Kara-Bogaz-Gol, Turkmenistan
1972, 1987

The Kara-Bogaz-Gol (KBG) is a large, shallow lagoon of the Caspian Sea, normally about 7,000 square miles and just a few meters deep.1 The Caspian's changing water level has been a concern for almost a century, but especially since the 1970s. Since the KBG's water flows in from the Caspian, the Caspian's fluctuations have affected the KBG dramatically.

Look at the 1972 Landsat image. Note the difference in color between the Caspian to the west and the KBG to the east. Pure water reflects very little EMR (electromagnetic radiation, from the sun), but the KBG water has suspended solids (including precipitated salt) which reflect some EMR. The KBG is also shallow, so the bottom is reflecting some EMR back through the water. Dry or shallowly-covered salt-beds appear white because they are highly reflective in all three bands. Also notice the general absence in these images of bright reds, which would represent heavy vegetation.

The Caspian Sea is the largest inland body of water in the world, often categorized as a large salt lake. It is salty because rivers (especially the Volga) flow into it, but none flow out. So water leaves through evaporation, and the dissolved salts remain.

The Caspian is below sea level, and the KBG is even 2-3 m lower, so water flows from the Caspian through a narrow strait into the KBG, where it evaporates. (The name Kara-Bogaz-Gol, literally "black throat lake", can be translated as the "mighty strait lake", after the steep Caspian-KBG channel.)2 The KBG is far saltier than even the Caspian, and is one of the saltiest bodies of water in the world; at one time its salt concentration was about 350 per 1000 while the Caspian's was only about 13 per 1000.3

The KBG's salt industry

The salt in this natural evaporation basin has been used commercially since at least the 1920s. Then the commodity was just whatever accumulated on the shore from wave action and evaporation. Especially on the southern shores of the KBG, people harvested this accumulated salt by hand and shipped it away by animals and barges. The new port town of Kara-Bogaz-Gol, just south of the strait, grew to a peak population of 7,000 in 1936 from this salt trade.4

In the 1930s manual collection stopped and the industry shifted northwest to its present center near Bekdash, a town of about 10,000 on the shore of the Caspian. In this area people built canals linking the KBG to large settling basins, which they filled in the summer and left in winter for the salts to precipitate. (This process was used at least through the crisis years of the 1970s.) From the 1950s on, groundwater was pumped from levels lower than the KBG itself, yielding more-valuable types of salts. In 1963 construction began at Bekdash on a modern plant for increased production of salines, year-round and independent of natural evaporation. This plant was completed in 1973.5

The fall and rise of the Caspian

The Caspian's level normally fluctuates a small amount from year to year, but for the century before 1977, the net trend of these fluctuations was consistently downward. Until 1933 the decline was modest; from 1933 to 1940 (years of drought in America) it dropped rapidly, and from 1940 to 1977 the drop continued. The range was about 3 m, from about -26 m (i.e. 26 m below sea level) at the turn of the century to a 1977 record low of -29 m.6 This resulted in a loss of 10% of the Caspian's surface area.7

Then it began to rise; from 1977 to 1995 the Caspian rose almost 2 m, up to a level not seen since the 1930s. This has caused its own major problems; human settlements, oil wells, factories, and even a nuclear waste dump have all been flooded or threatened with flooding.8

The main factors of the Caspian's level are river inflow (especially from the Volga) and evaporation off its surface. River discharge into the Caspian obviously varies with regional rainfall, but is also diminished by upriver irrigation projects and by dammed reservoirs. This water usage upriver increases evaporation and allows less water into the Caspian. Evaporation from the Caspian itself is more constant and immutable, but the Soviets eventually tried to exert some control over it as well, by blocking off the flow into the KBG. Though the KBG held a tiny fraction of the Caspian's total water, its higher surface-to-volume ratio attracted notice as a point of upward "leakage".

