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History
The Aral Sea degradation
Impact on climate regime
Impact on soil structure
Impact on criosphere
Impact on inhabitation sphere
Impact on biodiversity
Impact on ecosystems
Impact on social and economic sphere
Neutralization of the Aral crisis

"Previous generations have always been anxious about the future, but we are the first who decide if the Earth inherited by our children will be inhabited".
Lester Brown, USA.

"The Aral crisis is the brightest example of the ecological problem with serious social and economic consequences, directly or indirectly connected with all the states of Central Asia. Critical situation caused by the Aral Sea drying off was the result of agrarian economy tendency on the basis of irrigated agriculture development and volume growth of irrevocable water consumption for irrigation".
Conference of the Central Asian region ministers. States of Central Asia: Environment Assessment. Aarhus, Denmark, 1998.

C entral Asia (territory is 1.7 mln. sq.km) is situated in the mid-part of Euroasia at the crossroad of ancient caravan routes between Europe and Asia, Middle and Far East and mainly coincides with the geographical borders of the Aral Sea, completely including territories of Tadjikistan, Uzbekistan, a large part of Turkmenistan, Kyrgyzstan and the south of Kazakhstan.

As one of the most ancient centres of world civilization, this region has vast territories of arid and semiarid zones(1 mln.sq.km) with only 5% of densely populated oases. The basin is inner water body of the dischargeless Aral Sea which was the fourth largest inland lake in the world before 1960. The dependence of the Central Asian civilization's development of water resources dates back to ancient times. Water and irrigation have always been the basis of life, the development of every living thing, and the main component of nature in the region.

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By the beginning of the 20th century, 7-8 million people lived in the region. Irrigated lands made up about 3.5 million hectares and had irrigation networks of different levels. It was the foundation of society's economic base. At present the population of the region has increased 7 times, exceeding 50 million people (54.2 million people in 1997). Irrigated lands had doubled (7.5-7.9 milllion hectares).

Up History

On the basis of geographical and archeological research it was established that the Aral Sea has had periodical changes of its water area, i.e. expansions are followed by withdrawals. This was brought about by climate change and changes in the state of the environment in the region. With the development of land use, anthropogenic factors affected the natural periods of sea fluctuations changing flows of the SyrDarya and AmuDarya. This is especially explicit in the present.

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Evolution of periodic fluctuations of the Aral sea water territory during 10000 BC - 1990 AD

The beginning of irrigated agriculture in the region dates back to the 6th-7th centuries B.C. and coincides with flourishing the most ancient civilization where irrigation was a major decisive factor of historical and socio-economic development.

Today the Aral and surrounding territories are world-known for ecological disasters attributed mainly to anthropogenous factors. The growth in water consumption connected to cultivation of new irrigated territories, where mainly cotton and rice are grown, together with the increase in the population working in agriculture, the flow of water to the sea from the two major river systems -the AmuDarya and SyrDarya - completely stopped.

In spite of intensive glacier melting which should have led to increase of territory of the Aral Sea, during last 25 years disastrous reduction of the largest inland water body takes place.

Up The Aral Sea degradation

T he Aral Sea is the largest inland body of salty reservoirs in the world. Situated in the centre of the Central Asian deserts at an altitude of 53 metres above the sea level, the Aral Sea functions as a gigantic evaporator. About 60 km2 of water evaporates per year.
The sea contributed to hydrothermal regime improvement, influenced water regimes of arid plants, pasture productivity, and provided normal functioning of artesian wells etc. Ecological balance in the basin was formed in the first half of the 20th century and was stable up to the beginning of the 1960's, with a volume of 1,064 km�, and a water territory of 66.4 thousand km�.

Because of irrevocable removal of river water on irrigated territories, ecological balance began to decline. Only half of the previous river runoff reached the Aral Sea. But even this quantity of water was not sufficient to support sea level at 53 m. Large-scale photos of the Aral Sea see here 1973, 1987, 1996, 1997 ��.

