Nevada filed a federal lawsuit on Monday challenging the Trump administration’s new plan for the imperiled Colorado River, launching what could become the first of many court battles over the waterway that supplies 40 million people, dozens of tribes and 5.5m acres of farm land across the American west.

The federal plan, issued Friday, cut roughly 20% from the water supplied to lower basin states – Nevada, Arizona and California – over the next two years, with a potential for harsher cutbacks in the future, based on conditions.

Filed in the US district court of Nevada, the state of Nevada, the Colorado River commission of Nevada and the Southern Nevada Water Authority filed the suit against the Department of Interior and the US Bureau of Reclamation.

Southern Nevada stood to lose more than 70% of its share under the framework, according to Joe Lombardo, the Nevada governor, who said in a statement issued with an announcement of the lawsuit that the so-called upper basin states – Colorado, Utah, New Mexico and Wyoming – were “not required to contribute a drop”.

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