Callide Dam – FAQ

Callide Dam Gates Project

Callide Dam, Biloela, Queensland

This maintenance project has been set up to investigate, repair and restore Callide Dam’s gates to address intermittent occurrences of vibration during their operation. This project will ensure ongoing dam safety and long-term water security.

Frequently Asked Questions

What was the issue with Callide Dam’s spillway gates?

Callide Dam’s six large spillway gates, which were installed in 1988, have only been required to operate on seven occasions.

The gates are an integral part of the Callide Dam operating system and allow flows from upstream to pass through the dam. The gates operate this way to protect the integrity of the dam structure from water rising above the full supply level and to maximise the amount of water stored in the dam.

During three of these occasions, Sunwater had observed vibrations of the spillway gates which could lead to operational issues with the gates. Sunwater then undertook the Callide Dam Gates Project to investigate and remediate the gates.

What did Sunwater do to fix the issue?

Sunwater completed on-site works at Callide Dam which included strengthening of each gate structure at key locations, an upgrade to the manual gate control system and the replacement of gate seals.

Works in 2022 included thorough investigations and testing to confirm that further mechanisms to control vibration were not required and the vibration risk of Callide Dam’s spillway gates is within an acceptable range, meeting industry standards.

Is Sunwater confident that the vibration issue is resolved?

Rigorous and robust investigations were conducted. Sunwater is confident that through the works undertaken, the likelihood of a gate vibration has been significantly reduced and any potential gate vibrations are low risk. The upgrade of a manual control system enabled Sunwater to increase control of gate operations, allowing override of the automated system to raise and lower the gates as required.

Is the dam now safe?

Callide Dam remains safe and will be operated in line with an amended Emergency Action Plan (EAP).

When will you return the dam to its pre-project level?

Sunwater has finalised all documentation as part of the Callide Dam Gates Project to return the dam to its pre-project full supply level.

A Section 399B notice has been submitted to the Dam Safety Regulator to operate Callide Dam at the pre-project level. Amendments to the Operations Manual and Emergency Action Plan (EAP) to reflect changes to the gate control system have also been completed.

There was no change to flood operation trigger levels or to downstream resident messaging as part of the EAP update.

The updated Callide Dam EAP can be found on the Emergency Management page of Sunwater’s website, here.

Will the dam be operated differently now that the project is complete?

Sunwater submitted an amended EAP to the Dam Safety Regulator after consultation with the Banana Shire Local Disaster Management Group. This amendment reflected changes to gate sequences due to the installation of the manual control system.

The majority of the EAP will remain the same, including the point at which the gates are operated depending on storage level, and early minor water releases to provide a visual warning to downstream residents.

How much did the project cost?

The Callide Dam Gates Project cost $13 million which will be paid for by Callide Valley Water Supply Scheme customer annuities, in line with maintenance works carried out across our water supply schemes.