The Tretya River is a stream in the Beringovsky District

Beringovsky District

Beringovsky District was an administrative district of Chukotka Autonomous Okrug, Russia, which existed in 1957–2011. Municipally, together with Anadyrsky Administrative District, it was incorporated into Anadyrsky Municipal District...

 of Chukotka Autonomous Okrug

Chukotka Autonomous Okrug

Chukotka Autonomous Okrug , or Chukotka , is a federal subject of Russia located in the Russian Far East.Chukotka has a population of 53,824 according to the 2002 Census, and a surface area of . The principal town and the administrative center is Anadyr...

, 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...

. It drains part of the southern Anadyr Lowlands (very flat with wetlands and tundra). It flows northeast and then northwest into the Anadyr Estuary (its mouth is the southernmost notch on the image on that page). To the east of the Tretya is the Avtatkuul' zakaznik

Zakaznik

Zakaznik is a type of protected area in Russia and other former Soviet republics such as Ukraine that meets World Conservation Union's category III, or more frequently category VII criteria....

 protected area. To the south is the Tumanskaya River

Tumanskaya River

The Tumanskaya River is a stream in Far East Siberia. It flows through a region of wetlands and tundra into the Bering Sea at the Anadyr Bay.The Tumanskaya River and its tributaries belong to the Chukotka Autonomous Okrug administrative region of Russia....

.

Belugas are common common in its waters.