SACRAMENTO, Calif. (AP) — California sued the Trump administration on Thursday to block new rules that would let farmers take more water from the state’s largest river systems, arguing it would push endangered populations of delta smelt, chinook salmon and steelhead trout to extinction.

The federal rules govern how much water can be pumped out of the watersheds of the Sacramento and San Joaquin rivers, which flow from the Sierra Nevada mountains to the San Francisco Bay and provide the state with much of its water for a bustling agriculture industry that supplies two-thirds of the country’s fruits and nuts and more than a third of its vegetables.

But the rivers are also home to a variety of state and federally protected fish species, whose numbers have been dwindling since humans began building dams and reservoirs to control flooding and send water throughout the state.

Two massive networks of dams and canals determine how much water gets taken out, with one system run by the state and the other run by the federal government.

Historically, the federal government has set the rules for both systems. But recently, state officials have complained the Trump administration’s proposed rules don’t do enough to protect endangered species. Gov. Gavin Newsom’s administration threatened to sue the federal government in November, but delayed action in the hopes he could work out a compromise.

But the federal government finalized the new rules this week. Trump traveled to Bakersfield on Wednesday to celebrate them before a jubilant crowd.

“We’re going to get you your water and put a lot of pressure on your governor,” Trump told the crowd. “And, frankly, if he doesn’t do it, you’re going to get a new governor.”

Newsom responded on Thursday with a lawsuit, filed in partnership with state Attorney General Xavier Becerra.

“California won’t silently spectate as the Trump Administration adopts scientifically-challenged biological opinions that push species to extinction and harm our natural resources and waterways,” Becerra said.

The lawsuit, filed in federal court in San Francisco, challenges the actions of the U.S. Bureau of Reclamation.

U.S. Interior Secretary David Bernhardt, who oversees the bureau, warned Thursday night of unpredictable consequences that could result from the lawsuit.

“The governor and attorney general just launched a ship into a sea of unpredictable administrative and legal challenges regarding the most complex water operations in the country, something they have not chartered before,” Bernhardt said in a statement. “Litigation can lead to unpredictable twists and turns that can create significant challenges for the people of California who depend on the sound operation of these two important water projects.”

Wednesday, the U.S. Department of the Interior touted the new rules for pledging $1.5 billion of federal and state funds over the next 10 years to restore habitat for endangered species, scientific monitoring of the rivers and improvements to fish hatcheries.

But state officials say the rules would mean less water in the rivers, which would kill more fish. In particular, the low flows would hurt chinook salmon and steelhead trout, which once a year return to the freshwater rivers from the Pacific Ocean to spawn.

The state’s lawsuit says the federal government did not properly analyze the rules to see if they would “tip a species toward extinction.”

Lawsuits over water in California are common, but it’s something the Newsom administration has been trying to avoid. For the past year, state regulators have been negotiating with water agencies on a set of voluntary agreements to set water quality standards in the delta. Newsom hopes these agreements, if they are ever reached, would avoid decades of lawsuits that have plagued prior water regulations.

The lawsuit announced Thursday could put those agreements in jeopardy. A representative for the State Water Contractors declined to comment on the lawsuit, but pointed to the group’s previous comments where General Manager Jennifer Pierre said they were “disappointed” the two sides could not compromise.

“We are concerned about the impact any litigation may have on the Voluntary Agreements process,” Pierre said at the time.

Thursday, Newsom said his goal remains to “realize enforceable voluntary agreements.”

“This is the best path forward to sustain our communities, our environment and our economy,” the governor said.