Fish lift in Sihlhölzli, Zurich

Project overview

As part of the licence renewal process for the Etzelwerk power station, ecological substitute and compensation measures need to be planned. One possible substitute measure is the Sihhölzli fish lift in the Sihl river in the centre of the city
of Zurich. Here, the fish lift is intended to overcome the almost 5 m high Sihlhölzli weir, under which the SBB Ulmberg tunnel runs, so that it can be passed by salmon, thereby enabling the fish to move all the way into the Sihl Valley. As part of a pre-study, the technical and legal feasibility of various variants was investigated.

Expertise involved

Hydraulic engineering


SBB Infrastructure, department for large-scale energy projects

Our services

Project planning for the SIA phases 21/22: Status and deficit analysis, definition of need for action and project goals, study of variants with seven variants and recommendation of the best option. Hydraulic calculations of the system and overall system. Structural calculations for the system, impact analysis on existing river engineering structures and on the Ulmberg tunnel. Close cooperation with the fish ecologist, Grün Stadt Zürich (‘Green’ Planning Office of the Civil Engineering Department of the City of Zurich) and the Office of Waste, Water, Energy and Air of the Canton of Zurich.

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