ABSTRACT
The US Army Corps of Engineers has implemented a study to evaluate structural and operational changes that reduce the saturation of total dissolved gases caused by spillway releases into deeply submerged stilling basins. The stepped spillway concept is one of many gas abatement alternatives under consideration. A 1:8 scale physical hydraulic model of a stepped spillway was constructed and tested for it’s ability to dissipate the energy of flow over the length of the spillway chute, thereby reducing the stilling basin depth necessary to force and contain a hydraulic jump. A shallow basin will reduce the hydrostatic pressure acting upon the aerated flow and lessen the potential for supersaturation of the atmospheric gases. Several stepped spillway configurations with slopes of 1:1, 1:2 and 1:3 (vertical:horizontal) were tested. The hydraulic characteristics determined from these experiments and the application of the stepped spillway, as a structural gas abatement alternative, are presented.
