The extremes of the Colorado river's water supply have been forecast over the next 25 years, and there's some good news for the drought-hit waterway.
The Colorado River has been on the brink of a crisis in recent years. Warmer temperatures and prolonged drought conditions have been linked to a concerning decrease in its water flows, which have reached such low levels that officials were concerned whether the river could ever recover.
But a new paper, from researchers at the Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder (CIRES), estimates snow and rainfall could play a big part in the future of the Colorado River's flows between 2026 and 2050, despite climate warming.
Better management of Lake Mead and Lake Powell reservoirs could also help bring the river back to life, according to the lead author.
"There are two pieces to the puzzle of the future flows that we examined. One is the dynamic range of natural variations in the river's flow, which we learned have resulted almost entirely from precipitation. The recent drought has much to do with such a cycle, and a recovery to wetter conditions is therefore probable," lead author and CIRES affiliate Martin Hoerling told Newsweek in an email.
The scientists made their forecast by taking precipitation into account and accounting for its "range of extremes between wet and dry 25 year periods.
And the new study says, although the temperatures are rising, precipitation is also likely to increase, replenishing the river's flows.
"That leads to a better outlook than those based on fears that warming alone had caused the recent drought (it hasn't), and that recovery would be impossible given that warming would only intensify. Warming has indeed made matters worse, but has not caused either the drought or the crisis," Hoerling added.
The second piece of this puzzle is water management itself, Hoerling said. The water crisis exposes a problem with how water is used in the West, especially in the lower Colorado River basin. This includes Lake Mead and Lake Powell, the two huge Colorado river reservoirs that provide water storage and hydro power to the region.
"Improved management of Lake Mead and Lake Powell water resources is under discussion as part of the planned new Interim Guidelines to be issued in 2026, so as to prevent a further crisis while equitable sharing water among all parties," Hoerling added.
To reach their conclusions, the authors analyzed flow data dating back to 1895 at Lee's Ferry, where the upper and low Colorado basins divide. They discovered that precipitation largely influenced the flows of the river.
For example, the megadrought that has gripped the region since 2000, caused low precipitation which depleted the water to only 12.5 million acre-feet.
They also looked at climate models to predict what the river's future could look like. The river is largely fed by snowmelt in the mountains from Colorado and Wyoming. These regions only account for 15 percent of the basin, the authors report. However it created 85 percent of the river's entire flow. And just small increases in this precipitation, will offset further declines in water linked to warm temperatures, they report.
"Core to the study is understanding what drives Colorado River flows. Over 80 percent of the ups and downs of those flows from one decade to another result from precipitation," Hoerling said.
"Warming due to climate change is now acting to deplete the river, but precipitation variability has been, and is likely to continue to be, a more critical factor at least to mid-century. Importantly, we find climate change will likely increase precipitation in the Colorado headwaters. This will compensate some if not most of the depleting effects of further warming."
Overall, while climate change is certainly causing a change in weather patterns, the study reports it unlikely that precipitation would decline even further then it already has.
The researchers hope this new study will help inform further guidelines on the river for the next 25 years.
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Uncommon Knowledge
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Robyn White is a Newsweek Nature Reporter based in London, UK. Her focus is reporting on wildlife, science and the ... Read more
