Innovative automatic spillway gates to provide assurance of operation for dam safety.

Conventional hydro- mechanical spillway gates are mainly operated by electro-mechanical mechanisms usually connected to sophisticated control systems. Since the inception of the Tainter or Radial gates in the early 1900’s, there have been numerous incidences of the gate failures, some with catastrophic consequences to lives and property.

Electro-mechanically operated gates can therefore be a major risk to dam safety. This risk is increased in developing countries where the remoteness of the dams, lack of maintenance, operator unreliability, uncertainty of power supply and backup systems; all add to the risk of gate failure and therefore to dam safety.

However, an innovative self-actuating automatic gate has been developed in South Africa to eliminate the problems associated with electro- mechanical gates. These gates open and close automatically in response to water levels only. They are therefore not reliant on any external mechanisms, or operators, to operate the gates. They can therefore be used with confidence and assurance for dam safety.

This paper presents this type of automatic gate, explains its operation and refers to existing working installations in Southern Africa.