For the past 20 years, the Colorado River has been operated under a set of guidelines negotiated between the seven states that depend on the river. Those guidelines expire this year, and after five years of grinding negotiations over a new agreement, the upstream states of Colorado, Wyoming, Utah and New Mexico remain deadlocked against the downstream states of California, Arizona and Nevada. … That has set up a showdown over a legal time bomb that’s been ticking away at the heart of the Colorado River Compact since the river’s guiding document was signed more than 100 years ago. The Lower Basin states believe the Compact promised them a minimum delivery of water sent down the river from the Upper Basin. The Upper Basin states believe the Compact promised them a fixed amount of water that they could rely on to meet future growth. As the river’s flows have dwindled, those two supposed guarantees are proving to be irreconcilable.

Other Colorado River management news:

• Aspen Journalism (Colo.): Western Slope lawmakers take Colorado River managers to task
• NBC9 (Denver, Colo.): Colorado’s top negotiator says lower basin states are draining Colorado River reservoirs as deadline looms
• Arizona’s Family: How will Colorado River water cuts impact Arizona? Depends on where you live
• California WaterBlog (UC Davis): A tributary approach to learning the Colorado River
• Circle of Blue: Blog: An online prediction market offers wagers on a shrinking Lake Mead
• Coyote Gulch: Blog: What if the Department of the Interior focused on buying the water rights of large-scale forage producers, first?
• ABC15 (Phoenix): Video: Take a tour of Lake Mead’s decline
• Complete Colorado: Video: A deep dive into the battle over Colorado River water​