Plummeting reservoir levels at Mead and Powell solidify Arizona cutbacks next year and near-future threats to all the Compact states, from Colorado to California
Jul 13, 2021
A blunt new report based on June runoff conditions from the Colorado River into Lake Powell and Lake Mead shows the reservoirs fast deteriorating toward “dead pool” status, where stored water is so low it can’t spin the massive hydroelectric power generators buried in the dams, and large swaths of Arizona farmland going fallow.
The enormous, life-sustaining buckets of water in the drought-stricken West are emptying so fast that the Bureau of Reclamation added a new monthly report – on top of three already scheduled this year – to keep up with the dam
The bureau said the loss of water is accelerating, confirming projections that massive water restrictions will begin in 2022 for the three Lower Basin states in the seven-state Colorado River Compact. Conservation groups believe Arizona will lose more than 500,000 acre-feet of water usually delivered by the Colorado in 2022 through voluntary and mandatory cuts, forcing significant reductions to irrigated farming in the desert state. Some, but not all, of Arizona’s share will be replaced in trades using water already “banked” in the reservoirs.
The bureau’s report for June, added on to previously scheduled reservoir updates for January, April and August, paints a dire picture. As snowpack runoff disappeared into dry ground instead of hitting the reservoirs, engineers calculated a 79% chance Lake Powell will fall below its minimum target water height of 3,525 feet above sea level next year.
That minimum provides only a 35-foot cushion for the minimum water level of 3,490 feet needed to spill water into the electric turbines. The bureau said there is now a 5% chance Lake Powell falls below the minimum needed to generate any power in 2023, and a 17% chance in 2024 — the odds are going up with each new report.
Lake Mead, which feeds the three Lower Basin compact states of Nevada, California and Arizona, is in even worse shape. The compact requires declaration of restriction-triggering “shortage condition” if Mead hits 1,075 feet or lower. Mead is falling now, and the bureau affirmed the shortage declaration will happen in August. Las Vegas, a short drive from Mead and Hoover Dam, hit 117 degrees on July 10, and longtime local users are alarmed at how fast the pool is evaporating into desert skies.
Mead is also in great danger of hitting “critical” elevations of 1,025 feet, a sort of emergency-stop minimum, and the minimum pool for generating power at 1,000 feet, the bureau’s new report said. The chances of draining past the minimum by 2025 are now 58%, and the chances of falling below a power pool that year are 21%.
Weather plus climate change
Long-term climate change is being exacerbated by a short-term drought lasting more than 20 years in the West, scientist and water engineers say. Even with a future snowpack bonanza – not currently in the forecast – the compact reservoirs will remain in deep trouble, said John Berggren, water policy analyst for the nonprofit Western Resource Advocates.
The Colorado River basin’s latest snowpack was just about 100% of normal, Berggren noted, but delivered only 50% of normal runoff into the river and the giant reservoirs. Water is soaking into parched ground or evaporating entirely before it can contribute to stream flows.
“It’s startling how with each new projection, you had thought it can’t possibly get worse,” Berggren said. “Even just a year or two ago, most people would have thought these projections are pretty far away from ever happening.”
Major water cutbacks for the Lower Basin states are now an unavoidable reality, Berggren said. “This just shows that we no longer have the luxury of thinking it’s a decade down the road.”
“The June five-year projections for the Colorado River System reaffirm this is a serious situation,” Wayne Pullan, Upper Colorado Basin regional director for the Bureau of Reclamation, said in a statement about the latest river modeling. “We are actively engaged with the Colorado River Basin states and other partners to respond to changing conditions to avoid critical elevations at Lake Powell.”
The original compact between Upper Basin states – Colorado, New Mexico, Utah and Wyoming – and the Lower Basin was negotiated in 1922. It was given real teeth in 2019 with a Drought Contingency Plan that first penalizes Lower Basin states if levels and inflows into Powell and Mead fall below trigger points.
Upper Basin states face future cutbacks in water use as well if they can’t deliver agreed-upon amounts of water to the basin separation point at Lee’s Ferry, Arizona, just above the Grand Canyon. Colorado water engineers, agricultural interests and utilities are in ongoing discussions and experiments on how best to leave more in the Colorado should those downstream treaty calls eventually come.
Mexico is also part of the historic compact. Some states are negotiating with Mexico to build ocean water desalinization plants near the Pacific Ocean, so that Mexico could use that water and the states could keep more river water.
Colorado tries to refill the Yampa
Colorado water managers, meanwhile, are working quickly to mitigate some of the intense near-term impacts of recent drought, including along the severely depleted Yampa River in northwest Colorado, which is a tributary of the Colorado River.
On July 8, the Colorado Water Trust bought 1,000 acre-feet of water in Stagecoach Reservoir, with an option to buy 1,000 more, for releases over the rest of the summer into the Yampa to keep fish alive and keep the river basin healthier in hot temperatures. The Water Trust has made similar purchases in other years, but will likely have to release the water far earlier than usual this season in order to prevent high water temperatures and stagnant flow that stress fish and hurt their spawning chances.
After spending about $46,000 on the July purchase, the trust has spent just under $500,000 to buy water from Stagecoach’s reserve since 2012. In announcing the deal, the Upper Yampa Water Conservancy District noted the late-May stream flow into Stagecoach was at less than 10 cubic feet per second, when it should have been more than 100 cfs. The district said it has separately released more than 1,500 acre-feet of its own water from Stagecoach so far this year in order to support river health.
Cash donors to buy the Stagecoach water include the Yampa River Fund, the Yampa Valley Community Foundation and the Tri-State Generation and Transmission Association, among others. Tri-State operates coal-fired electricity generating units down the Yampa to the west of Stagecoach.