Wanaka water quality advocates want the Queenstown Lakes District Council to consult more widely about plans to divert stormwater and development sediment through the Wanaka Showgrounds reserve to Roys Bay.

The Queenstown Lakes District Council (QLDC) has applied to itself for non-notified resource consent to build a swale system through the Wanaka Showgrounds.

It also needs a suite of Otago Regional Council (ORC) consents.

ORC’s general manager regulatory and communications, Richard Saunders, said this week the regional council could not comment until the applications had been lodged, processed and decided upon.

QLDC communications spokesman Sam White has clarified a man-made wetland system is not proposed.

Rather than creating a wetland, the project would involve a planted treatment train, which is a series of swales through which stormwater will flow,” Mr White said.

Wanaka Community Board chairman Barry Bruce confirmed last week any decisions would be made by the QLDC and the ORC, not the board.

However, the board would be updated by the council’s project manager Simon Brackstone at a closed workshop on July 26.

Some of the affected parties are Otago Fish and Game and Friends of Bullock Creek.

Mr Bruce said he understood a decision was still to be made whether to open the application to wider community consultation.

Community groups were welcome to make submissions at a public forum before the board’s next meeting, via Zoom, on August 4, he said.

The swales are a retrospective solution for repeated discharges into Bullock Creek from the Alpha Ridge Series subdivision during heavy rainfall.

A run-off pond at the southern end of the Otago Fish and Game wetland on Stone St has overflowed several times into Bullock Creek, discharging sediment into Roys Bay near the Dinosaur Park.

This has prompted complaints to the QLDC and Otago Regional Council.

Mr Bruce said the proposed stormwater diversion would follow a Stone Street paper road through the showgrounds, exit via culvert under Aspiring Rd, join Middle Creek and then discharge into Lake Wanaka at the north end of the swimmer’s buoy line in Roys Bay.

Wanaka Show board chairman Mike Scurr said the show was clarifying the paper road issue with the council because some of the show infrastructure sits on it.

Friends of Bullock Creek president Nancy Latham said the group hoped for wider consultation.

“There is a lot to take in. It is a complex environmental issue, not just engineering. It is important to all the community,” she said.

Freshwater scientist Chris Arbuckle said some groups had things to gain from it, while others would lose.

Issues included the swale design, risks to Middle Creek aquatic environment and swimmable water quality in the lake at the discharge point, he said.

Guardians of Lake Wanaka chairman Don Robertson said he had spoken to council staff and the Friends about the diversion.