Arizona has filed to join a lawsuit against the federal government over its new plan for managing the Colorado River. The federal plan would cut Colorado River supplies for Arizona, California and Nevada by about 20% through 2028, and could cut them by about 40% after that. The lawsuit, originally filed by Nevada in August, argues that the plan is too harmful to water users in those states. Arizona would take the largest cuts under the new federal plan, and state officials have openly criticized it. … The lawsuit is not the so-called “nuclear option” that could bring Colorado River matters before the Supreme Court. That would likely require one state to sue another. Arizona has laid out its case to sue if it determines that upstream states are not sending a legally-required amount of water downstream, but has not yet done so.

Other Colorado River management news:

• Nevada Current: Arizona joins Nevada lawsuit over Colorado River cuts
• Las Vegas Review-Journal: Nevada finds ally in legal battle with feds over Lake Mead
• KLAS (Las Vegas): ‘Important step’: Arizona joins Nevada lawsuit over Colorado River plan
• Arizona Mirror: Arizona moves to join lawsuit against federal Colorado River plan
• Inside Climate News: Arizona joins lawsuit challenging the federal government’s plan for the Colorado River
• The Washington Post: Arizona joins lawsuit over required water cuts in Colorado River plan
• Wall Street Journal: Opinion: Colorado River states could head back to the Supreme Court