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Three Colorado River Basin reservoirs will be partially drained to keep Lake Powell producing hydropower

Drought made an expected 2.5 million acre-feet of water disappear before it ever reached the key reservoir in the Colorado River Compact, forcing federal officials to siphon from Blue Mesa Reservoir and other big pools to protect the electric grid.

The receding shoreline of Blue Mesa Reservoir, near Gunnison, Colorado, shows signs of severe drought on July 16, 2021. Two years of low snowpack and below average rainfall in the Gunnison River basin has lowered the Blue Mesa Reservoir to less than 44% of capacity as of today according to the Blue Mesa Reservoir's official data base. (bluemesa.water-data.com).The reservoir is dropping 4 inches a day. Because the reservoir is one of the key water storage facilities in the Colorado River Basin its water is being released to flow downstream to supplement Lake Powell. Lake Powell is also drawing water from the Green River's Flaming Gorge Reservoir which is at 93% of capacity. (Dean Krakel, Special to The Colorado Sun)
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The nation’s Western drought is so severe that federal predictions of Colorado River flows into Lake Powell for 2021 dropped by the equivalent of 10 Lake Dillons in just six months, according to a key new report. 

In issuing the report Friday, U.S. water engineers said they will for the first time take water from Flaming Gorge, Blue Mesa and Navajo Reservoirs to protect electric power production at Lake Powell’s Glen Canyon Dam, where water levels are in danger of falling below the electric turbine intakes. 

The bureau is now predicting 2.5 million fewer acre-feet of water coming into Lake Powell from natural runoff in 2021 than they had forecast six months ago. That loss is 10 times the entire working capacity of the Lake Dillon reservoir along I-70 in central Colorado. 

The sobering 24-month prediction and dam operation plan from the Bureau of Reclamation said that while the decades-old system of massive storage buckets on the Colorado has served tens of millions of Western residents well, the extended drought and climate change forced an early and dramatic switch to Plan B. 

“Here we are now in 2021, and the basic underlying assumptions that we’ve been able to rely on are beginning to erode,” said Wayne Pullan, director of the bureau’s Upper Colorado River Basin region. 

Pullan said it’s essential to begin refilling Lake Powell with the cooperation of other reservoirs, state officials throughout the basin, and environmental, agriculture and recreation interests, “now that we’ve reached that place we feared we might reach.”

“It’s going to require the best everybody has to give to thread this needle,” Pullan said. 

Pain ahead for Upper Basin states

The new plan announced to shore up Powell for the rest of this year signals pain for all the Upper Colorado Basin states of Wyoming, Colorado, New Mexico and Utah. A lowered pool in upstream reservoirs can affect fishing, water recreation and more, with other conservation pilots in the works in coming years to pay ranchers to give up some of their water without relinquishing long-term rights. 

Flaming Gorge Reservoir, on the Green River in Utah and Wyoming, will let an extra 13,000 acre-feet of water flow down river toward the Colorado in July, jumping to 42,000 acre-feet in August. By fall, Flaming Gorge will have contributed a total of 125,000 acre-feet to protect Lake Powell’s hydroelectric pool. 

Blue Mesa Reservoir, west of Gunnison, will contribute 14,000 acre-feet beginning in August, 18,000 in September and 4,000 in October, for a total of 36,000 acre feet. Blue Mesa dams the Gunnison River, which joins the Colorado River at Grand Junction. 

TODAY’S UNDERWRITER

Navajo Reservoir, on the Piedra and San Juan rivers in southern Colorado and northern New Mexico, will give up a total of 20,000 acre-feet to Lake Powell in November and December. Taken altogether, the releases will raise Lake Powell 3 feet, enough to protect hydropower production. The idea of banking extra water in Lake Powell from the upstream reservoirs became the official federal plan in 2018

Federal officials in a press briefing Friday said the extra releases will mean about an 8-foot drop in Blue Mesa’s already-depleted pool, 2 feet from Navajo and 4 feet from Flaming Gorge.

“There’s a disparity in the size of these reservoirs,” said Christopher Cutler, a manager in the water and power services section of the Bureau of Reclamation. “The bigger the reservoir, the less the elevation drop will occur for the given amount of water.” 

The federal agency said it had no choice but to move more water for power operations at Lake Powell’s dam after drought burned up their previous river predictions. 

Blue Mesa Dam on Blue Mesa Reservoir near Gunnison, Colorado, on July 16, 2021. Federal officials will use water stored in Blue Mesa, Flaming Gorge and Navajo Reservoirs to raise the level of Lake Powell downstream in order to keep that important pool viable for producing hydroelectric power. (Dean Krakel, Special to The Colorado Sun)

Lake Powell will see only 3.2 million acre-feet of natural inflow this year, just 30% of a normal year’s total, the bureau said. As part of the compact between Upper Basin states and the Lower Basin states of Nevada, California and Arizona, the bureau will release a total of 8.23 million acre-feet from Lake Powell to downriver users in 2021. The lake’s enormous pool has drained precipitously in the ongoing 22-year southwestern drought. 

“Yes, the snowpack wasn’t great,” Pullan said. “But the real concern was the dry soils. And then on top of that, things just dried up.” 

Water officials in western Colorado have spoken this year of soils stricken by long-term drought sucking down any runoff before it reaches streambeds, and of snowpack simply evaporating into warm air. 

Another federal report pending in August is expected to verify long-anticipated cutbacks in 2022 releases from Lake Powell and Mead to Lower Basin compact states, as the reservoirs fell below trigger levels set in the compact agreement between the seven states. Arizona will be the first to get severe cutbacks next year, expecting to lose as much as 500,000 acre-feet of water from levels it received in recent years. That will primarily mean a loss to farmers. 

Impacts already being felt

Upper compact states were not supposed to be affected by 2022 cutbacks under the official agreement. But Colorado water experts say the impacts of compact “calls” are already here. 

“I would say that Colorado is already facing real consequences, but so far they have been limited to the agricultural community, mostly on the West Slope, and the environment, as streams run very low and warm,” said Andy Schulteiss, executive director of the nonprofit Colorado Water Trust, which helps arrange water purchases to promote river health. 

“Many ranchers and farmers have been cut off (by local providers) this year because of the extreme low flows, and many more will be in the coming months. That means their primary source of income is gone or severely limited,” Schulteiss said. 

More formal compact cuts to water available in the Upper Basin states “seem inevitable and not far away,” he added. 

The latest U.S. Drought Monitor puts nearly all of western Colorado in the “extreme” or “exceptional” drought categories, along with most of Nevada, Utah, Arizona and a large portion of California. Climate scientists have identified the current 20-plus years as a western “megadrought” among the worst in 1,200 years

Federal officials announcing the partial refilling of Lake Powell Friday were asked what they will do if there’s no drought relief, and the upstream releases are not enough to last. 

“We are preparing for that now, by modeling,” Cutler said. “So we’re modeling not only normal hydrology next year, but dry and extremely dry.” 


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