Interview anyone of any stripe about the Giant Marsh living shorelines project and the same two words will be in every other sentence: high tide.
construction step of this California Coastal Conservancy-led effort to build
new native oyster reefs interspersed with eelgrass off the Contra Costa County
shore must consider the timing of tides. High enough to float a barge or Boston
whaler into the shallows, do a day’s work, and get back out again on the next
cycle. Three feet at least of draft – the amount of boat below the surface
which varies depending on its weight — and preferably not in the middle of the
On April 18, as the contractor Triton Marine placed 180 1000-pound reef
balls topped with clean Pacific oyster shell in the shallows off Point Pinole
Regional Shoreline, the day time high tide occurred at 12:44 pm, and lasted longer than in other seasons.
That’s up to five feet above mean lower low water (MLLW), a mouthful of metric
related to the high- low tidal cycle caused by the pull of the moon on the
ocean and familiar to most people designing, building, or permitting projects
within San Francisco Bay.
we didn’t expect was for Triton to want to rest the barge on the mudflat at low
tide,” says Renee Spenst of Ducks Unlimited, which managed construction. Despite
initial worries about damage to the bayfloor, regulators concluded the
footprint was small and the local organisms in the oozes would rebound – a
decision that helped optimize work periods for Triton, avoided night work which
would bug the birds, and eliminated the need to explore alternatives such as heavy-lifting
work is not for the weary,” says the Conservancy’s Marilyn Latta, who led the
three-year, 19-partner effort to birth this new living shoreline. The $3
million project is designed to test the ecological and shoreline protection benefits
of nature-based infrastructure in San Francisco Bay, and was partially paid for
with Cosco Busan oil spill settlement
Scaling up from the Marin Test Run
Latta and a team of scientists from the SFSU’s Estuary & Ocean Science
Center (EOS), the Smithsonian Environmental Research Center, UC Davis and others
built a pilot oyster reef on the San Rafael shore in 2012, four million native
Olympia oysters settled on the new structures. The Marin pilot tested a variety
of reef structure types and planting methods for associated eelgrass, and
measured the response of wildlife. The results of these tests are informing the
scale up at Giant Marsh project on the East Bay shore.
impetus for all this experimentation is to beef up biodiversity. “Oysters and
eelgrass are what we call foundation species,” says Katharyn Boyer, lead
scientist for the San Rafael and Giant Marsh Living Shoreline projects, and a
ecologist with the EOS Center. “This means they provide habitat and functions
that benefit other species.”
There’s much more to the Giant Marsh
project than expanding habitats for a mollusk and a seagrass, however. A map of
the design shows a mosaic of plantings, oyster reef structures, and experiments
extending from Bay shallows all the way to the edge of the uplands, and
encompassing the tidal marshes in between. Seven habitat treatments with a
footprint of about two acres are scattered across this shore zone habitat
gradient over an area totaling 350 acres. In one spot, biologists are
reintroducing the locally extinct California sea-blite — a salt tolerant succulent.
In another spot, they will collect cobbles to which Pacific rockweed has attached
itself and place them around some of the new reefs to add shelter and shade for
the oysters. In still another, they will remove invasive Atlantic cordgrass and
hybrids, and replant with the native species, then monitor the site to make
sure the invader doesn’t make a comeback.
“We’re integrating eelgrass and native
oyster restoration with wetland and upland transition zone restoration treatments
at one location in the Bay for the first time,” says Latta.
“It’s easy to focus on a single
species but to step back and consider the ecology of whole system – and how
your target species might benefit as well – is an exciting way to think about
doing restoration,” says Chela Zabin, a biologist with the Smithsonian
Environmental Research Center also on the Giant Marsh team. “It makes sense,
it’s more holistic.”
The team hopes to recreate or enhance
the historic function of each kind of plant, habitat, and species in the shore
zone. It also hopes to confront sea level rise head on in the habitats of
thousands of people and the last few California Ridgway’s rails and salt marsh
harvest mice. Nature-based infrastructure may be able o help us all adapt in
ways seawalls cannot.
project is a great opportunity to understand what’s possible,” says Matt Graul
of the East Bay Regional Park District, which shares ownership of the property
dedicated to this big experiment with the State Lands Commission.
