Vienna is drilling for the future: Mega tunnel project started under the Vienna River!

Vienna is drilling for the future: Mega tunnel project started under the Vienna River!

Vienna is pushing ahead with a massive construction project that aims to revolutionize the history of wastewater management in the city. Construction work on the Wiental Canal, the city's largest canal project, has reached a decisive phase. On the night of Tuesday to Wednesday, March 12, 2025, an impressive 135 meter long tunnel drill, also known as a “super drill”, was delivered to the city. This drill will create a tunnel tube with an external diameter of almost four meters under the Vienna River from Margareten to Auhof in order to relieve the sewer network during heavy rain by 2028 and to protect the Vienna River from contamination, as Climate City Councilor Jürgen Czernohorszky emphasized. The project involves a huge investment of around 270 million euros and will provide significant infrastructure improvements in six districts.

The tunnel boring machine, manufactured by Herrenknecht AG in Germany, consists of over 20,000 individual parts and required precise logistical planning in order to be safely transported to Vienna. Right from the start, several special transports were necessary because the dimensions of the machine components exceeded the requirements of the road traffic regulations. Once on site, the parts, which weigh several tons, have to be assembled precisely using a special mobile crane. According to Vienna Canal Director Andreas Ilmer, lifting the components is a delicate moment that requires maximum precision and steady hands. Completion of the drill is planned for the end of March, followed by a final check at the beginning of April, before it is actually “ready to drill” in mid-April.

Historical insights into the Vienna River

The current work on the Wiental Canal is related to a longer history of the Vienna River, which was already documented cartographically and hydrotechnically between 1847 and 1857. These “Vienna River Photographs”, carried out by engineering students at the Polytechnic Institute under Professor Josef Stummer, show a city in transition. During the early 19th century, Vienna expanded rapidly, which also brought with it the questions of flood protection and bank regulation, which were already recognized and addressed by engineers at that time. The students' detailed protocols offer valuable insights into the challenges and progress in the field of hydraulic engineering and are evidence of the long tradition of engineering in Vienna, which can also be seen in today's project developments geschichtewiki.wien.gv.at ) and presse.wien.gv.at report.