Sea in Soviet times
Starting from the 1960th, since the commencement of lowering in the sea levels, the trees and shrubs began to degrade, the areas occupied by reeds and licorice reduced, turanga disappeared and the elaeagnus dried out. In areas where some vegetation remains, its diversity is much poorer. Muskrat is extinct here. The quantities of commercial game species reduced dramatically. Most waterfowl changed their nesting sites, having moved north to the lakes of Turgay trough.
Commercial use of the Aral Sea was primarily associated with fishing. Catches reached 40-50 thousand tons, including more than 20 thousand quintals of the most valued Aral fish, the barbel. Until the 1960s, the Aral ranked third among the inland reservoirs of the USSR, annually contributing about 13% of the total fish catch. The main fish species of the Aral Sea, apart from the barbel, were bream, carp, shemaya, roach, perch and chub, which accounted for 80% of all production. The sea used to be the habitat of the Aral Salmon, listed in the Red Data Book of the former USSR.
In 1980th, due to the increase in salinity from 11 to 20 g/l, and drying of the river channels that since antiquity used to serve as routes to the spawning sites, fish catches have dropped to 14 tons and the sea lost its commercial fishing value, and in 1984, the fishing in the sea completely ceased.
In the hunting areas of Amudarya and Syrdarya deltas, the catch of muskrats used to reach up to 1 million 130 thousand animals each year. Most of the pelts were sold in the international fur auction and brought foreign currency to the state. The population of boars was rather numerous. Cane, which was used as a building material and livestock feed, was grown and harvested here as well.
Before the 1960th, the Aral Sea, being an internal body of water between Kazakhstan and Uzbekistan, served as a major link between the ports of Aralsk and Muynak, the turnover between which reached 250 thousand tons per year (mainly cotton, bread, salt, fish, chemicals and wood).
The economic significance of the Aral Sea is not limited to the commercial activities listed above. What is rather more important is the overall impact of the Aral Sea on the surroundings, in the form of moderating the climate. The evaporation from the Aral Sea conditioned and shaped climate across the entire Central Asia. Prior to the shrinkage, it used to evaporate over 60 km3 of water per year, which would then transform into precipitation falling over the region. And this immense evaporation was compensated by the Amudarya and Syrdarya river runoffs.
The use of water from the Amudarya and Syrdarya Rivers is the main pillar supporting the economies of Tajikistan, Uzbekistan, Turkmenistan, Kazakhstani part of the Aral Sea Region and, to a lesser extent, Kyrgyzstan. The flows of Amudarya and Syrdarya Rivers were almost fully regulated, in order to create the largest area of irrigated agriculture and the cotton base of the former Soviet Union, without making any forecasts as to the future of the rivers, the Aral Sea and the environmental consequences for the whole of Central Asia, leaving the sea without water inflow, thus dooming it to dry.
Development of cotton, and later, rice production, was largely based on progressive increase in the irrigated land area in the Amudarya and Syrdarya River Basins, from 4.1 million hectares in 1960 to 7.4 million hectares in 1990. These irrigated lands produced 95% of cotton, about 40% of rice, 25% of vegetables and melons, 32% of fruit and grapes of total production in the former USSR.
Naturally, since this period, the river water runoff to the Aral Sea began to decline sharply. If in 1910-1960, the Aral Sea annually received about 62 km3 of water on average, then in 1961-1970 it only received 43.3 km3, in 1971-1980 – 16.7 km3, in 1981-1990 – 3.5 km3 per year. In 1974-1986, the Syrdarya runoff did not reach the Aral Sea, the Amudarya runoff was partially missing in the period of 1982-1983, in 1985-1986 and in 1989. This resulted in a decrease of its level: in the 1960s by an average of 0.2 m per year, in the 1970s – 0.6 m, in 1980 – 0.85 m, and in the beginning of 1987 the level reduced to 36.4 m, i.e. 16.6 m lower than the average annual level before the 1961.
In 1975-1988, the Karakum Canal alone diverted from Amudarya 10 to 13.5 km3 of water annually, which enabled irrigation of about 850 hectares. Large quantities of water from Amudarya fed the newly developed lands along the Amu-Bukhara and Qarshi Canals (about 15 km3 additionally).
