Council identifies emergency water supply

The Mulgrave River Aquifer has been identified as an emergency water source for the Cairns LGA, but only under extreme drought conditions.

A $2.9 million Emergency Water Supply Plan (EWSP) to safeguard Cairns’ water supply in the event of an extreme drought was today endorsed by the Council’s Works Committee.

The EWSP, which allows for the successful execution of Council’s Drought Response Plan, involves the completion of designs and pre-construction works, in order to implement temporary critical infrastructure should it be required as a result of an extreme water shortage.

A bore field to the south of the Mulgrave River and temporary infrastructure, including associated pipework, packaged water treatment plant and booster pump station are all part of the EWSP, which will provide water supply availability under extreme, short-term drought conditions to the Cairns region between Aloomba and Palm Cove.

Mayor Bob Manning said that while it was unlikely the EWSP would be enacted, Council’s priority was to continue to provide the community with safe and reliable drinking water.

“We are simply getting prepared to ensure the best water source options are available should the need arise,” Cr Manning said.

“The emergency supply will only be needed in extreme or catastrophic drought conditions, which we have not ever yet experienced and this emergency plan will allow Council to move quickly and efficiently should the need arise.

“The EWSP infrastructure will be able to treat approximately 40 megalitres of the Mulgrave Aquifer bore water each day, which can then supply the Cairns network.

“It is important to understand that the work we are undertaking now involves testing, surveying, design and pre-construction, only if water supply levels at Copperlode Falls Dam were to drop below a third of its capacity, which has never happened to date, would Council look to start construction of the necessary infrastructure.”

The trigger levels in Copperlode Dam for the emergency water supply system are:

  • 60% capacity: Issue tender documents for construction of EWSP and booster pump station,
  • 50% per cent capacity: Award contract for construction of ESWP, and
  • 32% per cent: Commence construction of the EWSP infrastructure.

GHD Pty Ltd has been engaged as the engineering consultant to assist with further developing the EWSP.

It is expected Phase 1 of the EWSP will be completed at the end of June 2022.

The EWSP forms part of the Cairns Water Security Strategy (CWSS) which outlines measures to safeguard the city’s future water requirements.

The CWSS was developed and endorsed by the independently chaired Water Security Advisory Group (WSAG) and adopted by Council in 2015.

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