Baykeeper Update

Fish out of water: Debunking myths in the Bay-Delta water debate

California’s water wars are often framed as fish versus Big Ag. But a new study reveals just how much fish are losing out.

Lobbyists for industrial agriculture and big cities, including some in the Bay Area, have warped the debate around water use in California.  

They claim that protections for fish are taking up too much of California’s available water—and lots of media outlets have reported on the issue that way.

The President has even accused California of “shoving” water to the sea at the expense of farms to protect “a certain kind of 3-inch fish,” in reference to the endangered Delta smelt.  

But the numbers tell a very different story, according to a new study from researchers including Baykeeper Senior Scientist Jon Rosenfield.

Most of the water from Sierra snowmelt that should flow westward toward the Pacific Ocean never reaches San Francisco Bay. That’s because about half of Central Valley river flows are diverted for use by cities and farms.

The fresh water that remains is not enough to keep the ecosystem functioning, leaving the Bay under consistent drought-like conditions. As a result, six endangered fish species in the Bay are spiraling towards extinction.

Yet corporate farming operations and some cities want an even greater share of California’s freshwater flows. And they’ve shaped a story that blames environmental protections and endangered species for “taking” an ever-larger share of the available water.

To find out if this is true, Jon partnered with scientists at The Bay Institute and The Nature Conservancy to review decades of data. They wanted to see how much water had actually been allowed to flow to the Bay as a result of environmental protections like those provided by the Clean Water Act.

It turns out the answer is: very little. Overall, the percentage of winter-spring flows that reach the Bay has steadily declined over the past 90 years.

The Endangered Species Act didn’t cause much water to flow to the Bay, either. In the last nine years, less than 3% of Central Valley river flows made it to the Bay as a result of limits on water exports intended to protect endangered species.

In fact, in some years, endangered species safeguards for Delta smelt had zero impact on the amount of water flowing to the Bay.

And when water was left in rivers to flow unimpeded, most of it was not for fish or the environment—rather it was to keep salty water away from pumping stations or because there was no place to put any more of the diverted water.

As the debate about water rages on, it’s critical to recognize how little water is left in nature for imperiled fish, wildlife, and habitat. Baykeeper will continue advocating for more freshwater flows to protect the Bay and Delta.

Read the new study by Jon and our colleagues published in the journal San Francisco Estuary & Watershed Science.


Above: The Clifton Court Forebay by John Chacon, Department of Water Resources