South Aral Sea

The South Aral Sea is a large lake located in the basin of the former Aral Sea. It formed in 1987 when the original sea divided into two separate parts. This division occurred because water from incoming rivers was diverted for agricultural use. This change has transformed the landscape and the environment of the region. Today, the area is a complex system of changing water levels and salt concentrations. Understanding this lake helps us see how human decisions impact massive natural water bodies.

The shrinking of the Aral Sea began in the 1960s. During this time, the Soviet Union decided to divert two major rivers. These rivers are the Amu Darya and the Syr Darya. The water was moved to irrigate cotton and various food crops. These crops were grown in the countries of Kazakhstan and Uzbekistan. This diversion caused an accelerated loss of water within the sea. By 1987, the loss of water was so great that the Aral Sea split. This split created a northern part, known as the North Aral Sea, and a southern part.

In 2003, the South Aral Sea underwent further division. It split into two distinct basins: the Eastern Sea and the West Aral Sea. A narrow channel connected these two basins. This channel sat at an elevation of 29 meters. The channel helped to balance the surface water levels between the two sides. However, the channel did not allow the waters to mix together. Because they did not mix, the salt levels in each basin began to change differently.

Salinity, or the amount of salt in the water, became a major factor in these basins. In 2007, the western basin had a salinity of 70 g/L. In the same year, the eastern basin was much saltier at 100 g/L. If the water level drops below the 29-meter channel, these salinity levels diverge even more. The eastern basin may occasionally receive water from the Amu Darya during wet years. This can cause flooding in an area of up to 4500 km2. Such flooding reaches a depth of about one meter and stops economic activity. Meanwhile, the western basin continues to become increasingly saline.

The history of the Eastern Sea is one of extreme changes. In 2008, the Eastern Sea split once again. By May 2009, it had almost completely dried out. This left only a small permanent body of water called Barsakelmes Lake. This lake sits between the Northern and Western Seas. The drying of the sea also increased the expanse of the Aralkum desert. The Eastern Sea did receive some water from snow melt in the spring of 2010. However, it often alternates between being completely dry and occasionally flooding.

Efforts to manage the water have led to significant structural changes. In 2005, a dam was built to protect the North Aral Sea. This dam was meant to prevent the collapse of its fisheries. However, the dam also cut off the only remaining inflow to the southern lakes. In 2010, a second dike was started to reduce certain types of flooding. The West Aral Sea is expected to stabilize at a certain level. This stability depends on groundwater discharge at a rate of 1 km3 per year. The West Aral Sea currently has a mean depth of 10 meters.

The West Aral Sea continues to change its shape today. In 2015, the western part began to split into two separate sections. This happened because the channel connecting the central part to the north-eastern part grew skinnier. By 2018, this split was entirely complete. The West Aral Sea still receives some replenishment from groundwater in the northwest. This process shows how a large body of water can fragment over time. The shifting levels and salt concentrations continue to define this changing environment.