The Rwaba River forms in the northwest of Makamba Province to the north of Murinda and flows south, then southwest to enter Lake Tanganyika just north of Nyanza Lac.

[1] The Rwaba River drains the sedimentary plain of Nyanza-Lac, which is about 16 kilometres (9.9 mi) wide and backed by high ground.

[2] Open forests on the steep slopes around the plain form a natural water catchment system, and prevent sedimentation of the river and damage from landslides.

[4] The surroundings of the Rwaba River are a mosaic of agricultural land and natural vegetation.

The warmest month is September, when the average temperature is 25 °C (77 °F), and the coldest is November, with 19 °C (66 °F).