However as a result of a tendency of economy development in agrarian areas, leading to growth of irrigated territories and volumes of irrevocable water consumption during years of water shortages, water flow into deltas of the AmuDarya and SyrDarya rivers was reduced sharply. In 1982 and 1983 this made up only 2.28 and 3.25 km3, respectively. Since 1961 the sea level has declined with increasing speed from 20 to 80-90 cm per year.

During the last 35 years, from 1960 to 1995, the sea received less than 1,000 km3 of river water, which led to the lowering of the sea level by 17 m, accompanied by a reduction of the volume of the water area by 75%.

As a result of the complete stop of the AmuDarya and SyrDarya runoff and expansion of irrigated territories without any control of the Aral Sea and environmental needs, a serious complex of ecological, social and economic problems was formed in the Pre-Aral area. These problems by origin and level of consequences have an international character. The sea has lost its fishery and transport importance. It was divided into two parts, the Bolshoi and the Maly (Northern) Aral, and moved 100-150 km away from the original shore.


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From exposed salty bed (35 thousand km�) up to 100 million tons of salty dust flew out annually. Suspended solids in the form of aerosols with agricultural pesticides, fertilizers and other harmful components of industrial and municipal wastes prevail in the composition of the winds.

Development of ecological crisis in the basin of the Aral Sea (1966-1996)

  Units of measurement 1966 1976 1996 2000
Territory of "new" salty desert appeared as a result of the sea drying off. sq. km. No 130200 38000 42000
Physical mass of salt, dust and wastes within salty desert mln ton. No 500 2300 3300
Territory of salt and dust spread thousand sq. km No (in fact,mitigate and favourable impact of the Aral sea on territory 68900sq.km) 100-150 250-300 400-450
Growth of withdrawal and fall out of salts and dust kg/hect No 100-200 500-700 700-1100
Population in the zone of ecological crisis thousand people No 500-600 3000-3500 3500-7000

Due to the reduction in the sea dimensions, and the increase in evaporation and drainage-collecting water, water salinity considerably increased from 9.94 g/litre in 1965, to about 15 g/litre in 1996.

During the last 3-4 years as a result of abundant water and some measures on rational use of water resources, practical level lowering was reduced, and even tendency to growth is observed in the" Maly" Aral sea.

Up Impact on climate regime

Sharp continental climate is a feature of the Pre-Aral area climate.

During the the last 5-10 years the drying off of the Aral Sea, brought about noticeable changes in climate conditions. In the past the Aral was considered a regulator mitigating cold winds from Siberia and reducing the summer heat. Climate changes have led to a dryer and shorter summer inthe region, and longer and colder winters. The vegetative season has been reduced to 170 days. The pasture productivity has decreased by a half, and meadow vegetation destruction has decreased meadow productivity 10 times. On the shores of the Aral Sea precipitation was reduced several times. Average precipitation magnitude is 150-200 mm with considerable seasonal ununiformity.

High evaporation (up to 1700 mm per year) is marked while air moisture is reduced by 10%. Air temperature during winters has fallen, and summer temperatures have increased by 2-3 degrees C, including observations of 49 degrees C.

Frequent occurence of long dust storms and ground winds is characteristic feature of the Pre-Aral area climate. Strong winds often blow in the region. They are the most intensive on the western coast - with perhaps more than 50 days of storms per year. Maximum wind velocity reaches 20-25 m/s.

These climatic conditions defined that agriculture without irrigation is impossible. The result is intensive accumulation of salt in the soil leading to water use for watering plants and washing off lands.

Up Impact on soil structure

M ost of the sands and soils in the Pre-Aral area are light and easily transported by wind.

The drying off of the Aral Sea resulted in two different kinds of desertification. The newly dried sea bed, and the artificial water logging of irrigated lands. As a result, a new desert "Aralkum" appeared in the centre of the great deserts. It is solid salt-marsh consisting of finely-dispersed sea depositions and remnants of mineral deposits, washed away from irrigated fields.

