I amsterdam - Water Levels

Amsterdam’s water level measurements are set to a fixed point, known as the Normaal Amsterdams Peil (NAP), the Normal Amsterdam Water Level, based on the average level of the River IJ in Amsterdam in the 17th century. This measurement has become a basis for altitude measurements throughout Western Europe. The current NAP height can be seen in the freely accessible passage between Amsterdam's City Hall and the Muziektheater opera house on Waterlooplein - three glass columns filled with water rising from the floor near the northeast entrance.

Two of the three indicate the actual water level at the coastal towns of Vlissingen and IJmuiden. At high tide, the water rises well above knee-level. Fortunately, sturdy dikes and dunes along the coast to keep the North Sea at maintainable levels.  Even more spectacular is the third column, in which the water bubbles up far above your head. That was the height of the North Sea during the flood disaster in the province of Zeeland in 1953.

The real NAP can be seen if you descend the staircase by the water columns: a large bronze plate indicates the exact level of NAP. From Helsinki to Rome, altitude is always measured relative to this bronze mark when roads, houses, bridges are built and, of course, when gauging the water level.