Dam emergency plan to be strengthened

Published: 13 Jun 2018

Communications methods will be re-evaluated as part of a review of Cairns Regional Council’s Emergency Action Plan (EAP) for the city’s major water supply.

An independent report completed by Ironside Risk Partners confirms that flash flooding at Redlynch Valley on 26 March was not caused by overflow from the Copperlode Falls Dam.

However, the report did highlight improvements that could be made to Council’s EAP to ensure best practice response to emergency situations involving the dam.

Key recommendations contained within the report relate to:

  • Improved internal communications protocols;
  • Improved clarity around responsibilities and actions;
  • Inclusion of additional contact details; and
  • Greater involvement by the Local Disaster Management Group in times of EAP activation.

Mayor Bob Manning said the report recognised that Council officers performed well during the recent EAP activation, particularly given the timing of the overnight event.

“But it also tells us there are many areas in which we can improve, particularly in terms of streamlining our communication processes,” he said.

“It points out the significant amount of time it can take to contact all relevant officers, especially when an event occurs in the middle of the night – as this one did – and suggests improved methods to get everyone up to speed quickly.”

There are three progressive stages of escalation relating to an event that triggers the EAP: “Alert”, “Lean Forward” and finally “Stand Up”.

Following heavy rain in the catchment area, the EAP was initially brought to “Alert” at 6.32am on Monday 26 March, when the dam level had reached 1m above the spillway. The level peaked at 1.33m and then began to drop.

Further heavy rainfall that evening resulted in re-activation of the EAP and escalation to “Lean Forward”, as the dam level rose to greater than 2m above the spillway. Further escalation to “Stand Up” was not triggered, as the water level over the spillway did not exceed 3m.

Under the EAP, it is at the point of “Lean Forward” that initial advice is provided to residents to start preparations in case of an increased threat.

On the occasion of this activation, a decision was made not to issue public communications due to the spillway level dropping quickly and the low level of risk to residents.

“In this case, it may have posed more of a safety risk for residents to leave their homes during the middle of the night in heavy rain,” Cr Manning said.

Council will implement all recommendations contained within the independent report as part of a review of the EAP, and consider the scope of events that fall under the plan.

“This plan had been written to deal with a ‘sunny day’ failure – that is an event that would probably have no prior warning and which is capable of causing catastrophic failure, such as an earthquake,” Cr Manning explained. “They tend to be the most unlikely of events, but ones we must prepare for nonetheless.

“Where there is a major rain event, our current relies on the LDMG having already been activated, which – as this event has shown – is not always the case.

“This event was over very quickly and – as the report confirms – the flow from Copperlode Dam and the implementation of the EAP did not have an impact on the outcomes of the flood event.

“But we will take this opportunity to look very seriously at the impacts that a prolonged spillway event could have on areas downstream and make sure our EAP properly reflects that.

“We will be implementing every recommendation put forward by the Ironside report.

“This whole process is about continuous improvement. We must constantly question what we’re doing so that next time we can do it better.”

View the report

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Last updated: 13 June 2018