The Hamme (in its upper reaches Giehler Bach) is a 48 km (30 mi) long river in Germany, Lower Saxony, north-east of Bremen.

From this geest ridge, a terminal moraine from the Saale glaciation, the Giehler Bach flows northeastwards and descends within a few kilometers between the villages of Hülseberg and Freißenbüttel to a height about 15 m above sea level (NN).

Between the former moor colonies of Bornreihe and Hüttenbusch the river now continues in the direction of Worpswede, where it is joined by three left-hand tributaries, the Rummeldeisbeek, Schmoo and Umbeck.

In the 19th century, this part of the Hamme was straightened and the numerous meanders were cut at a total of seven places, so that the length of the river was reduced from 9 to 4.3 km.

3") southeast of Scharmbeckstotel was de-sludged in 2007 as part of the Hamme Depression Nature Conservation Project and in 2008 a sill was added to prevent it from running empty at low water.