Donaudüker, Underground water infrastructure in Linz, Austria

The Donaudüker is an underground pipe system that runs beneath the river, connecting the two banks on either side. The network consists of several parallel lines that carry different types of water through the same route.

The project emerged in the 1970s when the city needed a solution to provide services across the wide river. The drilling technique used at that time was innovative for projects of this scale and set standards for future work.

The name Donaudüker combines the German words for Danube and culvert, describing a pipe crossing beneath the river. The structure is not open to visitors; its two entry stations stand on the banks, the northern one in Plesching on the Urfahr side, the southern one near Boote Feichtner on Saxingerstraße in Linz.

The system operates continuously underground and is not directly open to visitors, but can be observed from outside. Entry points are located at specific spots along the riverbank where you can see the technical installations.

The tunnel is not open to the public: its 2.40 m inner diameter holds a central inspection walkway of about 75 × 190 cm, lit and fitted with drainage pumps in sumps at both ends. The walkway serves maintenance crews flushing the three sewage pressure pipes, not visitors.