Satellite-based measurements of evapotranspiration, a form of water flux, can indicate where land has been irrigated, or help forecast drought. Water manager Julie and climate scientist Josh join us in this episode to explain how a new tool, initially tested with flux data, can inform decisions in state government. Conserving water in New Mexico doesn’t just save money for farmers and help plan future housing developments, it can also ensure more water reaches downstream states, like Texas.
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In this episode of Meet the Fluxers, we learn about developing an operational decision-making tool through a collaboration between Josh and Julie. The tool provides four decades of state-wide high resolution satellite evapotranspiration estimates, a valuable resource for New Mexico, which faces unique challenges as one of the driest and poorest states in the US. Josh explains how his academic research evolved into applied science through patient relationship-building with state officials, while Julie describes how the tool helps state officials make critical decisions related to water rights, drought management, water conservation, and interstate agreements. Their partnership demonstrates that bridging the gap between pure science and application requires good communication and understanding users' needs through human-centered design as well as building diverse teams with complementary skills.
Transcript
Maoya: Start by telling a little bit of your story of how your career took you into this direction.
Josh: I did my Ph.D. with Dennis Baldocchi, who a lot of the listeners might know of. I did my undergrad and graduate work at Berkeley. I worked at the Tonzi Ranch site installing sap flow sensors and looking at evapotranspiration while most people were looking at carbon.
I was also trying to figure out how to model evapotranspiration (ET) because it was still very difficult to measure. That was kind of right when the MODIS era was taking off. I wanted to see if I could get evapotranspiration using satellite data. I went off to do a postdoc in England. I thought I'd leave eddy covariance and evapotranspiration behind me, doing something different in my postdoc with nutrient cycling and more on the climate modeling side.
The work that I done on the evapotranspiration side started taking off the community. People were using the model that I had developed, the data, and doing more validations against flux sites as they rapidly started popping up around the world. I returned back to California to take up a scientist position at NASA's Jet Propulsion Laboratory, JPL. There was a thermal remote sensing expert, he was very excited that I came because he knew that thermal remote setting could connect to evapotranspiration. We teamed up and developed a lot of different research projects, the most notable of which was a mission called ECOSTRESS, which focuses squarely on evapotranspiration from the International Space Station. So, I was the science lead for that number of years. I left JPL after 12 years. Now, I'm the science lead for Hydrosat. We're launching a whole constellation of thermal sensors to drill down the spatial resolution and frequency of thermal remote sensing evapotranspiration and the related products.
Maoya: Julie, tell us a little bit more about your path.
Julie: I have a Bachelor's in Environmental Engineering from the New Mexico School of Mines. Right after college, I started working for the Office of the State Engineer. My first year, I worked in the Water Rights Division. I worked two years in our Litigation & Adjudication Program, did a lot of field checks looking at properties and trying to determine what their irrigation water right would be. I had the opportunity to move to the Water Use & Conservation Bureau. I previously had worked with a lady in water rights who really wanted me to make the move to water use. I kind of asked her, “What do you guys do there?”
First and the foremost, we review subdivision proposals. What we review is water availability. If a subdivider is proposing to use groundwater wells for their subdivision, we have to ensure that there is going to be a 40-year supply of water. Also, if they're a proposing to use the public utility, the eastern part of the state has a lot of shortages. So, we're now looking at water providers, do they have a 40-year supply of water? The next thing we do is, we review conservation plans. If a public water supplier has water rights that they want to use, they have to demonstrate the need for that water. So, we'll either approve the plan or not approve the plan.
We have a pretty good outreach program, and we really target K-12 on how to conserve water. So, we'll go into schools, but we also do a lot of presentations to, like, Homeowners Associations. Anybody who wants us to go and talk about conservation, we'll go do that. We compute irrigation water requirements for adjudications, for water rights permits, for hydrology, or help monitor the drought. We're kind of the go-to bureau for a lot of things that don't fit in the box for other parts of the agency. Throughout my years, I had really good mentors. And we've worked on many projects related to ET using different methodologies. So, I was pretty excited to learn more about ET.
