Dnieper reservoir cascade

The Dnieper reservoir cascade (Ukrainian: Дніпровський каскад гідроелектростанцій, romanized: Dniprovsʹkyy kaskad hidroelektrostantsiy) is a series of dams, reservoirs and hydroelectric power stations (HPPs) on the Dnieper in Ukraine. The first HPP on the Dnieper was built at Zaporizhzhia in the 1920s. It was created to prevent uncontrolled flooding, and improve water transportation infrastructure. In 2018, the reservoirs stored approximately 70% of Ukraine's fresh water resources. Water is used to cool nuclear power stations, in transport, for fisheries, by industrial and urban centres for numerous purposes, and to irrigate farmland. The cascade’s 900-kilometre-long (560 mi) shipping lane provides a navigation route from Kyiv to the Black Sea.

The first HPP provided energy for the armaments industries of southern Ukraine. In 1941, NKVD agents blew up the Dnieper Reservoir dam, supposedly in an attempt to hinder the German advance across Ukraine. The resulting explosion killed thousands of civilians and Red Army troops. It was rebuilt in 1947, and over the next two decades, three new HPPs were built. After Russian armed forces took control of the Kakhovka Dam at the start of the Russo-Ukrainian war, Ukrainian troops fortified the five other dams. On 6 June 2023, the Kakhovka Dam was breached; the reservoir has since drained away.

As a result of the construction of the reservoirs in the Dnieper cascade, many of the features of the river were permanently transformed, causing severe disruption to the hydrology of the Dnieper basin. Pollution levels worsened in the 1990s and there has been little improvement to the cascade since, in part as a result of mismanagement of the issue by the Ukrainian government, a situation that has attracted international criticism. The geoecological state of the cascade has been degraded by ecological and manmade causes (radioactive and chemical pollution, eutrophication, the increased risk of flooding, erosion, abrasion of the banks, silt accumulation, the increase of karst processes, Increased evaporation, and waste from farmland). Many fish species have been adversely affected, and measures to re-establish fish populations have not been successfully implemented.