Eider

The Eider (German: Eider [ˈaɪdɐ] ; Danish: Ejderen; Old Norse: Egða; Latin: Egdor or Eidora) is the longest river on the Jutland Peninsula, and flows through the German state of Schleswig-Holstein along its entire length. The river crosses the peninsula almost across its entire width from east to west. It starts between Bordesholm and Preetz. Shortly after its source, the river reaches the city of Kiel on the Baltic Sea, whose southwestern city limits it partially forms. At the point where the Eider is only a few kilometers from the Baltic Sea –at Lake Schulensee– a terminal moraine –the Hornheimer Riegel– blocks its path, and the Eider from then on turns towards the much more distant North Sea, into which it flows at Tönning.

The wide estuary of the Eider is called Purrenstrom, which is crossed by a closeable storm surge barrier, the Eider Barrage. It has tidal flats and brackish water. The lower part of the Eider was used as part of the Eider Canal until that canal was replaced by the modern Kiel Canal.