Treene

The Treene is a river, hydrologically 95km and nominally 73.4km long, in the north of Schleswig-Holstein. It is a right-bank tributary of the Eider River. It starts in northern Angeln, southeast of Flensburg, and flows mainly south-south-west before joining the Eider near Friedrichstadt.The upper course is called Bondenau. Its source is situated in the ground of Mohrkirch. The name 'Treene' begins at the Tresssee lake near Großsolt in the district of Schleswig-Flensburg. After about 73 km it reaches the town of Friedrichstadt . There it is released through valves into the estuary of the Eider, 25 km above the Eider Barrage. It is the most important tributary of Eider river. Since the construction of Kiel Canal, it is even stronger than Eider river itself.DetailsThe Bondenau, as the main headstream of the Treene, rises 15.6 km east of the Tressee on the peninsula of Angeln, bounded by the Flensburger Förde and the Schlei. So the Treene is an unusual case of a river that rises on a peninsula in the Baltic Sea, but flows into the North Sea. The length of Bondenau is 20.43 km. Half a kilometer before the Treßsee (Lake Tress), it is joined by a stream named Kielstau or Kielsau, by some people considered another headstream of Treene river. Between the Treßsee and Tüdal, there is a natural reserve covering an area of 20km2 called Obere Treenelandschaft that extends along the river. Especially the lower part is a retreat area for migratory birds ("stork village" Bergenhusen).