Abstract: A dam spillway for the passage of water from a forebay to an afterbay comprises a means for compressing the atmospheric air by the passing water and a floatation chamber connected to said means. The floatation chamber incorporates a froth separating cavity having a lower wall thereof in the form of a smooth concave curve. Accommodated in the upper portion of the froth separating cavity substantially above the water level of the afterbay is a froth remover in the form of a tubular member provided with a longitudinal slot facing the interior of the cavity. Secured on the froth remover is an assembly of water sprinkling froth suppressing sprayers adapted to communicate with the forebay. Connected to the upper portion of the froth remover adjacent to the sprayer assembly are perforated air ducts secured at the bottom of the afterbay.

Abstract: A dam spillway to pass water over the crest from a forebay into an afterbay comprises a mixing chamber communicating with a diffuser; said mixing chamber has an intake arrangement ensuring formation downstream of the diffuser of a flotation zone with a froth collector installed at the end thereof; said intake arrangement includes a water flow divider, a water breaking grid and air intake ducts, the divider being installed above the chamber and made in the form of a screen composed of chutes; said water breaking grid of the intake arrangement composed of bluff members is provided in the inlet portion of the chamber, whereas the air intake ducts of said intake arrangement are made in a wall of the mixing chamber below the grid in close proximity thereto.