Esteras River Nature · Valdemanco del Esteras, Valle de Alcudia, Ciudad Real Image of Valdemanco del Esteras, not of the place itself. The río Esteras, the main watercourse of Valdemanco del Esteras and a tributary of the Zújar within the Guadiana basin, rises in the municipality of Saceruela at the confluence of several streams flowing down from the sierras of Almadén and Saceruela, and runs about 65 kilometres from east to west until it flows into the reservoir of La Serena. Together with its tributary the rivera de Riofrío, it forms part of the Special Area of Conservation Ríos de la cuenca media del Guadiana y laderas vertientes, for its good stands of ash groves and its populations of calandino and pardilla, two fish joined by communities of pez fraile, jarabugo, boga de río and barbo comizo. Its banks, with ash groves, ferns and varied flora, have traditionally sustained local beekeeping. Photo: 19Tarrestnom65 (CC BY-SA 4.0) What to see and do in Valdemanco del Esteras