A look at #ColoradoRiver Basin water year precipitation so far #COriver #aridification #DCP

Morrow Point Dam spilling June 2014 via USBR

From The Colorado Sun (Katie Klingsporn):

…in the long-term puzzle of ensuring that the Colorado River — the main artery of the American West — provides water to the millions of people in the basin who depend on it, the challenges are mounting. And in the face of a complicated tangle of population growth, long-term drought and climate change, does 2019’s water stand a chance of making a meaningful impact?

Water experts say the answer is: Sadly, not likely.

Colorado River District general manager Andy Mueller likened it to a year-end salary bonus. It’s a great development in the short term, but if it’s an anomaly in the broader picture, its effects will be minor.

“This is a short-term boon, and we should be happy,” Mueller said before adding the caveat stressed by many in the water community: “But we’re not out of the woods yet.”

Blue Mesa Reservoir

A pattern of aridification

Going from the record-breaking drought of 2018 to the record-breaking water year of 2019 is a stroke of luck that has enabled a much faster recovery of fisheries, soils and watersheds, said Taryn Finnessey, Colorado’s senior climate change specialist.

Here, reservoirs such as Blue Mesa, Navajo and Ridgway are expected to rebound as snowmelt flushes through rivers.

“However, on the broader Colorado River, even with a banner water year, we won’t see a significant recovery,” she said.

Large inflows are expected into both Lake Powell on the Utah/Arizona border and Lake Mead downstream — the big reservoirs considered to be the savings accounts for the Colorado River basin. The reservoirs, which have been steadily dropping for years, are projected to end the year at slightly higher levels.

But both are so far from capacity — as of June 24, Mead was only at 40 percent, while Powell was at 51 percent, according to the Bureau of Reclamation — that these increases will, at best, put them a little more than half full by year’s end.

“So we’re not seeing a huge rebound in those really large storage buckets that provide long-term storage in the Southwest,” Finnessey said.

Ridgway Dam

Why not? The short answer, she said, is climate change.

Over the past 20 years, the broader Colorado River system has experienced not only decreased precipitation — in the form of 19 years of drought — but also increased temperatures. The hotter weather creates more rapid evaporation and thirstier soils, and causes the snow to melt more quickly, transforming it from the steady flows that were once typical, into an annual big-water flush that’s harder to capture and store.

The result, Finnessey said, is a slow shift in the basin “from drought to long-term aridification” that’s drawing down the water. A growing population only exacerbates the problem. And one good year of water won’t reverse that.

In fact, Mueller said the river district’s engineer guesses it would require eight to 13 years “exactly like this one” to emerge from the deficit. So, relying on Mother Nature to turn things around isn’t a reliable option.

James Eklund, the state’s representative on the Upper Colorado Basin Commission, said the problem is that the entire system of storing, capturing and using the water of the Colorado River is predicated on the way things functioned before climate change…

Make no mistake, Eklund said, managers will store every drop they can in a year like this. Unfortunately though, “climate change is boxing Colorado water managers in from all sides.”

[…]

The result of those talks is the Colorado River Basin Drought Contingency Plan, which was signed in May. In that agreement, the Lower Basin states agreed to specific decreases in water use.

The plan is designed to bank water and leave it in Lake Mead, which in turn keeps more water in Lake Powell (by preventing large releases from Powell required to bail out the Lower Basin’s supply.) And unlike in the past, the water that is banked in Powell by the Upper Basin states will belong solely to Colorado, Wyoming, Utah and New Mexico as a sort of emergency water account.

Previously, all the water saved by Upper Basin states in Lake Powell could be released to Lake Mead for the Lower Basin states to use.

“That was a perverse incentive,” Eklund said of the former arrangement that didn’t really reward water conservation by Upper Basin states. “What we decided to do is make it a positive incentive.”

The Upper Basin states, meanwhile, agreed in the Contingency Plan to explore methods for managing and reducing consumption.

(As part of that promise, the Colorado Water Conservation Board has assembled eight workgroups to study a demand-management program for the state, which is envisioned as a voluntary program that would pay users to not use their water rights. The water saved through that program, the river district’s Mueller said, could be stored in Lake Powell to be used explicitly for Upper Basin needs.)

Finally, the contingency plan makes reservoir operation more flexible for Colorado’s Blue Mesa and Navajo reservoirs and Flaming Gorge in Wyoming — while still respecting the environmental considerations of their water releases…

But it’s also a problem that can’t be ignored away. “Everybody in the basin has to get better, faster, smarter at our jobs,” Eklund said. “Our policies have to become more flexible, smarter and better.”

Mueller echoed that, noting that if Lake Powell is a measure of how secure the Upper Basin should feel about its future, “we should not feel that secure.”

He said it’s time to take a hard look at measures such as removing sod, improving agricultural efficiency, crop switching and even cloud seeding.

There are models of success out there. Denver Water, which serves 1.4 million people in Denver and the surrounding suburbs, has seen its per-capita water use drop 34 percent since 2001 thanks to major conservation efforts.

“We’re actually using the same amount of water that we used in the ’70s even though our population has grown by half a million,” said Dave Bennett, the utility’s director of water-resource strategy. “And that’s really a testament to conservation.”

When it comes to the Colorado River, conservation may not be enough. For now, though, it’s one of the best tools available. So, while nobody has come up with the end-all answer for solving the long-term crisis, water managers are unanimous on one thing: Users can’t afford to waste a single drop of water, even in a year of abundance.

“We were lucky this year,” said Finnessey, the climate change specialist. “But I don’t think that’s something that we can ever assume will happen again. So we need to be really wise stewards of our resources.”

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