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Gravel & cobbles and implications of the Colorado River Basin’s slow bake

by Allen Best

Gravel yards annoy me. I’ve driven around Las Vegas and Albuquerque, both places of considerable aridity that depend greatly upon the Colorado River. Gravel has come to dominate the front yards in both places. In Vegas, they pay people to remove their grass. I’ve seen a lot of gravel. Yuck.

Driving around metropolitan Denver, I see more and more gravel, too. Candelas, the giant subdivision that sits on a table just short of where the prairie sweeps up into the foothills of the Rocky Mountains, has hulking houses big enough to be gymnasiums, crowded together like rugby players in a scrum. The yards are not quite opposite, but close, the space devoted to turf pinched by gravel and cobbles and water-stingy shrubs.

Is this good or bad?

As in most things, there are two sides to this story. Both sides emerged during a session sponsored by Patty Limerick’s Center of the American West on Tuesday. The webinar was the first of four sessions focused on the twin topics of water and energy. Whether those two topics actually pair very well, I’m not too sure since I started Big Pivots in January, choosing to use the tag line of “Energy and Water Transitions in Colorado and Beyond.” Limerick also wonders about the pairing, as became evident in that first session.

Eric Kuhn

Eric Kuhn began his career at the intersection of energy and water, serving as an electrical engineer aboard nuclear submarines in the U.S. Navy and working as a nuclear start-up engineering for the Bechtel Power Corp. Then, on whim, he applied for a job with Glenwood Springs-based Colorado River Water Conservation District.

In the nearly 40 years since, he has become among the foremost experts about the Colorado River, a topic that annually inspires yet another book or three. Kuhn has written a book, too, along with water journalist John Fleck, “Science be Dammed: How Ignoring Inconvenient Science Drained the Colorado River.” It deserves to be on the top shelf of Colorado River books.

See my review here.

In that book, Kuhn and Fleck document how the Colorado River was divvied up based not on what the river could be expected to yield, given the scientific evidence, but rather what the power brokers from across the basin (and from Washington D.C.) preferred to believe it would. They make a case that the Colorado River development reflected rotten public policy.

Kuhn managed to be both grim and hopeful. “What we know is that in the future there will be less water than there is today, and we’re using every drop today,” he said of the Colorado River. “And in the future there will be less. That means people in the future will use less.”

Who exactly will use less? Two-thirds of the Colorado River is used for irrigation, and another one-sixth or so is for municipalities and for tribal reservations, and the rest goes to evaporation from these big reservoirs.”

And, as he said, it could get worse. Instead of the 17.5 million acre-feet (or more) presumed by the Colorado River compact, the river in a time of warming climate will produce 10.5 or 11 million acre-feet—even as environmental problems, such as struggling fish populations, and other environmental repercussions of dewatering are becoming more apparent.

This is from the Aug. 14, 2020, issue of Big Pivots. Go HERE to subscribe.

Grim indeed, right? Well, maybe not. The future is bright because of conservation, conversation and collaboration,” he said. “As human beings we learn how to use less water than we have.”

Las Vegas is the shining star. In 2000 it was using 320,000 acre-feet of water. Since then, the metropolitan area has nearly approached a population of 2 million—and the water use has declined. It has banked water in Arizona. Really.

“The future of the Colorado River is all about grass: water for parks, grass or lawns. If we can manage grass, we can live with the water supply we have,” he said.

Cities along the Front Range of Colorado, he said, have yet to hit the same stride as their hotter, more arid siblings.

“If you look at the progress made elsewhere in the world, the Front Range hasn’t even dared to restrict lawn sizes or pay people to take out their turf,” he said.

This is from the Aug. 14, 2020, issue of Big Pivots. Go HERE to subscribe.

The Colorado River at Palisade, Colo. Photo/Allen Best

Where does this subdivision called Candelas fit into this narrative? I’m not sure. Arvada gets 78% of its water from Colorado River tributaries via Denver’s Moffat diversion network in the Fraser and William Fork Valleys.

But what gives somebody in Montrose the right to have a half-acre front yard while somebody in Arvada can have one about the size of a trampoline. This discussion can go on for a while – and, in fact, has been going on for decades.

Organizers of conferences or their pandemic-equivalent Zoom sessions can safely return to this topic again and again, because it will never be answered to everyone’s great satisfaction.

