Nera (Danube) basin and it is not navigable. After the filling of the artificial Lake Đerdap, as a result of the Iron Gate I Hydroelectric Power Station which was finished in 1972, the mouth of the river into the Danube was flooded. In order to allow the optimal electricity production, the water level of the Nera at the mouth should not go below , while it must not exceed it if the flooding of the banks is to be avoided. Since the mid-1990s, there are significant problems in fixing the river's level, as the process is costly and complicated. In 2018, representatives
Lech (river) the Lech valley from Neuschwanstein Castle, near Füssen. Inscriptions from 8/7 B. C. prove that the river name is first mentioned in the Celtic tribe name "Licates". The river itself is called "Likios" or "Likias" in the 2nd century. Around the year 570 the name "Licca" is found in records. In the 8th century, names such as "Lecha" and "Lech" appeared. The term "Licus" is still used in 1059. The name stands in analogy to the Welsh word "llech" ("stone slab") and the Breton word "lec'h" ("gravestone"). In this context, the meaning of the word "Lech" is explained as "the