GATE FOR FREE SPILLWAY WEIRS

A gate is provided with a barrier capable of retaining water with a central barrier wall that is inclined in a direction away from the water, a bottom structure beneath the water that is capable of delimiting by a weir a bottom chamber filled with air and holding the barrier in its water retaining position by the water pressure exercised on said bottom structure, and an inlet extending beyond the retaining level of the barrier with an upper opening that allows water to flood the bottom chamber so as to offset the water pressure on the bottom structure and thereby allow a tipping of the gate, wherein a wall structure forms a wall chamber on the central barrier wall, wherein the wall chamber is capable of being flooded so as to assist the tipping of the gate.