Cr Jim O’Malley said at a council meeting yesterday leaving the Kettle Park area in St Clair as it appeared now did not seem to be a viable long-term option.
He suggested at least some of the landfill material would need to be removed before erosion exposed it and asked if removing part of it could happen at the same time as further investigations.
The council’s infrastructure services general manager, Simon Drew, confirmed this was a possibility.
Extraction of landfill material had been flagged by the city council as one approach it may have to pursue in the long term.
A study by Tonkin + Taylor showed the landfill area beneath sports fields was closer to the sea than had been thought.
Cr Kevin Gilbert asked if this created a more urgent need for action.
Council transport delivery manager Ben Hogan said there would be some targeted investigations at the dune face.
The park area was used as a landfill from about 1900 until the 1950s, before it was capped and covered by turf.
Storms in the past 10-15 years have exacerbated erosion of the nearby beach and dunes.
Tonkin + Taylor test results from bore holes indicated metals such as copper and zinc in the old landfill were at a concentration that made leachability a risk for class-A landfills if the material was to be shifted to one.
Some treatment would be needed, such as mixing it with other material.
The council was told Dunedin had the capacity to perform such pre-treatment.
Both Dunedin Mayor Jules Radich and Cr Brent Weatherall indicated reinstating a groyne at St Clair Beach might help the situation.
"It’s imperative we throw the book at sand retention measures along our coast line," Cr Weatherall said.
Mr Radich also said it was reassuring nothing in the report seemed to show the tide was moving through the old landfill.
