VORTSJARV

also spelled Vrts-jrv, or Virtsjrv, Russian Ozero Vyrts-yarv, lake (jrv) in south-central Estonia, with an area of about 110 square miles (280 square km). Vrtsjrv forms part of the 124-mile (200-kilometre) course of the Ema River (German Embach, Lithuanian Emajgi), which enters the lake from the south and drains it north and east into Peipsi Lake on the Estonia-Russia border. The Vrtsjrv is navigable, as is the lower course of the Ema. The lake and river together divide the hilly Haanja region of southeastern Estonia from the flat remainder of the republic. The lake and its swampy, level basin are believed to be remnants of a much larger, ice-dammed prehistoric lake whose original drainage was toward the west. A Zoological and Botanical Institute was established on the lake in 1961.