| Treene (Trenen) | |
|---|---|
 The Treene nearWohlde | |
 | |
| Location | |
| Country | Germany |
| State | Schleswig-Holstein |
| Physical characteristics | |
| Source | Bondenau |
| • location | Mohrkirch,Angeln |
| • elevation | 50 m (160 ft) |
| 2nd source | lake Tresssee,Oeversee |
| • elevation | 20 m (66 ft) |
| Mouth | Eider |
• location | Friedrichstadt |
• coordinates | 54°22′6″N9°5′9″E / 54.36833°N 9.08583°E /54.36833; 9.08583 |
| Length | 95 km (59 mi) |
| Basin size | 797 km2 (308 sq mi) |
| Discharge | |
| • average | 10.7 m3/s (380 cu ft/s) |
| Basin features | |
| Progression | Eider→North Sea |
TheTreene (German pronunciation:[ˈtʁeːnə];Danish:Trenen) is a river, hydrologically 95 km (59 mi) and nominally 73.4 km (45.6 mi) long, inSouthern Schleswig in the north ofSchleswig-Holstein,Germany. It is a right-bank tributary of the RiverEider. It starts in northernAngeln, southeast ofFlensburg, and flows mainly south-south-west before joining the Eider nearFriedrichstadt.
The upper course are calledBondenau (Danish:Bondeå) andKielsau (Danish:Kilså). Its source is situated in the ground ofMohrkirch.[1][2] The name 'Treene' begins at the Treßsee (Danish:Træsø) lake near Großsolt in the district ofSchleswig-Flensburg. After about 73 km (45 mi) it reaches the town ofFriedrichstadt (inNordfriesland district).[3] There it is released through valves into theestuary of theEider, 25 km (16 mi) above theEider Barrage. It is the most important tributary of the River Eider. Since the construction ofKiel Canal it has been even stronger than the Eider river.
The Bondenau, as the main headstream of the Treene, rises 15.6 km (9.7 mi) east of the Tressee on the peninsula ofAngeln, bounded by theFlensburger Förde and theSchlei. 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 (12.69 mi). Half a kilometre before the Treßsee (Lake Tress) it is joined by a stream named Kielstau or Kielsau, by some people considered another headstream of the Treene. Between the Treßsee and Tüdal there is a natural reserve covering an area of 20 square kilometres (7.7 sq mi) calledObere Treenelandschaft that extends along the river. The lower part especially is a reserve for migratory birds ("stork village"Bergenhusen).
The middle section betweenLangstedt andTreia developed to be a popular canoe area and the lower section can also be used by pleasure craft. InSchwabstedt there is a public swimming site in the river.
Fromantiquity toHigh Middle Ages, the strip of dry land between Treene wetlands andSchlei had the function of an isthmus. Here theDanevirke secured the south border of Denmark, which at that time was marked by the Eider, more than 20 km (12 mi) further south. And the route Eider - Treene -Rheider Au (tributary of the Treene) - Schlei served as a shipping route between theNorth Sea andBaltic Sea (see alsoHedeby). Whether thereby boats were pulled between Selker Noor (an extension ofSchlei inlet) and the Rheider Au 16 km (9.9 mi) on primitive rollers over the 20 m high land ridges (usual opinion), or whether the Kograben, 1 to 2 km south of and parallel to the walls of Danevirke, also served as a shipping canal, has not yet finally been clarified.
