Decreased flow projected for Southwest streams by end of century — @USGS #ColoradoRiver #COriver #RioGrande #aridification

Graphs showing water-year time series of basin-mean, annual-mean (A) precipitation (millimeters per year), (B) temperature (degrees Celsius), (C) April 1 snow water equivalent (millimeters), (D) surface albedo, (E) surface net radiation (watts per square meter), (F) evapotranspiration (millimeters per year), and (G) discharge per unit area (millimeters per year). Blue curves represent estimates from observations, and grey bands represent ensemble range of model outputs. Black line represents least-squares linear fit.(Credit: Paul (Chris) Milly, USGS)

Here’s the release from the USGS:

Streamflow in the Southwestern U.S. is projected to decrease by as much as 36–80% by the end of this century, reports a new study by the U.S. Geological Survey. Decreases of this magnitude would challenge our ability to meet future water demand in this region and could jeopardize compliance with interstate and international water-sharing agreements.

The study projects streamflow for the seven major river basins that comprise the U.S. Southwest, including the Colorado River and Rio Grande basins. Projections were done for three 30-year intervals starting in 2020 using seven different climate models, two greenhouse gas concentration scenarios, and a streamflow model. The maximum projected decreases for the river basins range from 36 to 80%. Some increases are projected as well, mostly during the next 30 years. However, most models suggest that substantial water stresses in the region are likely by about 2060.

Streams in the region provide water for drinking, agriculture, hydroelectric power, recreation, and ecosystems. Water-supply shortages would affect all uses and would affect interstate and international water-sharing agreements. Decreases in streamflow in key areas for interstate and international water sharing agreements show potential declines up to 62%, putting agreement compliance at risk.

The results of this study, reached using an entirely different approach, are consistent with and support those of a recent USGS study that investigates how declining snow cover is playing a key role in decreasing the flow of the Colorado River.

Citation: Miller, O.L., Putman, A.L., Alder, J., Miller, M., Jones, D.K., Wise, D.R., 2021. Changing climate drives future streamflow declines and challenges in meeting water demand across the southwestern United States. Journal of Hydrology X, 11: 100074. DOI:

#Drought news (February 18, 2021): Beneficial precipitation fell on higher elevations of #Nevada, central #UT, W. and E. #WY, W. #Colorado, N.E. #AZ, and most of #NM

Click on a thumbnail graphic to view a gallery of drought data from the US Drought Monitor.

Click here to go to the US Drought Monitor website. Here’s an excerpt:

This Week’s Drought Summary

Arctic air spilled into the Nation’s midsection and persisted throughout the week, producing weekly departures of more than 25 deg F below normal from the northern Plains and upper Midwest southward into Texas. Numerous daily record lows were broken, with minimums plunging to -50 deg F in the northern Plains, and sub-zero readings southward into the Texas Panhandle. In contrast, high pressure over the Southwest and Southeast kept temperatures above-normal for the week. With several storm systems traversing along the boundary of the cold vs mild air, ample precipitation, much in the frozen form, fell on most of the West Coast, Intermountain West, Rockies, southern and central Plains, and much of the eastern third of the U.S. The combination of extreme cold and frozen precipitation across the South and Southeast taxed the power grid, made transportation hazardous, and brought down trees. The snows, however, were welcomed in the West as snow packs and basin snow water equivalents (SWE) increased throughout the West, although many basins were still below normal as of Feb. 16, especially in the southern Rockies. Frigid conditions also enveloped Alaska, with precipitation limited to western and southwestern sections. Shower activity continued across Puerto Rico, especially along the northern and eastern portions, but rain was lacking in the northwest. Across Hawaii, a weak cold front brought some showers early in the period, with trade wind conditions and windward showers later in the week…

