Sunshine Coast Council has successfully managed the ponded water at the Airport Expansion project site, largely through treatment and reuse on-site.
As a result, Council will not be releasing the ponded water to the ocean.
At its peak, it was estimated that 325 megalitres of rainwater had accumulated at the site, equivalent to 130 Olympic swimming pools.
Council worked closely with the Queensland Department of Environment and Science (DES) and qualified environmental specialists, to ensure the water would be removed in an environmentally responsible manner.
Deputy Mayor Tim Dwyer said Council had always pursued a number of options for the release of the ponded water, with the prevailing dry conditions having enabled Council to remove a large volume of water through a combination of actions, over several months.
“In October 2019, Council proceeded with the option to install a Water Treatment Plant on-site,” Cr Dwyer said.
“The plant processed around six megalitres of water per week, and the treated water was used to suppress dust, and for compaction around the site.
“Due to the dry conditions, evaporation has also significantly contributed to reducing the volume of water on site.
“As Council needed to ensure all viable options remained available if needed, we proceeded to seek approval to construct a temporary pipeline, to allow the water to be released into the ocean in a controlled manner – but this will now not proceed.
“If heavy rainfall had occurred, the pipeline would have been necessary to prevent uncontrolled releases of fresh water into the Maroochy River estuarine environment.
“As Council has always advised our community, it was responsible and prudent to start mobilising a range of solutions, to manage the ponded water on-site.
“As the water has been substantially reduced via other means, the proposed pipeline is now no longer needed.
“Works have now occurred to enable the site to return to a self-draining area as it has always been, thus preventing further rainwater accumulation.”
Council initially estimated the pipeline would cost approximately $2.5 million to construct. As it has not been necessary to progress beyond Development Approval, the actual cost was less than $50,000.
The water accumulated on the construction site earlier this year when above average rainfall was received and was unable to drain away, due to bunding installed to comply with the conditions of the Airport Expansion’s environmental approval.
The bunding was in place to prevent ocean water entering the adjacent national park, when sand was pumped in for the new runway. As sand dredging and filling is now complete, the bunding is no longer required.