake, but what is magnitude? What goes into that measurement? It’s also far from the only thing that scientists measure when a quake hits. And while we’re asking, how were quakes measured in the past?

Using a scenario Bay Area earthquake as a starting point, seismologist Julian Lozos will describe what measurements happen during, immediately after, and a little while after a big quake. There are also ongoing measurements that help make sense of past earthquakes and possible future ones.

Julian Lozos, a postdoctoral researcher with the US Geographic Survey and Stanford University, will present material for a general audience and answer your questions. Julian’s research is focused on using computer models to help understand the physics of earthquakes; he is particularly interested in understanding earthquakes that involve more than one fault. There are many faults in the Bay Area which tend to interact. Bring your friends and your questions.

Creeks to Sewers

Joel Pomerantz and Greg Braswell came out to talk to us May 15th about creeks and sewers. One particular creek in fact, Precita Creek, and how this creek was developed to the sewers that are there today.

Joel walked us through the natural flow of this creek and early history. The name Precita comes from a Spanish word meaning dam or weir. Native Americans would use weirs which were funnels with a basket in the middle into which they would drive the fish. The creek flows down from under where Market Street is today (from the Mission Mountains according to early maps), down along the north side of Bernal Heights and through the gap between Bernal and Potrero into Islais Creek. The creek has left it’s traces in odd little bends in streets (Joel was hoping to have Burrito Justice join us, but alas!).

The creek ended in the wetlands that pushed up through this gap, and the water joined Islais creek. For early San Franciscans this swampy area ended up in the late 1800s a perfect dumping ground for fill, effluents from tanneries and soap factories, and their sewers. The word fetid probably does not do it justice.

The first master sewer plan was in 1875, and many more have since followed. Before that there was a lot of add hoc sewers that did not really go anywhere (This talk almost cured me of my nostalgia for seeing San Francisco back in the day!). The first houses in this area were built in the 1860s and some had wooden sewers bringing waste down the hill.

The 1875 Humphrey plan had to get the state legislature to redraw streets for the plan to go forward. And it wasn’t til 1881 that a sewer was complete under (now) Cesar Chavez. The brick arch of this sewer was 11.5′ wide and 8′ tall. It’s had work done it since, but it is in essence still in use today.

The sewers extended out into the Marsh becoming the bones in a sense of later fill. The earthquake and fire of 1906 provided a lot of that fill.

The city didn’t see its first treatment plants to around the ’30s. Plants in Golden Gate Park and Fort Point. The SW treatment plant wasn’t built until the 40s. The city treats both sewer and storm water in one system — and for good reason — the water that falls onto San Francisco takes with it a lot of nasty crap, which we wouldn’t want pouring back into the oceans.

One could sense that Greg could tell amazing stories about just about any piece of our sewer system. Whether its current state, or how it came to be the way it is today.

 

Streams to Sewers - SF’s Natural and Un-natural Drainage
Guest Speaker: Greg Braswell
7:30pm, Thursday, May 15th, 2014
FREE at the Randall Museum, 199 Museum Way, San Francisco, CA 

How did the old Precita Creek become the complex sewer crossing which now goes under Highway 101? When, where and why did Mission Creek go into the sewer? What are the ramifications of our sewer history and the ancient creeks they sometimes follow for today’s urban outflow systems? Greg Braswell will lead a pictorial exploration and discussion of his research on the muck and brick of San Francisco’s sewer history.

Water coming in from land on ocean beach

Most of us know Yerba Buena Island (aka YBI), if we know it at all, is from tunnel we drive through to get from one end of the Bay Bridge to the other. We may have even gone to Treasure Island, but Yerba Buena is a bit of a forbidding mystery — it’s current owners do not encourage visitors. Ruth Gravanis joined us April 17th, 2014 to uncover some of that mystery.

Two thirds of the island is still mostly owned by the Navy — although not for long, the intent is for them to hand the island over to the city. The other third is owned by the Coast Guard whose station will remain after the Navy is done for good.  Soon this island, will be a proper part of the city, and connected to the easy bay by a pedestrian & bike bridge, with new development slated for both it and treasure island. There is much to know and discover about this place.

~10,000 years ago, it wasn’t an island at all, but a hill in the broad valley that was soon to be the bay. The story of who lived there before the Spanish is still uncertain, but the Island seems to have been used by two different people’s of differing statures and burial practices. The island was used as a fishing camp and a place for gathering acorns. An extensive archeological survey was done, but details have been kept private.

