Altenau (Oker)

Altenau
Altenau ford near Küblingen
State	Lower Saxony, Germany
Reference no.	DE: 4826
Basin features
Main source	northeast of Eitzum in the Elm about 206 m 52°10′08″N 10°51′17″E / 52.16889°N 10.85472°E / 52.16889; 10.85472Coordinates: 52°10′08″N 10°51′17″E / 52.16889°N 10.85472°E / 52.16889; 10.85472
River mouth	Oker near Wolfenbüttel 77 m 52°08′10″N 10°33′24″E / 52.136175°N 10.556703°E / 52.136175; 10.556703
Progression	Oker → Aller → Weser → North Sea
River system	Weser
Basin size	140 km²
Landmarks	Small towns: Schöppenstedt
Tributaries	Left: Rothebach Right: Sauerbach, Hachumerbach, Glue Riede
Physical characteristics
Length	25 km

The Altenau is a small river that rises in the Elm in central Germany, northeast of Eitzum and discharges from the right into the Oker near Halchter, a district of Wolfenbüttel.

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.