A biologist with a PhD in Plant Physiology and a computer engineer, Jaume Casadesús is the head of the Efficient Water Use in Agriculture program at IRTA (Institute of Agrifood Research and Technology). A deep connoisseur of the needs of the people who irrigate Catalonia’s farmland, he experienced firsthand the extreme drought of spring 2023 and is very clear about the path to being better prepared when water shortages return—which they will. He discusses this in the following interview, where he also reveals some interesting facts about his professional career, such as his knowledge of the Ukrainian fields affected by the 1986 Chernobyl nuclear accident.
World Water Day was recently celebrated with the theme 'Save Our Glaciers.' The planet’s major glaciers are melting—and so are the much smaller ones in the Pyrenees. The melting of glaciers—both in the Pyrenees and around the world—is a clear sign that average summer temperatures are rising. This trend is well-documented. Glacier levels have never been this low, and it's a wake-up call we can't ignore. In fact, the first signs of climate change were declared following the observation of the Antarctic glaciers. Although in Catalonia we are not directly connected to the water cycle of these major glaciers, knowing they are melting proves to us that climate change cannot be denied.
In Catalonia, the recent climate-related news is the rain, which is refilling the reservoirs. Are farmers breathing easier?
More than a year ago, certainly yes. But it depends on where they are located.
We have to divide Catalonia into two parts, right?
One half corresponds to the west: the Ebro basin, mainly Lleida and part of Tarragona. It’s a sparsely populated area where agriculture plays a major role. This half of Catalonia is mainly supplied with water from the Ebro or its tributaries. There is a good amount of water and many reservoirs. In this part, water supply issues shouldn't be common; during the 2023 drought, the problems had more to do with how the water was being managed, not just with climate-related issues. Today, we can breathe fairly easily. There are reserves, and snow still needs to melt. That’s why, in fact, water is even being released from the reservoirs in anticipation of more water arriving from the thaw. But we always need to stay alert because these reserves must be replenished each year.
And what about the eastern part?
In this area—Catalonia's internal river basins—irrigation must rely on a more diverse combination of water sources, which vary depending on the region. These include surface water, groundwater from aquifers, and, in some specific locations, even reclaimed water from treatment plants. The internal basins hold less than 40% of Catalonia’s total water volume. There are fewer reservoirs, and they are smaller in capacity. However, more than 90% of the population lives here, and it continues to grow, alongside a very dynamic economy. This part of the territory faces a situation of chronic water scarcity. With the recent rainfall, we can breathe a bit easier, but we need to stretch the use of this water because we don’t know how long we’ll have to rely on it. At IRTA, we focus on the needs of farmers and study how to maximize water use efficiency both in the Ebro basin and in the internal basins.
An IRTA vehicle on the way to field trials in Raimat.
Which crops or producers are suffering the most in the current context of climate change?
Those in Alt Empordà, Priorat, and Baix Camp, where water scarcity has become severe and ongoing. In Penedès—traditionally a dry-farming area—they’ve experienced several consecutive years of low rainfall, though it’s uncertain whether rainfall will return to normal in the future.
Who decides when and how much irrigation is done?
When it comes to surface water from rivers or reservoirs, farmers are usually organized into irrigation communities that manage distribution. On the other hand, with aquifers, farmers historically would just dig a well and operate independently. But now, it’s clear that water is a finite resource: if one person extracts too much from their well, others may be left without. That’s why, about ten years ago, Water User Boards began to emerge. The first was in the Baix Ter region—a success story—and others have followed. The value of these boards is that they bring together all users: farmers, but also municipalities and industry. Municipalities tend to have more financial and technical resources. Everyone manages the water responsibly, because they’re all in the same boat—no one wants to run out. At IRTA, we see this as a highly valuable model.
There’s a lot of room for improvement in irrigation water use, right?
Yes, we’re behind. One of the main reasons is outdated infrastructure. For example, 150 years ago in Ponent, the Urgell Canal irrigation system was very advanced and innovative. At that time, flood irrigation was the only available method. But now, it’s inefficient—we have better technologies and more crop options. Today, water needs to be delivered to fields under pressure, not through open canals.
Do you mean channeling river water?
Yes, because water from wells is already pressurized. But water from rivers is still often delivered via open ditches, which suffer losses, and many fields are still irrigated by flooding—very inefficient. A pressurized system using pipes, with in-field distribution through sprinklers or drip irrigation, is much more efficient in converting water into crop yield. You lose less water and can control when and how long to irrigate. In times of drought, fields that rely on flood irrigation are more vulnerable because they have less flexibility. In this sense, the Lleida plain still has a lot of work to do—it’s often discussed—and so does Girona. Efforts are underway on both fronts.
Why are we behind?
Because many of these canals were built through private initiative, and now the burden of modernizing them shouldn’t fall entirely on farmers. Expecting them to invest in improvements just to save water for everyone’s benefit isn’t much of an incentive—especially considering that many landowners are not active farmers but lease the land to others. We need to find a solution. In the meantime, modernization has been delayed.
What would that solution look like?
Through cooperation between public administrations and farmers. Above all, farmers need to have full confidence that their investments will pay off.
Could the proposed water transfer from the Ebro River to eastern Catalonia be a solution too?
It could be, of course, but that’s not for me to decide—it’s a political issue, not a technical one.
At IRTA, we've been working on agricultural water management since the organization was founded four decades ago. This has given us deep insight into both crop and soil needs, while allowing us to develop technologies that, not long ago, seemed like science fiction. Can you tell us what you're focusing on now?
