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
Citizens United to Protect the Maurice River and Its Tributaries, Inc. report by the National Wild and Scenic River Study states that “[t]he study area functions as critical migration-related habitat for shorebirds, songbirds, waterfowl, raptors, rails and fish. The Maurice River and its tributaries drain the Southwest portion of the Pinelands National Reserve, which is also an International Biosphere Reserve under the United Nations Man and Biosphere Program.” The New Jersey Landscape mapping indicates the Maurice River watershed as habitat for bald eagles, waterfowl, and several other migratory birds. In addition, the area contains the world’s largest population of "Aeschynomene virginica", (sensitive joint vetch). Its NatureServ Conservation Status is G2, globally