The Altenau is a small river of Lower Saxony, Germany. It rises in the Elm, northeast of Eitzum, a district of Schöppenstedt, and discharges from the right into the Oker near Halchter, a district of Wolfenbüttel.
Altenau ford near Küblingen
|Reference no.||DE: 4826|
|- location||northeast of Eitzum in the Elm|
|- elevation||about 206 m|
|Oker near Wolfenbüttel|
|Length||25.0 km (15.5 mi) |
|Basin size||140 km2 (54 sq mi) |
|Progression||Oker→ Aller→ Weser→ North Sea|
|Landmarks||Small towns: Schöppenstedt|
|- right||Sauerbach, Hachumerbach, Glue Riede|
Between the heights of the Asse and the Heeseberg in the south and the Elm ridge in the north stretches an almost treeless arable plain, the roughly 25 kilometre long Schöppenstedt Depression (Schöppenstedter Mulde). Here the Altenau flows in an east-west direction in a meadow valley about 500 metres wide. The source of the river lies immediately west of the watershed between the rivers Weser and Elbe. In the southern part of the depression the Altenau picks up a succession of small streams from the slopes of the Elm as it cuts through the hollow as a regulated and relatively straight stream.