Groundwater in the Colorado River basin won't run out — but eventually we won't be able to get at it, scientists warn
When you buy through links on our articles, Future and its syndication partners may earn a commission.
Stark new satellite data reveal that the Colorado River basin has lost huge amounts of groundwater over the last few decades, with some research suggesting that this groundwater could run out by the end of the century.
But is that really the case? And if so, what could be done to prevent that happening?
While groundwater is being depleted, it's unlikely the water will ever run out completely. However, continued drainage of the basin could make the water table fall so far it's basically inaccessible, experts told Live Science.
The Colorado River snakes through seven U.S. states (Wyoming, Colorado, Utah, New Mexico, Nevada, Arizona and California) and two Mexican states (Baja California and Sonora). Some 40 million people, including those in Phoenix and Las Vegas, depend on it for their water needs. But as supplies of this surface water have dried up over the past two decades — reaching record lows — more and more people have been pumping groundwater from far below the surface, mainly for agricultural use.
To get a better idea of how much groundwater is being extracted, Jay Famiglietti, director of science for the Arizona Water Innovation Initiative at Arizona State University, and his colleagues turned to data from NASA's Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-On satellite missions. These satellites track changes in Earth's gravity field to measure shifts in the amount of water above and below the ground, and when combined with data on snowpack, surface water and soil moisture, this information can allow scientists to estimate how much groundwater has been depleted.
The researchers estimate that since 2003, pumping from wells has drained about 28 million acre feet (34 cubic kilometers) of groundwater from the Colorado River Basin. This is akin to the capacity of Lake Mead, the largest U.S. reservoir, which sits behind the Hoover Dam on the Colorado River. The study was published May 27 in the journal Geophysical Research Letters.
About three-quarters of the groundwater depletion is happening in the river's lower basin, largely in Arizona, where water is pumped from desert aquifers to irrigate farmland, according to the study. In these largely rural areas, farms aren't usually hooked up to municipal water systems, and instead rely on water pumped from wells on the property. Because the wells are private, there is often no municipal, county- or state-level measurement of how much water they are drawing up.
Famiglietti and his colleagues estimate that annual groundwater losses in the basin averaged more than 1.2 million acre-feet (1.5 cubic kilometers) and if the trend continues, it could lead to water shortages and limit food production.
"We're passing a critical point where it is getting more and more expensive to go deeper into the aquifer, and the water quality is dropping," Famiglietti said.
Dozens of wells have dried up in the area. Collapsing aquifers have caused land subsidence, and created fissures.
Ryan Mitchell, chief hydrologist at the Arizona Department of Water Resources, who was not involved in the new study, told Live Science that he welcomes the paper's findings and is concerned about the levels of estimated groundwater depletion in some areas. However, he takes issue with a sentence in the paper that suggests that an Arizona Department of Water Resources simulation indicated "complete depletion by the end of the century." He said the simulations don't indicate complete depletion of groundwater at all, let alone by the end of the century.
The groundwater won't run out, he said, but neither GRACE satellite data nor measurements of water use will tell us exactly how much water is left in aquifers.
"It's almost like it's an unknowable number in the same way that if someone said how many grains of sand are on the beach, you could make some assumptions and make some guesses but you can never actually know the exact amount of sand grains," Mitchell said.
Bridget Scanlon, a research professor in the Bureau of Economic Geology at the University of Texas at Austin, and her team recently used GRACE data to assess the implications of drought in the Colorado River basin. They saw similar patterns, finding that there was a period of high groundwater use as irrigation expanded between the 1940s and 1970s. Then, the amount of groundwater recovered during a wet period in the early 1980s and 1990s.
Related: Atlantic ocean currents are weakening — and it could make the climate in some regions unrecognizable
But since then, the picture has differed depending on how areas are managed. In "active management areas," or areas where water use is monitored, the levels of groundwater have stayed roughly level. In these areas, groundwater is pumped, but based on how much is drawn up, management agencies can divert more water to the depleted area to filter back down to the aquifer.
In unmanaged areas, no agency tracks how much groundwater is pumped, so agencies don't know when to replenish the aquifers. High extraction in unmanaged areas is driving the overall draining of groundwater, Scanlon told Live Science.
