The science of wetlands and wastewater


At Oro Loma Sanitary District, Save The Bay is playing an active role in a restoration project that could provide a blueprint for climate change adaptation around the bay. Though it has a simple appearance, the horizontal levee is actually a complex system that can protect traditional levees from storm surges, provide habitat for vulnerable Bay Area flora and fauna, and reclaim the water that flows out of wastewater treatment plants. Traditionally, this nitrogen containing water would be pumped into the middle of the Bay and forgotten about, but the increased presence of algae in the Bay serves as a helpful reminder that we are failing to protect our ecological neighbors.

Rethinking wastewater

Certain chemicals that come out of our wastewater treatment plants can cause algal blooms at high enough concentrations, but we shouldn’t necessarily regard them as “contaminants.” These chemicals, various forms of nitrogen and phosphorus that are given the label “nutrients”, are the same ones that we use to fertilize our plants and crops. In the wrong place, they can throw off the ecological balance (read: algal blooms). However, if we divert these chemicals to terrestrial plant roots and microorganisms in the subsurface, we can provide plants with nutrients that are needed for growth while preventing those chemicals from making their way into aquatic environments where they can be troublesome. This process can kill two birds with one stone (metaphorically of course, as the levee provides important habitat for birds!)

This is the root of my interest in the restored habitat at Oro Loma. As a part of my research at UC Berkeley, I will monitor the horizontal levee to track chemicals in wastewater as they enter and leave the restored habitat. This is a large-scale experiment, testing to see if a restored habitat can thrive on the outflow from a wastewater treatment plant, as well as whether or not the habitat reduces the concentration of potentially dangerous chemicals that flow through it. By measuring the levels of these chemicals in the water, soil, and plants that the slope is made of, we will be able to understand better the chemical transformations that occur in the horizontal levee, many of which are performed by microorganisms.

Filtering chemicals

But I don’t plan to focus on only nitrogen and phosphorus. Many other chemicals that we put in or on our bodies, such as pharmaceuticals, antimicrobials, food additives and chemicals in personal care products, are collected in wastewater and pass through treatment plants largely unaffected. These chemicals form a group of chemicals known as “trace organic contaminants” many of which may pose threats to living things. The hope is that they will get filtered out of water that flows through the horizontal levee. If everything goes as planned, the slope should act as a sponge, absorbing the chemicals into “sticky” components of the slope, such as dead leaves, roots, and residues from microorganisms. Once absorbed, it is possible that microorganisms will naturally break these chemicals down into less harmful byproducts. Depending on the chemical, this process could be very effective or may do little to help, but these processes are not fully understood and require further study.

This is a fairly new concept and we can’t be certain of how effective it will be, but that is why we are testing it. Before we line the Bay with horizontal levees, we need to make sure we understand how they work. This is a promising new way to pair enhanced wastewater treatment with habitat restoration, and I am thrilled by the role I get to play in studying it!

– Aidan Cecchetti

IMG_1988_cAidan Cecchetti is a graduate student at UC Berkeley where he is working on his PhD in Environmental Engineering. Originally from northeastern United States, Aidan grew up wandering the forests of New Hampshire. After finishing his undergraduate degree at the University of New Hampshire in 2013, Aidan made his way to the Bay Area for graduate school and has been here ever since. In his free time, Aidan enjoys exploring the pockets of nature around the Bay Area, entertaining his cat or playing piano.


Planting begins at Oro Loma

Oro Loma
Volunteers planted 3,200 native seedlings at the Oro Loma Horizontal Levee Project. Save The Bay will plant 70,000 seedlings at this site over the coming months.

Last weekend, over fifty volunteers gathered at the Oro Loma Sanitary District treatment plant in San Lorenzo to kick off an ambitious burst of planting activity in a soon-to-be restored wetland.  Participants included a contingent of local college students, parents and their teenage children, and a few veteran helpers.  Equipped with trowels and picks, attendees placed 3,200 plants into a plot of soil next to the sewage treatment plant.

Though the plants were all put in the ground in about an hour, an enormous amount of planning went into how they were selected and configured.  Save The Bay’s habitat restoration team has been working for over a year to cultivate several palettes of wetland plants that will be planted next to each other.  They will become part of a scientific experiment exploring what combination of plants and soils can best filter excess nutrients from the treated wastewater that will be pumped in from the adjacent sewage plant.

A new kind of levee

This is exciting, because if this pilot project is successful, it could be replicated elsewhere as a means of naturally improving water quality, providing needed habitat for sensitive species, and forming a more durable barrier to flooding from storms and sea level rise.  This horizontal levee is an alternative to steep earthen or rock walls that traditionally separate the Bay from vulnerable land — this marsh will gently slope upwards, enabling it to better adapt to rising tides.

