Caniçada dam complementary spillway. Design, hydraulic model and ongoing works

Abstract

In order to meet the updated requirements of the Portuguese Dam Safety Legislation, Caniçada dam (double-curvature arch dam, concluded in 1955 and located in the Cávado River) hydraulicoperational safety assessment has been developed by EDP, including the review of the design flood and the evaluation of safety devices capacity. Thereafter some corrective measures were implemented, including the construction of a new complementary spillway. The paper summarizes the main features of the new spillway design, developed by AQUALOGUS. The selected solution is a gate-controlled ogee crest, followed by a 200 m long tunnel scoped in the slope of the left bank, designed for a discharge of 2062 m3/s. The hydraulic performance of the designed structure was analysed by a study developed on a hydraulic physical model, built at LNEC on a scale of 1/62. Results and conclusions that allowed improving the design structure shapes are described, with particular emphasis on the use of the reduced physical model. Some aspects of interesting and nowadays challenging ongoing works of this new spillway are also presented.