Overflow spillway for dams, weirs and similar structures
AssigneeGTM Batiment et Travaux Publics
InventorFrancois Lemperiere
Life of this patent
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Abstract
For the purpose of effecting a quasi-permanent raising of the normal water level of an impounded reservoir and thereby augmenting its storage capacity except during the passage of major floods, the invention consists of installing on the sill of the spillway a water level raising means comprising at least one heavy element, the said means or water level raising elements being capable of resisting the water loads when spilling moderate heads (for discharging the floods of shorter recurrence intervals) by virtue of their own weight but breaching by overturning at a predetermined head corresponding to a level not higher than a predetermined maximum water level in order to discharge larger floods.
Claims16
Overflow spillway for dams and similar structures comprising an overspill sill whose crest is set at a first predetermined level, lower than a second predetermined level corresponding to the maximum reservoir level for which the dam is designed, the difference between the said first and second predetermined levels corresponding to a predetermined maximum discharge of a design flood, and a moveable water level raising means on the sill of the spillway, wherein the water level raising means comprises at least one rigid heavy element resting on the crest of the spillway sill and held in place thereon by gravity, the said element having a predetermined height which is less than the difference between the first and second predetermined levels and which corresponds, for a headwater level substantially equal to the said maximum level, to a mean flood with a smaller predetermined discharge than the predetermined maximum discharge, the said element being of such size and weight that the moment of the forces applied by the headwater on the element comes to equal the moment of the gravity forces tending to maintain the element in place on the sill so that consequently the element is destabilized when the water reaches a third predetermined level higher than the top of the element but not higher than the second predetermined level.
Dependencies are inferred from the claim text.