Why did the aral sea dried up

In normal conditions, the Aral Sea gets approximately one fifth of its water supply through rainfall, while the rest is delivered to it by the Amu Darya and Syr Darya rivers.

Evaporation causes the water level to decrease by the same amount that flows into the Sea, making it sustainable as long as inflow is equal to evaporation on average. Therefore the diversion of rivers is at the origin of the imbalance that caused the sea to slowly desiccate over the last 4 decades. Salinity of the rivers varies with place and time, as well as through the seasons.

When going through the desert, rivers often collect some salt compounds residues in the ground that result in higher salinity, but may well be lowered again after going through irrigated lands. At the other side of the same sea as Moynaq, the Kazakh city of Aralsk has undergone a very different fate Credit: Taylor Weidman. At more than 67, sq km 26, sq miles , the Aral Sea was once the fourth-largest freshwater lake in the world.

Water levels dropped and the once abundant populations of bream, carp and other freshwater fish dwindled with them. Today, the sea is a 10th of its original size and has almost split in two.

Mimicking the shape of a splintered number eight, the North Aral Sea — the top half of the body of water — lies in Kazakhstan. The South Aral Sea, which consist of a strip of water in the west and a dried-out basin in the east, sits in Uzbekistan. In the s, both bodies of water seemed headed for similar outcomes.

This included constructing a 12km-long 7. The return of the North Aral Sea has fuelled a revival of the fishing industry in Aralsk. In , the annual fish catch totaled 1, tons, which comprised a majority of flounder — a saltwater species that the Kazakhs dislike. By , the Aralsk Fish Inspection Unit recorded 7, tons of fish as freshwater species have returned, including pike-perch — which bring in a hefty price for local fishermen — breams, asp, and catfish.

For Aldanbek Kerinov, the return of the fisheries in the North Aral Sea has allowed him to change careers. Now the year-old works with his two brothers out on the lake. In sub-zero weather in February, they retrieved about 20kg 44lb of pike-perch from their nets submerged under the frozen surface of the Aral Sea. We prefer to catch even just one pike perch instead of driving a taxi.

Kerinov was too young to have seen the seawater lapping against the port walls of Aralsk. As the Aral Sea has dried up, fisheries and the communities that depended on them collapsed. The increasingly salty water became polluted with fertilizer and pesticides. The blowing dust from the exposed lakebed, contaminated with agricultural chemicals, became a public health hazard. The salty dust blew off the lakebed and settled onto fields, degrading the soil. Croplands had to be flushed with larger and larger volumes of river water.

The loss of the moderating influence of such a large body of water made winters colder and summers hotter and drier. Malik feels that considerable progress has been achieved. The seeds of the Aral Sea basin water crisis were planted in when the Soviet Union picked Central Asia to serve as its cotton supplier. Though cotton had been grown in Central Asia before, the scale and intensity of the Soviet plan were unique, and the Aral Sea's feeder rivers - Syr Darya and Amu Darya - were harnessed to provide the vast amounts of water needed to float this project.

By - just over 20 years later - Central Asia's production quotas reached 9 million tonnes, making it the world's fourth largest producer of cotton. But the Aral Sea paid the price for this success. As its volume precipitously dropped, the Aral's waters turned toxic for fish and wildlife - not to mention human - populations that depended on them. The soil around the sea has become more saline as well. In order to prepare fields for cultivation, which are mostly desert lands, farmers must first leach or rinse them, which brings salty minerals to the surface.

Moreover, as a result of the increased soil salinity, cotton harvests began to diminish. Aksoltan Ataeva, Turkmenistan's Permanent Representative to the United Nations, describes the sea change that took place. The United Nations has sought to address both the causes and the effects of the crisis in the Aral Sea basin, and primary among the approaches is water management.

As long as humans have lived in Central Asia, dry air and water scarcity have been simple facts of life. Traditionally, mirabs, or water masters, controlled the water resources in Central Asia and ensured that water allocations corresponded to farmers' needs. Reflected in a local proverb is the reverence with which water was once regarded: "In every drop of water there is a grain of gold.

By installing a centralized bureaucracy in Moscow, the Soviet Union successfully broke the power of the mirabs in the region. But, at the same time, it suppressed a sense of accountability for water use at the local level.

As a result, farmers developed wasteful practices which became entrenched throughout the region. Irrigation canals were rarely lined or covered, leading to massive water loss through evaporation and filtration. Turkmenistan's Kara Kum Canal, for example, flows for 1, kilometers over loose sands.

Overall, irrigation efficiency is estimated to be no more than 40 to 50 per cent, according to a UNDP background report.

Moreover, upstream farmers commonly allowed fertilizer run-off into the rivers with little thought or understanding as to its effects on their downstream neighbours. And instead of nurturing depleted soil back to life with crop rotation, they simply moved on to vacant, however marginal, lands.

These patterns, followed by thousands of farmers over nearly three decades, culminated in the full-blown environmental catastrophe that today affects the entire Aral Sea basin. Soviet scientists understood that the massive water withdrawals needed to sustain their cotton "king" would cause the Aral Sea level to plummet, but they believed that a hard crust would form over the exposed seabed salts and minimize health and environmental fallout.

They were wrong. In fact, toxic salts and minerals, including sodium chloride, sodium sulfate and magnesium chloride, now constitute the greatest danger from the Aral Sea catastrophe. Because of air blown salts, Mrs.