Maoya: Did you think that your career was going to direct you into the applied side of science?
Josh: In 2014, there was a meeting of the Western States Water Council, and they came to JPL to check out what we were doing there in terms of our hydrological capabilities. I gave a presentation on evapotranspiration, and the State Engineer of New Mexico came up to me afterwards and he said, “We could really use that type of ET data for New Mexico.”
We got to talking and said, “Sure, you know, let’s see what we can develop!” and we got a few interns to scope out, what are the needs of New Mexico for evapotranspiration? How are decisions made? How are data used in decisions? [We] got a couple of years of funding through NASA's Western Water Applications Office, WAO, to start building some prototype tools and software. That's when I left JPL and joined Hydrosat. I took on a faculty position in Chapman University and immediately got a big grant from NASA's Applied Sciences Water Resources program to continue the work that I had started with the Office of the State Engineer.
Julie Valdez stepped in and became the main point of contact. We had this continuity and continued interest from the Office of State Engineer, OSE. That was a big key to our continued success, because it's not easy to just say, “Hey Josh, we could use this.” “Hey John, okay!” And then it just happens. It took a lot of discovery and self-education along the way to figure that out. So, we got this big project a few years ago back in 2021. This project was a Category 3 project by NASA. It is top-level applied sciences. So, there are these different ARLs, application readiness levels. Low on the ARL scale, you’ve kind of gotten this idea, maybe some cool widget that you've made, some cool software, some cool data set. To get to ARL 9, the top of the ARL ladder, requires, basically, the scientist to step out of the picture. The end user is basically using it operationally.
Maoya: How did you start to build a common understanding of how to work together and co-create this project?
Julie: Everything was already, kind of, set in play before I joined the team. My predecessor had just retired. I asked to take the lead since I knew about the project, but I hadn't been one of the team members. There was already a set goal of what we wanted the outcome of the tool to be. But as time has progressed, things have evolved. Josh understood what we wanted, and they've been able to make those changes to the tool.
Maoya: Tell us a little bit more context. Like, what is a water right?
Julie: In New Mexico, a water right is a legal authorization to use a specific amount of public water for a beneficial purpose, such as irrigation, municipal use, or industrial use. New Mexico water rights are a governed by the Doctrine of Prior Appropriation, typically referred to as first in time, first in right. So basically, older or senior water rights holders have priority over junior water rights during times of shortages. Senior water right holders are typically Native Americans, acequias, and agricultural water users.
Jess: What is an acequias?
Julie: It's a lateral. It's really old for New Mexico. They've been around for about 400 years. In northern New Mexico, they're little earthen laterals that carry the water from the river to the farmer's piece of land. Junior water right holders are typically municipalities, industrial, residential, commercial, or recreational users. Some of the key elements of a water right include a priority date, which is the date when an application was filed or a water right was put to beneficial use, and then another element is the source of water. So, you have to specify whether your water is going to come from a surface or groundwater source. The point of diversion, which is the exact location where the water is going to be withdrawn. We have the place of use, which, you have to have a legal description of the land that the water is going to be applied on, the purpose of use, so, whether it's for agriculture purposes, municipal, commercial, et cetera. We do recognize those as beneficial uses, but if you're not using the right, then you may be subject to forfeiture or abandonment.
