Natural reservoir Nair Pitschen


The second Nair Pitschen natural reservoir will be built on Corviglia by the end of 2025. In order to be able to follow the implementation of Engadin St. Moritz Mountains' currently largest project away from the construction site, this website was launched at the same time as the ground-breaking ceremony. Here you will soon be able to read and see which steps have been taken and which will take place next. For all those interested in this important milestone in the long-term, sustainable development of the Corviglia ski and adventure area, it is worth checking back here from time to time. We would like to thank everyone who is directly affected by the construction site traffic for their understanding.


For now, let's briefly explain why the "Lej Nair Pitschen", which translates as "little black lake", is being built.

100 percent snow water recycling
Thanks to the Nair Pitschen natural reservoir as an additional reservoir to the existing Lej Alv natural reservoir, the slopes can be covered exclusively with snowmelt water.

More planning and snow reliability
The snowmelt water is available on the mountain at all times, which shortens the snowmaking time and helps to make the snow sports facilities available as planned.

Conservation of resources
The meltwater is collected on the mountain and no longer has to be pumped up from the valley, which saves electricity, groundwater and money.

Added value for summer visitors
The natural reservoir lake is designed as a local recreation area and opened up for a further mountain experience.

The project investment contributes to securing the livelihood of the Engadin population.

Interview with Adrian Jordan, Head of Snow Sports & Mountain Experiences

Switzerland Winter

“The second natural reservoir is a real win-win project.”

The “Nair Pitschen natural reservoir” project was approved by the St. Moritz electorate in 2023 with a pleasing 87%. A clear yes to a forward-looking project that represents another important step towards the long-term, sustainable development of the Corviglia ski area. In June, the ground-breaking ceremony took place for the natural reservoir, which will be built in the area below Munt da San Murezzan over the next two years. The driving force behind the project is Adrian Jordan, Head of Snow Sports & Mountain Experiences at Engadin St. Moritz Mountains. In this interview, he takes a look at the various aspects of this sustainability project and explains why it is a good example of how a tourism region can combine the careful use of resources with guest benefits.

What is the vision behind Mountains' Naturspeichersee Nair Pitschen project?
The driving force behind this project is to continue offering fantastic snow sports on Corviglia in the future, but in a more sustainable, efficient manner with greater planning reliability. Additionally, thanks to the two natural storage lakes, we will be able to fully cover the slopes with recycled snow water. In short, Naturspeichersee Nair Pitschen is a crucial piece for the long-term, sustainable development of the ski area.

Let's briefly touch on snow water recycling. What does it mean?
In winter, we have snow on the mountain, which melts in the spring. We capture the meltwater in the storage basins of the two natural storage lakes, store it over the summer, and use it for snowmaking in the next winter. Snow water recycling thus represents a cycle: water circulates on the mountain. By comparison, in the past decades, we had to pump all the water for snowmaking up the mountain without such a cycle.

The construction of the second natural storage lake is a comprehensive project within the sustainability triangle, i.e., the ecological, economic, and social dimensions. Let's first zoom in on the ecological aspects: What impact does the project have on the other resources used to provide the mountain experience?
Regarding resource use, the second natural storage lake offers several advantages: Since the water is already stored on the mountain, no groundwater needs to be pumped up from the valley—the pumping systems will be dismantled. All the necessary water is available on the mountain at any time, reducing the operating hours needed for snowmaking; thus, we save electricity, water, and money. Moreover, the second natural storage lake will also be designed as a recreational area for guests, similar to the Lej Alv natural storage lake. The Naturspeichersee Nair Pitschen is a true win-win project: it is a good example of how a tourism region can combine gentle resource use with guest benefits.

Economically, the project aims to ensure the long-term survival of the mountain experience on Corviglia. How is this achieved?
The project provides us with even more snow and planning reliability, which are two crucial criteria for us as a tourism region. Thanks to the two natural storage lakes, we will have all the water needed for technical snowmaking on the mountain. As soon as there is a cold window, we can start snow production. We refer to this as the so-called snowmaking time; the time needed to cover the ski area with snow. Many factors depend on this snowmaking time, including the scheduled opening of the ski area, which is highly relevant not only for us but also for the service providers in the valley. Previously, without any natural storage lake, the snowmaking time for the entire Corviglia was several weeks—depending on the water that could be pumped up, electricity, and other factors. With our first natural storage lake, Lej Alv, we were able to significantly shorten the snowmaking time. With the second natural storage lake, Nair Pitschen, we will optimize the cold windows even further, thus shortening the snowmaking time even more. Ultimately, this gives us more planning and snow reliability. Given the climatic changes, this is a crucial advantage for us as a snow sports destination.

What savings are achieved through the Naturspeichersee Nair Pitschen project?
Since we no longer have to pump groundwater up the mountain, we will save about one gigawatt-hour of electricity per year, which is roughly 10% of our company's total energy consumption. To illustrate: one gigawatt-hour corresponds to the annual electricity consumption of about 300 four-person households. Thus, with the second natural storage lake, we achieve a significant reduction in electricity consumption that we could not achieve through pure savings measures. Additionally, we will no longer need groundwater for technical snowmaking.

Let's look to the future in terms of the social dimension of the project: What does the natural storage lake offer future generations?
Our Corviglia ski area covers 155 kilometers of slopes from 1730 meters to 3057 meters above sea level. Various climate scenario studies indicate that ski areas at our altitude will have good to very good snow reliability with a snowmaking system for at least the next 60 years. The second natural storage lake is another important project in our long-term snow sports strategy regarding the offerings for our guests. The Upper Engadine, with its approximately 17,000 inhabitants, is largely dependent on tourism. With this investment in the new natural storage lake, we make a significant contribution to the livelihood of thousands of people living in Engadin, who are directly or indirectly dependent on snow sports tourism.

The groundbreaking for Naturspeichersee Nair Pitschen took place in June. What challenges does the construction bring?
The biggest challenge is the weather: we are building the natural storage lake at around 2600 meters altitude. At such a high-altitude construction site, we always have to expect precipitation in the form of snow. The weather conditions can significantly influence the construction schedule. Therefore, we hope for good, largely precipitation-free weather so that we can proceed as quickly as possible.

And what has been your personal highlight in the project so far?
I was overwhelmed by the great approval of the St. Moritz population for this forward-looking project. 87% of the people who went to the polls believe that the construction of the second natural storage lake is an important project that should be implemented. That is fantastic and motivates us greatly.


The current natural reservoir lake Lej Alv, the older and bigger brother of Lej Nair Pitschen, is popular for excursions on foot or by bike from summer to autumn. The "white lake" has a volume of around 400,000 cubic meters, which is around 100,000 cubic meters more than its smaller brother. The meltwater used for snowmaking in the ski areas saves the electricity requirements of around 400 households every year. The Lej Nair Pitschen, which is around 60 meters higher, is filled using pumps and pipes already installed from the Lej Alv as soon as it is full of meltwater from winter snow.

Important Information

The mountain bike trails and hiking paths starting at the Piz Nair mountain station are partly snow covered.

The hiking trail between Munt da San Murezzan and Suvretta Pass is closed, due to the increased risk of rockfall. There is an alternative route for the "Suvretta Loop" mountain bike route via Fuorcla Schlattain.