King Tides are the highest tides of the year that occur around the Winter and Summer Solstices. These extreme high tides provide a glimpse of the typical tides of the future as sea levels rise. Fortunately, restoration of transition zones around the Bay shoreline can act as a natural barrier, soaking up and redirecting bay waters. Read more about what the King Tides tell us about the future of San Francisco Bay.
The Science of Wetlands & Wastewater
As a partner on a groundbreaking, experimental project called the Oro Loma Horizontal Levee, Save The Bay is creating new habitat that may model how our region can adapt to rising sea levels. Meanwhile, UC Berkeley researcher Aidan Cecchetti is measuring another aspect of the project: How this habitat can filter excess nutrients and other pollutants from treated wastewater. Read more about the research at Oro Loma.
If you’ve been watching the news, you’ve probably heard some mention of King Tides in places like Sausalito, Mill Valley, San Francisco, and Alameda. A King Tide is no farcical aquatic ceremony, but it is one of the highest high tides of the year. A King Tide is a natural phenomenon that occurs near the Summer and Winter solstices, during the new and full moon phases, when the moon, sun, and Earth are aligned. This alignment causes the strongest biannual gravitational force on Earth’s oceans, resulting in these dramatic tidal fluctuations.
King Tides help us to see today what will be the average daily high tides in 2050 and they show us now where flooding will occur as the sea level continues to rise as shown in the photos below. These photos were submitted to the California King Tides Project, which encourages people to take pictures of their communities to document flooding during King Tides.
Tide gauge measurements can tell us about past and present sea levels — The sea level in San Francisco Bay has risen about 4 inches since the year 2000. Based on these measurements and more precise climate modeling, scientists can now predict with strong confidence that the Bay Area will see an additional 10 inches of sea level rise by 2050. Beyond 2050, scientists expect sea levels to rise much faster than the current rate, partly because of positive feedback loops associated with global ice melt. Even the most conservative estimates suggest sea levels will rise a minimum of 40 inches by 2100 and as much as 16 feet if the global ice continues to melt faster than previously estimated.
So, what does sea level rise mean for the Bay Area and the people who live here?
San Francisco Bay is one of the most urbanized estuaries in the world. The majority of our seven million Bay Area residents live and work within a half mile from the Bay. We’ve filled in over 80% of the wetlands that once ringed the Bay and built our communities right at the edge of a bay that is expanding faster every day. We can look to King Tide events to show us the areas of this urbanized coastline that will be at risk in the near future.
As I mentioned, King Tides already bring higher sea levels into our coastal communities and flood urban infrastructure, reaching highways and roads in several areas throughout our region, including San Francisco, Marin, Alameda, and San Mateo counties. What I find of particular interest in the images above are the clear skies, demonstrating that the streets are flooded from ocean tides, not rainfall. However, add rainfall and tidal action and these “interesting” images can become downright devastating. The water you see on the pavement and in the streets during the King Tides indicate where the sea level was at that moment in those areas and we can expect to see that sea level every day in 2050 or even earlier. Combining those extreme high tides with large storms could result in devastating impacts, as you can see in the last two images.
Transition zones and rising tides
The Bay has expanded and contracted several times throughout history, but early humans hadn’t established permanent structures at the edges so the wetlands and the people that relied on them were able to migrate inland. Ten thousand years ago, sea levels were rising so quickly that every generation of early humans living along the coast or Bay was probably forced to retreat inland. Wetlands historically transitioned from low tidal marsh to upland terrestrial habitat across areas that spanned a mile or more. Today, most of our existing wetlands are squeezed up against urban infrastructure with narrow or no transition zones so these wetlands have nowhere to migrate. Healthy wetlands act as a sponge, slowing down and soaking up large volumes of water, so healthy wetlands help to keep coastal communities safe by buffering the effects of severe storms and flooding. With narrow transition zones and no migration space, our urban coastal tidal wetlands will drown as the sea continues to rise and will no longer provide the services we need unless we plan ahead.
In 1999, over 100 scientists, managers, and urban planners published the Baylands Goals Report, which became the basis for wetland restoration in the Bay Area and identified the need to conserve and restore 100,000 acres of healthy wetland habitat to provide healthy wetland ecosystems in the Bay Area. In October 2015, more than 200 scientists, natural resource managers, and urban planners published an update to the Baylands Goals report to include recommendations based on climate change. The Baylands Goals Science update includes an entire chapter dedicated to identifying types of transition zones and defining their services while emphasizing the need to accelerate restoration of these important areas of transition. For more information on the science update to the Baylands Goals Report, check out our Habitat Restoration Director’s blog, Baylands and Climate Change and to learn more about the general benefits of transition zones, check out my blog, What is Life without Transition?.
Communities can help to prepare for sea level rise by becoming involved with and supporting tidal wetland conservation and restoration. So it goes – wide, healthy wetlands between the Bay and urban infrastructure help to keep coastal communities safe from sea level rise.
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!
After over 100 years, the Sonoma Land Trust achieved a major success in wetland restoration this past weekend: breaching the levee at Sears Point to reconnect 1,000 acres of wetlands to San Francisco Bay. This timely event comes within a week of the recently released update to the 1999 Baylands Ecosystem Habitat Goals Report, in which scientists urge accelerated restoration efforts over the next few decades in order to save over 80% of wetlands in the next 100 years.
We can only achieve this goal by acting now: if we continue to waver, the reality of climate change and rising sea levels would not only drive up the cost of restoration, but also place the ecosystem and communities of San Francisco Bay in a more vulnerable state. Projects like Sears Point are a crucial reminder to what we can do to improve health of the Bay; with over 30,000 acres of public land awaiting restoration, the major barrier is funding. That’s why we are supporting the Clean and Healthy Bay ballot measure in 2016, which will provide the resources needed to restore more of our Bay.
Here are some of the articles we think are integral to the conversation about the Bay’s future:
Ceremony near San Pablo Bay marks planned rebirth of wetlands
After 10 years of planning and three years of site preparation, it took less than a minute Sunday for workers to scrape a hole in a levee and begin the renewal of 1,000 acres of former North Bay marshlands. The mechanical excavator scooped aside a few buckets of dirt. Muddy water spurted and then flowed into the waiting basin. Now all that’s needed is time.
San Francisco Bay: Race to build wetlands is needed to stave off sea-level rise, scientists say
San Francisco Bay is in a race against time, with billions of dollars of highways, airports, homes and office buildings at risk from rising seas, surging tides and extreme storms driven by climate change. And to knock down the waves and reduce flooding, 54,000 acres of wetlands — an area twice the size of the city of San Francisco — need to be restored around the bay in the next 15 years.
Mercury News editorial: San Francisco Bay wetlands need to be restored
At stake are billions of dollars worth of highways, airports, businesses and homes on land immediately adjacent to the Bay. Water levels have already risen 8 inches since 1900, and they are expected to rise another foot in the next 20 years and two feet by 2050. It may not sound like much, but it could be disastrous.
Restoring wetlands is a green defense against rising bay Editorial by California Assemblyman Tony Thurmond (D-Richmond) — Climate change will harm people from all nations. But one segment of humanity is on the front lines: the poor. From the increased frequency of mega-storms like the one that devastated the Philippines in 2013 to rising seas displacing people of low-lying nations such as Bangladesh, it is the poor who will lose their homes first and suffer the gravest misfortunes.
What can you do to help wetland restoration in San Francisco Bay? Support an upcoming ballot measure that will fund over $500 million dollars to protect the Bay’s shoreline.
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.