High Plains

While bitterly cold air enveloped the High Plains this week (except western Colorado and southwestern Wyoming), frequent storm systems have zipped their way across much of the region, dropping snow across both high and low elevations. After several weeks of decent precipitation, some improvements were warranted for those areas with surplus precipitation out to 2-3 months and wet short-term SPIs. Although longer-term SPIs (>6 months) were still severe, the short-term conditions have been wetter, and this is what these improvements were attempting to depict. This included 1-cat improvements to parts of Nebraska and adjacent western Iowa, sections of Wyoming, southeastern Montana, northeastern Kansas, and portions of Colorado. As mentioned in the Midwest summary regarding western Iowa, low elevation snow melt and infiltration into the soils can have problems, so take these improvements with caution. Fortunately, higher elevation (mountain) snows tend to melt more evenly and slowly. In sharp contrast, storms and precipitation continued to elude the frozen northern Plains, but unfortunately the bitterly cold Arctic air did not…


Another in a series of Pacific storms battered the West Coast and tracked southeastward across the Intermountain West and Rockies, dropping heavy precipitation (more than 4 inches) along the Washington-Oregon-northwest California coasts and on the Cascades, with lighter totals (2-4 inches) falling on the Sierra Nevada. Beneficial precipitation fell farther east on higher elevations of northeastern Oregon, most of Idaho, northern Nevada, central Utah, western and eastern Wyoming, western Colorado, northeastern Arizona, and most of New Mexico. With precipitation increasing over the past 30 days or so, short-term indices not showing D3-D4 on multiple time scales (short-term much wetter), and SNOTEL basin average SWE (as of Feb. 16) improving and getting closer to normal (but still below), some improvements were justified to depict areas with the aforementioned conditions, although long-term drought still remained (going back to the failed southwest summer monsoon). However, there were some small areas of deterioration as not all locales received this beneficial moisture. This included portions of Oregon and Wyoming. No improvements were made for areas with very large deficits, lower weekly precipitation totals, and smaller basin SWEs. With February normally one of the wettest months for California, the moderate precipitation falling on the Sierra Nevada this week was enough to keep conditions stabilized. As of Feb. 16, the northern, central, and southern Sierra Nevada SWEs stood at 68%, 76%, and 54%, and the state average was 69%. When applied to an April 1 (normal peak snow) date, these values dropped to 54, 59, 40, and 53%, respectively. Basin SWEs remained the lowest in the southern Rockies (6-45% of normal), even though light precipitation fell across most of New Mexico…


Arctic air set-up shop in parts of the region, especially Oklahoma, Texas, northern Louisiana, Arkansas, northern Mississippi, and western Tennessee, with wintry weather blanketing or glazing many parts of these states. Although the precipitation was welcome after a rather dry 30-60 days prior, the form it came in (frozen) was not, nor was the Arctic air. With light to moderate totals (0.5-2 inches) from south-central and eastern Texas northeastward across the remaining Southern states, and heavier totals (2-5 inches) in southern sections of Louisiana and Mississippi, some D0 and D1 was improved, especially along the central Gulf Coast. However, since there were 60-day deficits of 3-6″, the precipitation in the lower Mississippi Valley was not great enough to eliminate them, thus many areas remained unchanged. But with the combination of the extreme cold (no evaporation) and widespread precipitation, no deteriorations were made this week…

Looking Ahead

During the next 5 days (February 18-22), temperatures should remain below normal across much of the lower 48 States, although moderating temperatures are expected later in the period in the northern Plains. A vigorous storm system will impact the Southeast and Northeast early in the period, with significant snow and icing possible. Tranquil weather should prevail in the Nation’s midsection, while a series of storms hit the Pacific Northwest, bringing heavy rains to the coast and heavy snows to the Cascades, and light precipitation to the Rockies.

The ensuing 5 days (February 23-27) brings enhanced chances of above-normal precipitation to the northern tier of States, from Washington eastward to the Great Lakes region, and across Alaska. The odds favor subnormal precipitation across the southern half of the Nation. With a pattern change, above-normal temperatures are most-likely across the northeastern quarter of the country, especially in the upper Midwest, across southern sections of the Southwest, and in southwestern Alaska. In contrast, subnormal readings are anticipated in the Northwest and the remainder of Alaska.

US Drought Monitor one week change map ending February 16, 2021.

