Name given to a set of 22 rotation watermills built in schist and covered with slate, arranged in a long line and supplied by the legendary “Rego do Boi” (ox waterway). The “Rego do boi” waterway is about 2.5 kilometers long and is fed by the brook of Bustelo; it is one of the first diversions between two river basins, leading the water from the Ardena basin to the basin of the Aguieiras stream. Alvarenga mills career dates from the eighteenth century and is located in the municipality of Arouca, being unique in the country, both by the number of mills, as well as the waterway driving water from one valley to another. The use of cascading for the water flow is a major work of engineering from local people. Currently only two of these mills are in operation, but a good part has undergone restoration work. The verdant parish of Alvarenga owes much to this work since, after serving the mills career, water is used for irrigation.
In the marshes of the Bustelo stream, and around Alvarenga plateau, pastures multiply, being the choice location for the rising of Arouquesa breed cow, resulting in the very famous Alvarenga steak. White-throated dipper nests in small waterfalls of the brook, and the appearance of the gold-striped salamander and the pyrenean desman show the excellent condition of these ecosystems. On the mountain top, granite blocks multiply in a profusion of curious forms and, nearby, on the moist wild lawns, the mountain arnica, the valuable medicinal plant, forms robes of deep yellow. Near the mills career we can observe the beautiful southern scarce swallowtail butterfly and the common toad, followed from above by the common buzzard.
The legend of Rego do Boi
In the middle of the Franqueira mountain borns a river of little memory that passes through the place of Noninha, and continues its course along the place of Bustelo, at the bottom of the lands of this place tradition is, in this land of Alvarenga, that its inhabitants took all the river water in one night, for fear that the inhabitants of Nespereira valley did the job better and sooner, and is called trench of the ox, as they ate an ox on the night that took place. Away from this land of Alvarenga a quarter of league, the aqueduct and its source is almost a league, fertilizes this valley with water, which is what makes it fertile of bread and wine, and the same water at the same time it grinds twenty-three mills, both summer and winter.
The legend of Rego do Boi (ox’s waterway), in archaic Portuguese, from the 1758 “Parish Memoires” from Father Luís Vieira Tristão, an handwritten book.
