Reservoir of Guístolas Nature · San Xoán de Río, Terra de Trives, Ourense Image of San Xoán de Río, not of the place itself. A reservoir laid out over the río Navea, with some thirty-seven hectares of water surface set among slopes of scrub and chestnut soutos; its banks are one of the quietest corners of the concello. Photo: Cristina Penin (CC BY-SA 3.0) What to see and do in San Xoán de Río