However, by the time the airport company sent a strongly worded legal letter demanding "immediate steps" be taken, the council’s decision to directly discharge treated effluent into the Shotover River was already six days old.
The escalation in pressure over the course of the summer finally bore fruit after a quarterly meeting between Mayor Glyn Lewers, council chief executive Mike Theelen, and the airport company’s chairman and chief executive on March 19.
After that meeting, Mr Theelen decided the council could invoke emergency provisions under the Resource Management Act (RMA) to enable direct discharge.
The broken disposal field could be taken offline, and the continuous overspilling of treated wastewater into the Shotover delta that was causing the council to breach its resource consent for the field could be stopped.
Councillors were told of the plan at a confidential briefing the following day.
Although an apparent formality, the March 25 letter clearly sets out the Queenstown Airport Corporation’s (QAC) position on the ponding issue.
Its monitoring showed the ponding was "attracting birds that are hazardous to aircraft operations, and has brought bird activity closer to the airport’s runway".
"The potential impacts of a bird strike event are significant, including loss of life."
"While QAC wishes to continue to work collaboratively with QLDC on this matter, if QLDC fails to act in a timely manner, QAC reserves the right to take such steps as necessary to address the effects, and will seek to recover its costs from QLDC in doing so."
The "mostly likely" option for addressing the issue was putting netting over the disposal field, but that would take several months, it says.
In a media statement, QAC chief operating officer Todd Grace said one of its managers first discussed its concerns about the ponding with a council senior manager on November 28.
The issue was raised again in a phone call the following month.
"Over the summer, it became evident the issue of the ponding water at the wastewater treatment plant disposal field was not temporary.
"It was also observed that an increasing number of birds were resident across the ponds and disposal field."
The need for "urgent action" was then discussed at a meeting between airport and council management on February 13.
The council publicly confirmed its direct discharge plan on March 26.
Discharge into the river began five days later.
