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
Pollera nera Corlaga, Corlage, Palera, Polera, Pollara nera and Pollora Nera. Pollera nera Pollera nera is a red Italian wine grape variety that is grown primarily in the Liguria wine region and northwest Tuscany. Ampelographers believe that the vine has a very long winemaking history but it is rarely seen today. It is believed to have been descendent from the Chianti wine grape Mammolo and the Corsican wine grape Sciacarello which would make it a half-sibling of Colombana nera. Pollera nera is a permitted variety in the "Denominazione di origine controllata" (DOC) wines of Colli di Luni that spans across the border