Study of California groundwater prompts a wake-up call for Arizona

Lessons learned from satellite data show urgent need to stabilize underground aquifers

January 9, 2023

A team of scientists that pioneered methods to observe changes in global groundwater stores over the past two decades using a specialized NASA satellite mission has made a surprising discovery about the aquifers that supply California’s Central Valley region.

Despite the Sustainable Groundwater Management Act adopted in 2014 to prevent overpumping and stabilize the aquifers, the groundwater depletion rate has accelerated to a point where groundwater could disappear over the next several decades. The act gives the state’s local groundwater management districts until 2042 to reach sustainability goals. NASA/German Research Centre for Geosciences rocket launches into the sky. Researchers used data from a special NASA satellite to discover changes in groundwater stores. In this image, the NASA/German Research Centre for Geosciences GRACE Follow-On spacecraft launched onboard a SpaceX Falcon 9 rocket on May 22, 2018, from Vandenberg Air Force Base in California. This mission measured changes in how mass is redistributed within and among Earth's atmosphere, oceans, land and ice sheets, as well as within Earth itself. Photo courtesy NASA/Bill Ingalls Download Full Image

Renowned water scientist Jay Famiglietti is the lead researcher of a scientific team that published a paper in Nature Communications in December 2022 that details their analysis.

Famiglietti has a blunt message: “All around the world, we have been kicking the can down the road for a long time on effectively managing groundwater. Now we are at the end of the road, and it’s a dead end." Famiglietti is a professor with the Arizona State University School of Sustainability in the College of Global Futures, a unit of the Julie Ann Wrigley Global Futures Laboratory.

Famiglietti joined ASU in January to assist in developing the new Arizona Water Innovation Initiative, established through a $40 million investment by the state of Arizona.

Among the world’s most productive agricultural areas, California’s Central Valley grows most of the produce consumed across North America. To do that, it relies heavily on aquifers — as much as 100% during droughts. While groundwater has been disappearing from the region for almost a century, the increasing rate of drawdown in recent years is completely unsustainable, Famiglietti said.

“If that water disappears, so does food production. That means less produce, higher prices, shortages and other shocks to food systems,” said Famiglietti, previously the Canada 150 Research Chair in Hydrology and Remote Sensing at the University of Saskatchewan and executive director of USask’s Global Institute for Water Security.

“My fear is that if we wait 20 years to bring these aquifers to sustainability, there may not be anything left,” he said. “Speeding up the implementation period may be worth considering, because there appears to be a rush to pump as much as possible before the hammer comes down.”

Portrait of .

ASU Professor Jay Famiglietti

His team analyzed nearly two decades of data collected by NASA’s Gravity Recovery and Climate Experiment satellite and the GRACE Follow-On satellite. Their research shows groundwater losses during 2019 to 2021 — the driest three-year period in California’s history — were 31% faster than in two previous drought periods of 2006 to 2011 and 2011 to 2017. This rate is also nearly five times greater than the long-term average rate of depletion since 1962.

Deep groundwater took millions of years to accumulate, Famiglietti said, and the current scale and pace of the depletion means that recharging the supply is virtually impossible.

“We talk about managed aquifer recharge and replenishing some of these aquifers. But that’s a small amount of water, and it’s close to the surface. This is industrial scale mining of groundwater, with virtually no chance on human time scales to replace the losses.”

The impacts of depletion extend far beyond food production, he said. A big issue is the subsidence, or sinking of the ground, which can potentially affect about one-quarter of the Central Valley.

Water for desert cities, including in major U.S. cities such as Phoenix, Las Vegas, Tucson, Arizona, and Salt Lake City, will be also scarcer, he said.

As groundwater disappears, there is ecological damage as wetlands are drained and streams run dry. And as water tables fall, costs increase to dig deeper wells and pump groundwater higher, creating affordability problems for people who need to access the water. Additionally, the poorer quality of deep water makes its treatment expensive.

Graph illustrating groundwater depletion.