Kuhn, when he ran the River District, argued the Western Slope perspective that Colorado’s growth cannot be borne on the backs of the Western Slope’s cultural history of agriculture. That is still the position of the River District.

Water can be shared, though —through agreements that allow cities to lease water from farms, to help in pinch times. This device been employed effectively by California’s Metropolitan Water District, the provider for southern California cities, in conjunction with the giant farming districts in California, Palo Verde and the Imperial Valley. In Colorado, cities have been more tepid.

But Los Angeles and its sunny southlands empire have also learned to live with less water, Kuhn noted.

Okey-dokey—but just keep in mind the heat-island effect of the warming climate and the cooling effect provided by irrigated landscapes, responded Laurna Kaatz. She has a Ph.D. (physics), too. She is Denver Water’s climate science, policy, and adaptation program director.

Laurna Kaatz

“Water goes a long way to making it comfortable and livable in a semi-arid environment,” she said.

Every Water 101 course in Colorado must point to this fundamental imbalance: 80% of the water falls on the Western Slope, and 90% of the population lives on the Eastern Slope, mostly in a relatively narrow corridor between Castle Rock and Fort Collins.

Another way of saying the same thing: The Colorado River produces 10 times the water of the South Platte River, where most Coloradans live, and Denver Water serves 25% of the state’s population, and those areas produce 30% of the state’s GDP—all on 2% of the state’s water (Agriculture uses 88% of Colorado water, and municipalities 8% altogether and large industry 4%).

And 80% of water that falls as precipitation In Colorado goes back into the atmosphere as a result of evaporation and transpiration.

Half of Denver Water’s supplies come from the Western Slope. But Colorado, said Kaatz, is warming more rapidly than much of the globe, because it lies in the middle of a great land mass. For Denver Water, planning for the future means trying to prepare for the next 50 years using a process called scenario planning. The goal of scenario planning might be characterized as trying to keep your options open.

At the outset, I said that this was a water-energy forum. In fact, it tilted heavily toward water. But energy and water do overlap, as Xcel’s representative, Jeff Lyng, pointed out. He’s the company’s director of energy & environmental policy. And, not unlike the scenario planning of major water utilities,

On the environmental front, Xcel became a national front-runner with its December 2018 announcement it saw a path to 80% emissions-free electrical production by 2030 as compared to 2005 levels. Then, at mid-century, zero-emissions.

The first goal can be achieved using existing technology, Xcel said. As for that goal 30 years hence? TBD.

First things first, said Lyng. “We can’t get to zero emissions without first getting to 60% and then 80%.” By the end of last year, he said, Xcel had reduced emissions by 44% — significant, he suggested, when considering what was required by the Paris climate agreement but also by what the Obama administration’s Clean Power Plan would have required, 32%.

Jeff Lyng

Major challenges lie ahead before the goal of a 100% renewable grid can be achieved. It’s not realistic to hit that goal by building just more and more renewables, because of land-use constraints, unmanageable costs, and other problems.

Instead, he said other types of technologies —advanced, dispatchable renewables, zero-carbon fuels, advanced nuclear, carbon capture and utilization, long-duration storage and demand-response, among other possibilities—will deliver the answer. In other words, the answer is probably already on the table, but it just hasn’t been developed sufficiently.

As for the intersection with water, Lyng delivered this interesting factoid: energy saved is water saved, because each kilowatt-hour capacity of energy use saves roughly one-quarter gallon of water (given power plant cooling). Continued integration of renewables, of course, will reduce that figure considerably.

Lyng’s comments about water use were nearly the only time that energy and water were joined in the same conversation—as Limerick, who has a Ph.D. in history, pointed out. “It’s interesting how the topics separate, even though we intended to bring them together.”

And Limerick also suggested why people tend to get excited about water, whereas with energy eyes soon glaze over. Water is something that people intrinsically believe they know, that they have an affinity with. Energy, well, it’s a little less tactile.

But, to the point of this publication, Big Pivots, how we produce and consume energy matters entirely to the climate. And, as Kaatz noted, climate change is water change.

Two sessions remain next week in the “Water and Energy in Colorado: Emulsifying Two Great Challenges in Four Parts.”

Allen Best
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