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
Salza (Enns) Salza (Enns) The Salza (also Mariazeller Salza) is an eastern tributary of the Enns. It originates on the Traisenberg in Lower Austria and flows South of Mariazell through the Styrian nature preserve of "Wildalpener Salzatal". After 90 km, it meets the Enns near Großreifling. Below the town of Weichselboden is the "Prescenyklause", which was constructed with a weir (a small dam) for a saw mill in 1848. Today the water of the reservoir is used to power a small electric power plant. Downstream from the reservoir, the Salza is a favorite site for kayakers. Many sources and tiny tributaries feed