The Piedra has an irregular flow, due to the long sunny season of the summer months, with often heavy rainfall in the spring and autumn.

The mean discharge at Monasterio de Piedra is 1.22 cubic metres per second (43 cu ft/s).

The place is popular with visitors, for it is a kind of oasis in the surrounding arid and harsh mountainous landscape.

The rivers Mesa, Ortiz and Munebraga also feed the reservoir and may be considered tributaries of the Piedra.

From La Tranquera, the river flows past Carenas and joins the Jalón near Castejón de las Armas and Ateca.