A consultant from Otago Regional Council recommended that Dunedin City Council’s request be denied.
A “very high risk to aviation safety” and uncertainty over how much wetland habitat could be affected were highlighted as issues in a report by Ahika Consulting’s senior planner, Hilary Lennox.
The proposed landfill would be near Dunedin Airport, which raised concerns about the potential increased risk of bird strikes from aircraft.
“I am not satisfied that the risk of bird strike has been properly assessed, or that the consent terms proposed by the applicant ensure that the very high risk to aviation safety will be avoided,” Ms Lennox said.
The City Council this month amended its application for the proposed roadway realignment to avoid any direct impact on wetlands by McLaren Gully Rd.
The consent for the city’s Green Island landfill will expire next year and the council has previously said it hopes to start building a new landfill at Smooth Hill in 2024 or 2025.
Public hearings on whether the proposed discharge should be allowed are due to take place next month.
The project has already run into problems, prompting the council to more than halve the scale of the planned facility.
Dunedin City Council chief executive Sandy Graham said the council would address any unresolved issues when it presents new evidence.
“The Otago County Council planner’s report recognizes that, overall, the potential effects of many aspects of the proposed landfill will be adequately managed,” Ms Graham said.
Ms. Lennox was confident that any geotechnical issues at the site could be handled appropriately.
There was uncertainty about the possible effects on surface water and groundwater, but they were likely to be minor in the wider Otokia catchment, the consultant concluded.
The shallow groundwater system was still not well understood, which meant there was uncertainty about the risk of contamination, Ms Lennox said.
She was convinced that all odor problems could be managed.
It was not convinced that adverse effects on ecological values would be avoided, corrected, mitigated, compensated or adequately compensated.
Dunedin International Airport Ltd, the New Zealand Airline Pilots Association and the Otago Aero Club were among the bidders raising aviation safety concerns.
Ms Lennox commented that it was important not to allow bird populations to become established as they were then difficult to control.
Methodologies proposed to control birds included maintaining long grassy areas to block the line of sight of birds and using topsoil as daily cover to reduce the attractiveness of the site to birds.
Certain types of waste could also be sorted before they arrive at the landfill.
The city council’s request was publicly notified in September last year.
Some 283 submissions were received.
Two were in favour, nine were neutral and the rest were in opposition.