Colorado River Reservoirs Expected To Be Less Than Half Full, Headed Toward Historic Low

Jun 15, 2018

Reservoirs that store water along the Colorado River are projected to be less than half full later this year, potentially marking a historic low mark for the river system that supplies water to seven U.S. states and Mexico.

Forecasters with the U.S. Bureau of Reclamation expect the river’s reservoirs -- Lakes Mead and Powell among them -- to be at a combined 48 percent of capacity by the end of September. That would be one of the lowest points ever for the combined water storage.

Without significant rainfall this summer and fall and above average snow this upcoming winter the combined reservoir storage could dip to 44 percent of capacity by April 2019 according to Reclamation models.

The previous low point for total system water storage came after the two driest consecutive years in the watershed on April 1, 2014, when the river’s reservoirs were at 47 percent of capacity.  

“We’re in uncharted territory for the system,” says Jeff Kightlinger, general manager of the Metropolitan Water District of Southern California, the water wholesaler for the greater Los Angeles area, which relies on the Colorado River for a portion of its supplies.

“Everything is new, and it is all bleak. None of it is positive,” Kightlinger says.

The root cause of this problem is two-fold: Low snowpack this past winter is causing reservoirs already sapped by 18 years of dry conditions to dip even lower. And the river itself is over-allocated, where more water exists on paper in the form of water rights, than what exists in reality.

Lake Powell, the water savings account for Colorado, Wyoming, New Mexico and Utah, is taking the brunt of this year’s dry weather, says Rick Clayton, a Salt Lake City-based Bureau of Reclamation engineer.

“Lake Powell is not getting a very significant inflow and we’re making a pretty large release,” he says.

Inflow to Lake Powell, provided by the Colorado River’s main channel and the San Juan River, is projected to be 39 percent of average. That places 2018 among the driest years on record for the river basin.

The river’s reservoirs have remained low for nearly the entirety of the 21st century, Clayton says.

“When a reservoir system is half full [it] isn't necessarily a reason to panic,” Clayton says. “It is not uncommon for the Colorado River reservoir system to be nearly half empty, especially during the recent protracted drought we have been experiencing since 2001.”

Colorado, Wyoming, Utah, New Mexico, Arizona, Nevada, California and the country of Mexico all claim some portion of the Colorado River’s flow. The river provides water for about 40 million people in the southwest and irrigates 1.7 million acres of farmland.  

This story is part of a project covering the Colorado River, produced by KUNC and supported through a Walton Family Foundation grant. KUNC is solely responsible for its editorial content.