The Mamberamo (Indonesian: Sungai Mamberamo) is the second-longest river on the island of New Guinea, after Sepik River (1,126 km) and the second largest in Oceania by discharge volume after Fly. It is located in the Indonesian province of Papua. It is the second largest river in Indonesia by volume of discharge after Kapuas and also the widest. The river is formed from the confluence of its upper tributaries, the Tariku and Taritatu Rivers in the Lakes Plains region, an interior basin with extensive freshwater swamp forests and grasslands. It flows northwards between the Van Rees Range (Pegunungan Van Rees) and Foja Mountains through a series of rapids and gorges. The last 160 km of the river are navigable. In the coastal lowlands, the river is lined with marshes and forms a broad river delta. The Mamberamo discharges into the Pacific Ocean at the northern point of Point D'Urville or Cape Narwaku (Tanjung Narwaku). The river's huge valley is home to various uncontacted peoples and incredible biodiversity. In the 1990s, the Indonesian Government had plans to construct a large hydroelectric dam on the Mamberamo that would have submerged much of the area. This plan was shelved after the Indonesian financial crisis from 1998 to 1999, but there are concerns by environmental groups that it could be resurrected sometime in the future. At present, the Mamberamo remains the second largest river in the world to be completely unfragmented by dams in its catchment, behind only the relatively nearby Fly. The Mamberamo area also broadly refers to several nearby mountain ranges, including the Van Rees and Foja Mountains (also known as Foya), which were the subject of a recent rapid biological assessment conducted by Conservation International, the Indonesian Institute of Sciences, and Cenderawasih University. The scientific team discovered the first new bird species from New Guinea in 60 years, and a wealth of other new plants and animals. The Foya Mountains appear to be a globally outstanding repository of biodiversity.
