Developing risk informed dam safety solutions to mitigate vibrating gates

Callide Dam

The Callide Dam is one of two zoned earthfill embankment dams that comprises the Callide Valley Scheme. The scheme, owned and operated by Sunwater, provides water supply to support major industries in the Banana Shire of central Queensland, Australia. This includes mining, beef production, power generation, and cropping.

With the ability to impound up to 136,000 megaliters of water, Callide Dam has a reinforced concrete spillway outfitted with six large steel radial gates. The gates are required to operate relatively infrequently, but during significant storm events, they’ve been known to vibrate significantly during operation, causing structural damage. Our team participated in a site inspection and performed a qualitative risk assessment that followed the hazard, failure mode, control scheme approach outlined in the Australia National Committee on Large Dams (ANCOLD) guidelines on risk assessment. A potential failure modes assessment (PFMA) helped Sunwater to gain a better understanding of the risks associated with the vibrations of the gates and resulted in a risk assessment workshop.

Now complete, our assessment allowed Sunwater to make informed decisions for addressing both short- and long-term mitigation measures, allowing safe operation of the dam during future intense storms.