Wyoming’s 10 year cloud-seeding experiment scrutinized

Cloud-seeding graphic via Science Matters
Cloud-seeding graphic via Science Matters

From the East Oregonian (Allen Best):

Wyoming just spent $14 million and the better part of 10 years on a rigorous scientific experiment to evaluate whether it’s possible to get extra snow from winter storm clouds through cloud seeding. The conclusion? The final results were thin: There was a 3 percent increase in precipitation, but a 28 percent probability that the cloud seeding had nothing to do with it.

Given the results of this and other winter weather-modification studies, the Bureau of Reclamation remains unimpressed. “As such,” said the agency in a draft analysis released in February, “the ‘proof’ the scientific community has been seeking for many decades is still not in hand.”

Proof in science requires a 95 percent probability of causality. But this standard is extremely difficult to achieve in complex atmospheric processes. Climate scientists, for example, mostly resort to asterisk-laden words such as “likely” to indicate lower levels of probability…

From the start, Wyoming’s cloud-seeding experiment was designed to ensure scientific rigor. Parallel mountain ranges southwest of Laramie, just north of the Colorado border, constituted the Wyoming laboratory. Propane was burned to loft silver iodide from ground-based generators into the clouds passing over the Sierra Nevada and Medicine Bow ranges. In the experiment, 154 storms during six winters had the temperatures needed for effective seeding, but only 118 developed adequate moisture content. And of those, 18 were tossed out because of contamination problems.

Dan Breed, project scientist with the National Center for Atmospheric Research, which designed and oversaw the Wyoming experiment, said that failing to achieve a 95 percent confidence level in results is not unusual in cloud seeding studies. The fundamental problem, he says, involves the difficulty of measuring atmospheric processes.

The challenge inherent in the complexity of the data has prevented most climate scientists from directly linking specific weather events, such as the September 2013 floods in Colorado, to rising global temperatures, or even to the 3 to 5 percent observed moisture in the global atmosphere.

“When it comes to the atmosphere, there are just too many variables, and that variability just keeps rearing its ugly head when it comes to cloud seeding,” says Breed. “Even in this case, where we tried to make things as homogeneous as possible to reduce that variability, variability still kind of hurt us.”

Breed thinks research might better be invested in understanding the interaction in the atmosphere of wind, temperature and precipitation. For example, how likely is it that silver iodide or other seeding agents released from the ground will get into the clouds? True understanding of atmospheric processes, says Breed, has mostly come from observations instead of experiments — because of that same variability.

This lack of certainty does not necessarily kill the prospects of cloud seeding, as is demonstrated by the continued interest of Wyoming legislators in funding projects. In the Colorado River Basin, cities and water districts seized upon the modeled projections of 5 to 15 percent snowpack augmentation as justification for continued or even expanded operations. Already, metropolitan Los Angeles, the Central Arizona Project and the Southern Nevada Water Authority, among others, pay for seeding clouds in Colorado, the source of half the water in the Colorado River, and last year they also paid to seed clouds in Wyoming, in the Green River drainage.

More cloud seeding coverage here.

Club 20 Annual Meeting recap

George Washington addresses the Continental Congress via Son of the South
George Washington addresses the Continental Congress via Son of the South

From The Colorado Statesman (Ron Bain):

A panel of seven Western Slope legislators — six Republicans and one Democrat — discussed diverse issues they’re working on in the state legislature at the Club 20 annual meeting on March 28, focusing on water, energy, the economy, TABOR and federal lands…

Preventing the Front Range from taking more Western Slope water was a popular theme during the panel discussion.

“We’re protecting West Slope water,” said Sen. Ray Scott, R-Grand Junction. “This is your front line of defense.”

Rep. J. Paul Brown, R-Ignacio, called for the Front Range to impound and store more of its own water.

“We keep sending more and more water to the Front Range,” Brown said. “I think water storage is important. The study of the South Platte is important.”

The last time the Front Range considered building a dam was 25 years ago, when the proposed Two Forks project was vetoed by the Environmental Protection Agency. The Denver Post recently called for water storage to be added to Gov. John Hickenlooper’s draft Colorado Water Plan.

“Our water infrastructure was dramatically cut back,” Roberts said. “You can’t build towns on air. You have to have water.”

“I’ve always been an advocate for storage,” Baumgardner said. “We must have storage or we’re going to have a huge problem.”

Coram said 400,000 acre feet of water could be conserved if “water thief” non-native species such as tamarisk and the Russian olive were eliminated.

Swan River restoration

Restoration plans are afoot for a degraded section of the Swan River, in Summit County, Colorado.

From 9News.com (Matt Renoux):

If all goes as planned, the Swan River between Frisco and Breckenridge will once again run like it did more than a century ago.

That’s because the Colorado Water Conservation Board and Colorado Basin Roundtable have given Summit County a $975,000 grant to restore 19 miles of the river that was drastically changed by mining activity…

The overall plan is restore the part of the river that’s separated by the huge dredge piles – and hopefully bringing back fish and wildlife in the area – returning it to how it was more than a hundred years ago.

