Runoff huge, but won’t solve drought thirst
Water managers will capture much of this year’s high runoff, filling most of the reservoirs in the upper Colorado River Basin and splashing much needed water into Lake Mead.
The runoff, though, won’t resolve the long-lasting effects of the drought of the past decade, a U.S. Bureau of Reclamation official said.
“We’re absorbing all the water we can,” said Rick Clayton, the hydraulic engineer who coordinates operations at Glen Canyon Dam. “We’re not in spill-avoidance mode this year.”
The Bureau of Reclamation operates the series of dams along the Colorado River that store water and generate electricity. The abundance of water so far has meant many of the reservoirs are expected to fill even as they’re letting water out at high rates.
“We have so much hydropower coming from every direction,” Clayton said. “There’s so much power that we can’t find customers to take it all.”
The high snowy peaks of Wyoming are full of enough snow that Fontanelle Reservoir above the town of Green River has been lowered to 35 percent of capacity in anticipation of flows that could fill and drain the reservoir three times over in the next two months, Clayton said.
Southwest Colorado is the lone exception to the heavy snowfall year, and Navajo Reservoir on the San Juan River is 85 percent full.
Come the end of the runoff season, all upper-basin reservoirs feeding into Lake Powell except Navajo should be full, Clayton said.
Reclamation is projecting Powell will be 75 to 80 percent of capacity by the end of the runoff, and the upper basin of the Colorado River will deliver 12.44 million acre-feet of water to the lower basin by the end of the water year, Sept. 30.
That exceeds the 7.5 million acre-feet the upper basin is required to deliver to the lower basin on a 10-year rolling average, under the compact by which the river is administered. It’s also 150 percent of what the upper basin has sent downstream annually during the drought, Clayton said.
The release will mark a significant step toward equalizing the levels of lakes Mead and Powell.
“We may not fully equalize, but we’ll be closer to where the discrepancy isn’t so great,” Clayton said.
The influx should bring Mead to 46 percent of its capacity, Clayton said.
If runoff is high enough next year, the Bureau of Reclamation plans to deliver more water to Mead, 12.78 million acre-feet, Clayton said. If it’s a dry year, the bureau will make adjustments month by month, he said.
As high as this year’s runoff has been, it’s not going to alleviate the drought, Clayton said.
“If we could just get one of these every three years,” he said, “we’d be in good shape.”