Gabčíkovo - Nagymaros Dams

The Gabčíkovo–Nagymaros Dams (more precisely Gabčíkovo–Nagymaros Waterworks, Hungarian: Bős–nagymarosi vízlépcső, Slovak: Sústava vodných diel Gabčíkovo – Nagymaros) is a large barrage project on the Danube. It was initiated by the Budapest Treaty of 16 September 1977 between the Czechoslovak Socialist Republic and the People's Republic of Hungary. The project aimed at preventing catastrophic floods, improving river navigability and producing clean electricity.

Only a part of the project has been finished in Slovakia, under the name Gabčíkovo Dam, because Hungary first suspended then tried to terminate the project due to environmental and economic concerns. Slovakia proceeded with an alternative solution, called "Variant C", which involved diverting the Danube, the border river. These caused a still unresolved international dispute between Slovakia and Hungary. Both parties turned to the International Court of Justice for a ruling.

The joint Hungarian–Czechoslovak project was agreed upon on 16 September 1977 in the "Budapest Treaty". The treaty envisioned a cross-border barrage system between the towns of Gabčíkovo, Czechoslovak Socialist Republic (now Slovak Republic) and Nagymaros, People's Republic of Hungary (now Hungary). The dams would eliminate regular flooding (like the disastrous ones of 1954 and 1965) and provide a clean source of electric power. They would also allow year-long navigability of the river and serve as a part of the Rhine-Main-Danube Canal system of inland navigation.

The plan was to divert part of the river into an artificial canal at Dunakiliti (a village in Hungary) to the hydroelectric power plant near Gabčíkovo (eight turbines, 720 MW). The canal would return the water into a deepened original riverbed and at Nagymaros a smaller dam and power-plant (158 MW) would be constructed. The plant in Gabčíkovo was to be a peak-power plant and the dam in Nagymaros, about 100 km downstream, was to limit fluctuations of the water level.

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