Larry Liebesman, a senior adviser with water-resources consultancy Dawson & Associates, said the suit highlights the fact that while the Trump administration professes to support states’ rights, this rule expressly denies a state's right to determine its own water quality. “The effect of the rule is to adversely affect the sovereignty of the states,” he says.

The rule gives states no more than one year to finish their review of energy projects such as pipelines under Section 401 of the Clean Water Act. It was cheered by energy groups that claimed some states were delaying approvals on pipeline projects unnecessarily.

“Today’s lawsuit is needed because the Trump Administration wants to take away California’s long-established right to protect rivers from the negative impacts of massive hydropower dams. Our rivers and streams are critical to California’s ecosystems and economy,” said Jared Blumenfeld, California Secretary for Environmental Protection, in a statement. “Giving the federal government the ability to control California’s environmental future is not an option. We must remain vigilant against these never-ending attacks on common-sense environmental protections.”

Liebesman says the suit will likely move at a relatively slow pace unless the states request the court to expedite it.