36-minute listen/watch | 22-minute read | 1-minute teaser
The Colorado River passes through five states on its way to Mexico, supplying water to municipalities, farms, and industry. It supports more than a trillion dollars in economic activity and supplies water to an estimated 40 million people. The overuse of the Colorado River and an extensive climate change-driven drought have significantly decreased the volume of the fifth largest river in the U.S. A research team is exploring how climate change and agricultural adaptation will affect water availability in the Upper Colorado River Basin and what is important to communities that depend on the river.
Transcript
Antonia Hadjimichael
In recent years, in the past 20 years or so, we've been seeing this prolonged drought in the region, which meant that while stream flows in the river are going down, it means storage in our reservoirs is going down. It also means that our ability to provide water to all these states is compromised.
Host
Welcome to Growing Impact, a podcast by the Institute of Energy and the Environment at Penn State. Each month, Growing Impact explores the projects of Penn State researchers who are solving some of the world's most challenging energy and environmental issues. Each project has been funded through a seed grant program that's facilitated through IEE. I'm your host, Kevin Sliman. The southwest United States is home to the Colorado River, a 1,450-mile-long river that provides water to seven states in the Western U.S. on its way to Mexico.
It's the fifth largest river in the U.S., but in recent years, overuse of its water and a years-long drought have led to the river drying up. In this episode of Growing Impact, a team of researchers discusses the challenges surrounding the Colorado River and their project that looks to understand how climate change and agricultural adaptation will affect water availability in the upper Colorado River Basin.
Antonia Hadjimichael
My name is Antonia Hadjimichael. I'm an assistant professor in the Department of Geosciences and my work generally revolves around planning for water resources, especially in the context of deep uncertainty about the future and complexity around human systems.
Meetpal Kukal
This is Meetpal Kukal. I am an assistant research professor in agricultural and biological engineering. My research is mainly around characterizing agricultural hydrology components. So I spend a lot of time working on measurement and modeling of evapotranspiration and topics around irrigation science, engineering, and management.
Alex Thames
Hi, I'm Alex Thames. I'm a Ph.D. candidate working with Antonia and her group. I'm in the Department of Geosciences with a climate science dual title, and I'm working with Antonia on issues related to synthetic weather generation in the context of the relationship between precipitation, temperature, and agriculture.
Cibin Raj
I'm Cibin Raj. I'm a faculty in the Department of Agricultural and Biological Engineering and the Civil and Environmental Engineering Department. I have a dual appointment. So my work is mostly with ecohydrological modeling. So we try to ask like different what-if questions with models.
Host
Again, thank you all for being here. I really appreciate your time and your willingness to dive into this project. So can we discuss the Southwest United States? There are challenges with water in the southwest as many of us know. Can we talk a little bit about climate change and maybe other factors, if there are other factors, impacting water availability in the southwest U.S.?
Antonia Hadjimichael
Most of the southwestern United States, and that includes states like Colorado, New Mexico, Utah, Wyoming, California, Arizona, and Nevada. I think I listed everything, as well as some states in northern Mexico actually depend on Colorado River water, and that essentially translates to over a trillion in economic activity that depends on that water. And that water is allocated for over 100 years now through several agreements of the states have between them as well as international agreements, they have with Mexico.
And in recent years, in the past 20 years or so, we've been seeing this prolonged drought in the region, which meant that stream flows in the river are going down. It means storage in our reservoirs is going down. It also means that our ability to provide water to all the states is compromised.
Host
The Colorado River is a large river. It's 1,450 miles long. I just wanted to see the areas. So, because I don't know how many people know where the Colorado River runs.
Antonia Hadjimichael
Yeah. So it has headwaters within the state of Colorado. Some are in Utah and Wyoming, and it comes all the way down. It, it ends in Mexico.
Host
Okay.
Antonia Hadjimichael
So it's pretty large. I think there's over 5 million acres of agricultural land that depend on it. And really a lot of that land, it is on those states, but it produces food or crops that feed cows. They produce fruit and vegetables for the rest of the states too. So it's not just, it seems like, it might seem at the face of it that is just the states that depend on Colorado River water, but in reality, a lot of the food production we depend on throughout the nation depends on it, too.
Cibin Raj
One reason why we don't hear about Colorado River basin is looking at on the eastern side, right? So in this side, like we always talk about, Chesapeake Bay we don't hear much about the issues in the in the Western watersheds. Here we talk a lot about the water quality, not the water quantity. Not so. So then when the water is limited, it goes like that.
It's like when the water is limited, we start talking about the water quantity and when the water is available, then we start thinking, okay, now the quantity is okay. Now we need to think about the quality.
