The Bezdna or Biznä is a river in Tatarstan

Tatarstan

The Republic of Tatarstan is a federal subject of Russia located in the Volga Federal District. Its capital is the city of Kazan, which is one of Russia's largest and most prosperous cities. The republic borders with Kirov, Ulyanovsk, Samara, and Orenburg Oblasts, and with the Mari El, Udmurt,...

, Russian Federation

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-bank tributary

Tributary

A tributary or affluent is a stream or river that flows into a main stem river or a lake. A tributary does not flow directly into a sea or ocean...

 of the Volga River

Volga River

The Volga is the largest river in Europe in terms of length, discharge, and watershed. It flows through central Russia, and is widely viewed as the national river of Russia. Out of the twenty largest cities of Russia, eleven, including the capital Moscow, are situated in the Volga's drainage...

, falling into the Kuybyshev Reservoir near Kuralovo, Spassky District. Its length is 45 km and its drainage basin

Drainage basin

A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean...

 is 806 km².

The maximal mineralization 300-500 mg/l. Average sediment in mouth per year is 129 mm. In 1963 average discharge was 197 m³/s. The town of Spassk, the ancestor of modern Bolgar

Bolgar (town)

Bolgar is a town and the administrative center of Spassky District of the Republic of Tatarstan, Russia, located on the left bank of the Volga River, from Kazan. Population:...

 stood on the river prior to 1956. In 1956-57 the Kuybyshev reservoir was created, flooding the town and the lower stream of Bezdna.