In the past, we focused more on cutting-edge irrigation methods and worked mainly with farms that were open to innovation. Today, we take a more holistic view—we don’t want to leave anyone out, and our focus goes beyond irrigation. To improve water use in agriculture, we don’t just look at how water is applied—we also consider other factors: soil management, pruning and planting systems that affect drought resilience or water demand, and the fact that not every area has the same water quantity or quality. That’s why we’re also researching the use of reclaimed water from treatment plants for irrigation. At the same time, we’re rolling out a network of technologies across Catalonia to provide support to irrigators.
IRTA has been a leader in implementing new irrigation technologies.
Right now, we’re especially working with digital twins. These are virtual replicas of farm plots that allow us to study what’s happening in each field and anticipate their needs in the coming weeks or months. Thanks to sensors installed in the plots—or via satellite remote sensing—we can monitor water use, soil moisture, crop types, and growth levels. That tells us whether they need more water now or in the near future.
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In addition, we link all this data with digital models that simulate crop growth and water movement. This is what allows us to predict what will happen a week or two months from now. We’re implementing digital twins at three levels: first, at individual farms—using a system we’ve already transferred to a company that markets it internationally; second, on large territories like Baix Ter or the Lleida plain, which proved very useful during drought conditions; and third, in managing irrigation communities. This last use is particularly successful because irrigation communities must request water from the reservoir managers. With digital twins, they can know how much water they currently have, guide irrigators on how to use it, and even predict how much the group will need next week—so they neither fall short nor ask for too much.
Water and CO2 flow measurement system to validate remote sensing, on a farm in Maials.
All of this work is done in collaboration with international partners, right?
Traditionally, we’ve been very connected with the University of Davis in California, which also has a Mediterranean climate, and we work with research groups across the entire Mediterranean region, as well as in South Africa, Australia, Chile, and Argentina, which also have the same climate. But, in fact, in Catalonia and the rest of Spain, we can be proud because we are probably the leaders in water management research, with the distinction that much of this management is collective and public.
You’ve been with IRTA for more than two decades. What brought you here?
My path isn’t entirely conventional. After my degree and PhD, I didn’t do a postdoc, but instead worked for five years as a technician in the experimental fields of the University of Barcelona. This allowed me to be part of several research groups at once. All of them had in common that they did fieldwork and needed technologies for their research: instrumentation, simulations, sensors… Well, this, rather than water, has been the thread that has guided my professional journey. You could say I’ve specialized in the digitalization of agriculture. And at that time, I ended up working on a project related to Chernobyl.
Can you tell us about it?
In the late 90s, many projects were underway to solve the problems in areas contaminated by the nuclear accident and to develop contingency plans in case something like this happened in Western Europe. Specifically, I worked on two European projects to study how contaminants moved from the soil to the roots. We did such a good job that the problem was resolved.
How was that possible?
It seemed that the accident would represent a long-term issue, that the affected areas in Ukraine and Belarus would remain contaminated for centuries. Now, we’re actually importing grain from those areas! One of the conclusions from these projects was that the situation stabilized much faster than we expected. The contaminants got stuck in the clay of the soil, and although they’re still there, they don’t pass into the crops. It was a pleasant surprise that left us without work! I had to re-skill myself, and I did that by joining IRTA.
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First, I focused on the digitalization of intensive horticulture in Maresme, but at that time, greenhouses were being built for urban expansion, so the work didn’t have much of a future. I ended up in Lleida, here at Fruitcentre, working on water issues.
What’s the most rewarding part of your job?
We don't just make bubbles in a fish tank; we’re playing with real fire in a trench. I mean, we don’t just do theoretical work, we’re dealing with real challenges on the ground. And when you succeed, the reward is truly fulfilling.
Can you give us an example?
In 2023, at IRTA, we were in the eye of the storm during the drought crisis. Different sectors were fighting, and we were positioned as mediators. In Lleida, the conflict was between irrigation communities fighting for access to the same reservoir, and in Girona, it was between urban water supply and agricultural needs. They were two different battles happening in parallel. We were fortunate that the situation eased, but it was really inevitable that a mediator was needed. Being placed in that role was intense, very risky, but also very motivating. It was a recognition.
Can we say there has been a before and after in your work?
Yes. At the beginning of 2023, farmers and irrigation communities couldn’t believe they would run out of water. They said it had never happened before. And now they believe it: it happened, and it could happen again. And it’s not just an environmental issue, but one of economic sustainability.
How would you like to see the Catalan agricultural sector in 2030?
I would like to see farmers more empowered. I want them to feel brave enough and confident in the future to make the investments they need. And, as I said, to achieve this, they must link economic sustainability with environmental sustainability. They are making efforts, and this is the direction.
And as for IRTA?
Well, I really enjoy being surrounded by such a competent team as the one I have. It’s one of the most rewarding things. Competent people who are also deeply committed to the sector. You don’t find this in just any institution, and it’s one of the most attractive aspects of IRTA.
A large part of the team from the Efficient Water Use in Agriculture program, which is led by Casadesús.
Today, what drives you the most as a researcher?
I believe we need to see water in an integrative, holistic way, across different scales at the same time. Individual plots, farms within irrigation communities—where if one plot receives more water, another may get less—and also on a national scale. A single reservoir or aquifer supplies water to many people, and we need to view it that way. The water for a farm is connected to how much fruit we leave on the tree, the size of the tree, the varieties, and it’s also related to what’s happening in the surrounding area. I believe collective governance of water is the way forward.