The World is Your Oyster
help chose the best place to grow a new oyster reef, one of Chela Zabin’s jobs
was to strap ceramic tiles, like those around your average kitchen sink, to
three PVC poles and push them into the Bay mud. She installed the tiles at two
different tide heights at seven sites in the waters off four Bay Area counties
Zabin is an artist turned Smithsonian center biologist. She wanted to see if there were enough native Olympia oyster larvae in each of the test sites to settle on the tiles and grow, among other experiments being performed by the living shorelines team at these test plots. Of the seven sites tested, Giant Marsh attracted the biggest crowd.
ceramic tile tests were part of a comprehensive body of research on how to
restore subtidal habitats and organisms in the Bay that has been underway for
more than a decade. “Fourteen years ago we were doing small scale trials,
everything from Save the Bay hanging oyster shell necklaces off piers to see if
they attracted more oysters to our teams experimenting with planting methods
for eelgrass,” says scientist Katharyn Boyer. “While we learned quite a bit
about how to restore these species for their own sake, the big evolution in our
thinking is to do restoration for all the possible ecosystem services provided
by their habitats.”
the hard substrate we surveyed there, everything from our tiles to a [deflated]
football, had oysters on it,” says Zabin. The Richmond shore surveys also
failed to detect any of the Atlantic snails that drill into oyster shells. This
invader arrived in the Bay over a hundred years ago with eastern oysters grown
for food but now preys on the natives. “The snails don’t move much, and there
are no new ones coming in, a combo that’s easy to work around [when you’re
looking for a good spot to build a new oyster reef],” she says.
Giant Marsh project has a much bigger footprint than the San Rafael pilot. Every
piece of the new eastshore project is based on lessons learned and research
questions raised by its predecessor on the Marin shore. On the west side, for example, they learned that
some reef designs held up better than others, and that eelgrass did better on
the shoreside rather than the bayside of reefs.
number of patterns also emerged that caught Zabin’s eye. “We saw more oysters
lower down, more oysters on north sides, more oysters on horizontal than vertical
surfaces. Taken all together, we’re thinking this is a signal that heat stress
Which is one reason why this will be the first living shorelines project to try to incorporate rockweed, one of the brown macro-alga, or seaweeds, that naturally drape over rocky intertidal zones around San Francisco Bay.
doesn’t mind getting dried out to a crisp, so it could help oysters with heat,”
says Zabin. Canopy forming seaweeds provide shade, structure, and moisture
retention during low tides. In places where there’s rockweed, oysters can live
higher into the intertidal zone, according to Zabin, an observation she wants
to test at Giant Marsh.
rockweed really helps oysters survive better when the tide’s out, it could be
really important with climate change, as oysters are exposed to higher and
higher temperatures and risk of desiccation,” says Zabin.
More than a Mere Meadow or Reef
about which way the wind blows off the Point Pinole shore, Michelle Orr takes a
moment to consider. As an engineer for ESA (Environmental Science Associates)
she’s designed dozens of marshes, floodplains, and habitat restoration projects
along the West Coast and on inland waterways, but working in a subtidal
environment is a new experience.
were looking for a site in terms of testing natural infrastructure that had
some wind causing natural shoreline erosion, but not such strong winds or big
waves that reef elements wouldn’t help. We wanted our structures to be
effective,” says Orr, adding, like any engineer worth their salt, the answer to
the original technical question. Apparently, the predominant winds at Point Pinole
are from the southwest, with occasional strong winds from the northwest. These
are the winds that generate the largest waves.
data from the San Rafael pilot site had shown that the reefs reduced wave energy
up to 30 percent. Historic research at
Point Pinole had also documented the erosion and retreat of the shore by up to
500 feet between 1855 and 1993.
In addition to wave energy, Orr and the living shorelines design team also had to think about shape and softness of the Bay floor, the swirl of sediment around any new structures, and the design, arrangement and size of the oyster reef elements. The team designed the reefs at different angles, densities, and distances from the shore to make the most of this living experiment (see map).
longer the reef, the less waves can bend around it,” says Orr. “It can’t just
be solid, you have to have ecological connectivity on both sides of the wall.
That’s why we designed it in a checkerboard pattern.”
and the Giant Marsh team settled on three reefs situated 500-1,500 feet from
the shore. The reef treatment farthest offshore is designed to achieve maximum
ecological benefits for deeper water organisms, fish and fowl. The treatment nearest
to shore offers a combination of ecological, wave attenuation, and shoreline
erosion prevention benefits that amount to the kind of ‘natural infrastructure’
we may need in the future as the Bay rises. The treatment in the middle is a
an engineering perspective, we spent the most time on the nearshore treatment,”
says Orr. While Zabin’s tile surveys suggested the highest oyster densities
occurred at MLLW, Orr knew she couldn’t create the reef at that level because
it would be too far from shore to slow waves: “We tested the design closer and
closer to shore, and higher and higher in the tidal range, and found there was
a sweet spot at 1.5 feet above mean lower low water. It was a bit of trade off,
fewer oysters but better wave attenuation. As sea levels rise, however, the
nearshore reefs will get deeper and be covered by tides more often, so they
will support more oysters into the future, which gave us some comfort.”
