Sestra

(also called Raiaioki), a river in Leningrad Oblast, RSFSR. The Sestra is 74 km long and drains an area of 393 sq km; it flows along the Karelian Isthmus. Until the early 18th century the Sestra emptied into the Gulf of Finland. The construction of a dam to supply the Sestroretsk Arms Factory resulted in the formation of the Sestroretsk Reservoir (Lake Raz-liv), with an area of 10.6 sq km and depths reaching 2 m; since then the Sestra has flowed into the reservoir. Lake Razliv is separated from the Gulf of Finland by a ridge of sand dunes; the surplus water is discharged into the Gulf of Finland through a channel 4.8 km long. From 1918 to 1940, the USSR-Finnish border ran along the Sestra.

a river in Moscow Oblast, RSFSR, flowing partly along the border of Kalinin Oblast; a left tributary of the Dubna (Volga River basin). The Sestra is 138 km long and drains an area of 2,680 sq km. The river originates in Lake Se-nezhskoe; in the lower course it passes under the Moscow Canal. The Sestra is fed primarily by snow. The mean flow rate 38 km from the mouth is 9.9 cu m per sec. The river freezes between November and early January, and the ice breaks up in late March or April. The main tributary is the Iakhroma, on the right. The city of Klin is situated on the Sestra.