Water levels at drought-stricken Lake Powell have dropped below an elevation water managers had fought to protect, dipping past a buffer meant to protect hydropower generation.
For the first time since water rose behind Glen Canyon Dam in the 1960s, the lake’s surface dropped below elevation 3,525 Tuesday, the U.S. Bureau of Reclamation said Wednesday morning. The dam can still produce electricity down to elevation 3,490, but shallower water reduces pressure and the power plant’s capacity, and further declines could damage the turbines.
The new low reflects the continuing dirty work of the region’s worst drought in 1,200 years, one that has deepened into a megadrought, according to scientists. High water demand from both a growing regional population and the effects of a warming climate promise to continue challenging water managers to shore up the Colorado River’s second-largest savings account.
Federal officials have set a goal of keeping the water higher than 3,525 feet above sea level, both for power production and for storage to safeguard Colorado River flows to Lake Mead and downstream users. The water is expected to rebound past that level when snow melts in the Rockies this spring, but Tuesday's plunge marks one more in a series of troubling firsts — some foreboding and others already costly — for a river in decline.
Reservoir's decline is 'disturbing'
Temporarily crossing below the target elevation of 3,525 feet is more bad omen than crushing blow, as Arizona water officials say they’re watching the long-term elevations, not the daily dips.
“Nevertheless,” said Tom Buschatzke, director of Arizona Department of Water Resources, “the continued long-term trend of decline in the reservoir is disturbing.”
The reservoir’s decline already has changed the physical and recreational landscape at Glen Canyon National Recreation Area, where new islands and peninsulas are emerging and ramps are dry.
Boaters returning to Lake Powell marinas this spring will find just one ramp open for launching motorized craft, compared to at least eight in past years. That ramp, Stateline Auxiliary near Page on the reservoir’s south end, was extended to reach the plunging water line. Last week, the National Park Service announced that a contractor also had begun extending a ramp at Bullfrog Marina, far upstream in Utah.
The new ramp should reach down to elevation 3,525 by the time spring runoff starts raising the reservoir around Easter, the agency said in a news release. After that, its continued use will depend on the water staying at or above that level.
The water’s continued depletion has energized the efforts of some environmentalists to restore Glen Canyon by eliminating the impoundment altogether.
“It’s time to decommission Glen Canyon Dam, a doomed structure that should never have been built in the first place,” said Gary Wockner, executive director of Save the Colorado. Propping up Lake Powell would require paying farmers to stop irrigating massive swaths of the Southwest, he said, “which would be a huge waste of money because the climate science indicates that the Colorado River will get even lower and drier in the future.”
Wockner’s organization has launched a contest for engineers and engineering students to propose ways of “rewilding” the river and bypassing the dam. Such a scheme would let the water flow freely to Lake Mead, a larger reservoir that has also plunged to new lows during the drought. Lake Mead is currently at 1,064 above sea level, and would trigger greater shortages for water users if it drops another 14 feet and stays there at the start of next year.
Loss of power would be costly
To those who use and promote the dam’s electricity, crossing the 3,525 threshold is an alert that more action is needed to protect the minimum power pool. The dam supplies some of the power for 54 Native American tribes and for 5 million customers across the region, and is important for grid stability and even restoring power to Arizona’s Palo Verde nuclear plant in the event of a grid outage, said Leslie James, executive director of the Colorado River Energy Distributors Association.
The U.S. Bureau of Reclamation has said it’s possible the dam will have to stop generating power this summer if snowmelt is insufficient, and that the odds of that happening will increase in coming years. Tribes and other power users across the West will have to find alternative energy sources if that happens, and already are paying higher rates because of the dam’s diminished output.
“The more that can be done to maintain generation, the better,” she said.
So far the Bureau of Reclamation has supported Lake Powell by releasing water from upstream dams and holding back some of what Powell owed Lake Mead this year. That water will eventually have to be released this year, though, leaving Powell’s fate to the snow still piling up in the mountains.
The winter’s precipitation and soil moisture readings currently do not foreshadow a quick reversal. After an auspicious start with December snowfall around the river’s Rocky Mountain headwaters, February brought a record dry spell in areas such as the Upper Green River in Wyoming.
“It’s been a bit of a roller coaster this year,” said Cody Moser, senior hydrologist with the Colorado Basin River Forecast Center.
The Green — largest of the Colorado’s tributaries — has about 80% of its normal snowpack for this time of year. Conditions are better in the Colorado Rockies, putting the entire basin’s snowpack at about 95% of normal. Still, the center forecasts a spring runoff of only about 70% of average, reflecting relatively dry soils that will soak up some of the runoff.
Those norms are tied to a 30-year period that includes the 1990s, a wetter decade than the river has seen since drought began at the turn of the century.
Conditions are worse still in the Lower Colorado River Basin, where a dry La Niña weather pattern is squeezing streams that enter the river downstream of Lake Powell. Those drainages contribute a relatively small share of the river’s overall volume.
Environmental coverage on azcentral.com and in The Arizona Republic is supported by a grant from the Nina Mason Pulliam Charitable Trust. Follow The Republic environmental reporting team at environment.azcentral.com and @azcenvironment on Facebook, Twitter and Instagram.
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This article originally appeared on Arizona Republic: Lake Powell plunges past a level that water managers sought to protect