The Aidar is a river of the Lugansk Oblast, Ukraine

Ukraine

Ukraine is a country in Eastern Europe. It has an area of 603,628 km², making it the second largest contiguous country on the European continent, after Russia...

 and Belgorod Oblast

Belgorod Oblast

Belgorod Oblast is a federal subjects of Russia . Its administrative center is the city of Belgorod. Population: 1,532,670 .-History:...

, Russia

Russia

Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

. A left tributary of the Seversky Donets

Seversky Donets

Seversky Donets is a river on the south of the East European Plain. It originates in the Central Russian Upland, north of Belgorod, flows south-east through Ukraine and then again through Russia to join the Don River, about from the Sea of Azov...

, it flows for 256 km and has a basin area of 7370 km ². The slopes of the valley are partitioned with ravines and gorges. In the spring, snow melt accounts for approximately 70 % of the flow . The average flow module is 1.7 liters • sec / km ². The river freezes in December.