Three authorities are now involved in a consent compliance investigation following last month’s stormwater discharge through the Hikuwai Conservation Area into the Clutha River.
The authorities — the Otago Regional Council, the Queenstown Lakes District Council and the Department of Conservation — and two landowners — Northlake developer Winton Property Ltd, which owns the land where the discharges originate, and Exclusive Developments Ltd, which owns the neighbouring Hikuwai subdivision — are involved.
The Queenstown Lakes District Council owns the stormwater discharge assets.
The system is a permitted activity under local authority rules.
The discharge travelled through Exclusive Developments land, into the reserve, down the Rockabilly Gully track and into the river.
It was caused byheavy rainfall on August 16. Residents took to social media during Covid Alert Level 4 lockdown to decry the erosion.
Wanaka residents Don McKinlay, Alan Cutler and Anna Simmonds complained to the councils.
ORC regulatory manager Richard Saunders said the discharge did not meet the threshold to ask staff to attend in person during Alert Level 4.
However, staff had called the contractor responsible for the earthworks site and had given instructions about appropriate controls.
Mr Saunders said the contractor repaired the sediment control assets and there would be more follow› up by staff once site visits were permitted.
Queenstown Lakes District Council communications spokesman Sam White said two district council teams were working on the case.
A monitoring, enforcement and environmental team was doing compliance work at the Northlake site regarding the erosion and sediment controls.
A property and infrastructure team was working with Northlake to find a stormwater storage solution, Mr White said.
QLDC chief engineer Ulrich Glasner will be leading the investigation over the next four to six weeks.
It will address options to improve discharge quantity and velocity throughout the network, review the suitability of the original stormwater system and look at how future connections to the network are managed.
Other actions would include talking with Doc about managing and mitigating the effects of the discharge, and an on›site meeting with ORC staff.
Department of Conservation senior community ranger Nicole Sutton said Doc was working with the councils regarding track damage and erosion.