The Negro River or Black River (Spanish, Río Negro[1]) in Chaco Province, Argentina. It crosses the Chaco National Park and flows southeast. Near its mouth it flows by the cities of Puerto Tirol, Resistencia, and Barranqueras, where it finally reaches Barranqueras River, arm of the Paraná River.
The river has changed it flatlands course several times along the years, leaving wetlands, meanders and lagoons. This took place because of three different factors; frequent draughts, sediments accumulation and human-made deviations of the riverbed. Sections of the river are currently contaminated by industrial waste, mainly from the leather tanning industry.
The Río Negro has historical importance to Resistencia, capital of Chaco Province, since most immigrants that populated Chaco arrived to the city in boats that drove up-river; on February 2 every year, the Festival of the Canoes and Boats is celebrated, remembering the day of the arrival of the first vapour that brought Friulian pioneers to the province.
The river is also used for sports such as rowing, and its importance as a means for commercial transport, once the main connection with the rest of the province, has since been eclipsed by road and rail transport. The river's propensity to floods has been controlled significantly by the construction of a dam near Resistencia.