Have you ever been 35 metres underground in Vienna? It may be hard to imagine, especially since Vienna's deepest subway station is only 30 metres below ground level…
On Friday, members of our team, together with environmental engineering students, descended 200 stairs to reach Austria's largest sewer, the Wiental Canal. The Vienna Open Sewer Days offered the unique opportunity to walk through the 35-metre deep sewer below the Wien River with an incredible inner diameter of 7.5 metres. Many thanks to Thilo Lehmann of Wien Kanal, who guided us along the 1.2 km section passing by five inlets that discharge between 1,000 and 30,000 litres per second into the huge Wiental Canal during rain events, to store the water and prevent overflows into the Wien River.
The tour ended at Ernst-Arnold-Park, 140 steps below ground, exactly where in 2027 the 135-metre long tunnel boring machine will reach its destination to connect a newly-built 9-km long sewer to the existing Wiental Canal. This is currently the largest waterprotection project in Vienna. "The times they are a-changin’": whereas the cholera canals of the 1830s were built to protect human health by preventing cholera outbreaks, today the Wiental Canal is primarily about water protection for environmental health.