| Hagener Au | |
|---|---|
| Location | Plön, Schleswig-Holstein, Germany |
| Reference no. | DE: 965529 |
| Length | 10 km |
| Source | Passader See |
| Mouth | Kiel Fjord between Laboe and Stein |
| Basin | Hagener Au |
| Villages | Probsteierhagen, Lutterbek, Stein |
The Hagener Au is a roughly 10 kilometres (6.2 mi) long stream in the district of Plön in the north German state of Schleswig-Holstein. It is an outlet of the Passader See. From the lake's southwestern bay the stream flows in a northerly direction and discharges between Laboe and Stein in the Baltic Sea.
Sections of the Hagener Au are very natural and surrounded by wetlands. In addition the stream is a habitat for the rare Spined loach. The stream has been straightened near its mouth and the last 50 metres (160 ft) runs through a pipe. Together with the Passader See the Hagener Au is a protected Special Area of Conservation.