Bay Area Wetlands Forever: Beauty, Biodiversity, and Balance

We are blessed to live in the Bay Area, where, in just a few hours, we can be in multiple enticing habitats: mountains, lakes, oak woodlands, wetlands, and more. Many of us travel to Yosemite or Lake Tahoe or spend a day at the beach or one of our local redwood forests. But one of the easiest ways to experience nature is by visiting wetlands. They are some of the most important habitats on Earth. Yet, they’re disappearing at an alarming rate. Let’s dive into why these vital landscapes matter, their challenges, and how POST restores and protects Bay Area wetlands like Laguna Seca and Bair Island.

WHAT IS A WETLAND?

In short, a wetland is a place where the ground is (or was) covered by water for all or part of the year, with plants adapted to living in saturated soils. Wetlands exist on the coast, where ocean, land, and creeks or rivers meet (tidal wetlands). You’ll also find them inland, where a depression in the soil or flat open spaces allow water to spread over the land (non-tidal wetlands). 

While, at first, you may think of such areas as a muddy mess, if you look closely, these soggy paradises are teeming with life. In fact, the Environmental Protection Agency has called them one of the most productive ecosystems in the world.

Bay Area wetlands are no exception. For example, at the Palo Alto Baylands on the edge of the San Francisco Bay, egrets, pelicans, and other birds pause on their journeys on the Pacific Flyway. Other winged creatures call the mix of salt and freshwater home. Here, where Matadero and Adobe Creeks meet the Bay, visitors have spotted many fascinating creatures. These include rabbits, butterflies, lizards, raccoons, crabs, foxes, and even beavers.

5 WAYS BAY AREA WETLANDS PROTECT THE ENVIRONMENT

In addition to protecting biodiversity, Bay Area wetlands benefit our environment in many other ways. 

Learn more about Laguna Seca in the video below, excerpted from A Valley Endures, our mini-documentary about Coyote Valley.

They reduce flooding downstream.

During big storms, creeks and rivers should be able to overflow their banks. The water can then disperse across a large area, reducing flooding downstream and depositing nutrient-rich sediment on the surrounding land. A wetland’s flat, open expanses allow this to happen.

They store water for dry seasons.

As rainwater absorbs into the ground, it refills underground natural aquifers, storing water for dry seasons. In fact, according to the Environmental Defense Fund, a single acre of wetlands can hold up to 1.5 million gallons of water! Imagine all that water in your neighborhood, and you’ll understand the importance of healthy, unpaved wetlands.

They clean and filter our drinking water.

Wetlands filter out pesticides, pollution, and sediment before they can enter rivers and streams on the way to your kitchen sink. Additionally, the slow speed of the meandering water and the plants that help keep soil from washing downstream also help control erosion.

They help mitigate the effects of climate change.

If all that isn’t enough, wetlands also act as carbon sinks. They keep carbon dioxide and other greenhouse gases out of our atmosphere, helping mitigate the effects of climate change. Able to store carbon for thousands of years, they protect our air and water.

They save us money.

Finally, all of this environmental protection has a monetary value. A single acre of wetlands provides an estimated $248 in water purification, $2,270 in water storage, and $1,055 in erosion prevention annually. That’s over $3500 per acre per year that would otherwise get paid out of tax revenues. Moreover, wetlands save us millions of dollars it costs to clean up our neighborhoods each time they flood.

WETLANDS IN DECLINE

Despite all the important work wetlands do, their flat nature makes it tempting to convert them into dry land. For over a century, wetlands have been — and continue to be — drained and destroyed at an alarming rate. Devastatingly, over 91% of the original wetlands in California have already been lost. Over time, humans have repurposed about half of historic U.S. wetlands for farming, salt farming, or development. We are sacrificing wetlands faster than conservationists can restore them. Even worse, these actions release stored carbon into the atmosphere, intensifying the adverse effects.

RESTORING THE AREA’S LARGEST REMAINING WETLAND

Just preserving our essential Bay Area wetlands from development isn’t enough. We also need to restore them so our open spaces can do their jobs. In the process, we’ll create homes for local species and recreational opportunities for people. This restoration process is vital to POST’s work to make our region more resilient to climate change.

An exciting restoration project is currently underway at Laguna Seca, San José’s largest remaining wetland.

About Laguna Seca

Laguna Seca is an inland, freshwater wetland  — the dominant type in the U.S., making up about 90% of the country’s wetlands. Their water level fluctuates; they may be dry for part of the year or they may remain wet year-round. Highly biodiverse, Laguna Seca is home to several threatened species. These include red-legged frogs and plants that can live in the sometimes damp, sometimes dry environment. It is an important part of the surrounding ecosystem because of its water-saving ability.

The Draining of Laguna Seca

Laguna Seca was once a thriving freshwater wetland. But in 1916, over 1,200 acres were dredged, drained, and burned for farming. This broke its connection with the watershed and left millions of birds on the Pacific Flyway to find new resting places. As part of the project, a four-mile-long drainage was created — now called Fisher Creek. It feeds into Coyote Creek and contributes to flooding issues we see today in San José.

Restoring Laguna Seca

Luckily, in 2017, Laguna Seca was recognized as a vital throughway for wildlife moving from the Santa Cruz Mountains through Coyote Valley to the Diablo Mountain Range in the east. In 2019, POST, the Santa Clara Valley Open Space Authority (the Authority), and the City of San José invested $93.5 million to permanently protect this vital community asset.

Now, partners are working to restore it. They’re researching to understand the state of the groundwater, how wildlife crosses the land, and how to reduce flooding in San José. The goal is enhancing the habitat for plants and animals that live in or move through the landscape. They also aim to let it return to controlling flooding, sinking carbon, and cleaning our water, as it was meant to do. POST transferred the land to the Authority in November of 2024, and the restoration work continues.

VISIT A RESTORED WETLAND: BAIR ISLAND

One example of what POST and its partners hope to achieve at Laguna Seca is the transformative work done at Bair Island in Redwood City. Once part of a 3,000-acre cattle ranch and then salt evaporation ponds, POST purchased this tidal wetland in 1997. Now a part of the Don Edwards San Francisco Bay National Wildlife Reserve, it took fourteen years to restore it to its former glory. It opened to the public in 2015, and its 1.7-mile flat trail is a great place to see a thriving wetland up close. 

Not only is it a bird watcher’s paradise, but visitors can spot rays and leopard sharks in the water, plus rabbits and other small mammals on the land. With its open water, winding channels, and native vegetation, Bair Island offers a front-row seat to the beauty and resilience of Bay Area wetlands.