The River Llobregat, the backbone of Catalan industrialisation during the 19th century, now provides the basis for a study of water as a source of energy, in the specific case of the Vidal Colony in Puig-Reig. Meanwhile, the river, which over just one hundred and fifty kilometres changes from an Alpine ecosystem (at the source) to a delta of wetlands and crops (at the mouth), can also be studied from the environmental perspective, in this case focusing on the upper and middle courses in the 19th century.