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
Indigirka River Indigirka River The Indigirka River (; ) is a river in the Sakha Republic in Russia between the Yana River and the Kolyma River. It is long. The area of its basin is . The river flows into the Kolyma Bay, East Siberian Sea. It freezes up in October and stays under the ice until May–June. The main tributaries are the: Main ports on the river are: There is a gold prospecting industry in the Indigirka basin. Ust-Nera, a gold-mining center, is the largest settlement on the river. The Indigirka River teems with a variety of fishes. Among the most