The Eiras reservoir and the Oitavén river Nature · Fornelos de Montes, Vigo, Pontevedra Image of Fornelos de Montes, not of the place itself. The reservoir that supplies Vigo lies beneath the summits of the Serra do Suído, which exceed a thousand metres. The Oitavén and its tributaries preserve upstream alder groves and very well structured riverside woods. Photo: Gabriel González from Valongo-Cotobade, España (CC BY-SA 2.0) What to see and do in Fornelos de Montes