Alte Donau, Facts and figures Alte Donau, a former river branch of the Danube, is situated in the municipal districts of Floridsdorf and Donaustadt. Some 30,000 people live within a one-kilometer radius of the urban lake. The urban lake covers a surface area of some 1.6 square kilometers, which is equivalent to over 200 football pitches. The … Continue reading Alte Donau, urban lake project in the middle of Vienna