The river Birveta flows through Lithuania and Belarus, the river Dysna right tributary. Length of the river 68 km (65km in Lithuania), catchment area 1613 km ² (818 km ²  in Lithuania). Suorce at Kirkuciai village. Flowing to east. From the lake Kancioginas  to the lake Erzvetas called the Kanciogina from the lake Erzvetas  to the river Kamoja called the Erzveta, downstream called  Birveta. Flows into Dysna 109 km from its mouth. Valley shallow, wide, marshy. Average gradient to Maruniskes 315 cm / km, downstream 27 cm / km. Average discharge at the mouth 13 m³ / s, at the Lithuania - Belarus border 6.6 m³ / s.

All year.
No
WW 0.

37.2 The river Erzveta flowing out of the lake Erzvetas. The river slowly flows through marshy meadows. Banks are low and marshy, bare, sometimes covered with single trees and shrubs. In several places the river approaches the forest. Riverbed width  5-25 m. Average gradient to Pivorai 29 cm / km.
37.0 Bridge. Erzvetas.
35.9 right Posiunai.
32.4 right Cekupis.
30.3 Hanging pedestrian bridge. left Kelpuciai. Banks in single places overgrown trees.
29.1 Small bridge.
25.3 right Sakelele. Road Adutiskis - Didziasalis bridge. right Kliukai.
24.0 right Svyla. right Peciurkos.
21.8 Railway bridge. right Kekstai. left Didziasalis.
20.5 right Kamoja. right Kekstai. The river runoff doubled. The river width  30-40 m, the current calm. The river banks are overgrown with single trees.
18.9 right Vilekos.
17.0 right Sapliai. Over the river a high-voltage line.
14.4 Bridge. left Kukuciai. right Pivorai.
14.0 left begins the ponds, the riverbed straightened. The river width 15 m.
0.3 Bridge. right Lazinkos. left the ponds ends.
10.2 right Juodasai upelis.
10.0 left tributary from the ponds. Straightened stretch of the river ends.
9.6 right Rimaldiske. The river banks are bare.
9.5 Small bridge. Downstream the Birveta flows the Lithuania - Belarus border.