The Queenstown Lakes District Council has been hit with a $24,000 fine for discharging sewage and polluting Lake Wakatipu.
Council contractor Veolia became aware that a developer had allegedly illegally connected to the QLDC's wastewater network in March 2017.
The developer was ordered to place concrete over the connection until it was approved and Veolia later flushed the main pipe in Loop Rd, in Kelvin Heights, releasing debris and freeing the flow of the pipe.
Routine maintenance and inspections before the developer's alleged connection to the network found no issues with the pipes.
The leak came to light when a resident reported a discharge from a manhole in the pipeline on August 3, 2017, which flowed over a popular cycleway-walkway and into the lake.
The QLDC pleaded guilty to the charge after being taken to court by the Otago Regional Council and was sentenced in the Queenstown District Court yesterday.
Speaking at the hearing, ORC prosecutor Nathan Laws said the trail had ``less capacity to absorb and deal with a discharge''.
"Lake Wakatipu is a sensitive receiving environment. There have been some decreases [in water quality] in recent times.''
Veolia cleared the blockage in the sewer pipeline within about two hours of the discharge being reported. The total amount leaked into the lake was believed to have been 912 litres.
The affected area of water failed to meet safe recreational use standards following the leak.
The area was cleaned and disinfected the same day the leak was reported. The full duration of the discharge was unknown.
The QLDC was fined $24,000 and court costs of almost $590.
Judge Brian Dwyer said the offence resulted in a ``small discharge'' that was not deliberate.
"As this particular discharge was into Lake Wakatipu it added an aggravating factor to the offence.
"There was a prompt and effective response on its [QLDC] part when the offence was brought to notice.''
He said the fact the lake was one of the country's ``iconic'' bodies of water factored into his decision on the fine amount.
He recently made a decision on a similar case, fining the Whanganui District Council $21,000 for its part in polluting the Mowhanau Stream in 2017.
The QLDC has previously received four infringement notices and one conviction for wastewater discharge, when it was fined $37,500 for leaking raw sewage into the Kawarau River in February 2017.
Its conviction yesterday came just weeks after signs were placed around the beach at Queenstown Bay warning swimmers of increased E. coli levels in the lake.
The area was declared safe for swimmers the day after the signs were installed, on January 6, once further tests found bacteria levels had subsided.
Judge Dwyer said it was "pretty sad'' to see such findings in the usually pristine waters of Queenstown.
ORC chief executive Sarah Gardner said the cause of the blockage, which resulted in the discharge, remained unknown.
The QLDC did not provide comment before deadline.