Host
Now, Antonia, you alluded to this idea. There are complexities, legal complexities with water in the Western U.S. Do you have anything else or does anyone else have any other thoughts on how these legal complexities make water sharing and usage more challenging in this area?
Antonia Hadjimichael
Basically, the Colorado River is shared by seven different states. It ends in Mexico. So across this well you can think of it, you can think of how the water is divided across different scales even. And so various international agreements that we have with Mexico and then bring it to the national level, we have interstate agreements like the Colorado River Compact. So that basically says there is a group of upper river basin states and lower so they have agreements between them about how to divide the river to upper and lower.
So low areas, Arizona, California, Nevada, upper Colorado, New Mexico, Utah and Wyoming. So, they divide it in half. And then between these two parts, they divided between them and then between each state and all the little watersheds and sub basins that exist there, water is allocated through water rights and specifically what's called the Prior Appropriation Doctrine that basically says whoever or they, they usually translated to first thing time, the first in right.
So the idea was that the first people that started using a certain volume of water, they were given the right to that volume until well, until they. And kept that ownership. And then any subsequent users can only use water as long as they don't affect their first user. So, this creates an inherent sort of priority. We call it seniority, but it's an order of priority in who gets water and when we have plenty of water, that's no problem. When we don't have enough water, it starts creating problems with who gets what because if I have a high seniority, I could get 100% of what I need. And if I have a low seniority or what they call I'm a junior user—sometimes they refer to them as that—I might get nothing.
So when we are in a phase of drought, like right now, the impacts of that drought are very disproportionate among users, which I think makes it a very interesting sort of human water interaction.
Meetpal Kukal
I do want to add a little bit around at the impacts of climate change on water availability. I like to look at it as a supply and a demand issue. So lets say we look at the demand perspective, just talking about what the environment looks like. So there's a term that we often use that's called evaporative demand, which is basically the thirst factor or the capacity of the atmosphere to get the water to evaporate at from surface.
And to simply put it I think the best way to explain it would be let's say you grow grass, just simple grass, and it's now taking more than 100 millimeters of extra water that gets evaporated from this grass or do what is needed to grow that grass surface than it took some three to four decades ago, and that's a huge change in demand. And the supply side and again, going back to Antonia’s comments around the headwaters and the snowmelt is another aspect, I guess, because snowmelt and as I understand is happening earlier and earlier in the season. So we get a lot of that flow in the river earlier in spring when the demand is low. But when the demand is high, at least from the agricultural perspective, and that's peak flow or peak demand time in July, we don't have much of that flow coming in.
So there is this tradeoff between what the supply is and what the environmental demand is.
Host
Is it accurate that the snowpack and generally has is less? And so even the snow melt than even it might be happening earlier, But it's also it results in less water flowing down into the rivers?
Meetpal Kukal
Yes, there is some variability around the snowpack itself, but that comes. So I would say, yes, you're correct Kevin, in saying that the combination of snowpack itself accumulated in the normal season and then when the timing of snowmelt, so they both determine what the flow rates are going to be.
Antonia Hadjimichael
The point that Meetpal is making is very important here because it's not just... so if the Colorado River water was only going to municipal use, you could argue that maybe we are diminishing the supply and the demand grows in population or something else. In this case because most of it is agriculture, that climate interaction that Meetpal mentioned becomes very key because it affects both sides of like how much we have and how much we need. And they're both exacerbating each other in a way.
Meetpal Kukal
That's correct.
Host
So there's no shortage of challenges. So, let's talk about the sectors that are being affected by this. Can you provide examples of whether it's individuals or organizations or states maybe and illustrate some of the can illustrate some of these changes and maybe even dive into a little bit of who is using the water from the Colorado River?
Alex Thames
I guess the way that I think about it is that any sector influenced by water or temperature could really be affected by these changes to water availability. So I guess in that respect, kind of any sector or almost every sector is affected, but far and away, the agricultural sector is probably the most affected. I saw a report that was pulling their statistics from a paper from The New York Times that suggested that nearly 80% of all the water consumed in the Colorado River Basin is is done by the agricultural sector.
And then there's other, you know, industrial and residential elements. But far and away, 4/5 of all the water is going towards agriculture. And amongst that 80%, most of that is going towards alfalfa and other grass hays. So it's livestock food, so we you can see that most of the actual supply and demand in both of those cases is actually going towards livestock for for humans, right.
Human consumption effectively. So water and temperature all as thinking a little bit more about my research and my expertise in this, since I'm perhaps the lowest on the rungs amongst the other three people here. Water temperature directly influence agriculture, though it's there's like obvious mechanisms through which that happens, things like evapotranspiration where the amount of water is required to supply a field, how much rainfall there is.
