Issyk-Kul

Issyk-Kul

a lake in NE Kyrgyzstan in the Tian Shan mountains, at an altitude of 1609 m (5280 ft.): one of the largest mountain lakes in the world. Area: 6200 sq. km (2390 sq. miles)

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Issyk-Kul’ 

(“hot lake” in Kirghiz), a lake without drainage, located in the northern Tien-Shan, in the northeastern part of the Kirghiz SSR. One of the largest mountain lakes in the world, Issyk-Kul’ lies at an elevation of 1,608 m (1969) in the intermontane Issyk-Kul’ Basin between the Kungei-Alatau Range on the north and the Terskei-Alatau Range on the south. Area, 6,236 km (according to other data, 6,330 sq km); length, 178 km; maximum width, 60 km; maximum depth, 668 m (other data indicate 702 m); average depth, 278 m; and volume of water, 1,738 cu km.

More than 50 rivers empty into Issyk-Kul’, their total annual discharge exceeding 3 cu km. The largest of them, flowing into Issyk-Kul’ from the east, are the Dzhergalan (with a mean annual discharge of 22 cu m per sec at the mouth) and the Tiup. The Chu River, which traverses the western margin of the basin several kilometers from Issyk-Kul’, at present is not connected to the lake. Issyk-Kul’ was drained by the Chu in periods of abundant water, when the lake level was 10–12 m higher than it is today. The last such period occurred in the 17th and 18th centuries. The rivers are fed by various sources, with snow predominating, and are deepest in late spring and in the summer. The basin area of Issyk-Kul’ is approximately 21,900 sq km. The scale of water-level changes caused by climatic variations is attested to by lake-shore terraces 8–10 m high and by submerged ruins of settlements at depths of up to 8 m. Over the past two centuries the lake level has been dropping; since 1886 it has fallen 4 m (according to other data, 7 m); against this background there have been small variations within these centuries. The formation of high terraces (35–40 m in elevation) is attributable to neotec-tonic movements. The shores of Issyk-Kul’ have small indentations: only in the eastern and southeastern areas are there deep coves (Tiup and Dzhergalan coves and Pokrovskaia Bay). The shoreline is 597 km long; over half of it is sandy, and there are also extensive silted and pebbled sections.

The lake basin has a warm, dry, and temperate climate. The air temperature on the shores is 16°-17°C in July, and in January it is -2° to -3°C in the west and -4° to — 7°C in the east. Average precipitation over Issyk-Kul’ is about 250 mm, with approximately 110 mm in the western region and 470 mm in the eastern. Evaporation from the lake surface is about 700 mm. Strong winds of up to 30–40 m per sec are frequent in the west and east; they give rise to sudden gales and storms in which windswept waves reach a height of 3–4 m. The yearly amplitude of fluctuations in water level is 10–50 cm, with the highest levels occurring in August and September and the lowest in February and March; in the western part there are wind-caused fluctuations in the level of the lake. The water temperature on the surface is 2°-3°C in January, 19°-20°C in July and August, and at a depth of over 100 m it is 3.5°-4°C throughout the year. Ice forms only in the coves in cold winters. The water is of a blue color (with a transparency of over 12 m); it is brackish (5.8 parts per thousand) and unsuitable for drinking and irrigation.

The coves have an almost continuous cover of characeous algae and pondweeds to a depth of 30 m. The bottom is mainly clays and silts. There are about 20 species of fish in Issyk-Kul’, with a commercial catch of Issyk-Kul’ chebachok, naked osman, Issyk-Kul’ chebak, carp, and Old World minnow (ranging from 2,500 to 4,000 centners a year). Between 20,000 and 50,000 waterfowl (pochards, mallards, coots, and swans) annually winter in the coves and the western part of Issyk-Kul’. In 1958 the Issyk-Kul’ Preserve was established.

Freight and passengers are regularly transported across Issyk-Kul’ by ships. The principal ports are Rybach’e and Pristan’ Przheval’sk. Close by the latter is the grave of the Russian explorer N.M. Przheval’skii. Most of the population centers are located on the northern shore and in the eastern part of the basin. The principal occupations are agriculture (crop farming, livestock raising, fruit growing) and fishing. The city of Przheval’sk is 7 km from Issyk-Kul’. There is a resort for climatotherapy, Cholpon-Ata, on the northern shore, and another, Tamga, on the southern. All along the shore there are numerous houses of rest, pioneer camps, and tourist centers.

REFERENCES

Berg, L.S. “Gidrologicheskie issledovaniia na Issyk-Kule v 1928 g.” Izv. Gos. Gidrologicheskogo in-ta, 1930, no. 28.
Sapozhnikov, D. G., and M.A. Viselkina. Sovremennye osadki ozera Issyk-Kul’ i ego zalivov. Moscow, 1960.
Korotaev, V.N. Beregovaia zona ozera Issyk-Kul’. Frunze, 1967.

V. A. BLAGOOBRAZOV and A. V. SHNITNIKOV