This is an unusual type of mobile gates which can retract below the riverbed level. It has been designed in 1990 – most likely fot the first time – to reconstruct the existing weir on Brembo river of Villa d’Almè hydroelectric plant, located in Bergamo province.
The weir consists of 4 flat gates – each of them characterized by 10 m of span and a height of 1,15 m – supported by hydraulic cylinders which, in the event of floods, lower the gates into a under-river tunnel leaving the relative spans completely free. It allows the undisturbed passage of water and related solid transport during floods.
The gates consist of steel shells filled with concrete in order to ensure – thanks to their own weight – their gravity closing even in the most unfavorable situations.
The weir can assume any position in order to keep the water level constant with respect to different flow rates for the optimal operation of the hydropower plant.