Colorado Basin snowpack still sub-par
April 28, 2015
Last week's storms, which snarled I-70 and calmed fears of an early start to wildfire season, didn't significantly improve the regional water supply picture.
April 20 snowpack levels in Western Colorado ranged from 40 percent of average in the Southwestern basins to 71 percent in the Colorado Basin. The statewide snowpack was at 61 percent of average.
The South Platte Basin snowpack, upstream from Colorado's most populated areas, got the biggest bump out of the storms and reached 94 percent of average. Combined with above-average Front Range storage, that should take some pressure off diversions from Grand County. However, statewide, the total amount of water in the snow that has fallen since the 2015 water year began on October 1, 2014, (as opposed to snowpack at this moment in time) was a little less than 80 percent of normal.
As mediocre as Colorado's snowpack is, it's in better shape than the snowpack in most of the rest of the West. Eastern Utah is down to just 4 percent of normal, with no basin in the state above 50 percent.
“The troubling long-term picture in the Colorado River Basin as a whole is not improving, and another year like this one will lead to those formal shortage declarations in the Lower Basin, as well as drop Lake Powell closer to the minimum level at which it can generate power.”
Unsurprisingly, forecast inflows into Lake Powell are significantly below average. The Bureau of Reclamation forecast released April 20 predicted inflows of just 6.832 million acre feet, or 63 percent of normal, for the full 2015 water year.
At the same time, the total forecast releases from Lake Powell to Lake Mead, under operating criteria agreed to several years ago by the states that share the river, are expected to be between 8.23 and 9.0 million acre feet.
So Lake Powell, which is currently 45 percent full, will certainly not be getting any fuller this year. Lake Mead is 39 percent full, and total Colorado River Basin storage is 48 percent full, up one percentage point from last year.
The US Drought Monitor predicts that the next three months are likely to be wetter than average for the Four Corners states, and that the relatively mild drought (compared to California) over most of Western Colorado is likely to improve. Farther to the south and west, however, drought conditions are expected to persist or intensify.
This year, due to good storage levels, we probably won't see severe water shortages in Colorado, and downstream, Lake Mead is likely to get just enough water to prevent a formal shortage declaration, which would lead to reduced water deliveries to some Arizona farmers.
But the troubling long-term picture in the Colorado River Basin as a whole is not improving, and another year like this one will lead to those formal shortage declarations in the Lower Basin, as well as drop Lake Powell closer to the minimum level at which it can generate power.
This regional context is important to keep in mind as Colorado's water leaders continue their work to complete a statewide water plan. The East Slope as well as the West Slope relies heavily on water from the Colorado River Basin, and both current and future uses of this water could be impacted if water storage levels drop much lower.
Hannah Holm is coordinator of Water Center at Colorado Mesa University. This is part of a series of articles coordinated by the Water Center at Colorado Mesa University in cooperation with the Colorado and Gunnison Basin Roundtables to raise awareness about water needs, uses and policies in our region. To learn more, go to http://www.coloradomesa.edu/WaterCenter. You can also find the Water Center on Facebook at https://www.facebook.com/WaterCenter.CMU or on Twitter at https://twitter.com/WaterCenterCMU.