These are the kind of factors that might go into figuring out how a field could be irrigated and how much water it actually requires. How humid is the air? How likely is it that water can evaporate in these circumstances? How hot and cold... these are all the different kinds of relationships that precipitation and temperature have with agriculture.
But other times that influence isn't necessarily immediately obvious, not as direct as these physical climate stressors, especially when we're thinking about precipitation and temperature, where a hotter day may require more water or a hotter day or a hotter period of time may require more water to effectively supply it. And also, as we were talking about, the demand is higher because now you've lost water through these processes, too.
So it's not simply, there's these direct relationships in, you know, the agricultural evapotranspiration equations that we're thinking about. But there's also this feedback, this positive feedback between temperature and precipitation that actually exacerbates this relationship and the issues of supply and demand for water management here.
Meetpal Kukal
Let's say I'm an agricultural producer, in a region where drought is prevalent, and then I'm also a junior water right user and I don't have access to the optimal amount. So what does that look for me? So somewhat so basically it hurts my profitability as a producer, right? And that could mean having a year where I just keep my land fallow so I don't grow anything.
Or I grow the same crop with a lesser amount of water, so I don't achieve the optimum productivity that I should have, or I start thinking about my crop choices. So those are some of the pressures that I would start feel as examples when I when I encountered that shortage in water. Now there are also some incentive programs offered by the state and federal.
There are programs that would let you get some cash payments in return for keeping your land fallow. So those are some of the decisions and some of the tradeoffs that our producers have to start thinking about as these problems grow.
Host
In the I think it's in your abstract, if I remember correctly, where I read this, you talk about the term stakeholder tradeoffs. Can we define stakeholders in this area? And so who are the stakeholders and can we maybe talk a little bit about what stakeholder tradeoffs are.
Antonia Hadjimichael
And a region that we are starting to study, it's a sub basin of the Colorado, which I think we haven't mentioned yet. We call it the Upper Colorado River basin within the state of Colorado. So it's a little watershed within the broader region, and it faces similar problems that the other sub basins face. But when we talk about tradeoffs there, often times we talk about this difference in rights.
So who who has and who doesn't have water. But also that means that cities like Denver or municipal water providers face a lot of risk in their supply and then they start purchasing or it's called oftentimes buy and dry. They start acquiring agricultural water rights to meet municipal demands. So that that creates this tension between the two where if I'm buying an agricultural water right, drying a farm, that might mean jobs are getting affected, communities are getting affected.
So there is there is a sense of loss there. And then another thing that came up actually in talking with Meetpal, in one of our first meetings, we talked a lot about using different irrigation methods and how that might affect water availability for downstream users. So if I'm in a watershed and I irrigate upstream, how I irrigate affects people downstream.
Meetpal Kukal
Yeah, that's a that's a great point. And I think the model that Alex and Antonia are working on would give us more insights regarding numbers. But conceptually that has to do a lot with the efficiency with which each of these irrigation systems operate. So for example, over the years in this particular region and generally in the West, we've seen producers adopt more efficient irrigation systems.
So for example, either moving from flood or furrow irrigation into more micro irrigation techniques like sprinklers and drip irrigation. And so basically all of these systems differ in the way that apply water. So that allows you to gain different efficiency numbers. For example, in a poorly managed furrow irrigation system, you would only be actually using 50% of what you apply versus in a nicely managed center pivot irrigation system.
You could take that number as high as 85%. So of course many, many invest in better irrigation techniques and systems. You definitely improve the profitability for yourselves, but also you dictate what folks downstream are going to see. And a lot of that has to also do with their return flows. So it's not only it's a tradeoff between what you gain in terms of efficiency and what other return flows from your systems.
Because even if a center pivot system allows you to get better efficiency, you lose a lot of the return flow that a lot of the downstream users are going to have access to. So it's a complex tradeoff there, too. And this requires addressing both sides with appropriate measures using the model that they're working on.
Host
Are there a number of individuals or groups using water inefficiently and then therefore causing challenges for other water users? Is that one of the things that we you happen to be seeing... you’re observing? And is there any idea as to why... is it maybe a cost thing or other issues that might be impacting that?
Meetpal Kukal
That's a great question. Kevin. So in terms of there's there's two dimensions to this. So first one, adaptation could be just moving to better irrigation systems. I would say the bulk of that shift has happened already in the past decades. But the other dimension is within the same system that you have. How better are you scheduling your irrigations.
