A new system for raising spillway gates

If spillway gates fail to open, a dam may be overtopped and fail, leading to damage and possibly a large loss of life. In recent decades, the majority of dam failures caused by overtopping have resulted from the malfunctioning of spillway gates. Therefore current practice is not as safe as it needs to be. This paper describes an innovative system for lifting spillway gates which offers a substantial improvement in reliability. The gates are lifted by simple, low cost rams instead of the conventional, expensive, tension rams. The extra security is unlikely to increase the overall cost. The new system offers a simple, low cost solution to the problem of modernizing obsolete winch lifting systems.