"Unrelenting drought and years of rising temperatures due to climate change are pushing the long-overallocated Colorado River into new territory, setting the stage for the largest mandatory water cutbacks to date.
Lake Mead, the biggest reservoir on the river, has declined dramatically over the past two decades and now stands at just 40% of its full capacity. This summer, it’s projected to fall to the lowest levels since it was filled in the 1930s following the construction of Hoover Dam.
The reservoir near Las Vegas is approaching a threshold that is expected to trigger a first-ever shortage declaration by the federal government for next year, leading to substantial cuts in water deliveries to Arizona, Nevada and Mexico.
Arizona is in line for the biggest reductions under a 2019 agreement that aims to reduce the risks of Lake Mead falling to critical lows."