A new qualitative phase of desertification affecting the Pre-Aral ecosystem degradation, regional and global climate, mountainous flow-forming systems and water-salty regime of agricultural zone takes place.

The sea bed, formerly referred to as a so-called "fresh water maker" of vast water collecting basin at the expense of rich sea hydrobiocenose activity, is an artificial anthropogenous volcano, throwing tremendous masses of salt and finely-dispersed dust into the atmosphere. Pollution is increased because the Aral Sea is locatedalong a powerful air stream running from west to east. It contributes to aerosol transference into upper layers and fast spread in the atmosphere of the Earth. That is why traces of pesticides from the Aral region were found in the blood of penguins in the Antarctic, and typical Aral dust has been found on Greenland's glaciers, in Norway's forests, and Byelorussia's fields, all situated thousands of kilometers away from Central Asia.

Up Impact on cryosphere

O ne of the dangerous consequences of the drying off of the Aral Sea, is the increasing degradation of mountainous glaciers of the Himalaias, Pamir, Tien-Shan, and Altay, feeding the SyrDarya and AmuDarya.

The increase of dust on glacier surfaces and mineralization of precipitation on them lead to intensive melting of glaciers. At present, 1081 glaciers have disappeared in the Pamir-Altay area , 71 glaciers in the Zaili Alatau area, and the volume of glaciers in Akshirak has been sharply reduced.

On average, valley glaciers in the Tien-Shan area retreat 7.5-13.1 m per year and grow thicker at the same time. This is a dangerous process for a dry region, because in Central Asia, mountainous glaciers are the only ancient remaining storage of fresh water supply and are the main atmospheric moisture condensators of the region.

If the cover of moraine depositions increase, they no longer will be moisture condensators and sharp reduction of the river flow will start.

Up Impact on inhabitation sphere

T he Aral disaster has deteriorated the sphere of inhabitation of the region sharply, due to polluting of the atmosphere, the drinking water and the soil.

An evaluation of the field withdrawal from the dry parts of the Aral Sea bed shows that this magnitude varies from several hundred thousand tons to 20-30 million tons per year. In the composition of dust cloud suspended solids in the form of aerosols with agricultural pesticides, fertilizers and other harmful components of industrial and municipal sewage prevail. Salt content makes up 0.5-1.5%. Sand-and-salt aerosol effects on oasis soils and pastures are predominantly negative. Replacing multilayer herbage by single-layer, reduces the quantity of useful feeding plants, and often plants that have no feeding value are cultivated.

Two million hectares of fertile lands disappeared as a result of overwatering and as a result of fast rise of ground water they got polluted for the second time.

Today these lands are either water logged or salinized. Former arid soils of the Pre-Aral area with automorphic feed and moisture regime became meadow-swamp soils with hydromorphic regime. To support this regime artificially it is necessary to raise standards by 2-3 times, in order not to activate the secondary salinization process. A vicious circle of agriculture was formed in this region, where heavy swamped lands are left.

The land-improvement condition of irrigated soils in Central Asia is worsened by collective-drainage water saturated with pesticides and discharged as return runoff into numerous local landscape depressions. As a result, artificial reservoirs-accumulators appear. These reservoirs are a real disaster for surrounding lands. Some of them cause secondary pollution when poisonous bed depositions become dry and are brought on irrigated lands, ruin them and pollute the atmosphere in the surrounding regions.

The most spread pollutants in the Aral Sea are: oil hydrocarbons, phenols, synthetic surface-active substances (SSAS), chlororganic pesticides (COP), heavy metals and minerals. The abundant use of pesticides with high physiological reaction (B-58, metaphos, corotan, butiphos, hexachloran, lindan, DDT etc.) poses a tremendous threat to living organisms. Reservoirs carrying water with undecayed compounds of heavy metals and chlororganic pesticides, led to the destruction of fishery, the appearance of cancerogenic diseases, and changes in citogenetic indices.

