What is "wiedau"

The Wiedau is a left-hand tributary of the Wümme in the north German state of Lower Saxony. The river begins near Bellen in the vicinity of Hemslingen in the district of Rotenburg (Wümme) at the confluence of the Hahnenbach and the Mehlandsbach, flows through the collective municipality of Bothel, a densely wooded and near natural depression, and discharges into the Wümme in Rotenburg shortly after being joined by the only slightly smaller Rodau.