Hohenfelder Mühlenau
| Location | Plön district, Schleswig-Holstein,  Germany |
|---|---|
| Length | 10 km |
| Source | Selenter See between Köhn-Pülsen and Giekau-Warderhof 54°19′09″N 10°27′48″E / 54.3191°N 10.4633°ECoordinates: 54°19′09″N 10°27′48″E / 54.3191°N 10.4633°E |
| Mouth | Kiel Bay near Hohenfelde-Malmsteg 54°23′07″N 10°30′35″E / 54.38528°N 10.50981°E |
| Basin | Hohenfelder Mühlenau |
| Villages | Köhn, Schwartbuck, Hohenfelde |
The Hohenfelder Mühlenau is a stream, about 10 km long, in the district of Plön in northeast part of the North German state of Schleswig-Holstein.
The Hohenfelder Mühlenau is classified as a gravel-bedded stream. It begins at the Selenter See in Holstein and, together with the Salzau / Hagener Au, is one of its natural tailwaters. The course of the stream has an incline of about 4%, a length of 10 km, a width of generally between 2 and 4 metres and a depth of 0.1 to 1.5 metres. It is interrupted by two barriers, the mill at Köhn, which has fallen into ruins leaving just a foundation behind, and poses an obstacle of 2 to 3 metres. This hurdle will now be bypassed, in line with the EU Water Framework Directive, using a drop structure (Sohlgleite) which will be built next to the existing building. The Hohenfelde Mill is another obstacle of about 4 metres, which is partly bypassed with a fish pass. The existing 50 hp Francis turbine is still an obstacle however. At the end of its 10 km long course the Hohenfelder Mühlenau discharges into the Baltic Sea with a water quality class of I-II.