Ferden dam - Emergency intervention

Following extremely bad weather in the Lötschental last October, the Ferden dam (Upper Valais) operated by the firm EnAlpin, had to be urgently purged of sediment which was blocking the outlet gates at the bottom of the lake. In less than one month, we extracted some 60’000m³ of sediment.

The outlet gates at the bottom of the dam were blocked with ~200'000 m3 of sediment suddenly accumulated during the exceptional flood on 10th October. Therefore, EnAlpin needed our support to re-establish the functioning of the harnessing of the water. The aim was to ensure the safety of the inhabitants in the valley. In fact, at the start of December, the level of the Ferden dam has to be lowered in order to avoid overflow of water and flooding should there be an avalanche.

The ROV and 2 pumping platforms

At the end of October, we inspected the bottom of the lake with the help of our underwater robot (ROV). The state of the premises caused us to rapidly install a first pumping platform, then a second, in record time. From 5th November, pumping took place virtually 24 hours a day, 7 days a week.

Approximately, 60’000m³ of a muddy layer highly charged with sediment were extracted from the reservoir. On the basis of the calculations made by our specialists, our client EnAlpin took the decision to open the outlet gate valves, successfully, on 21^st November.

This mandate led to a partnership with the TSM Perrottet SA company at Sugiez. It highlighted our competence in sediment management but also our faculty to intervene rapidly in order to manage emergency situations.

 

More information concerning our services in sediment management.