Once larger than Lake Huron, the Aral Sea has lost around 93% of its water volume since the 1960s largely due to river diversions for irrigation.
The Aral Sea, once one of the world’s largest inland water bodies, has suffered a dramatic decline over the past six decades, losing around 93% of its water volume due largely to extensive irrigation projects. Its disappearance highlights how human activities can transform an enormous lake within a single generation.
In 1960, the Aral Sea covered approximately 68,000 square kilometres, making it larger than Lake Huron and Lake Michigan by surface area. It was the fourth-largest lake in the world by area, behind the Caspian Sea, Lake Superior and Lake Victoria.
Today, its remaining water bodies cover roughly 8,300 square kilometres, according to the WorldAtlas article. Its water volume has fallen from approximately 1,089 cubic kilometres to around 75 cubic kilometres.
The scale of the loss is linked partly to the lake’s shallow depth. The Aral Sea averaged about 16 metres deep, compared with approximately 19 metres for Lake Erie, the shallowest of North America’s Great Lakes. This meant that large volumes of water could be lost without requiring the lake bed to drop dramatically across its entire surface.
Irrigation projects triggered the decline
The Aral Sea’s decline accelerated during the 1960s, when Soviet irrigation schemes diverted water from the Amu Darya and Syr Darya rivers to support agriculture, particularly cotton production.
The lake depended heavily on these two rivers because it had no natural outlet. As river flows were redirected, less water reached the Aral Sea, causing its surface area and volume to fall rapidly.
By 1998, its surface area had declined by around 60% and its volume by approximately 80%, according to the article. By 2007, the sea had shrunk to roughly 10% of its original size and separated into several distinct water bodies.
The shrinking shoreline exposed vast areas of former seabed, creating the Aralkum Desert. Salt and agricultural chemical residues left behind can be carried by winds into surrounding areas, posing environmental challenges for nearby communities and ecosystems.
Northern Aral shows signs of recovery
Despite the widespread loss, conservation efforts have produced some encouraging results in the northern basin. Kazakhstan built the 13 kilometre Kok Aral Dam in 2005 to retain water from the Syr Darya in the North Aral Sea.
The intervention has helped increase water levels and restore fish populations. The northern basin has deepened and expanded, providing renewed opportunities for fisheries and local livelihoods.
However, the recovery has been limited to the northern section. By retaining more river water in the North Aral Sea the dam also reduces the amount available to flow towards the southern basin.
The South Aral Sea continues to shrink and become increasingly saline. Some sections have dried out completely, while the remaining western basin has experienced a substantial decline in water depth.
The Aral Sea’s fate has raised questions about whether other major lakes could experience similar collapses. However, North America’s Great Lakes have important geographical differences.
Unlike the Aral Sea, the Great Lakes drain towards the Atlantic Ocean through the St. Lawrence River system and receive water from a vast drainage basin. They are also substantially deeper, particularly Lake Superior.
These differences make a comparable collapse less likely under similar circumstances, although the Great Lakes still face other environmental pressures, including climate change, pollution and changing water levels.
The Aral Sea’s transformation remains a stark warning about the consequences of diverting rivers without adequately accounting for the long term health of lakes and surrounding ecosystems. While the North Aral Sea demonstrates that targeted restoration can work, the continuing decline of the southern basin shows how difficult it can be to reverse environmental damage on such a vast scale.