Innovation in addressing climate-related glacial lake drainage
Now that the surface of the Plaine Morte glacier, located between the cantons of Bern and Valais, has melted below the level of the southeastern watershed divide, surface meltwater can no longer flow towards Valais. As a result, the glacial lake “Faverges” has formed over the last decades. Its volume doubled between 2011 and 2016, ultimately reaching a volume of 2 million m3.
Initially, Lake Faverges emptied annually over a period of several days in the direction of Lenk. On 27 July 2018, however, it emptied abruptly – within 24 hours. Damage amounting to approximately 2.5 million CHF was incurred along the Simme river all the way down to the village. In order to prevent this scenario in the future, a protection measure had to be implemented on the glacier – and quickly: the solution developed by GEOTEST had to be implemented before the next snowmelt.
In the spring of 2019, an artificial ice channel was created in only 2.5 months and under extremely challenging high-mountain conditions. In this respect it was absolutely pioneering work. The channel reduces the volume of Lake Faverges to 1 million m3 and thus prevents flooding in Lenk.
Click on the image to learn more about the project by taking a virtual tour of the Plaine Morte glacier.
The project was under the overall construction management of GEOTEST Ltd. GEOTEST was also responsible for the following work:
Analysis of the glacial lake drainage between 2013 and 2019
Hazard management during glacial lake drainage
Definition of the maximum tolerable lake volume
Evaluation of protective measures on the glacier
Safety concept for the high mountain construction site
Assessment of fall hazards to protect the construction site (rockfall modelling)
Assessment of the avalanche hazard to protect the construction site (avalanche modelling)
Radar measurements on the glacier to detect cavities
The client was the Lenk Flood Protection Authority (Schwellenkorporation Lenk). Construction management was the responsibility of Theiler Ingenieure AG.