The maximum pollution level by oil hydrocarbons in 1970 was 54 MPC (maximum permissible concentration) in the Maly Aral (MPC=0.05 mg/dm�), and 80 MPC in the Bolshoi Aral. Since 1978 the tendency to oil hydrocarbons pollution stabilization at the level of MPC is marked. Phenols made up 28 MPC (MPC=0.001 mg/dm�)in the Maly Aral, and 63 MPC in the Bolshoi Aral. At present there is no information about phenol pollution because observations have been stopped. Concentrations of SSAS and heavy metals do not exceed MPC.

Salinization increased from 10 g/l to 40-50 g/l because of lack of fresh water inflow.

Up Impact on biodiversity

I n the past the uniqueness of the Aral Sea contributed to richness and diversity of the biota which could be compared with Africa. The Pre-Aral area possessed half of the biological species of the former USSR, many of these, however, have disappeared or are threatened. There were 500 kinds of birds, 200 species of mammals and 100 species of fishes, thousands of insects and invertebrates.

Before 1960 the river deltas were home to over 70 kinds of mammals and 319 types of birds. At present only 32 kinds of mammals and 160 types of birds remain. In lowstreams of the SyrDarya River, more than 100 thousand hectares of alluvial soils became salt-marsh, and more than 500 thousand hectares of swamp and medow-swamp soil became dry. This resulted in the transformation and destruction 5-7 kinds of herbs needed for fodder for sheep, horses, camels and goats. Diseases and death of cattle began, musk-rats cultivation stopped, and sheep live-stock decreased sharply.

The regional flora is impressive and includes 1,200 flowers, 560 types of tugai forests of which 29 are endemic to Central Asia. The flora of the Aral-Sea coast includes 423 kinds of plants of 44 families and 180 genera. The highest diversity of sand vegetation is concentrated on the former islands of the western coast. The dry strip of the Aral is characterized by lower diversity in comparison with the coast. Among them are 30 species which are valuable fodder plants, 31 kinds of weeds, and more than 60 kinds of local flora are potential phytomeliorants for dried coasts. The change in water balance caused mineralization of the water in the Aral Sea basin, which led to the loss of unique biocenosis and a number of endemic species of animals.

 Inflow reduction into the Aral caused irreversible changes of hydrological and hydrochemical sea regimes and hydrosystems. Salt balance changes increased the sea salinity 3 times, transforming it into a desert. The formerly flourishing sea ecosystem supported 24 species of fishe that are disappearing. These include carp, perch, sturgeon, salmon, sheat-fish and spike. There were 20 kinds of fish in it, but fishery was based mainly on bream, sazan, aral roach (vobla). Barbel and white-eye fish were caught in the Aral Sea.

The first signs of the negative impacts of salinization on ichtyofauna of the Aral Sea, appeared in the mid 1960's when salinity reached 12-14%. On shallow water the salinity of water increased faster than in the open parts of the sea, negatively affecting spawning places. By 1971 the average salinity exceeded 15% and resulted in the destruction of fish spawn. Since 1971 the average salinity has reached 12% in the open part of sea, and the first signs of negative impact on fish have appeared. Some kinds of fish have slowed their growth, and the number of fish has been sharply reduced. By the mid 1970's average salinity of the sea exceeded 14%, and the natural reproduction of the Aral fish was completely destructed. In the late 1970s several species of fish did not reproduce at all. By 1980 salinity exceeded 18%.

The Aral Sea has lost its fishery completely. Of the ichtiofauna of the Aral Sea, only aboriginal species - pricles and acclimatizers - bullheads and sprats are left. In the estuaries of the SyrDarya and AmuDarya grown up fishes were caught occasionally. The researchers of the Aral department of the Kazakh Research Institute of Fishery in the 70's collected eurigaline and saltloving kinds of fish. They conducted experiments with Caspian sturgeons, Kurine salmon, Asov and Black sea plaice-glossa and plaice-kalkan. The most promising were the experiments with plaice-glossa having ecological plasticity, spawned at the places with 17% to 60% of salinity, at present its catch makes up 30% of the total number. Plaice quality is very high, and Dutch research showed that there are no traces of pesticides and heavy metals in them.

