Huepach, Canton of Berne

As a result of three heavy thunderstorms during the nineties, the mountain creek Hüpach caused shallow landslides, debris flows, and deluges. Debris and boulders blocked roads and railways in Oberwil near Interlaken. To prevent future hazards, our customer Schwellenkorporation Oberwil decided to install two retention structures. The construction is designed for a 300-year debris flow event. This project was a joint endeavor of the sister companies Geobrugg and Fatzer.

Benefits of the chosen solution:

• Minimal material requirement – an important factor because of limited site accessability
• Low total costs
• Minimized impact to nature
• Highest possible drainage permeability
• Full functionality of the entire system

The barrier was planned and installed to protect settled areas within the community, highly endangered by debris flow and flooding. The goal for the client (and therewith for GEOBRUGG and the planner) was to find a cost effective solution to saveguard lives, buildings and property.

Key figures of the drainage basin:

• Retention capacity: 16´000 m³
• Average slope inclination in the flow channel: 32 %
• Length of the main channel: 4150 m
• The peak discharge for a return period of 300 years is 350 m³/s. Debris flow modelling was calculated using the software RAMMS from SLF / WSL (Switzerland).

This solution is also documented in a video