How did irrigation and reservoirs reduce the amount of water reaching the Sea of Azov from the Don River?

The construction of large-scale engineering projects in the Don River basin has significantly reduced the volume of water reaching the Sea of Azov. This reduction is primarily attributed to two factors:

• Water Diversion for Irrigation: Since the early 1950s, the creation of the Tsimlyansk Reservoir and an extensive network of smaller ponds facilitated a massive expansion of irrigation. The area under irrigation in the basin grew from approximately 124,000 acres in 1950 to nearly 2.5 million acres by 1980, diverting substantial quantities of water away from the river's natural flow.1
• Evaporation: The creation of numerous artificial reservoirs, including the massive Tsimlyansk Reservoir, has increased the surface area of water exposed to the atmosphere, leading to significant water loss through evaporation.1

By 1975, these alterations had reduced the river's discharge at its mouth by an estimated 20 percent compared to 1950 levels. This decrease has caused the salinity of the Sea of Azov to rise considerably, which has negatively impacted the sea's biological productivity and lowered fish catches.1