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Pollution payback Ambitious engineering schemes were a feature of the former Soviet Union. When devolved to the new independent republics, they can cause headaches for their new owners as Judith Cruic

Environment; Aral Sea

Arguably the most bitter legacy left by the economic system of the former Soviet Bloc is the damage done to the environment. The destruction of the Siberian Taiga, the pollution caused by unregulated industry and intensive agriculture are unwelcome reminders of a system which ultimately failed its citizens.

Saddest of all is the case of the Aral Sea which has been called one of the greatest environmental catastrophes ever recorded. This landlocked inland salt lake is fed by two major rivers; the Amu Darya flows into the sea from the south while the northern end is fed by Syr Darya. At the beginning of the century the sea was rich with fish and the rivers provided water for irrigation and agriculture. But with the establishment of the Soviet Union, traditional agricultural practices were replaced by collectivisation and planners looked towards crops which could be exported for hard currency.

Among these was cotton, which was extensively planted in Uzbekistan and Turkmenistan, both bordering on the Aral Sea. Cultivation was stepped up in the 1950s and a series of dams constructed to divert water to the vast network of irrigation channels and produce cheap electricity. Work also began on the construction of the huge Kara Kum canal, some 1,200km in length, to irrigate the former desert areas of Turkmenistan. The Kara Kum draws a huge volume of water from the Amu Darya.

Consultant Gibb has already produced a mathematical model of Kara Kum which Water Group business director Mike Hart describes as a 'lifeline for Turkmenistan'.

However due to the amount of water being diverted to cotton growing from 1960 onwards, the level of the Aral Sea began to drop. In 1965 it received around 50km3 of water each year from the two rivers. By the early 1980s the flow had ceased, salinity increased and the sea began to shrink. The fishing industry which employed 60,000 people and landed 4,500t of fish a year was wiped out.

As the sea declined the climate became more continental and farmers switched from growing cotton to rice cultivation which demanded even more water. Pesticide use had been heavy throughout the area and residues had entered the water supply. Winds picked up the sediments from the exposed sea bed and the unhealthy cocktail of sediment, salts and pesticides has been reported in dust storms as far away as Pakistan and the Arctic.

The Soviet central government recognised that something had to be done. In 1988 it ruled that cotton growing was to be reduced so that the Aral Sea could receive some water. Plans were also drawn up to divert the waters of Siberia's Ob some 2,000km southwards to the Aral rather than flowing east to the Arctic. But the Gorbachov regime put an end to that scheme.

Then in 1991, the dissolution of the Soviet Union transferred the problems of the Aral Sea and the maintenance of the system of dams and canals into the remit of five central Asian nations which share the Aral basin: Kazakstan, Kyrgizstan, Tajikstan, Turkmenistan and Uzbekistan.

The problems of the Aral were well known, as were their effects on the population in its vicinity. These were not just the economic loss of fisheries and pasture land. The effects of the polluted groundwater and airborne sediments, salts and pesticide residues had resulted in abnormally high levels of anaemia, infant mortality, various cancers and thyroid disease among the population.

In 1993 the five nations established the International Aral Sea Rehabilitation Fund to develop a programme of urgent measures.

A meeting in Paris the following year brought financial support from a bodies including the World Bank, the European Union, the UN Development Programme and countries including Canada, Great Britain, Finland, Italy, Japan, Kuwait, the Netherlands and Switzerland. More than $25M was pledged.

Four objectives were set: to stabilise the environment; to rehabilitate the disaster zone around the Aral Sea; to improve the management of the international waters and; to build the capacity of the regional institutions. Earlier this year the World Bank approved a grant of $12.2M for the first and third of these objectives; stabilisation and water management.

As part of the latter programme Gibb has been awarded a $1M contract to assess 10 major dams and storage reservoirs in the region, two in each republic. Many of these were built in the 1950s and 60s to designs by the Soviet design house Gidroproject. There are both concrete and embankment type. The Gibb exercise will serve as a pilot project for the hundreds of dams in the region.

The firm, working with Australian sub-consultant SMEC will head a team of 24 specialists comprising dam specialists, mechanical engineers, hydrologists and seismic experts. The project is expected to be complete by 2001.

Hart says: 'From what we have found out so far the basic design philosophy for the dams appears to be sound. However, some of the concepts are unusual by Western standards, for instance the general absence of free surface overflow spillways, the very large diameter gate controlled tunnel outlets and optimistic assumptions regarding passage of the designed flood. A basic tenet with most of the dams is that a very large proportion of the design flood will be attenuated in a flood storage volume retained at above normal full storage level. With the break-up of the Soviet Union the central control necessary to safeguard this storage provision has tended to break down'. Under Soviet design standards of the time dams were constructed to cope with 1 in 10,000 year floods and 1 in 500 year earthquakes. Current Western standards allow for maximum possible floods and 1 in 2,000 year earthquakes.

There are very competent specialists in the area, says Hart, but they have been handicapped by lack of funds. Instrumentation when provided, has suffered from lack of maintenance. New instrumentation will be installed under the project and a monitoring regime initiated.

Gibb has been involved in projects in the region of the Aral Basin for some time, with offices established in Almaty, Ashgabat, Bishkek and Tashkent since 1995. These have enabled the firm to develop an appreciation of the regional problems.

One dam which is likely to be high priority is Nurek, an earthfill structure 80km to the east of the Tajik capital Dushanbe. At 300m and impounding a reservoir of 10.5km3 it is the world's tallest fully constructed dam, completed in 1980.

Concerns have been raised that over-optimistic assumptions about flood management procedures during the design of the dam have put it at risk of overtopping. 'We may find that a larger spillway would be desirable,' says Hart, 'but the cost may be prohibitive, so the emphasis is more likely to be on monitoring and flood management techniques.'

A real concern however is the Usoy dam 3,000m up in the Muzkol and Northern Alichursky mountains, formed by an earthquake in 1911. It holds back the 60km long Lake Sarez.

A team of geologists who visited the site in June this year reported that even slight seismic activity could breach the natural structure, which is already leaking. And an unstable cliff with deep cracks is hanging over the north bank of the lake.

'In the event of an earthquake it is likely that the cliff would fall into the lake,' according to a recent report commissioned by the UN international Decade for Disaster Reduction. 'A rush of water would strike the dam and cascade over the top.'

Should the dam rupture, predictions are that a 5,000m2 area, home to 5M people, would be inundated. As many as 36 earthquakes have been recorded in the region since 1990 one of which caused a 1km3 landslide just 5km away from the dam.

The government of Tajikistan has put forward a plan to draw water from Lake Sarez and pipe it to the Aral Sea. Hart is hoping to reinstate a satellite monitoring system to warn of movement in the dam.

Despite the massive amount of money promised to the Aral Sea area, Hart says it would be impossible to restore it to its original state. The Kara Kum canal is too important to the area, which is still reliant on cotton for hard currency.

The plan now is to stabilise the sea in its present condition, clean up the polluted areas, restore wetlands and ensure the safety of water supplies and structures. Most importantly, says Hart the message must be promoted that water is a finite resource. It must be used carefully and treated with respect.

Read this if....

You are environmentally concerned

you are interested in Soviet era constrction

you want to know more about the problems of the Central Asia republics

you are interested in large dams

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