L´enciena

I thought I´d shown this before but I can´t find it so I probably haven´t. It´s a tide mill. 
It´s a back view of the mill, taken from near Pando on the east side of the valley. 
Visible above the building is the Ría, which is tidal. Visible this side of the building is a lagoon. As the tide rises, it deposits water into the lagoon via the turning gates, and as the tide drops the water flows back into the Ría. In both directions the water turns wheels that drive the mill. At the time of this photo the lagoon is empty for low tide. When the tide is high, the water of the Ría reaches directly to the mill.  There´s a photo showing the mill from the Ría side, at high tide, here:  https://www.flickr.com/photos/don-roger/51237431137/in/photolist-2m4Fec8
I´m unaware (I have looked) of any other tide mill in Asturias, though there is one near Santander, in Cantabria. I also found one on the River Formosa on the eastern Algarve, and I found a record that said it was the only one remaining on the Formosa of a dozen or more. 
Simple and ecological - there should be more.