Up Impact on ecosystems

T he Pre-Aral area is characterized by a complex spatial structure of ecosystems. These are influenced by the physical and geographical conditions of the region, the consequences of its economic utilisation during many centuries, and the active influence of modern anthropogenous processes. Pre-Aral ecosystems are developing in extreme conditions of desert. The factors limiting biota development were established by nature itself. The Pre-Aral area has suffered from anthropogenous processes for a long time, both regionally and locally. Anthropogenous impacts have caused transformations of natural ecosystems which finally led to dramatic changes and degradation.

The ecosystems of delta valleys have been transformed greatly by agricultural land use for many centuries. Irrigated or cultivated fields, rice fields and non-cultivated agricultural lands which are characterized by different stages of soil and vegetation cover rehabilitation, are singled out. The following anthropogenic factors that brought about changes in the ecosystems should be considered according to their significance: pastures, land-use, agriculture, transport, city, rural, military objects, hydrotechnical (artificial reservoirs, dams, canals, sewage accumulators), and cattle-breeding.

Up Impact on the social and economic spheres

T he process of degradation in the Aral region caused progressive crises in the social and economic spheres. The primary victims of the crises were the most vulnerable layers of population, namely children, women, ill-paid inhabitants of cities and rural areas. The region has the highest child mortality rate in the former USSR (75 children per 1000 newly born), high level of maternity death: about 120 women per 10,000 births. Diseases such as TB, infections and parasites, typhus, hepatite, paratyphoid always accompany poverty.

The disease rate has a tendency to increase. In the epicentre of ecological disaster, anemia, disfunction of thyroid the gland, kidney and liver diseases are wide spread. Blood, oncological diseases, asthma and heart diseases are progressing. Medical research proves that the incidence and growth of these diseases are directly dependent on ecological disaster.

Up Neutralization of the Aral crisis

S ince the 1980's the cultivation of new large irrigated areas was banned and large-scale water resources projects have been introduced. At the same time measures to improve living conditions in the Pre-Aral area have been adopted at the expense of the construction of health-protection objects, water-supply, gasification, improved social care, and the watering of the AmuDarya and SyrDarya deltas. As a result 10.3m� and 12.56 m� went into the Pre-Aral area in 1995 and 1996 respectively. The AmuDarya River delta recieved 5.1 m� in 1995 and 7.46m� in 1996. This water was stored in artificial reservoirs in the AmuDarya delta, preventing desertification in the Pre-Aral area.

The first attempt to create the Maly Aral took place 1992, when the "Karateren-Kokaral" was constructed. But it collapsed in 1993 as a result of an increase of the water level. It was however restored.

crosspiece "Karateren-Kokaral"

The crosspiece divided the Aral Sea into two parts: the Bolshoi Aral and the Maly Aral. The SyrDarya waterflows into the Maly Aral and slowly filled its dry bed. The water level rose by 1.5 m, and the growth of salinity stopped at the level of 5 g/l. The water came to the city Aralsk covering a distance of 10 km. The first signs of improvement in the ecological situation appeared: It rained more often, vegetation cover rehabilitation took place in the coastal area, the level of sea water salinity was reduced in a new-born reservoir, giving the opportunity of fresh fish supplies.

In 1999 this crosspiece was destroyed.

Sources:
  • National report: "On the environment state and use of natural resources in the Republic of Uzbekistan". State Committee on Nature protection of Uzbekistan. Tashkent, 1998.
  • K.Isentaev. "Geological structure and perspectives of oil and gas reserves of the Aral Sea". Workshop report. Almaty, 1997.
  • Ministerial conference of the Central Asia. "Assessment of the environment". Aarhus, Denmark, 1998.
  • J.Mahambetova. "Non-government union "Aral tenizi". Aralsk, 1999.


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