DISCHARGE OVERFALL FOR WATER EXCEPTIONAL GROWTHS FOR A DAM WITH AT LEAST TWO DISCHARGE OF WATERS DEVICES FOR WATER GROWTHS

In order at less cost to replace particular sluices so as to close off virtually permanently, except during the passage of exceptional floods, all or part of the free spill-over sill (6) of a barrage, the invention provides the arrangement on the sill (6) of the spillway (5) a shutter (10) consisting of at least one solid element (11), said shutter (10) or the shutter elements (11) being made fusible by tilting for a predetermined water load corresponding to a level (N) at most equal to the maximum level (RM) and then allowing the passage of the exceptional floods, smaller floods being discharged by means of another permanent device (7).