Colorado River Basin Water Supply & Demand Study Interim Report #1 is hot off the press

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From The Pueblo Chieftain (Chris Woodka):

An interim report was issued this week by the Bureau of Reclamation in conjunction with states in the Colorado River Compact. The interim report is a step leading to the final report next year. The report says the supply of water in the Colorado River basin could decrease by 10 percent as climate changes continue to alter the hydrology of the river…

Climate change models vary widely in the amount of precipitation, but are consistent in predicting higher temperatures for the region and a shift that will mean less snowpack and more rain…

The Colorado River is important to the Arkansas and South Platte basins because nearly 500,000 acre-feet of water is imported across the Continental Divide each year. A reduction in water availability could mean curtailment of diversions.

More coverage from Brett Walton writing for Circle of Blue. From the article:

Studies using different climate models have shown larger decreases in the mean annual runoff, but the results of this latest study are consistent with a Department of the Interior report that was released in March and quantified climate change effects for eight major river basins in the West. Three of the supply models for this report used combinations of observed hydrological data and historical reconstructions. They showed future conditions hewing relatively close to past conditions in terms of runoff, but with longer dry periods. The fourth model used a down-scaled global projection that takes climate change into account. This made the water supply situation more complex: river runoff would peak earlier in the year, prolonged wet periods would almost disappear, and the occurrence of droughts that last longer than five years would happen 40 percent of the time, resulting in larger water deficits…

But the supply situation is a familiar tale, told by many scientists and policy wonks. The more interesting piece of the Reclamation’s study will come with the demand assessments section and the evaluations for how to close the gap. The latter will address efficiency and conservation, agriculture-to-urban water transfers, and augmentation options that range from respected (desalination) to controversial (pipelines from northern Nevada, or even the Mississippi River) to fanciful (icebergs).

From The Grand Junction Daily Sentinel (Dennis Webb):

Drought frequency and duration are expected to increase under a climate-change model, one of four different water supply scenarios used by the agency in an ongoing study of supply and demand in the Colorado River Basin. The report says projected changes in the basin include continued warming in the basin, along with snowpack decreases as more precipitation falls as rain. “Droughts lasting five or more years are projected to occur 40 percent of the time over the next 50 years” under the climate change assumption, the report says.

More Colorado River basin coverage here.

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