ecological

California’s biggest rivers converge in the Sacramento-San Joaquin River Delta, the waterways and wetlands forming an ecosystem where fresh water meets salt water from San Francisco Bay, and where native fish historically flourished.

Every few years, dozens of scientists examine the environmental health of the estuary in a report card that considers water flows, wildlife and habitat, as well as other factors. Their latest shows the bay is mostly in fair condition and stable, but the Delta is “mostly in poor condition and declining.”

According to the State of Our Estuary report, less fresh water has been flowing through the Delta in recent years, which creates “chronic artificial drought conditions” and harms fish.

To learn more about the findings, I called Christina Swanson, a biologist who for more than two decades has worked on the assessments. One reason the Delta’s health is declining, she said, is that giant state and federal pumps, as well as those of other entities, are taking more water out of rivers and the Delta, “degrading the environmental and ecological conditions that species need to survive and to thrive.”

“The amount of water that we’re taking out of the system, it’s too much,” Swanson said, and it has “been increasing for years, despite the fact that we know that it’s an environmental problem.”

The new report, the first since 2019, was prepared by the San Francisco Estuary Institute, an independent environmental research organization, together with the San Francisco Estuary Partnership. It was supported with federal funds that are funneled through the state for water initiatives.

California’s largest estuary provides vital habitat for fish including Chinook salmon, steelhead, green sturgeon, longfin smelt and Delta smelt, but the numbers of many native fish have declined over the last few decades.

On the positive side, the researchers found that wet years such as 2023 still allow some fish to rebound, at least locally, especially near floodplains that people have worked to restore.

Wetlands restoration projects have increased the tidal marshes around San Francisco Bay to 57,800 acres, nearly twice the size of the city of San Francisco. The Delta’s tidal marshes have grown from 8,000 to 13,000 acres over the last five years. Two types of birds that live in tidal marshes — black rails and yellowthroats — are rebounding.

The researchers said large wetland restorations, such as a recent 3,400-acre project at Lookout Slough, are helping the Delta’s native fish.

Still, fish have been struggling to spawn and survive as the amount of water left in their habitats has decreased since the early 2000s, and as they have endured longer and more severe droughts, Swanson said.

She noted that during the last 50 years, a series of rules and regulations were adopted to protect the estuary’s ecosystem.

“And yet, during those same five decades, freshwater flow has continued to decline. Today, flow is poorer than it’s ever been,” she said. “That says to me that our efforts to establish protections have not been effective, and we need to do a better job and be better stewards.”

The report does not propose policy solutions, but the findings will be discussed as California water officials debate options for the Delta. The State Water Resources Control Board is now updating a Bay-Delta water plan that will determine how much water may be taken out, and how much should be allowed to flow through the Delta.

Efforts to protect the Delta environment are further complicated by climate change, which is driving more extreme droughts in the West and altering precipitation patterns, bringing less snow and more rain.

The Trump administration, meanwhile, has adopted a controversial plan to pump more water from the Delta to Central Valley farmlands.

“The Trump administration’s attempt to take more water out,” Swanson said, “will do nothing but exacerbate the deteriorating condition of the system and the species that rely on it.”

More water news

Gov. Gavin Newsom’s administration is working on a plan to build a 45-mile water tunnel beneath the Delta, creating a second route to the aqueducts of the State Water Project. But as I reported for the L.A. Times last week, a state appeals court rejected the state’s financing plan for the project. The administration still has another case pending as it seeks to issue bonds.

For years, groundwater has been dropping beneath desert farmlands in Arizona, where the state has allowed landowners to pump unlimited amounts. Now, the state is finally imposing limits. Last month, I traveled to an area of Arizona called the Ranegras Plain, where the aquifer has been falling as a Saudi-owned dairy company irrigates vast alfalfa fields. This week, Gov. Katie Hobbs announced that Arizona is establishing a new “active management area” there to protect the groundwater.

I also wrote about a first-of-its-kind agreement between Arizona Atty. Gen. Kris Mayes and another of the state’s biggest farming businesses, which has agreed to leave some croplands dry and pay $11 million to help residents whose wells have gone dry.

The Trump administration has released an outline of new options for dealing with deepening water shortages along the Colorado River. As I reported for The Times, the federal government’s options could dramatically reduce the amount of water available for Southern California. The rules for dealing with shortages are set to expire at the end of this year, and representatives of seven Western states are holding difficult negotiations on how to share necessary cutbacks in the coming years.

More climate and environment news

My colleague Hayley Smith reported on one of President Trump’s latest moves to halt involvement in international climate efforts, as he pulled the U.S. out of dozens of international organizations and treaties, including the U.N. Framework Convention on Climate Change and the Intergovernmental Panel on Climate Change.

For months, federal disaster officials leading the Eaton fire cleanup claimed that soil testing was unnecessary, but as Tony Briscoe and Noah Haggerty report for The Times, the Environmental Protection Agency is now expected to announce that the government will pay to test the soil for lead at 100 homes destroyed in the fire.

An invasive beetle responsible for killing hundreds of thousands of oak trees in Southern California has now expanded into Ventura County. Lila Seidman reported for The Times that to prevent further spread, some experts are calling for regulations limiting the movement of firewood.

This is the latest edition of Boiling Point, a newsletter about climate change and the environment in the American West. Sign up here to get it in your inbox. And listen to our Boiling Point podcast here.

For more water and climate news, follow Ian James @ianjames.bsky.social on Bluesky and @ByIanJames on X.