(The Center Square) -(The Center Square) - Arizona and Nevada on Friday opposed a Colorado River usage reduction plan by the U.S. Bureau of Reclamation, which could define the crucial waterway for 40 million people over the next decade. The Colorado River states are California, Nevada and Arizona in the Lower Basin and Colorado, Utah, Wyoming and New Mexico in the Upper Basin. The previous Colorado River water usage guidelines from 2007 are set to expire at the end of 2026. The Colorado River Compact, originally signed in 1922, allocates each basin 7.5 million acre-feet of annual river water. While Arizona and Nevada widely expressed opposition to the Bureau of Reclamation plan, the Colorado River Board of California expressed more optimism about the future of the inter-state agreement.