Austria’s capital has won accolades in global rankings (as everything from having the world’s highest standard of living to being the least friendly city), recognition (Viennese coffee house culture and sausage stands have been added to UNESCO’s intangible cultural heritage list) and for its particularities (from its role as a driver of history to world-famous luminaries). One thing this city of two million people can be particularly proud of, however, is the quality of its drinking water.
For more than 150 years, water has flowed into Vienna directly from the Alps, via two pipelines. Propelled by gravity, and with no assistance from pumps, the liquid travels 150 km and 180 km respectively to reach 29 water tanks in Vienna und two outside the city, and it is one of the latter that is being expanded to create the world’s largest drinking water tank.
The reservoir currently consists of four giant chambers that hold 600 million litres of water. The first phase of construction will see these complemented with two new chambers by the end of 2028. Concrete pilings will first be drilled to support the excavations and then a hole up to 8 metres deep will be dug and earth removed. The foundations, the walls of the water chamber and the pillars to support the ceiling will be erected, and this phase of the expansion will take four years. The storage capacity of the chamber will be increased to 800 million litres. The second phases will start in 2029, and this will include the construction of two further chambers and renovation of the existing tanks.
Once completed, the drinking water tank will hold about a billion litres of water. This is 1 million cubic metres of liquid, which equates to a block of water with a base the size of an international standard football pitch and a height of 140 metres (St Stephen’s Cathedral in Vienna would just about fit inside).
Vienna intends to complete expansion of its drinking water tank by 2050. Population growth and climate change will increase the city’s water requirements and increasing the size of the reservoir is intended to ensure the city is prepared.