Mining the Best Materials
Marilyn Latta has started to stockpile clean oyster half shell. Since the most accessible local source of supply – the Drakes Bay Oyster Company – recently closed, she’s keeping a few tons from the company stored in Nicasio near to the old oyster farm for future living shorelines projects.
was the only local entity with a shucking facility that separated the meats for
sale separately, giving us half shell we could use,” says Latta. “If we place shell
in the Bay it has to be free of disease and invasives, and the Drakes Bay
company by-product was cured for two years in the sun to confirm it was clean.”
is just one natural ingredient in the recipe developed for what Latta calls
“baycrete,” the material from which the team creates reef balls and blocks. Baycrete
is a mixture of sand and fossilized oyster shell mined from the Bay and
layered up, shell has lots of nooks and crannies that provide plenty of
attachment space, shade and moisture,” says scientist Chela Zabin.
At the San Rafael site, Latta and the living shorelines team tested a variety of building block shapes and materials mixtures for the reefs. “We had a layer cake and reef ball stack that didn’t hold up well physically, and the shell bags [eventually] accumulated so much sediment around the bottom it smothered the oysters,” she says. “At Giant Marsh we’re trying a combined design – a truncated reefball with shellbags on top so we use the shells where they are most valuable for oysters.”
of the big challenges for scaling up was making large volume of building blocks,”
says Orr. In the end, local labor from CiviCorps
and the North Bay Conservation Corps built the blocks over three months in the
summer of 2018, guided by a Florida oyster reef expert and with the help of a
Latta is already thinking ahead about where to get more shells for living shorelines projects, and hopes to launch a shell recycling program with Bay Area restaurants (see upcoming article by ESTUARY reporter Nate Seltenrich in Bay Nature magazine).
Fill with Frills
no surprise to anyone familiar with the Bay regulatory environment that this project
– in all its multi-species, multi-habitat complexity — took time to get
approved. Three years passed between inception and implementation, and two of
those years involved permits.
have been oyster reef ball projects permitted and installed before, but never
on this scale in California or the West Coast,” says US Army Corps of Engineers
project manager Myla Ablog. “The process took longer. In addition, 2017-2018
was the year we had so much rainfall and so many fires we had more emergency
permits to approve than in all years prior. It was also the year of the federal
shutdown. So the oyster reefs came in two seasons behind on the installation.”
Initially, project leaders hoped Giant Marsh might be approved under the forward thinking nationwide permit for living shorelines the Corps released in 2017. If you can fit a project under a nationwide – which usually covers projects in the public interest — authorizations typically come faster. But for the subtidal work, permit conditions geared towards the East Coast and the Gulf Coast didn’t fit Bay conditions.
setback came when the construction company hired to do the job – Triton Marine
–finally worked out the details of how they would do it, which didn’t quite match
up with original permit conditions. Instead of working only during high tides, which
limits the work window, they asked if they could rest their barges on the bayfloor
at low tide. “It sounds daunting to an applicant when you say we may need to ‘reinitiate,’”
says Ablog, referring to having to go back to fish and wildlife agencies for
have these beautiful wide mudflats that feed all the shorebirds around the Bay
but create difficulties in terms of constructing new habitats in subtidal or
tidal areas,” says the Bay Conservation and Development Commission’s Brenda
Goeden. For the Hamilton tidal restoration project near Novato, she remembers,
they had to run five miles of pipeline over the mudflats to move marsh-building
material in the form of mud to the site – an expensive early experiment. “It’s
really challenging to get barges into such shallow water. When Triton asked if
they could just sit on the mudflat, we had to ask for how long, and what the
square footage of the footprint would be?”
unexpected twist in the approvals process was the discovery of a number of seasonal
hunting blinds right where the project was planned.
ended up relocating everything further north, which was a little hard because
the bathymetry changed,” says Orr. “But we didn’t want boats running into our
reefs or hunters shooting near our restoration sites.”
course the project had one big factor going for it – it aimed to make habitats
for fish and wildlife better not worse.According
to Ablog, “Projects that benefit the environment, or get done under the
nationwides, rarely get a lot of press. [Everyone thinks] the federal
government is slow and rejects everything, so applicants come in with knees knocking,
afraid they’re not going to get a permit. But 95 percent of all applications do
get permitted across the US. In California, our division permits billions of
dollars worth of public, private and NGO projects every year.”
