Skip to main content

See also:

Marshland in San Francisco

Herons Head Park
Herons Head Park
Jessica Hahn-Taylor

At one time San Francisco was a vast marshland. Thousands of years ago there was no bay, just an ancient river running through a channel between Angel Island and Tiburon. When glacial ice melted and the sea rose, water filled the basins. Seawater mixing with the river water (Sacramento, San Joaquin, Eel, Feather, American, Merced, and Tuolomne) turned the area into an estuary. Fast forward millennia upon millennia.

What we have here now is a city, a ring of them, and isolated pockets of estuaries. Have you ever tried walking the edge of San Francisco, where the water meets the land? If you’re in the southeastern area, you won’t get far. Broken pilings, cracked concrete, barbed wire above cyclone fences, old piers, rusty warehouses, and potholed roads impede your progress pretty quickly. One would think we were founded on concrete. Where’d the marshland go? Since 1849, the portion we haven’t drained, we’ve smothered—90% of the wetlands are gone. We’ve messed up, to say the least.

Of all habitats, estuarine marshes, like the one we have here, have some of the highest amounts of living creatures per unit area, writes Tom Garrison, Ph.D., marine sciences professor at Orange Coast College and author of the textbook, Oceanography.

Marshes clean water with their thick network of filament-covered roots, acting like natural filters. They can reduce human-created toxicity in some cases (they can’t make toxic compounds disappear, but lessen the impact of water pollution). In event of flooding, marshes can act like sponges; to some degree, marshes might be able to keep up with seawater rising as plants grow on plants. Perhaps most important of all, whether you be carnivore or herbivore, estuaries are awesome habitats for critters. Their protected waters make perfect little nurseries. Despite our pollution, the SF Bay is full of baby fish. The marshlands also provide food and refuge for animals.

"We live in the second largest continental estuary in the United States," says "Ocean Matt" Horrigan, oceanography professor at San Francisco State University. "But it doesn't mean we have the best environment for the animals."

San Francisco Bay is full of life. Cranes, swans, ducks, and egrets. Harbor seals and sea lions. Little salt marsh mice and mud-loving clams. Sharks, sanddabs, and flounder. A pelican roosting on an old piling. Salmon and herring. An occasional whale. A cormorant drying its lustrous, black wings, spread out like Dracula’s cape. The list would unroll and keep rolling.

Now remember late 2007 when a ship, COSCO Busan, entered the San Francisco Bay and hit the Bay Bridge. It was very foggy, but that’s to be expected, isn’t it? The pilot was impaired by pharmaceuticals. Over 53,000 gallons of fuel dumped into the bay. You can imagine the repercussions.

Three years later, almost to the day of the COSCO Busan disaster, I’m on a boat with the Marine Science Institute, collecting fish specimens and sediment samples for an oceanography class at SF State. One thing that stands out from all the other moments that afternoon are the tumors on the baby sole, tiny flatfish with funny eyes on the top of their head. It makes you wonder why so many people fish along the edges of the bay? (A whole ‘nother story, here. “Most of the Bay anglers who were unaware of the government health warnings were also people of color,” says the Natural Resources Defense Council website.)

Although people destroyed most of San Francisco’s marshlands, it’s people that are needed to bring them back.

“As for restoring wetlands, the problem (as always) is to convince the public that such a thing is a worthwhile endeavor,” says Dr. Garrison in a recent dialogue. “Ah, yes… Deep breath…”

Right now is a great time to visit San Francisco's marshlands. Winter approaches and so do the migrating birds. One interesting thing to remember is that the SF Bay is part of the Pacific Flyway, that big highway in the sky. Our estuary is a layover on the grand journey. According an interpretive sign at Heron’s Head Park, 11 million migrating birds get on the wing, cruising the Pacific Flyway, with 70% stopping at the San Francisco Bay for a little food and rest. Wherever you are right now, reading this, consider heading down to the water's edge. As Ocean Matt of San Francisco State University instructs his oceanography students, "Immerse yourself in the aqueous environment!"

Visit some of the marshlands in San Francisco’s southeast edge: India Basin, Heron’s Head, Candlestick Point State Recreation Area, Yosemite Slough, and more. Things are a-foot, changing in our city by the bay. Marshlands are coming back, little by little. But we've got to get on down to the water's edge, we’ve got to see it firsthand. Just going there and wandering along that magical zone where land and water meet might just do something to you. Relax you, perhaps. Incite acts of volunteerism? Perhaps. Open your awareness—definitely.

Relevant Links