Your donation supports our high-quality, inspiring and commercial-free programming.
Support Icon
Discover all the ways you can make a difference.
Support Icon
The Leadership, Advancement, Membership and Special Events teams are here to help.

What Do We Call the Bay Delta, and Why?

Support Provided By
Some of the names of some of the places mentioned in this piece | Image: U.S. Geological Survey

An explanatory series focusing on one of the most complex issues facing California: water sharing. And at its core is the Sacramento-San Joaquin Bay Delta. Stay with for all the project's stories.

It's a complicated estuary, unique in the world, where water from 75,000 square miles of California and sometimes Oregon drains into the Pacific Ocean, and it doesn't really have a name.

At least not one that everyone seems to agree on. You'll see the large body of water and related habitats where water from the the Sacramento, San Joaquin, and Mokelumne rivers joins that of the Pacific referred to with a couple standard strings of adjectivally modified names, which generally make logical sense, and none of them are really in common, colloquial use.

Californians generally just simply call it the "Bay-Delta," sometimes with a slash instead of a hyphen, when they have to refer to the whole set of natural and artificial waterworks that makes up the heart of California. That's a bit like calling San Francisco "The City." It works with locals, but not so much when the conversation is taking place where people from other places are listening in.

For what it's worth, throughout this Bay Delta series, we're using that generic descriptor without a hyphen or slash. We're not the first to do so, as witness the name of a multibillion dollar plan proposed by the state's Department of Water Resources intended to resolve conflicts over water allocations within the estuary and its tributary rivers: the Bay Delta Conservation Plan. The august organization Save San Francisco Bay opts for the hyphen.

But which Bay Delta?

The Environmental Protection Agency calls the whole ecosystem the San Francisco Bay Delta, which makes logical sense in one way, given that The City sits at the outflow of the whole system. But geographic names work on more than just a logical level: they also reflect how the locals feel about the landscape they live in. As the Bay Delta crosses a significant demographic boundary within California, running between the conservative interior and the more liberal coast, regional resentments can shape the way locals regard the landscape. Tell a person from Manteca or Knights Landing that they live in the San Francisco Bay Delta, and you may be met with a sneer.

But those locals may not have an alternative to suggest. Even people living within line of sight of the Bay Delta don't generally have a name for the whole system. In two and a half decades of living within an hour's walk of the estuary I never heard anyone other than agency staff or biologists refer to the ecosystem as a whole. There's the Bay, and there's the Delta. People who live in the Bay Area's nine counties regard the Delta as someplace nearby but other, and often not particularly admired. It's no accident that Bay Area songwriter John Fogerty chose the Delta town Lodi as his example of a place to escape from. Many folks in Lodi have opted to take the song as an ironic compliment.

Accidents of sociology aside, there's also the fact that both the Bay and the Delta have their own naming irregularities. San Francisco Bay has two definitions in common use. One is as the body of water that stretches from the westernmost part of the Delta around Antioch and connects to the Pacific. The other, stricter definition excludes San Pablo and Suisun bays, with San Francisco Bay limited only to that part of the estuary downstream from the narrows between Point San Pablo and Point San Pedro.

Meanwhile, the Delta -- usually called merely "The Delta" in the area -- is often called the Sacramento Delta when a more official-sounding term is desired. Again, there's a logical sense to that, in that the Sacramento River provides the lion's share of the Delta's water. But in places like Stockton, along one of the San Joaquin's northern channels, that doesn't play as well. So in a nod to inclusiveness, you'll also see people using the more complex phrase "Sacramento-San Joaquin Delta."

That still omits the third river that flows directly into the Delta, the Mokelumne, and it may well be that there are a few people in the towns of Terminous or Mokelumne City who'd like to be included. If you're one of them, let us know in the comments.

Obviously, this way lies madness: before long, if we tried to honor every single locality in the vast estuarine system, we might be calling it the Sacramento-Mokelumne-San Joaquin-Suisun-San Pablo-San Francisco Bay Delta, and the world's supply of hyphens would be seriously depleted.

Or we could go in another direction. The Delta is, often enough, referred to as the "California Delta." That naturally suggests calling the larger ecosystem the "California Bay Delta."

That, by the way, would be a neat if inadvertent echo of a little bit of paleohistorical scholarship. The Bay Delta has its geological roots in a catastrophe that happened about half a million years ago, when the giant freshwater sea accumulating behind the Coast Ranges -- runoff from the Sierra Nevada with nowhere to go -- finally cut a deep channel through the Coast Ranges right around the present location of Martinez. The resulting flood must have been impressive, and eventually a mighty river flowed out through that cut -- now called Carquinez Strait -- and then through the Golden Gate, and out to sea. When Ice Ages occurred, and much of the earth's water was locked up in glaciers, sea level dropped as much as 400 feet, and so that river flowed as much as another 30 miles west before reaching the Pacific.

Geologists call that river the California River. When sea levels started rising about 10,000 years ago, much of the California River's course was eaten by the sea, though you can still see hints of it in the Golden Gate, the Carquinez Strait, and Raccoon Strait between Angel Island and the Marin County hamlet of Tiburon.

Calling the whole flooded thing east of the Golden Gate the "California Bay Delta" would offer a nice bit of continuity, in an odd way, and a chance to explain a bit of geology to schoolchildren and tourists.

But habits die hard, and we may well be stuck without an actual common name for the whole system for the time being. Which is okay, because if we got that settled we'd have to start deciding where the Delta ends and the Bay begins. Suisun Bay is sometimes counted as Bay, because it's a big expanse of open water, and sometimes as Delta, because it tends to be a lot less saline than San Francisco or San Pablo bays. Ask a resident of the Suisun Bay town of Antioch whether they live in the Bay Area or the Delta, and the answer you get might shift with the tides.

I told you it was complicated.

Support Provided By
Read More
5 men sit at a table in front of a laptop

How a Coalition Creates Paths to Healing for Young Men of Color

The Brothers, Sons, Selves (BSS) coalition fosters life-affirming spaces for boys and men of color, where justice is rooted in transforming oppressive systems but also in building a trusting and loving community.
A member of the national guard in blue protective gear holds a box out to a person placing a coronavirus test in a box from a car.

California Braces for Omicron COVID Variant

The omicron variant has not yet entered the U.S., but California is already bracing for a surge in COVID cases.
COP26 Coalition Protestors Take Part In The Global Day of Action for Climate Justice

After a 'Disappointing' UN Climate Summit, California Youth Activists are Back to Work

Youth climate activists have criticized the COP26 pact for being "vague" and failing to limit warming to 1.5 degrees Celsius compared to pre-industrial levels. For one activist, the disappointment with negotiations at the global level inspired him to focus his work more locally in Southern California.