SALT LAKE CITY — U.S. officials announced Tuesday that Arizona and Nevada - two states reliant on water from the Colorado River - will face more water cuts as they endure extreme drought.

The move came as officials predict levels at Lake Mead, the largest U.S. reservoir, will plummet even further than they have. The cuts will place officials in those states under extraordinary pressure to plan for a hotter, drier future and a growing population. Mexico will also face cuts.

Lake Mead is currently less than a quarter full and the seven states overall that depend on its water missed a federal deadline to announce proposals on plans cut additional water next year.

The Colorado River provides water to 40 million people across seven states in the American West as well as Mexico and helps feed an agricultural industry valued at $15 billion a year. Cities and farms across the region are anxiously awaiting official hydrology projections — estimates of future water levels in the river — that will determine the extent and scope of cuts to their water supply.

And that’s not all: Officials from the states are also scrambling to meet a deadline imposed by the U.S. Bureau of Reclamation to slash their water use by at least 15% in order to keep water levels at the river’s storage reservoirs from dropping even more.

Together, the projections and the deadline for cuts are presenting Western states with unprecedented challenges and confronting them with difficult decisions about how to plan for a drier future.

While the Bureau of Reclamation is “very focused on just getting through this to next year,” any cutbacks will likely need to be in place far longer, said University of Oxford hydrologist Kevin Wheeler.

“What contribution the science makes is, it’s pretty clear that that these reductions just have to have to stay in place until the drought has ended or we realize they actually have to get worse and the cuts have to get deeper,” he said.