The Pyreneean village of Àreu (Alins) has preserved a saw and flour mill formerly powered by the waters of the river. A wheel with vertical blades drove the saw mill, while a horizontal wheel powered the flour mill.

The saw mill was built in the 19th century, but was damaged by flooding. The current saw mill was modernised after the Civil War. Saw mills use water power to saw trunks into planks, beams and boards. The flour mill is driven by a horizontal wheel, and provided the local population with their flour up until the 1960s. Around 1920, an electrical power station was set up in this building. The site shows how hydraulic power was used for two different functions: to mill wheat and to saw timber. Electricity generation was subsequently also added.