The Plaine Morte Glacier is melting rapidly: its surface has been thinning by about three meters per year over recent decades. This comes with consequences, for example for the village of Lenk. An impressive project at an altitude of 2,740 m a.s.l.
Click here to tour the Plaine Morte Glacier and learn more about the fascinating project.
Because the glacier surface has thinned below its original drainage divide, the surface meltwater no longer flows towards the canton of Valais, but accumulates on the south-eastern side of the glacier, creating seasonal glacier Lake Faverges. The lake volume doubled between 2011 and 2016 and finally reached a volume of 2 million cubic meters in 2018.
Initially, Lake Faverges’ annual drainage towards Lenk occurred gradually over the course of several days. On 27 July 2018, however, the lake emptied abruptly within 24 hours. This event inflicted around 2.5 million Swiss francs worth of damage along the Simme River in the village of Lenk. To prevent such an event from reoccurring, we developed a protective measure on the glacier next to the lake. In the spring of 2019, an artificial ice channel was excavated in just 2.5 months under extremely demanding high alpine conditions. This intervention reduced the volume of Lake Faverges to 1 million cubic meters and prevented further flooding in the village of Lenk.
GEOTEST AG managed the overall project and was also responsible for the following specific tasks:
- Analysis of the glacier lake drainage between 2013 and 2019
- Hazard management during glacier lake drainage
- Definition of the maximum acceptable lake volume
- Evaluation of protective measures on the glacier
- Design of a safety concept for the high alpine construction site
- Assessment of rockfall and avalanche hazards to protect the construction site
- Completion of ground-penetrating radar surveys to detect subglacial cavities
The contracting entity for this project was the Lenk Flood Protection Authority (Schwellenkorporation Lenk). Theiler Ingenieure AG managed the construction activities.