Driftwood rake in Sihl, Zurich

Project overview

In order to improve flood protection for the city of Zurich, a driftwood collector was planned and built at the site in Rütiboden, 15 km upstream of Zurich. This structure, which is designed to collect up to 12,000 m3 of driftwood, is a driftwood collector located on the outside of the bend on a parallel stream, which offers a retention efficiency of around 95%. Under the effects of the secondary flow, the driftwood is transported over a weir threshold on the outside of the bend into the retention area, where it is held back by a parallel rake. This type of uncontrolled retention mechanism in a parallel stream is unique to date in Switzerland.

Our services

Pre-project, construction project, submission up to and including implementation including supervision of the hydraulic model trials at the Laboratory of Hydraulics, Hydrology and Glaciology at ETH Zürich for optimisation of the best option.

Expertise involved

Geotechnical engineering, Hydraulic engineering

Client

Office of Waste, Water, Energy and Air (AWEL)