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Reservoir of Valmayor

Colmenarejo, Cuenca del Guadarrama, Madrid

1 Villages · 1 Monuments · 2 Nature · 1 Historical milestones

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Reservoir of Valmayor

Nature · Colmenarejo, Cuenca del Guadarrama, Madrid

The Valmayor reservoir, managed by Canal de Isabel II, is the second largest in the Community of Madrid by stored water, after El Atazar. The dam, closed in 1976 across the río Aulencia with a sixty-metre rockfill structure, the tallest of its kind in Spain at the time, stands within the municipality of Valdemorillo, and the reservoir, which stretches twelve kilometres upstream, also floods parts of El Escorial and Colmenarejo, holding 124.4 cubic hectometres over 755 hectares. The Aulencia, with a much smaller flow than the Guadarrama, was chosen for damming because of the width of its valley, its impermeable granite ground and the absence of population centres in the area; even so, the reservoir receives its largest inflows from the Guadarrama itself.

Photo: Esetena (CC BY 2.5)

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