"We can't manage what we don't measure," he said. "It shows that if you have rules in place and you keep a close eye on water use and you actively manage it, you can kind of keep it at a sustainable level."
One thing is for sure: Waiting for precipitation to end the drought and replenish aquifers won't be enough. Studies imply that the flow of the Colorado River is expected to continue to decline thanks to climate-linked reductions in snowfall and rainfall — and that means there will be less surface water to use, less water to recharge aquifers and more reason to extract water from underground.
Drilling deeper wells is one solution, but there are problems with that, Famiglietti said. At some point, it will cost millions of dollars for a deep-enough well that will have high energy costs to pump water, he said, and that water is likely to require treatment.
"As you go deeper into the groundwater, that water has been sitting around in contact with soil and rocks for a long time, so it's dissolving solids and salts," Famiglietti said. This can lead to water that is salty, poor-tasting or that contains high levels of arsenic. "And because these are often refilled by agricultural water, they [are] collecting higher concentrations of pesticides and fertilizer," Famiglietti said.
Another option is to reduce water use, by, for example, changing what is farmed, to shift from water-intensive crops like alfalfa, Famiglietti said. "It can't be business as usual," he said. "We have to think about what our priorities are for water use."
"I'm as concerned about tomorrow as I am about 100 years from now," he said. 'It's very clear that we need more groundwater management in the lower basin, which is mostly in Arizona. Only 18% by area is managed, and there's an awful lot of depletion happening outside of those areas."
Every expert Live Science talked with suggested that extending the area covered by active water management areas would help — first, by keeping tabs on what is being used where, and then trying to replace what is used.
As part of such schemes, water could be brought in from elsewhere, Scanlon said. For example, this already happens when San Antonio buys water and pipes it from East Texas more than 150 miles (240 kilometers) away.
RELATED STORIES
—Atlantic ocean currents are weakening — and it could make the climate in some regions unrecognizable
—Over half of the world's largest lakes and reservoirs are losing water
—'Precipitation, the source of all fresh water, can no longer be relied upon': Global water cycle pushed out of balance 'for 1st time in human history'
"Groundwater is a finite resource," Mitchell said. "You need to be able to let it recharge naturally or be able to replenish what you use. He said Scanlon's research shows that "we're doing OK in the active management areas, and we're not doing so hot in the areas where we don't have some kind of framework in place."
A legislative bill to extend the areas that are actively managed has been proposed in Arizona, but similar ones have stalled after facing opposition. Those opposed say restricting water doesn't protect existing agricultural use of groundwater and will stifle economic growth. Some also object to water use being decided at the state level when they would prefer smaller water districts with locally elected directors.
"We're not trying to spy on anyone; we just want to know what the water uses are," Mitchell said. "But it's hard because trust in governments is at an all-time low. We are trying to put things in place to help the mom-and-pop domestic wells — those folks who can't afford to drill 2,000-foot [600 meters] wells because it's just too deep and too expensive. We want to try to help them protect their water resources."
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
Medscape
an hour ago
- Medscape
Updates in Metastatic NSCLC From ASCO 2025
Dr Jonathan Goldman, of the University of California, Los Angeles, shares key updates in metastatic non-small cell lung cancer from ASCO 2025. Dr Goldman reviews findings from TROPION-Lung02, which evaluated datopotamab deruxtecan (Dato-DXd) ± pembrolizumab (pembro) in first-line metastatic NSCLC. The objective response rate (ORR) was 55% for Dato-DXd + pembro vs 56% for chemo. Improved outcomes in TROP2 NMR-positive patients may indicate a predictive biomarker. Dr Goldman then discusses results from OptiTROP-Lung03, in which sacituzumab tirumotecan (sac-TMT) showed superior efficacy compared to docetaxel in pretreated EGFR-mutated NSCLC. The ORR for sac-TMT was 45% vs 15% for docetaxel. Next, he highlights updates from KRYSTAL-7 of first-line adagrasib plus pembro in KRASG12C-mutant NSCLC. The combination yielded an ORR of 44% and median duration of response of 26.3 months. In patients with a PD-L1 ≥ 50%, ORR reached 50% vs 34% in those with lower expression. Dr Goldman also reports on HERTHENA-Lung02, in which patritumab deruxtecan (HER3-DXd) improved progression-free survival (PFS) vs chemo in resistant EGFR-mutated NSCLC, but the lack of overall survival benefit led to application withdrawal. Finally, Dr Goldman reviews phase 2b findings from REZILIENT1, evaluating zipalertinib in EGFR exon 20-mutant NSCLC. In patients without prior amivantamab, ORR was 40% and PFS was 9.5 months. In those previously treated with amivantamab, zipalertinib resulted in clinically meaningful results: an ORR of 23.5% and PFS of 7.3 months.
