Coming soon: Lots of water
Rivers may top banks in places
Endless winter in parts of the Rockies will result in much-needed water for the Southwest, but some of the waterways delivering it face a sizable flood threat as a result.
There’s currently more than a 50 percent chance of the Colorado River flooding at Cameo, and flooding is all but a certainty on part of the Yampa River, the Colorado River Basin Forecast Center says.
The upside is that runoff into Lake Powell is predicted to be 139 percent of average, possibly meaning even more inflow into that reservoir than during the big runoff years of 1995 and 1997, said Eric Kuhn, general manager of the Colorado River Water Conservation District.
That will enable Powell to deliver an extra 3 million to 4 million acre-feet of water downstream to Lake Mead, probably putting off for a few years the possibility of a shortage being declared for Mead. Last year Mead’s water level fell to its lowest since first filling in the 1930s, prompting expectations then that shortage criteria might be imposed by 2012, affecting Arizona and Nevada.
“That’s what a good year can do,” Kuhn said.
He added others are relieved that a big water year will buy some time in dealing with what Kuhn still considers to be an inevitable problem of overuse of Lake Mead water by states in the Lower Basin of the Colorado River.
Michelle Garrison, water resources specialist for the Colorado Water Conservation Board, said, “Being able to put that off and make a large delivery to them and prevent shortages for a while is, I think, helpful to everybody.”
Big water’s coming
Shorter-term, experts are closely watching just how high waters will rise in Colorado when runoff begins in earnest.
“They’re already experiencing flooding in northern Utah,” Garrison said.
The forecast center is predicting a 90 percent chance of the Yampa River reaching an average daily flow of 23,000 cubic feet per second, which is above flood stage, at Deerlodge Park in Moffat County, and odds are 50-50 that the flow could reach 28,000 cfs. It says flooding likewise is all but a certainty on the Green River at Jensen, Utah.
Its current forecast was issued April 26. It plans to issue an updated forecast today.
Snowpack in the Yampa and White river basins was a whopping 170 percent of average Wednesday, according to the Natural Resources Conservation Service. The Upper Colorado River Basin wasn’t lagging far behind, at 163 percent, and the Gunnison Basin was at 148 percent.
Southwestern Colorado had a less stellar snow season. The Arkansas Basin is at 120 percent of average; the Upper Rio Grande, 88 percent; and the San Miguel/Dolores/Animas/San Juan, 101 percent.
The forecast center says there’s a 50 percent chance of the Colorado River at Cameo topping out at an average daily flow of 28,000 cubic feet per second, and a 75 percent chance of it reaching 24,000 cfs. Flood flow at Cameo is 25,350 cfs. The average annual peak daily flow there is 17,500 cfs.
Aldis Strautins, a hydrologist with the National Weather Service in Grand Junction, noted the forecast peaks are for daily averages, and the instantaneous peak usually is higher.
At such high flows, structures such as agricultural outbuildings could be threatened, and bridges can be a concern, so the National Weather Service has been consulting with emergency-management officials so they can make preparations, Strautins said. The high water also can make boating dangerous and pose perils for recreationists along banks that the current can erode.
Strautins said a cool April that preserved existing snowpack and recent storms that added to it helped set the stage for a particularly high runoff season.
Warmer weather this week should help start reducing snowpack numbers, he said.
“But there’s still a lot of water up there to come off,” he said.
Ideally, he said, the Western Slope will see a cycle of warmer and cooler spells so runoff occurs in a prolonged, moderate fashion.
“We’re just at the mercy of the weather patterns,” he said.
A force for good
Garrison said one beneficiary of high water will be endangered fish such as the razorback sucker. Powerful currents can cause problems for the fish during a high-water year, but the flows do good in the long term by flooding backwaters that the fish favor.
As water officials look forward to filling Lake Mead, they’re also trying to figure out how to do it in a way that doesn’t let potential power generation slip through their fingers. Kuhn said there may be so much water this year “that they’re going to be operating the power plants at Lake Powell essentially at full capacity” to deliver to Mead the amount called for under U.S. Bureau of Reclamation operating guidelines for sharing water between the two reservoirs.
The matter hasn’t been helped by the fact that one turbine at Powell is down for long-term maintenance and another has a problem that is making it operate below its capacity, he said.
If the plant encounters further problems, or even more water reaches Powell that must be delivered to Mead, there is concern that some water would have to bypass turbines, meaning potentially millions of dollars worth of lost power generation. Kuhn said that’s not a problem for now, and he hopes it doesn’t become one because that’s money that is used by Upper Basin states for purposes such as operating hydroelectric plants and paying for transmission lines.
Meanwhile, commercial rafting operators in the Glenwood Springs area are looking forward to a bountiful water year on the river. Ryan Moyer, the new owner of Up The Creek Expeditions Inc., said runoff peaks aren’t necessarily good for business because they can scare some customers. But the companies stay off high-rapids sections such as just below the Shoshone Power Plant in Glenwood Canyon during the big water. Moyer said runoff offers the opportunities to run other area rivers such as the Roaring Fork and Crystal.
“It’s just going to be a year hopefully when we get a good, solid six or seven weeks out of those sections,” he said. “It’s going to be a nice runoff. It’s going to be an epic season.”