Now this is also very complex in a region like this because let's say as an irrigation engineer, I'm always in favor of using some kind of data, sensing, and analytics to schedule irrigation, but it would be much more complex in this region because a lot of farmers don't have untimed access to water, so they're already constrained by when they would get water.
So they are not in the best position to use a lot of these sensing techniques to schedule this, their irrigations. Of course, a subsection of the farmers would be very happy in investing in these techniques and sensing techniques to schedule irrigation. But a lot of the farmers are already constrained by the supplier.
Host
Farmers have been adapting to changes in the landscape for centuries. Can... Are there differences between what we're seeing now and maybe what has happened historically or are there differences?
Antonia Hadjimichael
There is a dimension. I feel like the institutions and their rights to kind of shape this a little bit. Meetpal mentioned it, too. It's not like if you're in the Midwest or in the East and you're a farm, your access to water is different. So you could maybe invest in technologies or something else that kind of works with what you have.
The institutional structure being so fundamental to the Southwest means that they kind of have to work with the right that they have. At the same time, you have a very senior right, So your supply is always there and safe. So some of those farmers don't have to worry as much about efficiency because they just have a right to that water.
So some of them I'm not saying a lot of them, but some of them could like flood irrigate, which is a very inefficient way of irrigating because they have the right to. They have a lot of water and it's safe and it's always there. So we we've I wouldn't feel comfortable talking about adaptation over this century timescale.
But we I still like there is adaptation happening and it's very much interacting with this institutional context that they are embedded on. So we see them adapt in different ways because of that too.
Host
Can you define hydro climatic and what are hydro climactic stressors?
Alex Thames
So when we think about like hydro climatic, that's the adjective form of the hydro climate, right? And the hydro climate is a term in the earth sciences that can field that includes the fields, combines the fields of hydrology and climate science in a way that kind of emphasizes the impacts of one on the other, and then vice versa.
Often these are used in conjunction with things like hydro climatic events or extremes, which are kind of moments in time, like spatial temporal objects, basically, that describe either compounding interactions between these two fields that exacerbate each other, which is sort of what I was talking about a little bit earlier in my previous response. It's kind of broadly due this interaction between these two systems is this strong temperature dependance on the hydrological processes.
Now stressors are groups or individual kinds of events or interactions that either stress or strain a system. So if we're talking about hydro climatic stressors in this case, you can think about these as events or extremes that push the hydrological or climate system in... I was I'm going to describe it as novel directions in this case. So like higher temperatures would be compounded with reduced rainfall, which may be compounded with lesser streamflow, which may be compounded with earlier snowmelt.
All of these things are interacting with each other and it's, I think, especially true when we talk about the hydro climate that we describe the interactions of these systems as opposed to just these individual pieces that comprise it.
Host
Let's discuss your project. Can you provide an overview of it and share your goals?
Antonia Hadjimichael
Well, the overview of the project is that essentially I have been working in this region for a while and I've been seeing this this quantifying the stressors and trying to understand what they mean for the different users of water. But the presence of agriculture is so I guess fundamental to the water balance event, like where the water goes and who takes it and who doesn't.
So I feel that I will it will be very interesting to approach Cibin and Meetpal and sort of bring in their expertise to better understand how that interaction plays out, especially in the context of potentially increasing stress. So the idea would be to focus in one sub basin of the Colorado and utilize some of the existing skills that we have and tools that we have, along with the new expertise in agricultural modeling and interactions with the water system, sort of quantify how hydro climatic stress would affect the region, especially considering the agricultural interactions.
And what I think makes this case very interesting is that the state of Colorado develops these models that are pretty unique in how detailed and well-documented they are. So they're they are really models of allocations are not it's not a hydrologic model that will describe how precipitation ends up in this stream. It's an allocation model that basically takes how much water we have and gives it, allocates it to the different users.
And because of how detailed and well-supported these models are in that in the state of Colorado, that allows us to ask questions like the questions that we're trying to ask. So how does the increasing hydro climatic stress, interact with the agricultural sector to shape the impacts for everybody in the region, especially considering the rights? We understand that, you know, increasing hydro climatic stress... so things getting drier and hotter in in simpler terms, things getting drier and hotter, we know that they're going to affect their region.
But exactly how much that effect will be and who will bear it is kind of hard to quantify if you ignore that fundamental interaction with agriculture that that we've been talking about and also the fact that the water is not allocated to everybody at the same time and at the same amount. So actually quantifying that effect is one of the key sort of goals of that of the project.
And then also in general, from we talk a lot about I think all of us here are in this space of what we would call human natural systems in the space of water, and that's more of a more recent direction in the literature that really recognizes this fundamental relationship between humans and their environment. And we have a lot of science from the hydrology side.
