Roman Dam of Belas

Antiga Barragem Romana de Belas is a Roman water structure at Mina de Água near Belas. The dam stands roughly 8 meters high, is supported by three large buttresses, and spans about 15.5 meters across the Carenque stream.

The structure was built in the 3rd century and was part of a water supply system for ancient Olisipo, now Lisbon. It was one of several projects that helped Romans establish reliable water delivery across greater distances.

The site shows Roman building methods with carefully cut stones laid in regular patterns. This type of stonework was typical for Roman water structures and demonstrates the skills of builders from that era.

The ruins lie between National Road 250 and a wooded area. Visitors should expect vegetation that partially covers the view of the old structure.

The structure used opus incertum, a Roman technique with irregularly shaped stones bonded with a special mortar made from brown lime and fine sand. This mixture helped the structure resist water over long periods.