Colorado River is named the most endangered river in the United States as the southwestern states face water shortages
An aerial view of Lake Powell is seen, where water levels have declined dramatically to lows not seen since it was filled in the 1960s as growing demand for water and climate change shrink the Colorado River and create challenges for business owners and recreation in Page, Arizona, U.

Seven U.S. Western states that share Colorado River water are poised to miss a federal deadline for drastic consumption cuts amid a megadrought.

The U.S. Bureau of Reclamation in June gave the states 60 days, until mid-August, to devise a plan as human-influenced climate change worsens the region's driest 22-year period in at least 1,200 years.

Without a deal, the bureau may mandate reductions.

"Despite the obvious urgency of the situation, the last 62 days produced exactly nothing in terms of meaningful collective action to help forestall the looming crisis," one of the negotiators, John Entsminger, general manager of the Southern Nevada Water Authority, said in an open letter to the bureau on Monday.

While officials had given the states 60 days to negotiate an agreement, the firm deadline was seen as Tuesday, when officials with the reclamation bureau were scheduled to release their projections for Colorado's two largest reservoirs, Lake Mead and Lake Powell. Bureau officials have scheduled a news conference on both topics for 1 p.m. ET (1700 GMT) on Tuesday.

The impasse is testing the strength of the 100-year-old Colorado River compact, which determines the water rights of Arizona, California, Colorado, New Mexico, Nevada, Utah and Wyoming.

Citing "dangerously low" water levels at Lake Mead and Lake Powell, federal officials called on states to cut their overall usage of Colorado River water by 2 million to 4 million acre-feet of water per year, an unprecedented reduction of 15% to 30% in the coming year.

The lakes hover at around 25% of capacity. If they fall much lower they will be unable to generate hydroelectric power for millions in the West, and also will not allow water to flow downstream.

"The bureau is asking institutions used to working over the time frame of decades to do something drastic in a few months. States have been given 60 days to come up with more than twice the cuts that they agreed to over 20 years of previous drought agreements," said author and former water manager Eric Kuhn, who supports the ambitious cuts sought by the bureau.

The Colorado River compact assumes the river would have roughly 20 million acre-feet of water each year. The river's actual flow the past two decades has averaged 12.5 million acre-feet, leaving state water managers with more rights on paper than water that exists in the river.