SACRAMENTO, Calif. -- The Trump administration on Tuesday unveiled new rules to govern California's scarce water, committing to send more to farmers in the Central Valley despite warnings from environmental groups that it would imperil endangered species in the fragile San Joaquin Delta.
The rules govern management of the federal Central Valley Project and the State Water Project, two complex labyrinths of dams and canals that corral rain and snowmelt to provide water to more than 25 million Californians and millions of acres of farmland.
An initial review by the national Marine Fisheries Services in July concluded the plan would threaten the existence of some endangered species, including winter-run chinook salmon, according to the Los Angeles Times. But the Trump administration never released that plan.
The report the government did release on Tuesday, known as a "biological opinion," said the plan "will not jeopardize threatened or endangered species," clearing the way for it to be implemented early next year. But it's likely environmental groups will sue to block it.
"I think this biological opinion is the end result of the Trump administration's junk science and political interference," said Doug Obegi, senior attorney with the Natural Resources Defense Council.
The plan would give water agencies more flexibility on how much water they can pump out of the state's rivers. When it's raining a lot, agencies can pump more. When it's dry, less would be pumped.
Also, the government said it would monitor the location of endangered fish species, including the delta smelt. If the fish are close to the pumps, the agencies would pump less to avoid sucking the fish in and killing them.
"We have a large degree of confidence that we know when fish are in the area, and therefore if we have a cause for concern" pumping would be curtailed, said Paul Souza, regional director for the U.S. Fish and Wildlife Service.
But there are so few of the delta smelt left they are almost impossible to detect, said John Durand, a research professor at the Center for Watershed Sciences at the University of California, Davis. Durand said there are not enough of the delta smelt to catch in nets or monitor with cameras. But he said officials can indirectly monitor them by measuring the amount of sediment in the water, which he said is "somewhat helpful."
"In terms of being able to monitor them, they are effectively extinct," Durand said. "We can't really detect them with any kind of reliability."
Other rules would impact the last natural population of endangered winter-run chinook salmon in the Sacramento River. The fish breed in a cold-water pool behind Shasta Dam, which is carefully managed by the federal government. If the water gets too warm, the fish die.
In 2014 and 2015, during a severe drought, the reservoir ran out of cold water and most of the salmon died.
The new rules change how much water is stored in the reservoir to prevent it from running out of cold water. Ernest Conant, regional director for the U.S. Bureau of Reclamation, said the new rules will result in more cold water storage than under the current rules.
But Obegi disagrees, saying the model the bureau is using to predict how much water will be available is flawed. He called the plan a "recipe for extinction."
It's unclear how Democratic Gov. Gavin Newsom's administration will respond to the new rules. The Democratic-controlled Legislature passed a law earlier this year seeking to block a lot of these changes. But Newsom vetoed that bill after intense lobbying from the water agencies.
Newsom has challenged the Trump administration on other environmental fronts, including its decision to strip California of the ability to set its own emission standards for cars and trucks.
Lisa Lien-Mager, spokeswoman for the California Natural Resources Agency, said the agency will evaluate the water plan "but will continue to push back if it does not reflect our values."
"California is, and will continue to be, a leader in the fight for clean air, clean water and endangered species," she said.