Two major dams have been constructed on the Black Drin in the former Yugoslav Republic of Macedonia. In Neretva andTrebisnjica hydro-geological basin, hydroelectric production infrastructure includes dams and underground channels for the transfer of water, including one that transfers water across the border between Bosnia and Herzegovina and Croatia, to the Dubrovnik hydropower plant. There arc a number of dams in the Bulgarian part of the Maritsa/ Evros/Meris River Basin, and as many as 722 reservoirs. As far as the Sava River Basin is concerned, there are 21 dams with a reservoir capacity of over 5 million m5. Five of them have a reservoir capacity between 161 million m3 and 340 million m3 (the highest (131 m) dam in Serbia, in the Drina sub-basin, has a reservoir with a capacity of 170 million m3). In addition to altering the character of the aquatic and riparian habitats, resulting from reduced sediment transport capacity — as was reported among the main effects of the construction of Iron Gates 1 and U reservoirs — related sediment deposition has induced the gradual increase of high water levels upstream, reducing the safety of the existing flood protection system.