Groundwater losses combining the USGS’s Central Valley Hydrologic Model and the GRACE/FO estimates since 1962. The black line represents the overall groundwater depletion from 1962 to 2021, calculated by combining the CVHM and GRACE estimates.

What’s happening in the Central Valley is also happening in the Lower Colorado Basin, the southern part of the High Plains Ogallala Aquifer, the Middle East, India and Bangladesh, and several other major food-producing regions around the world, he said.

This depletion of groundwater should be a wake-up call for Arizona, where groundwater constitutes 40% of the state’s water supply and contributes 43% to its GDP.  Yet, outside of the state’s 5 Active Management Areas, groundwater is largely unregulated.

“Arizona is at a crossroads with its groundwater use,” said Famiglietti. “The management decisions it makes today, including how to allocate groundwater for cities, agriculture, industry and the environment, will largely determine its vitality over the next century.

“An important first step will be to carefully measure how much groundwater we actually have in Arizona and how much we are using, so that we can balance that with declining surface water availability from the Colorado River. We need to be able to support innovation and food production, but we need to do it for centuries, not just for a few decades.”

Sarath Peiris with the University of Sasketchewan contributed to this article.

Sandra Leander

Assistant Director of Media Relations, ASU Knowledge Enterprise


Jay Famiglietti brings decades of water expertise as ASU launches water initiative

January 9, 2023

With more than 30 years of experience researching, writing and speaking about water, Jay Famiglietti’s passion about the subject is anything but fluid. 

From providing expert water commentary on HBO’s “Real Time with Bill Maher” to hosting an award-winning freshwater science podcast, Famiglietti has found many avenues to raise awareness about water security. Starting in January, Famiglietti brings this expertise and recognition to Arizona State University as a Global Futures Professor with the School of Sustainability Jay Famiglietti speaking into a microphone at the Resources for Future Generations event in 2018. Jay Famiglietti has spoken at dozens of events in addition to his research, writing and other works. Photo courtesy Resources for Future Generations Download Full Image

In his role prior to joining ASU, Famiglietti served as the executive director of the Global Institute for Water Security at the University of Saskatchewan and as the senior water scientist at NASA’s Jet Propulsion Laboratory. Now, Famiglietti will use his expertise to assist ASU in developing the new Arizona Water Innovation Initiative, established through a $40 million investment from the state of Arizona. The university is leading a multiyear effort, in collaboration with a diverse range of stakeholders, to provide immediate, actionable and evidence-based solutions to help ensure that Arizona will continue to thrive with a secure future water supply.

Related: Study of California groundwater prompts a wake-up call for Arizona

Question: The state of Arizona recently made a significant investment in creating the Arizona Water Innovation Initiative. How will this initiative support the university as it works to help meet the state’s water goals?  

Answer: The Arizona Water Innovation Initiative is designed to be an actionable, evidenced-based way of increasing Arizona’s water use efficiency through immediate interventions. The initiative is relentlessly focused on measurable impacts and outcomes to regional water security and resilience. There is an idea held by leading futures scientists within ASU’s Julie Ann Wrigley Global Futures Laboratory, including Peter Schlosser, that this decade in particular is a very decisive one in terms of forming our future outcomes. Like the name suggests, this is an innovation opportunity we can put into action in this decade that will lead to technology and process innovations, research and developments. 

Our primary priority is solving Arizona’s water challenges, but the policies and proposals we will put into motion through this initiative are meant to be scalable far beyond Arizona, and they will need to be if ASU is to reach its potential to be an international leader. We’re also focused on the importance of communication and how to communicate the information — whether it’s on social media, websites, publications, presentations, news articles, community conversations and more. We’re discussing the best ways to communicate the importance of water, water research discoveries and urgent steps that communities, industry and individuals can take to help secure a sustainable water future in Arizona. This effort involves everyone’s participation!

Q: How did you first get involved with hydrology?

A: I got into water mainly as a kid. I grew up in Rhode Island close to the beach. I was very outdoorsy, and I did a lot of camping and hiking near rivers and lakes. This was in the ‘60s and ‘70s, which was really the dawn of the environmental movement. I really took to that. Fun fact: I actually went to Tufts University to be a veterinarian, but I took my first geology class and that was it. I was hooked.

