A rake protecting Zurich

Any flooding of the Sihl can cause significant damage in Zurich, especially when the river carries a lot of driftwood. That is why the Sihl now features an unusual structure: a driftwood rake consisting of 67 planks that are up to 4.5 metres long, which are arranged in a right-hand bend parallel to the direction of flow.

Expertise involved

Geotechnical engineering


Office of Waste, Water, Energy and Air (WWEA), canton of Zurich

In case of high water, centrifugal force pushes the driftwood into the retainer, and thus the main stream is hardly dammed up and still able to transport bedloads. This unique structure was created after extensive option studies and modelling.

Our services

Option studies, construction project, invitation to tender and construction including site supervision, revitalisation interventions, ecological compensation measures

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