CNN
an hour ago
- CNN
A hunt for ghostly particles found strange signals coming from Antarctic ice. Scientists are still trying to explain them
Scientists are trying to solve a decade-long mystery by determining the identity of anomalous signals detected from below ice in Antarctica. The strange radio waves emerged during a search for another unusual phenomenon: high-energy cosmic particles known as neutrinos. Arriving at Earth from the far reaches of the cosmos, neutrinos are often called 'ghostly' because they are extremely volatile, or vaporous, and can go through any kind of matter without changing. Over the past decade, researchers have conducted multiple experiments using vast expanses of water and ice that are designed to search for neutrinos, which could shed light on mysterious cosmic rays, the most highly energetic particles in the universe. One of these projects was NASA's Antarctic Impulsive Transient Antenna, or ANITA, experiment, which flew balloons carrying instruments above Antarctica between 2006 and 2016. It was during this hunt that ANITA picked up anomalous radio waves that didn't seem to be neutrinos. The signals came from below the horizon, suggesting they had passed through thousands of miles of rock before reaching the detector. But the radio waves should have been absorbed by the rock. The ANITA team believed these anomalous signals could not be explained by the current understanding of particle physics. Follow-up observations and analyses with other instruments, including one recently conducted by the Pierre Auger Observatory in Argentina, have not been able to find the same signals. The results of the Pierre Auger Collaboration were published in the journal Physical Review Letters in March. The origin of the anomalous signals remains unclear, said study coauthor Stephanie Wissel, associate professor of physics, astronomy and astrophysics at the Pennsylvania State University. 'Our new study indicates that such (signals) have not been seen by an experiment … like the Pierre Auger Observatory,' Wissel said. 'So, it does not indicate that there is new physics, but rather more information to add to the story.' Larger, more sensitive detectors may be able to solve the mystery, or ultimately prove whether the anomalous signals were a fluke, while continuing the search for enigmatic neutrinos and their sources, scientists say. Detecting neutrinos on Earth allows researchers to trace them back to their sources, which scientists believe are primarily cosmic rays that strike our planet's atmosphere. The most highly energetic particles in the universe, cosmic rays are made up mostly of protons or atomic nuclei, and they are unleashed across the universe because whatever produces them is such a powerful particle accelerator that it dwarfs the capabilities of the Large Hadron Collider. Neutrinos could help astronomers better understand cosmic rays and what launches them across the cosmos. But neutrinos are difficult to find because they have almost no mass and can pass through the most extreme environments, like stars and entire galaxies, unchanged. They do, however, interact with water and ice. ANITA was designed to search for the highest energy neutrinos in the universe, at higher energies than have yet been detected, said Justin Vandenbroucke, an associate professor of physics at the University of Wisconsin, Madison. The experiment's radio antennae search for a short pulse of radio waves produced when a neutrino collides with an atom in the Antarctic ice, leading to a shower of lower-energy particles, he said. During its flights, ANITA found high-energy fountains of particles coming from the ice, a kind of upside-down shower of cosmic rays. The detector is also sensitive to ultrahigh energy cosmic rays that rain down on Earth and create a radio burst that acts like a flashlight beam of radio waves. When ANITA watches a cosmic ray, the flashlight beam is really a burst of radio waves one-billionth of a second long that can be mapped like a wave to show how it reflects off the ice. Twice in their data from ANITA flights, the experiment's original team spotted signals coming up through the ice at a much sharper angle than ever predicted by any models, making it impossible to trace the signals to their original sources. 'The radio waves that we detected nearly a decade ago were at really steep angles, like 30 degrees below the surface of the ice,' Wissel said. Neutrinos can travel through a lot of matter, but not all the way through the Earth, Vandenbroucke said. 'They are expected to arrive from slightly below the horizon, where there is not much Earth for them to be absorbed,' he wrote in an email. 