Harald Glenz, irrigation manager in Salgesch, is convinced that the same yields can be achieved with less water. swissinfo.ch
Due to the melting of a glacier, Salgesch in the canton of Valais lacks an important water source in summer. The village is now using a technology that reduces the water consumption of its vineyards by almost half. A project with exemplary character for other drought-prone regions worldwide.
This content was published on July 14, 2023 July 14, 2023
Luigi Jorio
If you walk down the main street from the train station to the church square, Salgesch’s main branch of industry becomes obvious: on both sides of the street signs with grapes invite you to a tasting in one of the 27 wine cellars in the region.
But the vineyards, which make up the wealth of the village at the foot of the Valais Alps in southwestern Switzerland, and the associated tourism are under threat. In summer, the water from the mountains becomes increasingly scarce.
Salgesch often has to resort to the water reserves of the neighboring communities to irrigate its more than 200 hectares of vineyards. You can’t count on the rain. With around 600 mm of precipitation per year, the region is one of the driest in Switzerland.
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The situation is unbearable. “We’ve had periods of drought before, but we usually had enough water. We didn’t have to think about how to distribute it,” says Harald Glenz, Salgesch’s irrigation manager. “Now we have a lot less and have to organize ourselves more efficiently.”
The local government has launched a project it describes as “revolutionary”: collecting and storing snowmelt water and testing a new irrigation system that could reduce water use by more than 40%.
The village of Salgesch (Salquenen in French) is one of the most important wine-growing communities in the canton of Valais and Switzerland. Panther Media Gmbh / Alamy Stock Photo
The river dries up earlier
Glenz takes me to the heights of Salgesch to understand the cause of the problem. After a few kilometers on a narrow, winding road, we reach a bridge over a stream. On this side of the valley, the Raspille marks the border between German-speaking Upper Valais and French-speaking Lower Valais.
Here, at around 1000 m above sea level. M., is the water intake for irrigating the vineyards and other crops in Salgesch. Glenz can open and close the valves using an app on his cell phone. With a single touch, it can drain up to 12,000 liters of water per minute.
The Raspille is fed by the melting snow. Up until about 15 years ago, the meltwater from the glacier of the Plaine Morte, almost 2000 meters higher, also found its way into the stream. This guaranteed some runoff and water for agriculture for much of the summer.
With the retreat of the glacier, however, the water mainly drains into the neighboring canton of Bern, leaving the Valais side almost dry. In addition, due to climate change, less and less snow is falling in the mountains. The result: the Raspille dries out faster than it should.
In this animation you can follow the retreat of the Plaine Morte glacier:
On this day in June, the Raspille still has plenty of water thanks to the snowmelt in spring. But if it doesn’t rain enough, the creek could dry up by the end of July, predicts Glenz.
The Raspille on June 6, 2023 at the water extraction point for irrigation in Salgesch. Luigi Jorio
The construction of an artificial lake on the plain to catch the unused water of the Raspille is out of the question. The space requirement would be too large, says Glenz: A reservoir the size of a football field and five meters deep would only be enough to cover the water requirements of the Salsch vineyards for one day.
Instead, the water will be stored at high altitude, in the Tseuzier reservoir. The reservoir is at an altitude of 1780 meters and has been in operation since 1957.
Storage of meltwater at high altitude
The “Lienne-Raspille” project envisages the construction of an underground pipeline network to collect the spring meltwater and store it in Lake Tseuzier. In summer, the water is then transported to the areas that are to be irrigated.
A multifunctional reservoir for energy generation and irrigation would be a novelty in Switzerland, says Gilles Florey, mayor of Salgesch.
In contrast to most reservoirs in the world, those in Switzerland are designed almost exclusively for hydroelectric power generation. According to that “World Register of Dams”Externer Link 87% of Swiss reservoirs are used exclusively for power generation, only 2.4% serve multiple purposes.
In Switzerland, the idea of multiple use of reservoirs “is far from being recognized as a prime example of water and energy management,” according to a recently published study Study by the University of LausanneExternal link.
>> In the following video you can learn more about this project, which is unique in Switzerland:
The cost of the project is estimated at around CHF 60 million. Although it has been under discussion for around ten years, it is currently failing due to resistance from the WWF. The environmental organization demands guarantees for the economical use of water.
“The idea of storing water is coherent and intelligent. We have nothing against it,” Marie-Thérèse Sangra, regional secretary of the WWF’s Valais section, told Le Nouvelliste newspaper. “But we have doubts about the use.”
But the mayor of Salgesch is not worried. “We should have reached an agreement with the WWF by the end of the summer,” says Florey. Optimizing water consumption and avoiding waste are among his priorities.
Automated drip irrigation in the vineyard
On the outskirts of Salgesch, two plots planted with the same grape variety were equipped with a new drip irrigation system. With this method, the water can be released to the plants slowly and in a controlled manner, which minimizes evaporation losses.
Compared to sprinkler irrigation or drip irrigation, a conventional drip irrigation system reduces water usage by about 20%. This system is used in about a third of the vineyards in Salgesch. With a fully automated system like the one tested here, the savings are even greater.
“Not only California or dry countries like Australia, Chile or South Africa need such technologies.”
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Sensors measure soil moisture and vine water stress in real time, and the system continuously optimizes irrigation. Drone overflights measure vegetation cover and leaf volume to study vineyard development.
The downside is that micro-irrigation requires filters to remove sediment or impurities in the water that could clog the drip nozzles.
Plus, the investment is not insignificant for those who decide to make the switch to drip irrigation. Glenz, himself a winegrower, spent around 4,000 francs on his 2,000 square meters of land.
Less consumption thanks to technology
On one of the two test areas, an even more innovative technology is used in addition to the automatic drip irrigation. Before the water falls to the ground, it is exposed to low-frequency electromagnetic waves in a special metal cylinder.
The one from the Valais company “Aqua4D”External link developed device can change certain physical properties of the water. This treatment improves water penetration into the soil and uptake by plants.
This solution is already being used in several countries, for example in some almond orchards in CaliforniaExternal linkwhich, like the Salgesch vineyards, depend on the snowmelt – from the Sierra Nevada.
“Not only California or dry countries like Australia, Chile or South Africa need such technologies”, says Eric Valette, co-founder of “Aqua4D”. The historic drought of 2022 has also made countries that have traditionally never faced water shortages more aware of the problem.
“The project in Salgesch is very important because it can serve as a reference for other regions of the world that may face water supply problems in the future,” says Valette.
The “Aqua4D” device changes the structure of the water. swissinfo.ch
The harvest is good, the wine too?
The test in Salgesch started in the summer of 2022, thanks in part to the support of the federal government and a Cash bonus from the electricity supplier AlpiqExternal link. It is part of a larger project to renew the village’s entire irrigation system. This dates back to the 1980s.
“The first results are promising,” says irrigation manager Glenz. In the plot with “Aqua4D” technology, which received 20% less water, a qualitatively and quantitatively similar yield was obtained as in the reference plot. “This means that we can also achieve good harvests with less water,” says Glenz.
However, it is still too early to draw definitive conclusions and know if the wine will be just as good. The project is now entering a second year to find out which results are due to the equipment used and which are due to the weather conditions.
If the project continues to be successful, all of the commune’s and canton’s vineyards could be equipped with automatic drip irrigation and “Aqua4D” technology.
That would mean a water saving of more than 40%, says Mayor Florey. “I don’t know of many other solutions that reduce water use that much,” he says.
Edited by Sabrina Weiss, translation from Italian: Christian Raaflaub
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