The Bely Iyus - the right source of the river Chulym (Ob basin). In Khakas language the name of the river sounds like Ах-Ӱӱс, where “ах” stands for “white” and “ӱӱс” means “river”.
The Bely Iyus rises from small mountain lakes at an altitude of more than 1000 m on the northeastern slopes of the Kuznetsk Alatau (on the border of the Kemerovo region and the Republic of Khakassia). In the upper reaches the river is called Pikhterek. The Bely Iyus together with the left source river Cherny Iyus forms the river Chulym. The length of the Bely Iyus is 224 km, the basin area is 5370 km2, which makes the 8th tributary of the Chulym in terms of the basin area and length. Main tributaries: the Turalyg, the Karatash (Kara-Tas), the Tunguzhul, the Tyurim (right tributaries); the Tyurtek, the Bolshaya Syya (Pravaya Syya) (left tributaries).
In the upper reaches (up to the village of Efremkina), the river has a mountainous character, in the lower reaches it is flat; here the river flows among the hilly steppe spaces of the western outskirts of the Chulym-Yenisei basin.
In summer, the Bely Iyus River is a popular place for catarafting