Colorado water managers are keeping a close eye on the historically low reservoir levels at Lake Powell.
Under the Colorado River Compact, the major river is divided between upper basin states and lower basin states.
Upper basin states, including Colorado, are obligated to deliver 75 million acre-feet of water into Lake Powell on a rolling 10-year average.
So far, those obligations are being met. But mountain snowpack depended on to fill the Colorado River has been below average over the past decade, creating two potential scenarios never before seen.
First, if the current trend of drier than normal winters continues, officials predict that by 2016, Lake Powell will drop below levels needed to operate the hydro-electric power plant at Glen Canyon dam.
The power is depended on by 5.8 million residential customers and generates critical funding for maintenance of federal water projects, including a recent $4 million renovation of McPhee reservoir’s pumping plants.
Second, if Lake Powell doesn’t receive its legal water share needed for power generation, upper basin storage reservoirs would have to make up the difference under the compact.
Lake Powell has only filled three times in the last in 14 years, and consistently hovers around 50 percent. If it drops much lower, it would trigger a “compact call on upper basins, causing immediate problems,” said Mike Preston, president of the Southwest Basin Roundtable, a group looking for solutions to conserve water.
In a compact call, three storage facilities would be tapped to fulfill Lake Powell’s share of the Colorado River Basin: Flaming Gorge reservoir in Wyoming, Blue Mesa reservoir near Gunnison, and Navajo Reservoir in New Mexico.
“They are designed specifically to store water for delivery to Powell to satisfy the compact,” Preston said.
Another ripple is that Colorado’s Front Range is looking to tap Blue Mesa and Flaming Gorge reservoirs, via transmountain diversions, to satisfy increasing water demands.
“That would diminish what is left for lower-basin compact compliance,” Preston said.
