hidden Syas River, the SYAS, a river in the south-eastern Priladozhye. Length: 260 km, of which, abt. 190 km within Leningrad Oblast. The average flow rate is 61.6 cu. m/s, and the catchment area, 7330 sq. km. It originates in the north-east of Novgorod Oblast, 6 km... more