Rising temperatures induced by global warming are enhancing a 14-year drought in the Western United States—the worst seen in the region in about 1,250 years. The region's dam system and the 30 million people dependent upon it are paying the price.
On the endangered Colorado River, a recent pulse flow linked the vanishing waterway to the Sea of Cortez, allowing a rare opportunity for adventurers to float its length. But the pulse was fleeting, and water supplies continue to be an escalating issue. Facing dire shortages, river authorities are, for the first time, considering rationing or cutting water to major cities in lower basin states such as Arizona.
Authorities began decreasing water flow into Hoover Dam’s Lake Mead, America’s largest reservoir, to protect the river and aged distribution policies for the first time this year. Recent water-level readings show that Lake Mead, which is only 40 percent full, has been losing a foot of water every day and is set to fall to its lowest level ever next month.
"Here's a reservoir that can hold two full years of the flow of the Colorado River, and it's now down to less than one year's worth of flow," said John Entsminger, general manager of the Southern Nevada Water Authority, which supplies water to Las Vegas, in an interview with the Desert Sun.
To pump water and generate electricity, Lake Mead can’t fall below 1,000 feet; it’s projected to reach that level by 2020. If lower basin states can’t ration water themselves by 2019, they won’t get any at all. Lower basin states need to reduce drawdowns to at least 800,000 acre-feet of the 10.2 million taken annually—as much water as naturally evaporates from Lake Mead each year thanks to its large surface area.
Although global warming is playing a huge part in Western America’s water crisis, problems were enhanced for upper and lower basin states by faulty math in the early 20th century. When politicians first agreed on water allocations, they referred to historical water levels that grossly inflated how much water was truly available annually along the river. States have been drawing more water than the river can handle for almost a century.