Are #NewYork billionaires different than #Colorado’s? Work group eyes new tools to stop #water profiteering — @WaterEdCO

A powerful sprinkler capable of pumping more than 2,500 gallons of water per minute irrigates a farm field in the San Luis Valley June 6, 2019. Credit: Jerd Smith via Water Education Colorado

From The Fresh Water News (Jerd Smith):

Imposing hefty taxes on speculative water sales, requiring that water rights purchased by investors be held for several years before they can be resold, and requiring special state approval of such sales are three ideas that might help Colorado protect its water resources from speculators.

The ideas were discussed Wednesday at a meeting of a special work group looking at whether Colorado needs to strengthen laws preventing Wall Street investment firms and others from selling water for profit in ways that don’t benefit the state’s farms, cities and streams.

The anti-speculation group was created last year by lawmakers and is charged with reporting back to them this August.

As prices for Colorado’s water have soared and Wall Street firms and others have begun buying up agricultural lands and their associated water rights, concern is rising that the state could lose control of its vast, though heavily used, streams and rivers.

“It’s a tough nut to crack,” said Joe Bernal, a rancher and work group member from the Grand Valley on the West Slope, where hedge funds are actively buying land and water.

Water has always been a scarce resource in Colorado. In the 1800s, as miners and farmers were moving in, the courts developed a system so that no one could hoard water, drive up its price, and profit from its sale. To combat the problem, they required that water rights be granted only to those who could put them to beneficial use, whether in farm fields or mines, or in people’s homes and businesses.

Under state law, water is considered a public resource. The legal right to claim it and use it for some beneficial purpose, such as farming or manufacturing or municipal use, must be approved in water court. Once obtained, water rights are considered a private property right and can be bought and sold, again with approval from the courts.

Colorado already has some of the strictest anti-speculation laws in the West.

But the rise in water prices and the purchase of water-rich farms and ranches on the West Slope by deep-pocketed, out-of-state investment firms, as well as in-state efforts to export water from the San Luis Valley, prompted lawmakers in late 2019 to call for more work on the issue.

The work group has yet to make any formal recommendations, but Alex Davis, an attorney for Aurora Water and work group member, said new ideas have to be considered because Colorado’s existing laws were written more than 100 years ago, long before hedge funds existed.

“This idea of appropriating water rights and not using them, we have that covered,” Davis said. “It’s well prevented by the laws that exist. It’s the financial speculation that we’re focused on here. How do you prevent it? It’s a very difficult question.”

Imposing a hefty tax on any profits made in a speculative sale, similar to a capital gains tax, could serve as a disincentive to investors, Davis said.

Still another work group member, Adam Reeves, an attorney with the Denver- and Durango-based firm Maynes, Bradford, Shipps and Sheftel, said forcing certain investors to hold onto water rights for several years before being allowed to sell them again could provide another powerful disincentive.

Still others suggested some kind of state approval by existing water courts or other state authorities could be required, effectively limiting any sales deemed speculative.

But key to any of these tools is defining what is and isn’t speculation.

“What are the criteria by which you determine that ‘x’ investment is speculative and ‘y’ investment is not?” Davis asked. “Any time anyone purchases an asset it’s an investment…when does it become an investment that is problematic or predatory? Is a Colorado billionaire different than a New York billionaire?”

Bernal said any definition of speculation should consider whether transactions in which cities are buying agricultural water with an intent to permanently remove it at some future date to serve a growing population could also be considered speculative and therefore subject to some limitation.

“The concern we all have here is where it might go and who will end up with it. Is it right, is it proper that it go to large municipalities?” Bernal asked. “Why are some of these transactions bad because of who they involve, and what limitations do we put on these transactions, and how does that affect people who’ve owned the water traditionally? Is there something we need to do that doesn’t interfere with private property transactions?”

Work group member Peter Fleming, a water attorney for the Glenwood Springs-based Colorado River District, said the state should be careful not to limit investment in ways that are harmful.

“There is no risk to Coloradans from a non-speculative investment in water,” Fleming said. “We need that to increase productivity and maximum utilization of the state’s water resources.”

The work group has six months to finish its research and craft recommendations for lawmakers to consider later this summer.

The group plans to meet next in March, though a date has not yet been set.

Jerd Smith is editor of Fresh Water News. She can be reached at 720-398-6474, via email at