'The ANITA anomalous events are intriguing because they appear to come from well below the horizon, so the neutrinos would have to travel through much of the Earth. This is not possible according to the Standard Model of particle physics.' The Pierre Auger Collaboration, which includes hundreds of scientists around the world, analyzed more than a decade's worth of data to try to understand the anomalous signals detected by ANITA. The team also used their observatory to try to find the same signals. The Auger Observatory is a hybrid detector that uses two methods to find and study cosmic rays. One method relies on finding high-energy particles as they interact with water in tanks on Earth's surface, and the other tracks potential interactions with ultraviolet light high in our planet's atmosphere. 'The Auger Observatory uses a very different technique to observe ultrahigh energy cosmic ray air showers, using the secondary glow of charged particles as they traverse the atmosphere to determine the direction of the cosmic ray that initiated it,' said Peter Gorham, a professor of physics at the University of Hawaii at Mānoa. 'By using computer simulations of what such a shower of particles would look like if it had behaved like the ANITA anomalous events, they are able to generate a kind of template for similar events and then search their data to see if anything like that appears.' Gorham, who was not involved with the new research, designed the ANITA experiment and has conducted other research to understand more about the anomalous signals. While the Auger Observatory was designed to measure downward-going particle showers produced in the atmosphere by ultrahigh-energy cosmic rays, the team redesigned their data analysis to search for upward-going air showers, Vandenbroucke said. Vandenbroucke did not work on the new study, but he peer-reviewed it prior to publication. 'Auger has an enormous collecting area for such events, larger than ANITA,' he said. 'If the ANITA anomalous events are produced by any particle traveling through the Earth and then producing upward-going showers, then Auger should have detected many of them, and it did not.' A separate follow-up study using the IceCube Experiment, which has sensors embedded deep in the Antarctic ice, also searched for the anomalous signals. 'Because IceCube is very sensitive, if the ANITA anomalous events were neutrinos then we would have detected them,' wrote Vandenbroucke, who served as colead of the IceCube Neutrino Sources working group between 2019 and 2022. 'It's an interesting problem because we still don't actually have an explanation for what those anomalies are, but what we do know is that they're most likely not representing neutrinos,' Wissel said. Oddly enough, a different kind of neutrino, called a tau neutrino, is one hypothesis that some scientists have put forth as the cause of the anomalous signals. Tau neutrinos can regenerate. When they decay at high energies, they produce another tau neutrino, as well as a particle called a tau lepton — similar to an electron, but much heavier. But what makes the tau neutrino scenario very unlikely is the steepness of the angle connected to the signal, Wissel said. 'You expect all these tau neutrinos to be very, very close to the horizon, like maybe one to five degrees below the horizon,' Wissel said. 'These are 30 degrees below the horizon. There's just too much material. They really would actually lose quite a bit of energy and not be detectable.' At the end of the day, Gorham and the other scientists have no idea what the origin of the anomalous ANITA events are. So far, no interpretations match up with the signals, which is what keeps drawing scientists back to try to solve the mystery. The answer may be in sight, however. Wissel is also working on a new detector, the Payload for Ultra-High Energy Observations or PUEO, that will fly over Antarctica for a month beginning in December. Larger and 10 times more sensitive than ANITA, PUEO could reveal more information on what is causing the anomalous signals detected by ANITA, Wissel said. 'Right now, it's one of these long-standing mysteries,' Wissel said. 'I'm excited that when we fly PUEO, we'll have better sensitivity. In principle, we should be able to better understand these anomalies which will go a long way to understanding our backgrounds and ultimately detecting neutrinos in the future.' Gorham said that PUEO, an acronym that references the Hawaiian owl, should have the sensitivity to capture many anomalous signals and help scientists find an answer. 'Sometimes you just have to go back to the drawing board and really figure out what these things are,' Wissel said. 'The most likely scenario is that it's some mundane physics that can be explained, but we're sort of knocking on all the doors to try to figure out what those are.'
