“Wiener Null” - Levelling the City of Vienna

Abstract

Nestled between hilly landscape (foothill of the Alps) and marsh land (Danube) the city of Vienna was prevented from easily spreading. During Gründerzeit (Historism 1848-1918), when the city experienced a rapid population growth (from 400.000 to over 2.2 Million inhabitants) the townscape was therefore modified radically: Not only has the river Danube and its wetland been regulated, but also has the soil of the entire city been levelled to a normative height: the "Wiener Null". The aim of this large-scale intervention was to prevent slopes and to build straight and ideal streets that subsequently would form a grid that was "as evenly and uniformly as possible". So far this major change in the cityscape has not been investigated appropriately. The paper will therefore examine the following themes and questions: How has the enormous amount of soil been removed? Which technical and organisational problems had to be approached? Where has the earth been stored? What (ecological) consequences did this intervention imply? Does the extensive levelling impose actual impacts on a climatic level (heat island effect; heavy rain drain problem)? Throughout the 20th century the levelling of the city of Vienna proceeded to some extent. Only in the 70ies, when because of the planned raising of the soil the catholic church feared to lose the grand staircases leading up the churches the levelling of a certain area in the 9th district was stopped - by leaving behind a site of houses with parterre-cellars. The paper aims to enlighten a peculiar and uncharted aspect of Vienna´s urban planning history.