The Colorado River cuts through the Grand Canyon, providing water for about 40 million people and 5 and a half million acres of farmland. To some, the water is as valuable as oil. In 1922, the seven U.S. states through which the river flows signed onto the Colorado River Compact, a water-sharing agreement that divvies up the river’s annual flow. The water must be shared equally between Upper Basin states: Wyoming, Colorado, Utah and New Mexico; and the Lower Basin: California, Arizona and Nevada. There’s been infighting ever since.