The last element of a water right is the amount of water authorized for use. Our average rainfall is less than 13 inches. We're a really arid state. We receive little rainfall, or none. We’ve been in a drought for the past 20 years, on and off, but a big bulk of it has been drought, which means, if there's not enough water in our reservoirs and our rivers, then our aquifers start to suffer. If a public system has been pumping their aquifer for a long period, there's a lot of drawdown. And then, they have to start seeking alternate sources of water. Farmers can't irrigate their crops. We're looking to develop tools that will help us with our water shortages or water scarcity. In New Mexico, 80% of the water that is used is agricultural. So, that's why we really wanted to focus on finding ways to save water in the agricultural sector. For water right applications or adjudications, we have to estimate how much water is needed for that particular farm or area. We’ve relied on older methodologies, which are still pretty good, but this tool for ET would help us speed up the process. For water rights if they're trying to assess whether or not an area has been irrigated, for transfers of applications or abandonment, we’ve historically relied on aerial photography to help with decisions as well as ground-truthing of the area in question. Using some of these older methodologies takes a lot of time. This tool is going to be another tool in our toolbox that's going to speed up the process, especially when you're doing a big area.
Maoya: At what point did you realize that this model that you had built had this potential?
Josh: So, I was trained as a scientist, not as an applied scientist, right? So, my foundation in evapotranspiration and remotely sensed ET, just the science of how plants use water, is grounded in just understanding how the world works and being, kind of, able to do cool things. Initially, I got into it because I grew up in California and Alaska. My parents split when I was little, so I went to school in LA, where we would be putting low-flow showerheads on my shower in my mom's place and be putting high-flow showerheads in my dad's place in Alaska.
When I got into my undergraduate work, I really wanted to focus on water. Why is it that California gets into droughts? What is it that we can’t predict about it? I was interested in the science of water, hydrology, because of the applied nature. We could measure every part of the water cycle, except evapotranspiration, at the time. We could measure rain through rain gauges, and groundwater through wells, and snow through snow measurements. But you couldn’t actually measure evapotranspiration. You could put out pans, see how it evaporated, but that was pretty much it. The eddy covariance technique wasn’t around. It only just started emerging in my formative educational years. I was just, kind of, trying to do it for the sake of doing it. Understanding the mathematics of models, understanding how properties of water and plants relate to measurements from space. So, I never returned to the applied sciences component in my evapotranspiration work. I had done some applied work through my internships at the EPA, in environmental justice. I found that extremely rewarding, but I never went into the environmental justice realm until more recently.
Another thing that I had been doing at JPL as well, I started working with artists and designers. There's this whole user-centric, or user-centered, design approach to understand what people need, how they're making decisions, how they are essentially purchasing goods. We thought we could apply those same methods to data and science as a service, not necessarily to sell. But at the time we just thought, how can we best serve up our data to be useful for people? I started learning these design principles and design methods that served well going into this relationship with OSE and those folks. And so now on this current project, I have a lead designer and he's been invoking a lot of these design principles. The success has come down to a combination of really good systems engineering, how to get stuff done, but also understanding and empathizing with what's going on from the user side. I need that communication and that patience from the user side and a lot of users don't have it. They change positions. It could have easily been that when Julie came in, Julie said, “Not interested.” We were fortunate to have this longevity of relationships and patience while we were developing the technical tools.
So, we developed this system on NASA supercomputers. We had to get it off NASA supercomputers. But then, I needed to transition the data to a user interface. So, we were able to be responsive to what OSE wanted in terms of the look and feel of how they interacted with the data.
Maoya: What are the goals of the projects for the end users?
Josh: I traveled around the state for a long time, talking with different end users and creating what I call “applications traceability matrices”, in terms of, what are these decisions? What are the use cases? How do they want their data? Do they want frequent data, graphs, summary charts, forecasts, historical, geotiffs? We created a system of high-resolution evapotranspiration from Landsat, so 30-meter evapotranspiration data, for the whole state for 40 years. No other state has that record. In fact, nowhere else in the world has that record. In fact, New Mexico is the only state in the U.S that is in the top 10 driest and poorest. They don't have a lot of resources to just go buy a ton of drones or soil moisture sensors, or eddy covariance towers everywhere. Anything that can help is really helpful. The tool creates this record of evapotranspiration that the state can then look at to see, how is water being used?
