Even a winter packed with rain and snow could not bring the Colorado River crisis to an end. The river is still drying out. And on Tuesday, government officials announced two historic proposals to prevent the system and the some 40 million people it sustains from crashing.

The proposals seek to slash the amount of river water supplied to cities and farms in the Southwest by as much as 2 million acre-feet, in addition to any existing cuts. It’s a massive number, equal to more than a quarter of the water that the region currently consumes. (An acre-foot fills one acre of land with one foot of water and is roughly what two average houses use each year.)

In a room overlooking the Hoover Dam and Lake Mead, the nation’s largest reservoir, Bureau of Reclamation Commissioner Camille Calimlim Touton presented two potential strategies for protecting the system in the near term. They apply to the lower basin states — California, Arizona, and Nevada — and the proposals have vastly different consequences for each.