Weir of Xerta Curiosity · Xerta, Baix Ebre, Tarragona Image of Xerta, not of the place itself. The Assut de Xerta is a dam built diagonally across some 375 metres of the río Ebro, three kilometres upstream from Xerta, whose function is to divert water into the Derecha and Izquierda canals of the Ebro and which gives rise to the Séquia Major irrigation system. Declared a Bien Cultural de Interés Nacional in 2002 (Catalonia's top level of heritage protection), a category later annulled by the Tribunal Supremo, it is today protected as a Bien Cultural de Interés Local (a local-level heritage protection category in Catalonia). Its diagonal layout is unusual, since most such dams run perpendicular to the banks; water that is not diverted is discharged through a large central spillway. Next to the dam stands the mill building, with a plaque from 1575, remodelled until it was used as a power plant in the late 19th century. Photo: Osikerda1 at Catalan Wikipedia (Public domain) What to see and do in Xerta