Restoring the Aral Sea

Once the world’s fourth largest freshwater lake, the Aral Sea has shrunk by 90 percent in the last 50 years as a result of unsustainable large-scale irrigation development in the region. Labeled “one of the world’s worst environmental disasters” by UN Secretary General Ban Ki Moon, the depletion of the Aral Sea has devastated the environment, crippled the local economy and today causes severe health threats to local communities.

While it is unlikely that it will ever return to its natural state, the five countries that share the sea should make every effort to replenish the Aral Sea and restore the local environment.

The Aral Sea Basin, which used to be situated entirely within the borders of the Soviet Union, today straddles the Central Asian states of Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan and Uzbekistan. The sea is mainly fed by two rivers, the Amu and the Syr, which originate in the mountain ranges of Kyrgyzstan and Tajikistan to the southeast.

The sea’s dramatic depletion – to a tenth of its original 60,000 square kilometers – can be ascribed to the development of a series of large-scale irrigation projects along the Amu and Syr rivers since the mid-1960s. Diverting water from the middle and lower reaches of the two rivers, these irrigation schemes allowed for intensive cultivation of water-thirsty crops including rice and cotton and a doubling of the region’s irrigated area from 3.9 million hectares in the 1960s to 8.11 million hectares today. Water demand tripled and the flow of the Amu and Syr rivers dropped dramatically. As a result, the Aral Sea rapidly shrunk and the salinity of its water rose sharply, decimating the fish stock. In 1987, the sea was split into two lakes – a larger southern sea situated mainly in Uzbekistan and a smaller northern sea which lies in Kazakhstan. An area of 23,000 square kilometers was totally depleted, exposing the dry seabed.

The near-depletion of the Aral Sea not only had a devastating effect on the local environment and wildlife; it also severely impacted local communities. The Aral Sea Basin has a population of 40 million, with 4 million people living in the ecological disaster zone in Uzbekistan and Kazakhstan.

The local fishing industry collapsed, while agriculture also suffered from the changes to the local environment. Vast stretches of dry seabed were exposed and powerful dust storms spread poisonous sulphate and salt chloride across populated areas, causing significant health problems. The local climate was also severely impacted, with more extreme temperatures and lower rainfall levels.

After several failed attempts to restore the sea in the 1990s – including the collapse of a dam in 1993 – Kazakhstan received World Bank funding in 2003 to restore several hydraulic structures around the lake and build the Kokaral Dam, a concrete dam which separates the two halves of the sea. The $85 million project was completed in 2005 and in 2006 water levels already started to rise. Since then, over a period of just five years, the water level of the Northern Aral Sea has risen from less than 30 meters to 42 meters.

This rise in sea level has revived the fishing industry, producing catches for export as far as Ukraine. The restoration reportedly also gave rise to long-absent rain clouds and possible microclimate changes, bringing tentative hope to the agricultural sector. The port-city of Aralsk which had been 100 kilometers removed from the sea before the construction of the dam, now lies just 35 kilometers from its shores.

Map of the Aral Sea Basin. Source: Philip Micklin, 2007.

The restoration of the Northern Aral Sea demonstrates that the ecological damage to the region can be – at least partially – reversed. However, the restoration of the larger southern part of the sea will prove a greater challenge and therefore requires a more active cooperation between countries in the region. Above all, they must realize that the Aral Sea is a water user in its own right and needs to receive a fixed water allocation like all other regional users.

Dursun Yildiz is a civil engineer and an expert on hydropolitics.

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