Abstract: An electric power generating arrangement includes a container which is situated below the upper level of a body of water and has an inlet and an outlet. Water from the body of water is admitted into the receiving space bounded by the container through the inlet and drives a turbine, while water is being pumped out of the receiving space through the outlet, preferably by energy derived from the force of wind or by excess electric energy derived from an electric distribution network during off-peak periods. The container can be constituted by walls which completely delimit the receiving space, or may be constituted by a wall which separates a bay or the like from the remainder of a natural body of water. When the receiving space is enclosed from all sides, a venting conduit is provided which admits replenishment air into the receiving space and lets air escape from the receiving space in dependency on the level reached by the quantity of water contained in the container.