Yahoo
an hour ago
- Yahoo
Biotech industry faces off: US vs. China
China has become a significant player in the biotech space, potentially threatening the lead the US holds. EY Americas industry markets leader for health sciences and wellness Arda Ural sits down with Josh Lipton and Yahoo Finance Senior Reporter Anjalee Khemlani to discuss the dynamics between the US and China in the biotech industry. To watch more expert insights and analysis on the latest market action, check out more Market Domination Overtime here According to a recent report from the Harvard Belfer Center for Science and International Affairs, China has the most immediate opportunity to overtake the United States in biotechnology. For more, let's welcome in Arta Rawi America's industry markets leader and Health Sciences and wellness, as well as Yahoo Finance's very own Anjali Camlani. Welcome to you both. All right, I'll start with you. Uh, maybe it's just a big question, big picture question. Does the US have the investment power, in your opinion, to overtake China in biotech? Yeah, thanks for having me. Uh, the biotech is the innovation feeder to the big pharmaceuticals and it only uh nurtures well in an ecosystem. So to answer your question, what do you need in that ecosystem for that to nurture? Uh, investment capacity, which we have been having for the last, you know, decades, if you will, to kind of keep investing in that innovation to move on. NIH has been probably the world's largest VC over $40 billion in non-dilute funding into the entrepreneurial startups. Then you have talent who has been, you know, coming all these top universities and MDs and PhDs who are dedicated to advance it. And then you need this technology transfer system so that those intellectual property translate into a startup. And then with that investment capacity, it keeps growing and then through testing and going to the humans and then ultimately being developed for everyone's use. So, uh, yes, the US still has the capacity to invest, but it is not potentially the only game in town given the development coming from China. I'm curious, Arta, because we know, I know you've been tracking the deals and uh, we've seen the number of deals steadily increasing over the years. I saw, uh, one of the ones that you sent, which looks at the number of deals so far to date for 2025 is more than half of what we saw in 2024. So we can expect that to really outpace 2024. What does that mean though? Because I know that some of the deals that are happening are more, um, what you would call licensing deals, right? It's not necessarily that this money is going to from scratch investment and innovation, but it's more stuff that has already happened and is built up. Talk to me about that and why that matters. I mean, first of all, the numbers are pretty compelling. A couple years ago, we had pretty much like no deals under a billion dollars in 2016. And as of last year, there were $30 billion worth of licensing deals from Chinese assets into the US, and 2025 is a very strong start, so they're definitely going to beat that number. So the reason why this is happening is in 2015, Chinese Communist Party put a priority of investing in biotech and that was a priority sectors. And it was 10 years ago, and that 10 years of journey started to play out for their benefit because China historically has been known for this active product ingredients and excipients, which is like the chemicals that pharmaceuticals were using to make small molecule products. And that journey now is taking them to upstream to more advanced innovation. Probably we still have not seen a first in class, but clearly they are going for best in class, like those are the shots on goal if you are seeing more and more. Well, that's why, that would be my question because I know that we've seen sort of they're doing copycats or metoos in terms of the type of innovation coming out of China. Um, do we expect that they have the wherewithal to outdo the US then in that sense, in terms of coming up with the next blockbuster for the entire world? I mean, there are a couple examples, early examples that some of the Chinese based assets actually head-to-head comparisons, you know, beat or exceed, at least match the efficacy and safety profile of some of the Western developed compounds. But this is also a journey as the audio question. So what is it, what do they need more to get there? So they have the talent. I mean a lot of Western educated MDs and PhDs went back to China working on that. The government itself as a part of prioritization program have been investing in it. So then the question is, do they have an exit strategy for those entrepreneurs? And that I think is where they are lacking because there's no like an IPO market that is comparable to the Western standards. There's no like an M&A exit until recently. I think that's where the weakness kind of may be the opportunity for them to come up. But the deals we were talking about, they're because of the intellectual property concerns, because of the concerns of reliability and trust in the data because, you know, there's no such institution in the world like FDA that everyone trusts and hopefully continue to trust. And for that reason, the deals seem to be more asset purchases. So I'm not taking a risk by operating in China, but I'm buying the asset and in a licensing deal, and I'll continue to develop it, especially if you can make this cheaper and faster in China, which has been their competitive advantage over the Western companies, then you bring that into a human fast and then the human testing can be done, validations can be done in the more Western setting. I think that can be a winning formula for the industry. Error in retrieving data Sign in to access your portfolio Error in retrieving data Error in retrieving data Error in retrieving data Error in retrieving data
