Following the tragic event in Blatten at the end of May, where a glacier collapse from the Birch Glacier buried the Upper Valais village, the role of the Ferden dam downstream in the Lötschental valley was highlighted for its proactive management of potential debris flows.
Hydropower infrastructure is not limited to power generation. It also plays a crucial role in protecting against floods, landslides, and inundations. Through multifunctional management and collaboration with leading scientific institutions, these facilities contribute to the safety of communities and settlement areas.
What is the specific role of hydropower facilities in protecting against natural hazards?
Dams and pumping stations go beyond their role in power production. They also regulate water flow. The floods of June 2024 demonstrated the effectiveness of these systems. In the Mattertal for instance, up to 55 m³ of water per second was diverted into the Grande Dixence dam, thanks to the Z’Mutt and Stafel pumping stations and water intakes in the valley. Without these installations, the flood peak in Zermatt would have been estimated 40–60% higher. Across the Rhône catchment area, such as at the Porte du Scex station, the cumulative effect of the dams led to a flow reduction of around 20%.
Across the Rhône catchment area, such as at the Porte du Scex station, the cumulative effect of the dams led to a flow reduction of around 20%.
How do you anticipate extreme events like floods or landslides?
We manage our hydropower assets in an integrated way, combining prevention, simulation, and real-time intervention. In Gebidem, during ground movements between 2015 and 2017, we conducted preventive simulations showing that the dam would completely mitigate downstream risk in the event of a landslide.
We also have alert systems and procedures for lowering reservoir levels. In parallel, we work closely with institutions such as EPF Lausanne and ETH Zurich to enhance our knowledge and adapt our infrastructure. Naturally, we are also integrated into cantonal alert systems.
How could this protective function be further improved?
Given climate change and the increase in extreme events, the protective role of hydropower assets will become even more important. This role, which we currently assume voluntarily, should be fully integrated into asset management in the future.
The planned multi-purpose Gornerli reservoir, part of the Grande Dixence installations, is a direct response to flood protection needs in the Zermatt region. It is designed to absorb large volumes of water and protect the entire area.
Discussions are also ongoing at the cantonal level, particularly within the Valais Association of Electricity Producers (AVPEE), in which we are represented.
Municipalities play a key role in managing natural risks. That’s why we invite them to contact us with any questions regarding the multifunctionality of hydropower facilities. Together, we can strengthen regional safety and anticipate tomorrow’s climate challenges.
