ABSTRACT
Up to now the investigations developed about the hydraulics of stepped spillways in RCC dams, are focused in analyzing the flow over an uncontrolled spillway. There isn’t much information about the behavior of gated stepped spillways. For this reason some dams built in RCC are designed with a smooth spillway instead of a stepped one. In this paper the interaction of a Tainter gate controlling the flow over a stepped spillway, is analyzed. For this purpose a scale model of the upper region of a stepped spillway adjusted to a Creager profile controlled by a Tainter gate was built in the laboratory of the Hydraulic, Maritime and Environmental Eng. Dept. of the Universitat Politècnica de Catalunya. The model was operated under Froude similitude criteria. Several scenarios have been tested: the discharge under a partially raised Tainter gate and two emergency situations characterized by the gate overtopping and a combination of flow over and under the gate. In order to make compatible the flow through the Tainter gate (over and/or under) with the hydraulic behavior of a stepped spillway, the stepped channel should begin downstream the ogee profile. The main guidelines about the location of the first step on the chute will be discussed.
