The river Zizma flows in Telsiai and Siauliai districts, the river Venta left tributary. Length of the river 24 km, the basin area 172 km ². The source at Pabalve village, 4 km south from Tryskiai town. Flows through the lake Balvis to east. At the brook Upyna mouth turns to northeast. Flows into the river Venta 269 km from its mouth at Reksciai village, 8 km west from Kursenai town. Average gradient 174 cm/km. Average rated discharge at the mouth 1.08 m³/s.

At high water level. Spring flood, or after heavy rains.
Rapids, shalows, dam, strainers.
WW 0/1- (1+).

6.3 right Upyna. left Tulkinciai. right Vozbučiai. Average rated discharge 1 m³/s. The river width 4-7 m. Average gradient to mouth 186 cm/km. Small rapids, shalows, can be strainers.
6.1 right Virsupis.
4.5 Bridge. Begins the pond of Raganiai. left Pazizme.
2.3 left Kepstys. left Raganiai.
0.7 The dam of Raganiai. Height 7 m. Downstream shalows, small rapids.
0.0 The Zizma flows into the river Venta.