In the first salvo of what could become a court battle over Colorado River water, the state of Nevada has sued to challenge the Trump administration’s plan for mandatory water cutbacks.

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The state filed the lawsuit on Monday, just three days after the Trump administration released the plan, which requires Nevada, Arizona and California to cut water use by about 20% for the next two years. The plan allows for much larger mandatory cuts over the next decade if necessary to prevent the river’s drought-depleted reservoirs from reaching critically low levels.

Announcing the lawsuit, Nevada Gov. Joe Lombardo said that under the plan issued by the Interior Department, “southern Nevada could lose more than 70 percent of its already meager Colorado River allocation,” while four other states — Colorado, Utah, New Mexico, and Wyoming — “are not required to contribute a drop.”

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“This isn’t about political posturing,” said Lombardo, a Republican. “This is a matter of survival for a community that represents about two-thirds of our state’s citizens and the lion’s share of its economy.”

The Colorado River’s reservoirs have dropped dramatically over the last 26 years during a historic drought that research shows is being intensified by global warming. The largest reservoirs, Lake Mead and Lake Powell, have fallen to their lowest levels on record.

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