Less than 40 km south of San Rafael is the Cañon del Atuel, a magnificent gorge through which flows the Rio Atuel. The river's fast-flowing crystalline waters, particularly popular with white-water rafters, links two man-made reservoirs, the Embalse del Nihuil and the Embalse Valle Grande. Visitors usually head straight for El Nihuil, some 75 km from San Rafael, along the winding Ruta Provincial 144 up the Cuesta de los Terneros from where there are wonderful views of the green valley below before turning off on to the RP-180. 

The Embalse Nihuil is the larger of the two reservoirs and here it’s possible to rent kayaks and windsurfers. The canon itself is collection of colourful and curious rock formations, many of which have been given names by those who often frequent the canon, such as the monsters, the nun, the toad, the lizard and Rivadavia’s chair. Near the northern end of the Valle Grande reservoir is the stretch of the Rio Atuel where white-water rafting trips generally start and there are several companies which offer trips. There are also cabins to rent and campsites alongside the river as well as the upmarket Hotel Valle Grande.