I ended up majoring in geology in college and got into water towards the end of my undergraduate career. I got my master's degree and PhD in water after that. I gravitated towards satellite remote sensing, which was just coming on the scene. Around the time I graduated from college was the birth of the modern satellite era. When I started my first faculty position at the University of Texas in Austin, I knew I wanted to build my reputation as an independent researcher, so I started focusing on remote sensing and satellite work, and that’s taken me to where I am today. 

Q: You’re coming to ASU from Canada while we’re seeing the world take part in these global crisis conversations. Why do you feel ASU is the right place to be?

A: ASU is a global leader in sustainability. This was a simple choice in terms of the reputation and the facilities, the infrastructure that is built up around sustainability and the incredible growth. I thought about moving to ASU in 2016, and the growth that has happened even since then is extremely impressive. It was an easy decision. ASU ranked at No. 1 in the country and No. 2 in the world in terms of impact towards the U.N.’s Sustainable Development Goals (Times Higher Education 2022 Impact Rankings). In that same ranking, ASU was seventh in the world for the Sustainable Development Goal regarding clean water and sanitation — and number one in the United States. That’s pretty hard to beat. 

Q: How does ASU’s mission align with your personal goals as it relates to water conservation?

A: The mission of accessibility and inclusivity — these are exactly the same terms that we must use with water. We can no longer be exclusive, not just with respect to availability of water but also when it comes to conversations about water and water management. Everyone needs to be at the table. I went to the new faculty orientation in August and heard a talk from President Michael M. Crow, and he really emphasized that inclusivity rather than exclusivity idea. That really resonated with me. The idea of inclusion over exclusion totally aligns perfectly with how I feel with respect to water and water security. 

Q: How will being located in the desert impact the work you plan to do here? 

A: There are a lot of great natural lab settings here. I’ll be very interested and engaged in local, statewide and regional work in the Southwest and the Lower Colorado River Basin. Arizona is in the crosshairs of water sustainability challenges. It’s these challenges that we’re looking at while we work on the new water initiative. While I’ll be based in Arizona, I also do work that expands globally. ASU has the structure that allows for both local and far-reaching research to succeed. ASU’s support for the work on sustainability really makes it the place to be.  

Q: You’ve been focused on water and climate change for decades. What are some of the most pressing issues and trends that you hope to address?

A: I think that there is urgency about water. First of all, let's help to convey it to the world. With that urgency comes the need for more transdisciplinarity efforts outside of just academics. So we’ll be bringing in industry, bringing in government, nonprofits, water managers, city and state officials, and bringing in the technology sector. I don't think that we can really sustain water unless we do that, unless we engage in this transdisciplinary manner. We need to engage deeply and stop thinking that as academics we have all the answers. We have to really engage in the co-development of important questions for the region and for the world.

Q: What are you looking forward to most in your time at ASU, professionally and personally? 

A: Professionally, I’m looking forward to building new collaborations and getting deeply engaged. I really want to focus on water sustainability — in particular, groundwater sustainability — which is critically important in Arizona. I want to really collaborate more with industry because that’s where you see a lot of water use. The food industry, for example, uses up to 80% of the water. If we want to really conserve and sustain water, in Arizona and around the world, we have to think hard about corporate water stewardship.

I also want to double down on our science communication work. We need to really talk about the work that we do at ASU. We need to make sure that our environmental managers, the general public and government officials know about the fine work that's being done, and we have to translate it in a way that isn’t too nerdy or sounds too sophisticated. We are doing great work, and we're going to continue to do great work, and we need to go that extra mile with communication so that everyone can understand why water and water security is so important and what it means to them.

Personally, I'm really looking forward to enjoying the desert. Moving back to a warmer climate is a really exciting chapter for me and my wife. We also have two adult children who live in California, so it will be great to be much closer to them.

Katelyn Reinhart

Communications specialist, Julie Ann Wrigley Global Futures Laboratory