The Aral Sea has the particularity to have a relatively low depth compared to its large surface. As water evaporation is proportional to the surface, the lake is somewhat suffering from this surface/depth ration.
One way to fight evaporation is to reduce the water surface while keeping some volume in depth.
The smaller Aral Sea has been isolated with the Kokaral Dam from the Greater Sea in the 90's. The dike was damaged during a storm in 2002 and water was lost to the South Aral Sea. Finally the dam was repaired in 2005.
Today, this lake has recovered: the average depth in the small sea is about 40 m and salinity has decreased enough to reintroduce some local fishing.
Dams are relatively cheap to build and their result is immediate.
The only drawback of such solution in the South is that the most populated area (East) would be sacrificed.
To be continued..