Pontón de la Oliva Dam

Downstream from the El Atazar reservoir, the River Lozoya cuts a limestone gorge in which the Pontón de la Oliva dam was built in the mid-19th century. The Community of Madrid presents it as the first attempt to supply Madrid with quality water from reservoirs. Today it is out of service and is not part of the Canal de Isabel II supply system, but it remains as an ashlar wall between rocks, on the border with Guadalajara, about ten minutes by car from Patones.

What you see

A stone dam wedged between cliffs, with the riverbed at its foot and the landscape of scrub and woodland around. In spring 2026, with the heavy rains of March and April and the releases from El Atazar, it almost filled.

The short stop is an hour: get out of the car, look over the dam and stroll a little along the bank. The Lozoya and Alto Jarama canals, the GR-10 and the Senda del Genaro (GR-300) also pass through this area, and the Sierra Norte tourism website also cites the La Parra dam, the Navarejo one and the Valdentales weir.

The water routes

In October 2025 the Canal de Isabel II and the Community of Madrid opened the Pontón as the first space of their free app 'Rutas del Agua Multimedia', for Android and iOS. It has two signposted routes:

• Linear: 3.5 km, 120 m of ascent and about 2 hours.
• Circular: 8 km, 360 m of ascent and about 3 h 30.

At the dam car park there is an information panel where you can download the app before you start. The app has geolocated maps, audio, video, augmented reality and an offline mode, useful because coverage is poor in the gorge.

With children, the linear one is the one that fits; the circular one needs legs. Take water and hiking footwear, and in summer set out early: the limestone gets very hot. Dogs on a lead.

Getting there

From Madrid, take the A-1 to exit 50, the N-320 towards Torrelaguna and the M-102 to Patones de Abajo. From there continue along the road towards Valdepeñas de la Sierra to the dam, where the car park is. ALSA buses 197 and 197A stop at Patones, and the dam is a few kilometres further on, by road.

What to combine

It combines very well with a walk around Patones de Arriba and lunch in the village, for example at El Rey de Patones or at Las Eras. If you fancy some rock, the walls of Patones de Abajo are a school for beginner climbing. Route information at the Patones tourist office.