Río Ñirihuau

Gazing at the Río Ñirihuau, have you ever wondered about its name? It means “ravine of the ñires” in the Mapuche language, a testament to the trees that grace its banks. The Río Ñirihuau, flowing between Bariloche and Dina Huapi, is more than just a picturesque waterway. It’s a vital part of this region’s history and ecology. The Río Ñirihuau begins its journey in the Cordón del Ñirihuau, nestled within Nahuel Huapi National Park. Until the 1970s, the lower part of the Río Ñirihuau actually formed the park’s boundary. As Bariloche grew, the city limits expanded, eventually encompassing the lower reaches of the Río Ñirihuau, separating it from the park. The Río Ñirihuau played a role in the late 19th-century explorations of the Nahuel Huapi region. Explorers saw the river as a potential route to the Vuriloche Pass. Colonel Liborio Bernal, part of General Conrado Villegas’s campaign, camped for months by the Río Ñirihuau. He was later granted an estancia encompassing the river’s basin. Interestingly, despite becoming governor of Río Negro Territory, he never actually visited his awarded land. Captain Jorge Rohde, exploring from Bernal’s camp, found the river a difficult path towards Vuriloche Pass. The Río Ñirihuau carves a varied path through the landscape. Its upper course flows through a valley, flanked by mountains and forests of lengas, ñires, and cypresses. It initially flows east, then turns northeast. The middle section meanders north across a steppe, interrupted only by a small rocky canyon near the village of Ñirihuau. This part of the river also skirts the eastern side of the Teniente Luis Candelaria International Airport. The final stretch flows northwest through a steppe that’s been significantly altered by human activity, now dotted with pine plantations. A wide, complex alluvial plain marks the river’s final approach into Nahuel Huapi Lake. The Río Ñirihuau holds a special place in the lake’s ecosystem. As the main tributary flowing into the western part of Nahuel Huapi Lake, it attracts salmonids seeking spawning grounds. This has historically made the Río Ñirihuau a popular fishing spot. Sadly, overfishing and increasing human activity along its banks have diminished the size and quality of the catch in recent years. More recently, in the early 2000s, oil was discovered near the lower-middle section of the Río Ñirihuau. The discovery sparked protests from environmental groups concerned about the impact of potential extraction on this ecologically sensitive and touristic area. This isn’t the first time the valley has been eyed for resource extraction. There were past plans to mine coal from a deposit located in the upper Río Ñirihuau valley. The Río Ñirihuau valley is also a treasure trove of geological and paleobotanical information, with valuable discoveries related to the development of Podocarpaceae and Araucaria. One intriguing historical detail: documents about the 1883 Conquest of the Desert refer to the river as Arroyo Reuau.