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
Enns (river) In total, ten power plants, with a total generative power of 345 megawatts, have been built by the "Ennskraftwerke AG". Currently, there are 15 hydroelectric power stations on the Enns. The power stations are listed beginning at the headwaters: The most important inflows are the Palten, the Salza and the Steyr (river). A major transit route connecting Germany and Slovenia through Austria runs through the Enns valley. The so-called "Eisenstraße" ("iron road") runs along the river between Hieflau and Enns, along which iron ore has been transported from the Styrian Erzberg ("ore mountain") to the steel mill in Linz. Enns