Bystraia

a river in Rostov Oblast, RSFSR. Left tributary of the Severskii Donets. The Bystraia is 218 km long, and the area of its basin 4, 180 sq km. It flows along a plain and is fed primarily by snow. In their upper reaches the Bystraia and its tributaries dry up in the summer. The city of Morozovsk is located on the Bystraia.