After the planting was completed, participants joined the public open house being hosted by the Oro Loma Sanitary District.  Horizontal levee project scientists and treatment plant workers were on hand to give tours, and Save The Bay staff answered questions about their work.  Also present were local elected officials, representatives of the Castro Valley Sanitary District, which co-owns the treatment plant, as well as UC Berkeley researchers who will analyze the filtering capacity of the wetland once it is operational.

Over the next two months, our goal is to put in 70,000 plants at this site.  If this project sounds interesting and you’d like to pitch in, you’re in luck!  Save The Bay will be hosting 3 more volunteer planting workdays at Oro Loma, on November 21, December 5, and December 12.  Click here to volunteer!

Meet science teacher Jeff Sandler

Students at Creekside
Jeff Sandler’s class out on a SEED program with Save The Bay at Creekside Marsh in Marin.

Meet Jeff Sandler from Fairfax, a science teacher in Berkeley who brought his 7th grade class out to the shoreline to participate in Save The Bay’s SEED program.  SEED — Students Engaging in Ecological Design — engages middle and high school students in the full restoration cycle.

How did you get involved with Save The Bay?

Years ago, I took my high school classes out on the Bay with the Canoes in Sloughs program.  For the last three years, my middle school classes have been participating in the SEED program – where we help restore wetlands around the Bay.  A great service learning opportunity!

Do you have a favorite site or experience?

I guess my favorite site is the Native Plant Nursery at the MLK Shoreline. Having the students’ work there – doing everything from re-potting seedlings to cleaning out old planting tubes and flats – gives them a great sense of accomplishment as they can literally do 100’s of these in a few hours.  The students also get to “close the loop” on the whole restoration cycle. Working there shows us where the small plants in the tubes that we use for wetland restoration come from!

What other activities or hobbies do you enjoy?

Fishing, mountain biking, trail running, cooking

What is your first/fondest memory of San Francisco Bay?

Bringing my own children to the shore of the Bay to fish.  Now that they are grown up, they still enjoy fishing and I’d like to think that their great patience and appreciation of the natural world is the result of all of those hours spent on the Bay.

To learn more about our SEED program and see our resources for teachers on our website.

Thanks to Jeff and all the students who came out to learn about the complete cycle of tidal marsh restoration, from seeds to ecosystems!


Tide Rushes in at Sears Point: A Great Example of what Measure AA Can Do

The Sonoma Land Trust captured this dramatic video of the Sears Point levee breach.
More than a decade of planning, permitting, and restoration work culminated on October 25 with the breaching of a levee that had separated San Francisco Bay from a newly restored marshland at Sears Point, located near San Pablo Bay in Sonoma County.  For the first time in over 120 years, tidal flow is now occurring between the Bay and the 960 acre site, which was historically a wetland but had been diked, drained, and used for farming for decades.

The successful restoration at Sears Point illustrates the many benefits of regional Measure AA, which will fund similar crucial projects around the Bay Area.

The new marshland will filter excess nutrients from runoff and prevent them from reaching the Bay.  It will be a carbon sink, sequestering carbon dioxide from the atmosphere.  It will serve as habitat for species like the endangered Ridgway’s rail and salt marsh harvest mouse.  And it will serve as a natural bulwark against flooding caused by future storms and sea level rise.

Previously, the Sears Point Ranch property was proposed to be developed into a casino owned by the local Federated Indians of Graton Rancheria.  However, the Graton Tribe ultimately dropped its purchasing rights for the site in 2003.  The Sonoma Land Trust, which preserves environmentally significant land in Sonoma County, bought the property in 2005 and began working with several funders and stakeholders to restore the ecosystem to its natural state.

The wetland restoration project broke ground in June 2014.  Agricultural hayfields were replaced with a grid of specially designed dirt mounds.  The mounds will help slow the speed of incoming water, causing the sediment contained in the water to drop out and settle into the marshland, where it can help anchor ongoing plant growth.  Additionally, a new levee was constructed to protect adjacent property and infrastructure.  The levee will double as new habitat for species that inhabit the ecological transition zone between the tidal marsh and the upland.

On October 25, hundreds of spectators came to observe the removal of the levee separating the Bay from the future wetland.  Within moments of an excavator crane scooping away the earthen barrier, water began pouring down into the site, to sustained cheers and applause from the gathered crowd.  Attendees were given small pods containing pickleweed seeds in order to participate in the re-seeding of the marshland.  I had the pleasure of witnessing the breach, along with Save The Bay’s habitat restoration director, Donna Ball, and our communications director, Cyril Manning.

The project also demonstrates the value of governmental and non-governmental entities working together towards a common environmental goal.  The Sonoma Land Trust partnered with the US Fish and Wildlife Service, California Department of Fish and Game, and Ducks Unlimited, among others, in funding and planning this $18 million restoration effort.

The work at Sears Point Ranch is by no means complete.  In the coming years, more investments will be made to improve the newly constructed levee, enhance public access, and fully reestablish tidal action and hydrology at the site. However, it is already contributing to a region-wide movement to reverse the damage caused over the past 150 years by wetland degradation and destruction.

