A study released by the Pacific Northwest National Laboratory explored groundwater extraction and how growing demand will affect remaining resources. Scientists focused on when and where groundwater levels could peak, meaning the water becomes so inaccessible that deeper wells or costly equipment are needed to meet demand.
As it becomes more difficult to access groundwater, international agriculture could be affected and the cost of food could rise.
The study illustrates that groundwater has finite characteristics, and basins around the world — including some in the western United States — are reaching their limits. We learn more about the study from Hassan Niazi, an earth scientist with the national lab.
Note: The following transcript was created by a computer and edited by a volunteer.
Jenn Chávez: This is Think Out Loud on OPB. I’m Jenn Chávez in for Dave Miller. Water is a precious resource. Groundwater in particular is becoming more difficult to access as demand for it grows around the globe. A new scientific study by the Pacific Northwest National Laboratory looked at how it’s being used worldwide and what could happen in the future as it becomes harder to get. Earth scientist Hassan Niazi worked on the study and is here now with me to tell us more about it. Hassan, welcome to Think Out Loud. Thank you for being with us.
Hassan Niazi: Hello, thanks for having me.
Chávez: Of course. So, very, very basic question first. I think what often comes to mind when people think of water sources are things we can see: rivers, lakes, reservoirs. That surface water which in at least some cases is renewable because of the water cycle: evaporation, condensation, precipitation. But today we are talking about groundwater. So what is groundwater and how is it different?
Niazi: Absolutely. You named the two most important categories in fresh water usage, or fresh water availability of water ‒ surface water ‒ which is where rivers make everything that you said. And then there’s groundwater which is below our feet. And you would not believe that 98% of freshwater is actually below our feet. And the water that we see is only 2% of the freshwater.
Chávez: So why, for this research, have you chosen to focus on groundwater specifically? Why is it important to pay attention to right now?
Niazi: That’s a great question. Because groundwater is often thought of as the backstop technology, which we can always tap into when we run out of surface water. And because there are not a lot of studies that have investigated the future evolution of groundwater extraction, that’s why I focused to see how will we use groundwater in the future over the 20%.
Chávez: So what are the different things groundwater is used for now, globally?
Niazi: It is used for primarily irrigation, which is basically to produce agriculture, which is to basically to do agriculture and produce food. And then it’s also used as a domestic water ‒ water used for drinking purposes. It’s also used in the energy sector which is for thermoelectric cooling, but extraction is really low. Another use is in industry sector, where water is used in different industrial processes. So ranging from agriculture to domestic use to industry use is primarily the main applications or main uses of groundwater.
Chávez: OK. And so things like food and drinking water seem very important in terms of uses for this. So you have been looking at potential future use of groundwater and you have not just considered a few or maybe 10 or 20 different possible futures, you have modeled 900 potential futures for groundwater, which is just an amazing thing to fathom. How did you model all these different scenarios?
Niazi: That’s true. And you spoke of food ‒ about 1/5 of global food is produced using groundwater. So just another contextual detail. You’re right, I modeled 900 scenarios. And when we were designing this study, we sat down and thought, what are the things that affect our water use in the future? What are the factors that can, if they change, that can affect government use in the future? And we came up with all sorts of narrative, all sorts of scenarios that could happen in the future, ranging from socio-economic evolution ‒ so population, GDP. And by the way, just a small detail, the model that we use is global in scope. So we model all countries and all water basins around the globe.
We thought of population growth, GDP growth in the future. But along with socioeconomics, we also thought of how might the climate evolve. So we modeled climate scenarios as well. And as you know, with climate change, it has impacts on society. So we modeled variations of climate impacts on water resources and other sectors as well. Along with these three models, three other categories which are surface water availability, or reservoir construction ‒ dams that we see on rivers ‒ how will they evolve and affect groundwater use? And lastly, we modeled depletion limits, which is to say, how much volume of groundwater are we allowed to pump [inaudible]. So, the combination of these factors together made 900 plausible futures that we investigated in our study.
Chávez: And your research talks a lot about peaks ‒ an aquifer peaking at one point or another. What does that mean when an aquifer peaks?
Niazi: Right. So this peak is basically the peak in groundwater extraction or groundwater withdrawals. So over time, you can imagine growing demands for groundwater which will eventually make groundwater a feasible source to pump into when surface water becomes expensive and scarce. So groundwater is relatively inexpensive at the start. But when we get to a point where we have many demands to cater to, groundwater becomes if not primary, an almost equal source of water for human usage. And that is the point where we see the peak in groundwater extraction, in time. And then there is a decline where groundwater becomes too expensive to pump or runs into physical limits, or society evolves and chooses other water sources to use.
Chávez: Okay, thank you for explaining peak. So it’s basically when it reaches the point when it becomes almost prohibitively difficult to access. Is that right?
Niazi: That is true. That is right. Yeah.
Chávez: Okay, so what did the various models you studied tell you about what to expect in terms of aquifer peaks in different places of the world and what consequences that folks might see when this happens?
Niazi: We have a really unique model at Joint Global Generation Institute of the Pacific Northwest National Lab. It has been in development for more than three decades and a lot of people work on it. So this is really a flagship model that is used across the world. The uniqueness of this model is it integrates many sectors that we see in the study. For example, ranging from energy sector, to agriculture, to water, socio-economic, to emissions, climates ‒ it integrates everything in a consistent framework ‒ and groundwater is part of it, under the water sector.
So that’s why we were able to investigate so many different influencing factors that were impacting groundwater use. This model is called the global change analysis model, and we use this model with multiple sectors, multiple spatial categorization, to simulate groundwater over the 21st century. It has a historical component, it has a future protection component as well, which also makes it really unique to investigate evolution of resources or transitions or changes in technologies. So we use this one.
Chávez: So, we’re having this conversation about global use. We’re having this conversation sitting here in the Pacific Northwest. Oregonians I know are no stranger to water issues. At OPB, we’ve talked about droughts, we’ve talked about groundwater pollution. There’s a wide variety of issues. Through the lens of this study though, focusing on the demands for groundwater, what issues have you been seeing in the Pacific Northwest or the western U.S.?
Niazi: The western U.S. generally is emerging as stress ridden ‒ primarily California basin. But where Oregon is, it falls under the Pacific Northwest basin due to Columbia’s diverse presence which provides good enough surface water for the region. We have not seen too drastic results for the Pacific Northwest region or basin, but I can imagine with growing demands or you’re right, drought conditions, that there might be a future in which the Pacific Northwest basin also undergoes stress.
Chávez: Well, I just have about a minute left with you, but I want to close by asking you, with all that you have found in these studies, how do you feel we should all be thinking about water as a resource?
Niazi: That is exactly, I think, the main point of the study. I think, specifically for groundwater, there is a perception that we can always tap into it and it’s abundantly available and water generally is a renewable resource. But with this study, we have proposed that groundwater also needs to be perceived as something that is limited, not in terms of volume, but in terms of economic accessibility. So while we may have enough ground water in volume terms, we may not be able to pump it because of the increasing cost of pumping as water tables fall lower.
Chávez: Well, Hassan, thank you so much for your work and for joining us today to walk us through this.
Niazi: Thank you so much for having me.
Chávez: Hassan Niazi is an earth scientist with the Pacific Northwest National Laboratory.
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