More restoration/reclamation coverage here.

#ColoradoRiver: “When do we say no, and who do we say no to?” — Mark Squillace

Colorado River Basin including out of basin demands -- Graphic/USBR
Colorado River Basin including out of basin demands — Graphic/USBR

From the Mountain Town News (Allen Best):

By its natural flow, the Colorado River originates in Rocky Mountain National Park and ends in the Sea of Cortez. But flows of the Colorado decades ago ceased to be natural, as Phil Fradkin famously captured in his 1981 book “A River No More.”

A discussion on April 3 sponsored by the University of Colorado Law School’s Environmental Law Society examined two aspects of the unnatural flows. All three speakers, in different ways, talked about different management regimes for water revolving around the adage of “just add water.”

Since 1999, Jennifer Pitt has shepherded efforts on behalf of the Environmental Defense Fund to restore flows to the river’s delta in Mexico. Water has not reached the sea with regularity since the 1960s and, until special releases last spring, not at all since the late 1990s.

Eric Wilkinson talked about the diversions of the river and its tributaries to cities along the Front Range of Colorado and to benefitting farms at least as far downstream as the Nebraska and Kansas borders. He’s general manager of the Northern Colorado Water Conservation District, which administers the single largest diversion across the Continental Divide, the Colorado-Big Thompson Project.

Introducing the session, law professor Mark Squillace framed the primary issue of the Colorado as one of management that recognizes inherent limits and demands choices: “When do we say no, and who do we say no to?”

The two giant reservoirs on the Colorado, Powell and Mead, together were at 94 percent of capacity in 1999. By 2007, that storage had dropped to 54 percent of capacity.

This year looks even worse: 42 percent of storage capacity for the two reservoirs, and more decline as the year progresses look inevitable. The National Oceanic and Atmospheric Administration this year projected runoff in the Colorado River to be just 52 percent of normal. “Things are not looking good,” Squillace said.

“Are we facing a crisis?” he asked rhetorically, before answering his own question: “I would suggest it’s not a water crisis. It’s a management crisis.”

In talking about the successful effort to return water to the river delta in Mexico during March 2014, Pitt described a long, evolving process that essentially began in 1999 with a study that found that ecosystem functions in the river delta could be restored with just 1 percent of annual flows. Securing that water for a successful pulse of water last year required persistence and new levels of cooperation.

Wilkinson continued Pitt’s theme. “Everything you do with water takes time,” he said.

The Colorado-Big Thompson Project itself took time. It was conceived in at least some vague ways in the late 1890s as farmers in the South Platte Valley of northern Colorado noted insufficient water for late-summer irrigation. Recurrence of drought in the 1930s added argument for a giant, federally funded capital works project. Work began in 1938 on Green Mountain Reservoir, to serve needs of the Western Slope, but final work was not completed until 1957.

This and other diversions from the Colorado River headwaters have created a thriving economy along the Front Range. Weld County, the largest in the basin, is 8th in the nation in total agricultural production. By itself, Weld County produces more than all 20 counties on Colorado’s Western Slope combined.

All this belies the impression of Zebulon Pike who, upon encountering the high plains leading up to the Rockies, made comparisons to the deserts of Africa. “Just add water,” Wilkinson advised. He said that two-thirds of irrigated acres in Colorado get at least some of their water from the Colorado River.

The munificence of Colorado River water extends to the cities of the Front Range corridor, where about 85 percent of Coloradans live, mostly in the fast-urbanizing strip along I-25 north from Denver. The Front Range, said Wilkinson, represents 80 to 86 percent of Colorado’s economic activity.

Wilkinson’s description of Colorado’s transmountain infrastructure was a story of triumph. The future, he acknowledged, is far more muddled.

One outstanding issue is whether Colorado can expect to divert substantial amounts of additional water from the Colorado River and its tributaries. It’s not clear how much Colorado has left of its apportionments as specified by two major compacts governing the Colorado River, the seven-state compact of 1922 or the 1948 compact among the four headwaters states.

But even if there is water, said Wilkinson, there are additional questions: “If so, how do you develop it, and if so, how do you develop it in ways that protect basins of origin and still make the project economical?”

Then there’s this simple fact: existing diversions are not an absolute. They depend upon volumes of water in the river to meet compact requirements—and deepening drought could throw even long-standing diversions off the rail.

Responding to a question about California’s drought, Wilkinson said that he is “scared” that the federal government—administrator of the compact—will someday force curtailment of diversions with appropriation dates after 1922. That would include the Colorado-Big Thompson.

As the northern Front Range looks to add 2.5 million people during the next 35 years, the equivalent of the existing Denver-Boulder metroplex, there will be questions of where the water will come from. There is, said Wilkinson, a “disconnect” between the people who provide water and the people who approve residential developments.”

All this points to a new era of water management, as opposed to the “just add water” mantra of the mid-20th century.