According to scientists, the Bay needs to see accelerated action on more projects like Sears Point in next few decades. You can help ensure that the 36,000 acres of baylands awaiting restoration are given the funding they deserve by voting YES on Measure AA this June 7th.

Report: The Baylands and Climate Change


The Baylands and Climate Change: What We Can Do, The Baylands Ecosystem Habitat Goals Science Update was released earlier this week.   More than 200 scientists and climate change experts have worked over the last three years to update the 1999 Baylands Goals Report to address the threat of climate change.   This Science Update addresses threats facing the Bay including rising seas, extreme weather events, the effects of climate change on urban functions, and decreased sediment supply.

Not just another report  

This report highlights the urgency and the boldness with which we must act to save over 80% of our existing wetlands over the next 100 years during this period of rapid change.  Sea levels are rising; weather patterns are shifting, and the sediment supply that has helped nourish our wetlands since the Gold Rush appears to have been exhausted.  We have modified our key natural processes such as freshwater flows, tidal exchange, flood-plain productivity, and the balance between native and nonnative species.

Much of our critical infrastructure such as levees, flood-control channels, roads, railways, storm drains, landfills, and sewage treatment systems are all built at the edge of the bay.  Our human built infrastructure as well as our remaining natural habitats needs immediate investment in adaptation strategies to be resilient in the face of the coming changes.  We need to adjust our policies and our methods to encourage rapid restoration and enhancement of natural infrastructure to protect people and property while also supporting natural processes, and protecting habitat for native plants and animals.

Sea levels are predicted to continue to rise at what is currently thought to be a fairly predictable rate through mid-century.  After 2050, sea levels are predicted to rise at a much higher rate.  We need to accelerate restoration to get ahead of the sea level rise acceleration that is projected for the middle of this century.    This Science Update incorporates the latest science – and advances the understanding of climate change and sediment supply in the baylands. This proposed science-based path forward to address threats facing the Bay emphasizes working with nature to protect existing wetlands and help them grow to keep pace with sea level rise.

This report and the online science chapters place emphasis on:

  • Restoring complete baylands systems. Many of our watersheds and habitat are disconnected from adjacent habitat types and are disconnected from the physical processes that keep them healthy.  Diverse, connected habitats can help sustain wildlife and humans during extreme conditions.
  • Accelerate restoration of complete baylands systems by 2030. This can be done by ensuring that we restore as many tidal marshes before this time so that they are intact to provide benefits when sea levels begin to rise more quickly.  This requires acceleration of restoration projects on available land.
  • Plan for a dynamic future. Instead of reacting to events, we need to create policies that anticipate change over time.  This means that we need to prepare for the landward migration of the baylands by conserving transition zones between the baylands and adjacent uplands.  We also need to develop and implement a regional plan for sediment reuse that takes advantage of sediment from dredged, excavated, or naturally occurring sites so that it can be used to restore and sustain the baylands.
  • Increase regional coordination. Working together is going to be key to implement the recommendations in this report in a timely way.  The recommendations included in this report will require even more collaboration to build consensus, identify barriers, solve problems, and promote shared learning.

The original Baylands Ecosystem Habitat Goals Report was released in 1999 and much progress has been made on restoring San Francisco Bay’s tidal wetlands as a result of the recommendations included in that report.   A number of large tidal marsh restoration projects have been planned and restored.  However, much work remains to be done to reach the goal of 100,000 acres of healthy wetlands and there are numerous pending projects that need funding in order to be implemented.

Shorelines will need to be protected by a combination of gray and green infrastructure but we need to resist the temptation to erect hard infrastructure in every location.  We can use wetlands to provide effective protection from storm-induced waves, absorb excess water from both uplands and from the Bay, filter pollutants, sustain fisheries, and provide wildlife habitat and places to enjoy nature.  While hard levee protection will be needed in some areas of the way we also need to work with nature to use bay shore wetlands to buffer and protect the Bay area’s seven million people from rising seas and extreme storms.

What does this report mean for Save The Bay’s work? 

Our Habitat Restoration Team has been working on restoring transition zone habitat for the past 15 years.  In the past several years we have stepped up that work to work with our partners on much larger projects that can provide protection and migration space.

We are currently working on the Oro Loma Horizontal Levee Project that will serve as a demonstration project for implementing innovative restoration methods to use natural systems to respond to climate change.  Our Policy and Communications Teams are responding to the call from scientists to accelerate marsh restoration by working with other Bay area leaders to place a $12 annual parcel tax measure on the June 2016 ballot that would raise $500 million over the next 20 years for wetland restoration and flood control.  These are only a couple of the ways that we are addressing the threats facing the Bay.  We look forward to working with other Bay area leaders and scientists to implement the recommendations included in this report.