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
Grisa nera it is grown around the town of Pinerolo in the province of Turin and along the lower reaches of the Susa Valley. A few plantings of Grisa nera can also be found in the province of Cuneo. Throughout Piedmont, the grape is most often found in the field blends in the vineyard and in the winery is often blended with other local Piedmontese wine grapes including Barbera, Neretta Cuneese and Barbera. Over the years, Grisa nera has been known under a variety of synonyms including: Bigia, Grigia, Grisa, Grisa di Cumiana (in Pinerolo) and Uva Bigia. Grisa nera Grisa nera