1911 Encyclopædia Britannica/Urmia, Lake of

URMIA, LAKE OF (also spelt Urumiah), a lake in north-western Persia, between 37° 10′ and 38° 20′ N. and between 45° 10′ and 46° E., which takes its name (Pers. Deryacheh i Urmia, Turk. Urmi göl) from the town of Urmia, situated near its western shore, but is also known as the Deryacheh i Shahi and Shahi gol. The limits of the lake vary much, the length, N.–S., from 80 to 90 m., the width, E.–W., from 30 to 45, being greater in the season of high water—in spring when the snows melt—and considerably less in the season of low water. A rise of the level by only a few inches extends the shore of the lake for miles inland, and it may be estimated that the surface covered by the lake during high water is half as much again as that during low Water, The Shahi peninsula, which juts out into the lake from the eastern bank, is an island during the season of high water and also sometimes after heavy autumnal rains, separated from the mainland by several miles of shallow water. The mean depth of the lake is 15 to 16 ft., and its greatest depth probably does not exceed 50 ft. The lake has in recent years exhibited extraordinary changes of level, and it is not certain whether some occasional extraordinary rises of level were due to a movement of the earth's crust or merely to an increase of rainfall as compared with evaporation. Gunther calculated that the lake covered 1795 sq. m., but he did not state whether during high or low water. De Morgan gives 4000 and 6000 sq. kilometres (1544 and 2317 sq. m.) for low and high water respectively. In the southern half of the lake is a cluster of about fifty rocky islands composed of Miocene strata with marine shells, echinoderms and corals, much resembling the beds of the Vienna basin. The largest of these islands, Koyun daghi, i.e. “ Sheep-mountain,” is 3 to 4 m. long and has a spring of sweet water near which a few people settle occasionally for looking after herds of goats and sheep taken there for grazing. All the islands are uninhabited and some are mere bare rocks of little extent. Although fed by many rivers and streams of sweet water the lake is very saline and its water is about three-fifths as salt as the water of the Dead Sea—far too salt to permit the existence of fish life. The specific gravity of the water is 1.155 during low water and 1.113 during high water. The principal salts contained in solution are sodium chloride, bromide and iodide and sulphates of magnesia, soda and iron. The only organisms living in the lake are a species of artemia, a crustacean known from other brine lakes in Europe and North America, the larva of a species of dipterous insect, probably allied to ephydra, and green vegetable masses composed of bacterial zoogloeae covered with a species of diatom. The rivers which flow into the lake drain an area of nearly 20,000 sq. m.; chub and roach are found in all of them, silurus in some. The lake is navigated by a few round-bottomed boats with round bows and flat sterns, each of about 20 tons burden and carrying an enormous square sail.

Strabo (xi. c. 13, 2) mentions the lake with the name Spauta, a clerical error for Kapauta, from Pers. Kapaut, New Pers. Kebud, meaning “ blue.” Old Armenian writers have Kapoit-dzov, “ the blue sea." in the Zendavesta and Bundahish it is called “ Chaechasta," and Firdousi in his Shahnamah (11th century) has “ Chichast."

See J. de Morgan, Mission scientifique en Perse (1894); R. T. Günther, “ Lake Urmi and its Neighbourhood,” Geogr. Journ. (November 1899).  (A. H.-S.)