Multi-purpose top-performance Hobas GRP culvert for Switzerland

A stream nearby Zurich was culverted with highly abrasion resistant Hobas PU Line pipes. Special features: a fish ladder, sediment barriers, and a water duct.

Ländenbach is a small stream flowing through Wetzikon, a municipality in the Zurich Highlands. In autumn of 2018, it was decided to culvert a section of the stream flowing through a residential area. The municipality had several demands with regard to the 20 m long duct: Since the stream transports abrasive stones and debris it required a particularly durable pipe material, and the pipeline would also need to provide a feature for the migration of fish living in the stream. Amiblu designed and supplied a custom-tailored solution for this project.

Hobas PU Line pipes DN 1800 SN 20 000 with a wall thickness of 49 mm were prefabricated with a special interior: a fish ladder made from GRP plates, and sediment barriers with a water duct for holding back the debris from the river water and distributing the water flow. The single GRP pipes were connected with mechanical couplings, and the culvert eventually encased in concrete and covered with road asphalt. Parallel to the PU channel, a second Hobas GRP pipeline DN 1000 was installed which will serve as bypass for the culvert in case of very heavy rainfall.

After no more than five days the installation was successfully finished to the satisfaction of the client and the residents of the housing estate.