The first westerner to name the island was Juan de Ayala in 1775, who called it La Isla de los Alcatraces (Island of the Pelicans — there is some controversy as to whether he called it this, or the map was transcribed correctly). For whatever reason, it was an English Captain, Frederick Beechy, who called named Alcatraz Alcatraz. He named Yerba Buena after the herb that grew all over the island at the time (the plant no longer grows there naturally).

The name didn’t entirely stick, it has been referred to as Sea Bird Island, Wood Island, and Goat Island. When the island became an official part of San Francisco in 1850, Goat Island was the official name. Goats had been exiled to island after they wrought havoc on the mainland. It was the petition by the Native Daughters of the the Golden West that brought the name Yerba Buena back to the island.

The Island was quarried in the 1860s and the stone was used extensively in Oakland and San Francisco buildings. The Army had a base on the island in the 1860s-1880s as well, but nothing remains on the island of this period. However, two buildings were moved to Angel Island. A lighthouse was built in 1875. Many of the trees seen on the island today are a result of an Arbor Day in 1887 where schoolchildren were brought by ferry to plant trees… a project of Sutro, General Vallejo, and Joachin Miller.

The Army handed over their base to the Navy in 1898 and officers mansions began to be built. Admiral Nimtz was the one of the last Naval officers in residents.  Aside from the mansions, the bridge, and treasure island, all sorts of things got built: administrative buildings, a 1 room schoolhouse, a mine factory, a tower for tracking ship movements.1973 the Coast Guard took up their third of the island. The Navy ceased operations on the island in 1997.

But the cultural/historical side of the island is no the only thing — it has a rich natural history as well. A rare plant study commissioned by the Navy found significant remnants of the original habitats, oak woodlands, dune habitat, tide pools, riparian scrub. A rich mix of native plants, insects, fungus, marine mammals, and birds.

There are many threats to these pockets, invasives like ice plant, eucalyptus (thanks to the Arbor Day in 1887). Eucalyptus isn’t completely without merit, it does provide roosting sites for falcons, and potential for bats, but they need light and space around them to let other things in (here in the Bay Area, not in Australia, very little grows under eucalyptus except invasive ivies).

The next question of course, is when the bike path comes in, and when the Navy has handed over the Island, what comes next. It is likely to become more of a recreation destination, more people will be living on it, and on treasure island, and we have to make sure we do not love it to death. A habitat and sustainability plan is already part of the development agreement, but there are still many things that have yet to be decided — how and where the bike path comes in being a big one.

You can follow the ongoing project at http://sftreasureisland.org

To learn more about the natural side of the island, check out this video from ShengChun Li, and the Treasure Island Museum

 

David Liittschwager’s idea of one cubic foot partly started with the idea of having a manageable sample size (the talk was given March 20th, 2014). It is not an uncommon practice to find a limit around observations. So looking at a one cubic foot volume for visible species collecting at different times to find representatives of one day’s time. The size also reflects a common collecting practice of using 5 gallon buckets for collecting, and it is a similar volume.

But in has not turned out to be very limiting. The “dirty secret” for David is that he’s never really finished cataloging within those limitations. The biodiversity that can be found is amazing if we take the time to look. Even a pile of leaf litter in new york city turned up 100 species.

The spots to which he went were chosen by the likes of E.O. Wilson for the biodiversity they know is present. And the most spectacular of these locations have been tropical reefs. He flipped through amazing photo after photo of creatures collected from this little space and carefully sorted out to be identified and photographed.

All those creatures aren’t there all the time of course, but things move and water flows over the reef and through the open skeleton of one cubic foot. Collecting at different times of day and night then going through the process of sorting and identifying and photographing. It took about a month to come up with a representative sample of 24 hours. 

David looked up with some chagrin at a leafy acquatic plant, and said they should have spent time looking through the leaves, they would have found a ton more.

More recently he was out just at the mouth of the San Francisco Bay 100 yards west of the GGB, 100 yards south of the north tower, seeing what pass through a cubic foot of water as the tide moved in out, pulling in with a 300 micron net: mites, water fleas, tons of cephalopods, algae, crab and fish larvae, skeleton shrimp. With an 80 micron net they pulled in the glistening forms of diatoms. On a back of the napkin calculation, in a normal 24 hour period of spring tide, nearly a quarter million linear feet of water would pass through that cube — and maybe  2.6 billion creatures would flow through that space. 

David’s work in these small spaces shows us a different magnitude of beauty and grandeur, life, diversity, and abundance at scale we would not expect. Another lesson in all that we do not know about the planet we inhabit.

Find out more about David Liittschwager’s work at liittschwager.com.

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