Material ropeway for the construction of the Braunwald drainage tunnel

The ‘Braunwald drainage 2025-2030’ project is gaining momentum. A specially built material ropeway is the centrepiece of the entire construction site logistics. Various preparatory work will be carried out in the valley and on the mountain until the autumn of 2026. The excavation of the drainage tunnel will begin immediately afterwards.

Since 2025, preparatory work has been underway for the major project to drain Braunwald, which will last until 2030 and is estimated to cost CHF 45.9 million. The area for the installation and transhipment site at the valley station of the material ropeway near the Braunwald funicular car park has now been prepared. The area for the installation site at the mountain station has already been cleared. The foundations for the three pillars of the material ropeway, which will be dismantled after the drainage tunnel has been excavated, are also visible. All the areas used for the ropeway and the construction site installation will be restored to their natural state at the end of the project. In the coming months, the installation site at the mountain station of the material ropeway will be built and a cut will be made in the terrain to allow the underground construction of the tunnel to begin.

Material ropeway ensures careful construction in Braunwald

Work underground is expected to start in the autumn. Before that, the tunnel construction company and specialist firms will deliver and install the necessary installations such as site barracks, equipment and water treatment plants. During the summer months, construction work will continue to focus on the surface construction sites. For project manager Robert Strukely, the new material ropeway is a key component in the project’s implementation: ‘Material transport will be carried out exclusively via the material ropeway. This will keep Braunwald car-free throughout the multi-year construction phase. This will avoid additional burdens for the village and the landscape’. The ropeway will not only transport machines and materials to the construction site, but later also the excavated material from the tunnel. The pendulum ropeway with a continuous drive system is about 1.5 kilometres long and has a payload of up to 13.5 tonnes in normal operation. The height difference is just under 600 metres.

Why a drainage tunnel?

With the drainage tunnel, Braunwald is responding to a challenge that has been known for generations: the ground in the settlement area is slowly moving downhill over an area of around four square kilometres. By draining water from the landslide mass in a targeted manner, the pore water pressure is reduced and the stability of the subsoil is increased in the long term. This is achieved by building a main tunnel 918 metres long and an additional side tunnel. Draining the ground mass significantly slows down the movement, thus preventing damage to buildings and infrastructure in Braunwald and the valleys below in the future.

The concept of underground drainage has already proven its worth on several occasions: similar projects have been successfully implemented in Beckenried (Nidwalden), Campo Vallemaggia (Ticino) and in the La Frasse tunnel below the Col des Mosses (Vaud). The drainage tunnel currently under construction under the village of Brienz/Brinzauls (Graubünden) is already having a positive effect. The land mass is moving significantly more slowly. (see information bulletin from the Albula/Alvra municipality). The cost-benefit ratio between the investment and the potential future damage is more than ten to one in the case of the Braunwald drainage tunnel. The construction of the tunnel in Braunwald thus also fulfils the federal government’s requirements for the economic viability of measures to protect against natural hazards by several orders of magnitude.

Greater safety for the population and infrastructure

The monitoring of the Braunwald landslide, which is already being carried out, will continue in parallel with the construction work, so that the movement of the slope and the effects of the construction work can be monitored at all times. Markus Hefti, President of the Drainage Corporation, emphasises: ‘The drainage project makes a significant contribution to the safety of the population, guests and infrastructure. At the same time, it reduces the long-term risk of damage from slope movements and mudslides.’ According to the current planning, the drainage tunnel is to be completed and put into operation by 2029. The implementation of the land reclamation, ecological compensation measures and reforestation will take until 2030.

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Drainage Braunwald 2025 – 2030

The ‘Drainage Braunwald 2025 – 2030’ project is intended to provide long-term stabilisation of the Braunwald settlement area. A 918-metre-long drainage tunnel is to be built, with 90 additional drainage boreholes, which will drain water from the landslide mass in a targeted manner and thus reduce the movement of the slope. The total cost of CHF 45.9 million will be borne by the Confederation, the canton, the municipality of Glarus Süd and the Braunwald Drainage Corporation.

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Project management and realisation

• Client: Drainage Corporation of Braunwald, with the support of the Confederation, the canton of Glarus and the municipality of Glarus Süd
• Project management: Infranext AG, Kriens
• Contractor: ARGE AFT Frutiger AG, Thun / Toneatti AG, Bilten
• Project documentation: AFRY Schweiz AG, Zurich
• Geologist: Dr von Moos AG, Zurich
• Client support: tbf-marti ag, Schwanden
• Environmental construction supervision: AFRY Schweiz AG, Zurich

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Braunwald drainage tunnel

E-Mail: stollen@ewkb.ch
Telephone: + 41 44 365 20 20

Caption:

The material ropeway will be the core of the ‘Braunwald drainage 2025 – 2030’ project. © Drainage Corporation of Braunwald / Samuel Trümpy
Material ropeway intermediate support © Drainage Corporation of Braunwald / Samuel Trümpy
Material ropeway construction work © Drainage Corporation of Braunwald / Samuel Trümpy