Giant Step into the Future
Katharyn Boyer, wading into the Bay in a wetsuit, has been on the cover of this
magazine and the book Natural History of
San Francisco Bay, among many other action shots. Her work – restoring
eelgrass and studying other Bay habitats – regularly takes her into the
shallows – sometimes upright on foot, sometimes belly-down on a surfboard
pushing her way across the wet mud by hand, sometimes half slogging and half
swimming. These are not easy places to get to.
labors mirror the kind of tenacity, grit and ingenuity required to undo some of
the damage we’ve done to our shoreline ecosystems and estuarine environment in
the process of growing the metropolitan Bay Area. They also reflect the
opportunity smart people like Boyer, Latta, Zabin, and Orr –not to mention the
19 project partners — see in working with nature, not against it, to achieve
mutual benefits. And finally their Giant Marsh project embraces the kind of big
picture, silo-busting thinking we now need in spades to play bridge with
doing projects like this throughout the park district, we’re really committed
to restoring these habitats,” says East Bay Park’s Matt Graul, which recently
completed restoration of the nearby Dotson Family Marsh, for example. “The
science says we don’t have much time, things are changing fast, so we need to
and Dotson marshes sit on a county shore that’s getting lots of attention in
terms of innovative, forward thinking improvements. At nearby Point Molate, the
Coastal Conservancy recently removed derelict creosote-coated piers and the Red
Rocks warehouse (hauling away 445 tons of debris). At Point San Pablo, an
earlier 2016-2018 Conservancy project has already placed 200 oyster reef
elements and planted four acres of eelgrass in the area. At another site,
Chevron has worked with Baykeeper and the City of Pinole to open Point Molate
Beach Park. All these projects also dovetail with the North Richmond Shoreline
Community Vision that not only recommends implementation of the Giant Marsh
project but also addresses local concerns about affordable housing and
The Giant Marsh project also nests nicely within recommendations
of a new Adaptation Atlas co-published by the San Francisco Estuary Institute
and SPUR. The atlas aims to help planners better understand existing habitats
and science based goals for restoration in their watersheds that might help
them adapt to climate change. It also describes in more detail 30 specific
“operational landscape units” or OLUs, as a basis for adaptive decision-making
including the Wildcat OLU where Giant Marsh is located (see map).
“This is the only OLU in the Bay where all the adaptation measures
that we mapped are suitable,” says one of the atlas authors, SFEI’s Julie
Beagle. “Its a great example of a project that is piloting and monitoring many
living shoreline approaches, which have great potential to be used elsewhere.”
This potential was first recognized in the 2010 Subtidal Habitat Goals report, which in turn built on the potential realized in hundreds of acres of restored wetlands by the 1999 Baylands Goals report. Giant Marsh is the fifth and largest pilot living shorelines project to be built since 2010. “It’s good to see they are helping to meet subtidal goals set ten years ago,” says BCDC’s Brenda Goeden, one of a variety of agencies involved in the goal setting (SCC, BCDC, OPC, SFEP, and NOAA).
In the meantime, the team and the construction crew hopes to
complete the oyster, eelgrass, and rockweed elements of the Giant Marsh project
by July 2019. But even that won’t be the
end of it. The project includes additional cordgrass and transitions zone
plantings, and a comprehensive monitoring plan that will measure everything
from plant survival rates to wave energy deflection to biological response.
even trying to measure the degree to which these restoration projects sequester
carbon and reduce acidification,” says Boyer, referring to planned tests of
carbon levels in live and dead plant material above and below the soil. Low pH
(high acid) waters hamper the ability of oysters to make shells. But eelgrass, through
photosynthesis, can draw carbon from the water and raise pH. “The question we
hope to answer is ‘Can we use restoration of eelgrass to promote that process?
Can we actually measure a lasting effect locally?” says Boyer.
‘We’re encouraged to see
experimentation with alternative methods moving forward,” say Goeden.
are going to see sea level rise effects magnify. We need to know what tools are
in our toolbox sooner rather than later,” says Boyer.
Ariel Rubissow Okamoto is both today’s editor-in-chief and the founding editor of ESTUARY magazine (1992-2001). She enjoys writing in-depth, silo-crossing stories about water, restoration, and science. She’s a co-author of a Natural History of San Francisco Bay (UC Press 2011), frequent contributor of climate change stories to Bay Nature magazine, and occasional essayist for publications like the San Francisco Chronicle. In other lives, she has been a vintner, soccer mom, and waitress. She lives in San Francisco close to the Bay with her architect husband Paul Okamoto.