SAN DIEGO, Calif. — Western state water officials will spend the next few months trying to agree on how to divvy up water from the Colorado River, which sustains a region of 40 million people across seven states but has been devastated by the worst drought in more than a thousand years. Reaching a deal, however, has thus far proved challenging. Arizona, Colorado, Nevada, New Mexico, Utah and Wyoming have jointly made a proposal to the federal government over how to decrease consumption of Colorado River water. California, however, has a different plan. If the seven states can’t agree, federal ...