DENVER (AP) – Tension over the drought-stressed Colorado River escalated into a public feud when four U.S. states accused Arizona's largest water provider of manipulating supply and demand, potentially threatening millions of people in the United States and Mexico who rely on the river.
The four states – Colorado, New Mexico, Utah and Wyoming – plus Denver's water utility said the Central Arizona Project was trying to avoid a reduction in its share of the Colorado River while others are voluntarily cutting back to avoid a crisis amid a prolonged drought.
"It's one water user taking advantage of a situation for their own benefit, to the detriment of a river that supplies nearly 40 million people," said Jim Lochhead, manager of Denver Water, which gets about half its supply from the Colorado River.
The Central Arizona Project denied the allegations and said it's been conserving. The utility uses canals, pipelines and aqueducts to carry water 336 miles from the Colorado River to about 5 million people in central and southern Arizona.
The Colorado River is the lifeblood of the southwestern U.S. and northwestern Mexico, but it's under increasing strain because demand is rising while the river is shrinking. Researchers blame an 18-year drought and climate change for the decline.
The outlook is getting worse. Last winter was exceptionally dry across most of the central and southern Rocky Mountains, so there will be below-average melting snow to feed the river.
The dispute over the Central Arizona Project revolves around how much water flows from the upper part of the Colorado River system to the lower. The upper part, called the Upper Basin, includes the four states challenging the Arizona utility. The Lower Basin includes Arizona, California and Nevada.
Each basin is entitled to about half the river's water under rules laid out in a collection of interstate agreements, court rulings and international treaties.