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
Nera Gorge-Beușnița National Park ("Zingel streber"), Balkan loach ("Cobitis elongata"), Kessler's gudgeon ("Gobio kessleri") or Amur bitterling ("Rhodeus sericeus amarus"). Nera Gorge-Beușnița National Park The Nera Gorge-Beușnița National Park () (national park category II IUCN) is a protected area situated in Romania, in Caraş-Severin County. The Natural Park is located at the south-west limit of the country, in the south of the Anina Mountains (group mountain included in Banat Mountains), in Caraș-Severin County, on the middle course of Nera River and on the upper Beu River. Nera Gorge-Beușnița National Park with an area of 36.758 ha was declared natural protected area by the "Law