IJ (Amsterdam)

The IJ (pronounced [ɛi̯]; sometimes shown on old maps as Y or Ye) is a body of water, formerly a bay, in the Dutch province of North Holland. It is known for being Amsterdam's waterfront. It is considered a river by Rijkswaterstaat (a branch of the Ministry of Infrastructure and the Environment), though some contest this qualification, calling the IJ a lake. Its name is an obsolete Dutch word meaning "water", derived from the West Frisian word ie "stream, small river" (from Germanic , "water") and is cognate with Dutch for bodies of water. The name consists of the digraph ij, which behaves like a single letter. Therefore, both letters are capitalized; cf. IJmuiden.

Today, the IJ is divided into two parts:

The IJ is connected to the North Sea to the west and the IJmeer to the east by a set of locks.

There are several theories about the origins of the IJ. Perhaps it began as a stream, following a breakthrough in the dunes of Castricum. More likely, the IJ is a remnant of a northern arm of the Rhine delta. Finally, the IJ could also come from the lake Almere or Flevo. During the Roman period the IJ communicated on one side with the lake Flevo and the Vecht (Utrecht) and the other with the North Sea. Connection with the North Sea has subsequently disappeared, while the IJ in the Middle Ages has expanded. This is due to the emergence of the Zuiderzee, itself a bay of the North Sea resulting from a number of storms.

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