[1][2] The river is 13.6 km long and drains parts of the northeastern slopes of the Pirin mountain range.

[1] The river takes its source from the Valyavishki Lakes, at an altitude of 2,400 m in northern Pirin.

It flows at an average gradient of 102 m/km, forming numerous jumps and waterfalls.

The numerous tributaries make the river relatively abounding in water for its size, with average discharge of 1.5 m3/s.

[4] Its drainage basin covers a territory of 37 km2 and includes six glacial lake groups in Pirin — Vasilashki, Valyavishki, Prevalski, Tipitski, Karkamski and Gazeyski.