They end up processing a lot of applications. When people want to change what they're doing with water, when they want to sell their water rights to somebody else or buy water rights or whatever, the state basically has to determine, do you really have that water right? Or are you just making it up? The way that they determine it is, you have to have been using it. How do they know you used your water in 1989? But we can see that from space. If we didn't have that record, it takes them a lot of time and there's a lot of uncertainty. This system basically creates that record of consistency and spatial coverage.
Julie: So, currently the end users or stakeholders are going to be OSE staff, which includes our Water Rights Division. They're using it for when a farmer wants to transfer water from one area to another area, or if they want to sell their water. Then, they have to go in and start doing their analysis. They need to determine that that water has been beneficially used. We don't want anyone wasting water. That's when they start doing their research and they start looking at aerial photography. That's one tool in the toolbox. The other one is ground-truthing, and they'll also now be using the key tool. That's the information that they'll use to make their determination on whether or not they can transfer that water right. That also includes our Hydrology Department. They need to determine, if they move the water from this area to another area, how is that going to impact existing water right holders? Typically, when they run their models, they reach out to my group and they want us to provide them with some ET numbers. Now, using this tool, they can just run the ET tool on their own.
Hydrology also wants to start using the tool for historical supply analysis, which helps with estimating how much water can be transferred, or even for adjudications, for a slew of different things. All the water that is coming into the state of New Mexico and going out of the state are under Interstate Compact Agreements. So, there's a threshold of water that we need to send to Texas. Because of the water shortages, we have to find different ways and get creative to figure out, how do we meet those compact requirements? So, what we’ve done on the Pecos River is, we will buy up farmland and we basically retire the water right. In the lower Rio Grande Valley, it's a little bit different but similar. They’ll reach out to farmers. Those who want to participate in the program, they’ll pay them a certain dollar amount per acre to not irrigate that year. It just depends on funding that we get from the legislature. But to do so, they have to look at the piece of land that the farmer wants to fallow for a few years. They’ve got to make sure that that piece of land was irrigated. Once they're in the program, then they’ve got to ensure that the farmer is not using any water to irrigate.
We also have some partners, the State Climatologist and the National Weather Service that will be using the tool for drought monitoring. The last stakeholder that we've helped is the Forest Service, and they can use that for forest management. It's just exciting for us to be able to use this tool in a lot of the work that we do. I am charged with compiling our water use by categories report that we do every five years. There are seven categories, I won’t go over all of them, but the one category that is really difficult to estimate is ag. In the past, it was really easy to collect data from farmers or county extension agents. That's, kind of, not happening anymore. It can help speed up the process for the agency’s work overall. That's what I'm really excited about.
Josh: If there is a declaration of drought for a county or the state, all of these actions and policies get kicked into place. Eventually, the top of the line is, the state runs out of money and the feds come in. But the state really doesn’t want that, because when the feds do that, they take over all the management of everything. Getting that declaration right is really critical. A couple weeks ago when we were in New Mexico, we talked with the State Climatologist and NOAA, and figured out, how do you make these decisions? And they're often looking at the U.S Drought Monitor (USDM). You'll see these giant, amorphous, blobby polygons that kind of give you no good local-scale information. If you look at a county using the USDM in New Mexico, it's just one color. It just assumes the entire county is exactly the same, but it's totally not. The State Climatologist and NOAA actually have to drive out, every week, all over the state, to figure out this one giant red blob for this county.
Our data are coming in at 30 meters resolution, telling them, “This county is kind of in drought, but there are certain areas that are worse than others.” So, it gives them this much more rich information.
Maoya: Who needs to be at these training sessions to really accelerate progress?
Julie: We invited everybody in the agency to these training sessions. I thought the most important part was interpreting the data. The output has the geotiff for every month, the precipitation, the cloud coverage, potential ET, and then the uncertainty. During the training sessions, it was interesting to see staff’s reaction and all the good questions they had.