Maybe we have some science from like the economics literature or like legal aspects, but actually putting it together and putting numbers on that interaction, I feel like it's an important innovation.
Host
You're abstract talks about synthetic weather generation. Can you expand on that? What are we talking about when you say synthetic weather generation?
Alex Thames
Synthetic weather generation, which also you'll see in the literature as stochastic weather generation. Sometimes it's describing a technique that modelers can use that directly produces indefinitely long sequences of weather variables or hydro climatic variables. In our case, we're interested in precipitation and temperature. But there I've seen other cases in the literature where they're interested in things like solar radiation, not just temperature, but mins and maxes for temperatures across a given period of time.
You could even, you know, I think they had things like average wind direction I've seen. But basically the idea of the sequence of weather variables that you can produce is is that this generator can also match and maintain the regions local temporal and spatial correlations. So for your model, it's really important that the data that you're feeding into it is validated against what you've seen historically and this synthetic weather generator does a good job of producing new combinations of precipitation and temperature.
in my case, that matched this region in the upper Colorado River basin, the correlations in space and time and we can get these totally new combinations that we haven't seen historically, which is a real benefit to the system, because now we're testing a bunch of completely novel situations that historically haven't been investigated yet. In our case, when we're looking at this bottom-up approach, we're kind of throwing everything at the model, all these new novel combinations.
And then after we've explored all of them in this exploratory modeling philosophical lens, we can then look at the outcomes and see which outcomes are important to stakeholders.
Antonia Hadjimichael
So the bottom-up approach is basically saying, I know what I care about locally, so how about I go discover what futures matter to me? So I flip that problem upside down and I explore all sorts of different combinations of things. I could put me in a desirable or undesirable thing, and then I go say, okay, this is consistent with global scale climate projections, or this is a highly unlikely, implausible situation.
I will never find myself and so I won't worry about it. So it kind of flips a problem on its head to make sure that whatever impacts that we are calculating are directly relevant to the people and the stakeholders affected by them. And these are sort of, as Alex said, it is a sort of different school of thought about how you go about climate assessment.
Host
Can we talk about what success will look like at the end of this project? And I welcome all of you to to add in. If you if you feel lead.
Antonia Hadjimichael
Success for the IEE seed grant for me will be that we're successful in acquiring additional funding to get this going at a more at a bigger scale. So we're planning a proposal submission this fall to kind of help us going after this initial seed funds. But the idea is that we'll use the grant for sort of capacity development so we can do the bigger things.
That we are hoping to do later because a lot of these problems, as might have been apparent, I hope it was apparent. They're very complex, so it's not an easy one and done kind of cute little study that we can do. So hopefully we’ll get more sustained funding and we'll keep working as a team and maybe have more graduate students working with us.
Cibin Raj
To me, bringing together these these different say you know components of work together and thinking in a holistic way of that region looking at from different perspective and then coming up with some preliminaries research to explore different things. And then at an initial stage for us, I'm not thinking about like studies, like you know one year project will be solving.
The Colorado River basin issue that coming up with perfect solutions, no but will be. We are thinking of getting this as a starting point and to a bigger collaboration and bigger effort into looking into some of these complex issues in the Colorado River basin.
Alex Thames
And for me, since this is a part of my dissertation material, success for me in this context, obviously a you know, a successful endeavor to this first part of the project so we can continue to keep going. But then a body of research for me to include in my dissertation would be success.
Antonia Hadjimichael
And graduate that’s another success.
Alex Thames
I, you know I was predicating graduating on having the material but.
Meetpal Kukal
Yeah, what Antonia and Cibin said, I think that really resonated with what I believe about this project. I think the synergy is, is great and very natural and to have all that here in the Northeast within one single institution I think that really is exciting. And I think I could definitely see this fast turning into bigger and better impacts essentially.
Host
Thank you all for participating. I really appreciate your time. I know you have busy schedules, so thank you. Alex, Meetpal, Antonia, Cibin, I just appreciate your time.
Antonia Hadjimichael
Thank you. Thank you for having us.
Alex Thames
Bye, thanks.
Host
This has been season four, episode five of Growing Impact. Thanks again to Antonia Hadjimichael, Meetpal Kukal, Alex Thames and Cibin Raj for speaking with me about their research. To read the transcript from this episode and to learn more about the research team, visit iee.psu.edu/podcast. Once you're there, you'll find previous podcast episodes, related graphics, and so much more.
Join me again next month as we continue our exploration of Penn State research and its growing impact. Thanks for listening.