The fall and rise of the KBG

In 1980 the Soviets dammed the Caspian-KBG strait. Though the Caspian had been rising for more than two years by then, the Soviets apparently believed that the rise was only temporary and that the Caspian's water still needed to be conserved. The Soviets intended that some water would remain in the KBG, sufficient to keep the salt industry operating; there were reportedly plans to someday add a canal or locks to the dam to allow a limited amount of water through. It was believed that even without such inflow, the existing water might last up to 25 years.

But by November 1983 the KBG had already dried up entirely. Construction crews rushed to build an aqueduct of 1.5 m concrete pipe letting water through the dam-- 2 km3/year compared to the pre-dam 5 km3/year-- believed to be enough to restore the KBG to a mean depth of 1 m.9 But the Caspian continued to rise, and the Soviet Union broke up. In the spring of 1992, President Sapamurat Niyazov of Turkmenistan took a spade to the dam to symbolically begin its demolition.10

Water-level's effects on the KBG area

Setting aside broader regional problems, how did this century of fluctuation affect the immediate area of the KBG?


Footnotes

1. Shabad, Theodore, 1985, Aqueduct Completed to Feed Caspian Water Into Dried-up Kara-Bogaz-Gol: Soviet Geography, V. H. Winston and Son, Inc., Silver Spring, Maryland, vol. 26, no. 1, January, p. 59-61.

2. Shabad, Theodore, 1980, Caspian Sea "Leak" is Stopped: Soviet Geography, V. H. Winston and Son, Inc., Silver Spring, Maryland, vol. 21, no. 5, May, p. 322-323.

3. Shabad, 1980.

4. Shabad, 1980.

5. Soviet Geography, 1973, Kara-Bogaz-Gol Sodium Sulfate Plant Opens: Soviet Geography, V. H. Winston and Son, Inc., Silver Spring, Maryland, vol. 14, no. 4, April, p. 276

6. Rodionov, S. N., 1990, A Climatological Analysis of the Unusual Recent Rise in the Level of the Caspian Sea: Soviet Geography, V. H. Winston and Son, Inc., Silver Spring, Maryland, vol. 31, no. 4, April, p. 265-275.

7. Pearce, Fred, 1995, How the Soviet Seas were Lost: New Scientist, New Scientist Publications, London, England, vol. 148, no. 2003, 11 November (p. 38-42), p. 42.

8. Bond, Andrew, 1991, Caspian Sea level rising, flooding along lower Volga: Soviet Geography, V. H. Winston and Son, Inc., Silver Spring, Maryland, v. 32, n. 7, September 1991 p. 516. Pearce, 1995, p. 42.

9. Shabad, 1985, p. 60.

10. Rich, Vera, 1992, Demolition of a Disastrous Dam: New Scientist, New Scientist Publications, London, England, vol. 134, no. 1816, 11 April, p. 8

11. Pearce, 1995, p. 42.

12. Vera, 1992, p. 8.

13. Shabad, 1985, p. 60.

14. Shabad, 1985, p. 59.

Other references

Leont'yev, O. K., 1988, Problems of the Level of the Caspian and the Stability of its Shoreline: Soviet Geography, V. H. Winston and Son, Inc., Silver Spring, Maryland, vol. 29, no. 6, June, p. 608-616.

Satellite images

LM1177031007233990 (Landsat 1 MSS, 4 December 1972)

LM5164031008726890 and LM5164032008726890 (mosaicked Landsat 5 MSS, 25 September 1987)

Special Projects Image

A comparison image of 4 December 1972 and 25 September 1987 is available as Special Projects Image E-1868-810CT from EDC Customer Services.

Map

Defense Mapping Agency, 1974 (compiled 1970, revised 1974), Operational Navigation Chart F-5: scale 1:1,000,000.


Bookmark www.usgs.gov/Earthshots for Earthshots, 8th ed., 12 January 2001, from the EROS Data Center of the U.S. Geological Survey, a bureau of the U.S. Department of the Interior.