Josh: It got a huge turnout. I wanted to do the training very effectively. So, we did a lot of prep for the training. We used a lot of pedagogical techniques of human-centered design, active learning, storyboards of how people would use it, slide decks, videos. We set up a Wiki for documentation. Eventually we're supposed to go away. So, how does the next OSE staffer who gets hired learn it? There has to be seeds planted for training the next generation.
We also trained the IT staff to update software if there's a change in the satellite data file format. We had a survey beforehand. We had a survey afterwards. We’re going to follow-up. There's all these great testimonials, but how do we know, quantifiably, how much time does this save you? How many dollars? What are the economic implications? How much water does this save? The final stage of this project is to start getting an impact assessment going.
Jess: Are you ground-truthing every single decision that you make, or was it just ground-truthed when you were building the tool?
Julie: Water rights staff will go out and ground-truth the area.
Jess: What is it that you're ground -truthing?
Julie: It’s more of a field check. They'll go out and look at the area and then they'll look to see if it's being irrigated by an acequias, if the acequias is still functional. Or if it's a well, is the well functional? Has it collapsed? They take lots of pictures.
Josh: The ET data have already been validated against eddy flux towers, across dozens and dozens of papers. Then there's a bunch of towers that we validated against. You know, nothing's ever perfect, but it's pretty good. In a state like New Mexico where everything's quite dry, you can really see if water was being used or not.
Julie: I think they're still going to continue to do the field checks, look at historical photography and then also the ET tool. The reason being because any of the work that is produced by this office can go to litigation. So, we always have to make sure that we crossed all our T’s and dotted all our I’s. That's another reason, at the training sessions, we did extend the invitation to our attorneys. We want them to be well aware of what the tool was being used for. The Water Rights Division will be the ones defending their work, but the attorneys need to understand what that work is.
Josh: There is no way the State Climatologist will declare a drought without going to these areas. When it comes down to it, any decision that gets made that affects a human being has got to have a human element.
Julie: We're still learning a lot about the tool, and cost is a big issue for us. We have to learn, like, what's the cost going to be to have this tool on Amazon Web Service for a year?
Josh: If you open it up to the public, then you can easily get giant queries all the time, and you have no idea why it's being used. Someone's got to pay for that, and that someone is the state and OSE. So, we also interface with the OpenET system for more of the modern data, not so much of the historical data. That's open for anyone to look at.
Jess: Would you be able to replicate this?
Josh: Yeah. In fact, on this project we have a collaborator from Arizona. Arizona wants it, Texas wants it. There's nothing really stopping it, because it's global data from Landsat.
Maoya: What have you learned about what we could do better as a community to have longevity on these types of projects?
Josh: You can't win a championship with a bunch of point guards. You’ve got to have different players playing different positions. They all have to be really good and working well together. There's this team effort there. So, I brought Julie into other proposals, where we’re developing new datasets, new tools that could useful to the state, because Julie has this working relationship with me. It also helps them NASA continues to push me and others, making sure we report our application readiness levels, to give them testimonies, quarterly reports. They provide a good structure and push.
Jess: If other scientists who are listening to this are interested in work that will have more of an impact in their state or local government, that the first step would be to just do it. You might get approached by someone who wants to use that, but also the second thing is, potentially to reach out to state government yourself?
Josh: People have been asking for a playbook or a recipe to success. I don't know if I have it. I might have some ingredients. I also got lucky. For folks listening to this who want to really take their science and have it be societally applicable and beneficial, there are a lot of ways. You definitely have to have a partner on the other end that is willing to work with you. You also have to have a partner with skin in the game. So, this all NASA-funded. So, I was at NASA when I started. But now I'm a University Professor, and I also help run a space company called Hydrosat. I now have a foot in the commercial world. For students who are listening, who might be graduating trying to figure out if they want a career in academia or government or NGOs or industry, those walls have greatly blurred and eroded. There's no, “you're in one path”. You don't do one thing, because I'm now in all these paths: the NASA world, the University world, the industry world, just kind of doing my thing.