Archives for July 12, 2006

The following comments by Australian forester Frank McKinnell are based on three visits to the Aral Sea region between 2004 and 2006, including trips out onto the Dry Aral Seabed (DAS) on both the Kazakhstan and Uzbekistan sides of the border:

“The Dry Aral Sea (DRA) is one of two serious environmental problems that Kazakhstan inherited from the former Soviet Union, the other being the Polygon nuclear test site, near the city of Semey, where about 600 nuclear weapons were set off.

The Aral Sea lies roughly half and half in Kazakhstan and Uzbekistan, and in a region of largely flat topography, covered by shrubby steppe vegetation. At the present time (2006) it is about half the area it was in 1960 and the rate of drying up is continuing, at least in the southern portion. In some places the edge of the Sea is said to now be 200 km away from where it was in 1960. One can go to what were formerly seaside fishing villages and see marooned ex-fishing boats many kilometres out of sight of the water.

The Aral is fed by two major rivers, the Amur Darya (formerly known as the Oxus) and the Syr Darya. Since 1960 the rate of inflow into the Aral has been greatly reduced by diversion of the water into a series of ill-conceived irrigation schemes in Uzbekistan and Kazakhstan.

The irrigation schemes were ill-conceived in two ways:

• Part of the irrigated area was located on land that had a saline subsoil, with the inevitable consequence that groundwater tables rose, the salt rose to the surface, and the surface soil became saline. This is now largely wasteland.
• The main crops grown on the irrigated land were cotton and rice, and both had disastrous effects. The rice cultivation required huge volumes of water, which had adverse effects on the river flow, and exacerbated the rise of the groundwater. The cotton required heavy applications of insecticide, some of which washed out in the irrigation tailwater and ended up in the Aral Sea. When the Sea dried up, the chemicals remained in the sediments and were subsequently blown about in duststorms. This is widely believed to have had adverse effects on the health of people living downwind of the Sea, although definitive scientific studies to demonstrate this are so far lacking. People living in the region that I spoke with are emphatic that the incidence and severity of duststorms has greatly increased as the Sea dried up and that their health problems have become worse.

Despite the land management problems, large scale irrigated agriculture continues, for economic and social reasons.

As the sea retreated, it exposed a large area, now some 4 million ha, of flat or slightly undulating land. In some places it is mobile sand dunes, and in others it is heavier textured silty soils. There is a large area of the solonchak soil type, which is particularly difficult to work with, being both alkaline and saline. The salts in this case are both sodium chloride and sodium carbonate.

Figure 1. Newly exposed seabed

Figure 2. After a time sand dunes develop, but the depressions usually have solonchak soils.

The prospects for improving the condition of the DAS are severely limited by the extreme climate of the region. The annual rainfall is about 300mm and the climate is an extreme continental type, with temperatures falling to as low as -40ºC in winter and rising to +40ºC in midsummer. Furthermore, the wind strengths are very high, and make working out in the open almost impossible in the late afternoon, especially in winter.

The DAS does develop a vegetative cover naturally, starting with salt tolerant plants such as Salicornia, but the process is slow. The soils are quite variable and some types are very difficult to vegetate. Nevertheless some research in the early 1980s indicated that it was possible to speed up the rate of revegetation and achieve a more diverse plant assembly.

Figure 3. Natural revegetation.

The duststorms have been recognised as a problem for many years. In an effort to reduce their effect, a revegetation program was commenced in the 1980s, but this ceased, due to lack of funds, after the breakup of the Soviet Union in 1990. In the last 5 years, an aid project funded by Germany has been working on revegetation of the DAS on the Uzbek side of the border. The World Bank and the Government of Kazakhstan are jointly developing a similar project on the Kazakh side.

There are two possible approaches to the addressing the environmental issues arising from the DAS: try to refill the Sea again, and develop a vegetative cover on the exposed sea bed and so reduce the amount of dust transported by wind. Both avenues are currently being tackled. I should add that there is now a good deal of cooperation between Kazakhstan and Uzbekistan on this issue. While the level of cooperation might not yet be ideal, it does exist and is improving.

1. Refilling the Sea
In Kazakhstan, a EU-funded project is promoting more efficient use of irrigation water and supporting river bed improvement schemes that will increase the flow into the northern Aral. Similar work is under way in the irrigation areas fed by the Amur Darya in Uzbekistan, although the emphasis there seems to be more on changing cropping away from water-hungry rice to more water-efficient crops.

An overall review of the prospects for the Aral has found that there is no chance whatever of refilling the entire Sea in the foreseeable future. However, there is a good chance of partially recovering the northern section of the Aral, if the inflow from the Syr Darya is prevented from moving into the southern section. It has been decided that, on balance, a partially recovered North Aral is better than a devastated whole Aral. To this end, a dam is being constructed across a narrow neck of the Aral west of the town of Kazalinsk. I have not seen this dam myself, but have been told that the dam will raise the level of the northern Aral by about 12 metres. If so, a large part of the northern section will be restored, although salinity will probably be higher than in the Aral before 1960. In April 2006, people at Aralsk told me that the northern Aral had started to rise again.

2. Developing a Vegetative Cover on the DAS
The philosophy lying behind active programs to develop vegetative cover is basically that, left to itself, nature will do the job, but not very well and it will take an inconveniently long time about it. Therefore, some assistance to the process is justified. Research in the mid 1980s was able to develop methods of establishment of salt tolerant species on some of the soil types. This research has been continued by the German GTZ project in Uzbekistan and is intended to be a major part of the new project in Kazakhstan.

Figure 4. Research trial of saxaul (Haloxylon sp) about 6 years old. The need for a variety of other species for revegetation is apparent.

The idea of the revegetation programs is to hasten the rehabilitation process, which will bring about relatively rapid environmental benefits for the region, and also produce a more diverse ecosystem.

The long term use of the DAS has not been decided, but the thinking in Kazakhstan at the present time seems to lean towards making the area some sort of nature reserve. This would certainly provide the best protection for the soil, and so minimise the dust problem, but it will require attention to be given to control of wildfire, so that the soil is not bared once again. A wildfire problem on a former sea bed must be a unique situation!”

Thanks Frank McKinnell for sharing this information with us.