The water from Syrdarya running through a system of canals irrigated vast areas in Ferghana Valley, south-eastern regions of Uzbekistan and lands in Kazakhstan. Only a small part of the flow used for irrigation would return back to the river. The best part was irretrievably consumed or discharged into the drainage systems - which are an integral part of any irrigation system and aim to ensure the optimum level of groundwater and adequate soil productivity – while constituting closed drainage basins in the desert, which led to the emergence and development of desertification processes and pollution of the environment. The latter occurred through the use of pesticides in an average amount of 20-25 kg/ha per year, and fertilizers in an average amount of 400 kg/ha per year. The total volume of drainage water in the Amudarya and Syrdarya River Basins would reach 32.71 km3 annually.
The drainage resulted in formation of two large evaporation ponds, Sarykamysh on Amudarya River, and Arnasay on Syrdarya River. The latter was formed at the former sites of Aydar salt marsh, the Arnasai system of lakes and the Lake Tuzkane. The irrigation drainage water from the Golodnaya Steppe and the floodwaters from Shardara Reservoir are still being discharged there.
The Aydarkul Salt Marsh hollow filled up with water in 1969, when during a high-water season on Syrdarya, the Shardara reservoir discharged 21.8 km3. The Lake Aydar merged with the Lake Tuzkane and formed a single lake system of 2,400 km2. Now the Arnasai Lakes (or Arnasai) area ranges from 1,775 to 3,100 km2, the overall water volume ranges from 12.5 to 35 km3, and water salinity in different spots of the system varies from 4 to 12 g/l, with an average of 10.3 g/l.
Apart from Arnasai and Sarykamysh, there are about 100 ponds which accumulate drainage water, with the total area exceeding 10 km2. These volumes of diversion and losses of water from the two rivers cannot be compensated, and the evaporation from the sea surface still continues. A natural consequence of reduced water inflow was a rapid drop in the level of the Aral Sea and an increase in its salinity. The reduction of water levels resulted in a 23 km2 reliction of the sand and marsh surface of the sea bed. Meanwhile, since 1961, only in the Amudarya delta, more than 50 lakes have dried up, the tugay (black forest stretching along the coasts of Central Asian Rivers) and reed areas reduced 2-fold to 1 million hectares. Flora and fauna of the Aral Sea Region had lost 50% of their gene pool. Desertification involved more than 4.5 million hectares, turning pasture lands to deserts, causing serious damage to the livestock production industry.
Groundwater levels dropped over the entire Aral Sea Region too, and this has caused changes in the feeding regimen of plants, and in soil-forming processes.
The dry bed of the Aral Sea has become a source of powerful dust storms. The dust is blown and spread in the radius of 150-500 km. Just the former south-eastern coast of the Aral Sea alone produces 15-75 million tons of dust annually. The dust contains toxic sulfate and chloride salts and sets on hundreds of thousands square kilometers, harming the generative and vegetative organs of plants, reducing pasture productivity and crop yields.
The dust discharge resulted in almost a three-fold increase in atmospheric turbidity, which affects the dissipation of solar radiation and temperature of the soil surface. The Aral Sea used to absorb heat in summer and release it in winter. It contributed to hydration of the entire Aral Sea Region. Nowadays, the hydrating impact of the sea had reduced twice.
The salt spread by the wind is a significant issue. Currently, the sea water contains about 10 billion tons of salt. If this salt is scattered on the ground with a 5 cm layer, it will cover a land area of about 10 million hectares. The spread of such amounts of salt to the adjacent irrigated areas is very dangerous. The salt dust falling on pollen of flowering plants destroys or severely reduces yields.
The inhabitants of the Aral Sea Region are witnessing formation of a new desert, the Aralkum. The nature suffers, but people suffer even more. As a result of the large-scale development of lands in the Aral Sea Region, and as a consequence of drying of the sea, the levels of morbidity and mortality in the region increased significantly, especially among children. The incidence of typhoid, cholelithiasis, chronic gastritis, kidney disease, esophageal cancer, and tuberculosis rose dramatically. The overall stress of the population living in the area grows as well, which leads to social tensions.