Abstract: A valve that switches between open and closed states includes a pivoting body having a reservoir, at least one filling port for filling the reservoir and at least one port for draining the reservoir, and a counterweight. The valve further includes a first conduit separate from the body, connected to the filling port, and having a water intake located at a higher position than the filling port, whether the valve is open or closed.

Abstract: An automatic flashboard (10) comprises a wall (12) installed on a hydraulic structure (11) so as to be capable of passing from an erect position in which it retains a mass of water to a lowered position in which it allows the water to pass substantially without obstruction, and at least one elongate retaining member (13) for holding the wall (12) in its erect position against horizontal thrust (P1) from the mass of water (25). The retaining element (13) extends between the wall (12) and a reaction point to which it is connected by a connection (15) that can be automatically eliminated when the water reaches a certain level. The flashboard (10) also includes a massive element (16) movably mounted on the structure (11) and coupled to the mass of water so as to be in a stable state so long as the water remains below a predetermined level (N) and to pass into an unstable state and to be moved when the water reaches the predetermined level (N), the connection (15) being eliminated by the massive element moving.

Abstract: This device for triggering the destruction of a selected portion (1 or 11) of a hydraulic structure such as an embankment dam, dike, or levee built out of erodible material so as to be destroyable by hydraulic erosion is constituted by at least one massive element (5) which is disposed on the top of the selected portion (1, 11) of the structure and which is held there by gravity, the massive element (5) being dimensioned in size and in weight in such a manner as to be expelled by the water when it reaches a predefined level (N), the vertical dimension of the massive element measured beneath said predefined level (N) being selected in such a manner that the nappe which is released after the massive element has been expelled is of a thickness (z) suitable for causing reliable and rapid destruction of the selected portion (1, 11) of the hydraulic structure.