But how high is high-water?
In Venice (and only in Venice) the median level of the sea as measured in 1897 is used as the reference level. The reason is so that the situation of embankments and buildings in relation to the tides may always be monitored with respect to the same reference point, known as the ‘tide-level-zero’ at the Punta della Salute, where a monitoring station is located. In the rest of Italy, the median sea level (IGM) refers to the level in Genoa in 1942, which is about 23 centimeters higher.