Bad weather causing swells from the northeast is both pushing pollution on to St Kilda and St Clair beaches, and hampering an all-but finished project planned to fix the problem.
The beaches were again closed yesterday, as enterococci levels rose above the recommended maximum, and the Dunedin City Council's Tahuna outfall looks set to pass a hoped-for August commissioning date.
Council Tahuna upgrade project manager Brian Turner said when the weather came from the northeast, sewage from the outfall at Lawyers Head travelled towards St Clair.
While enterococci levels - supposed to be below 280 per 100 millilitres of water - had not risen much above that, the rule was to close the beaches when levels did.
Mr Turner said there were few closures during summer, but they had increased over winter.
The outfall pipe is part of a project to improve the quality of effluent discharged from the Tahuna sewage-treatment station and dispose of it 1.1km out to sea, where the council says it will more efficiently and quickly be diluted and mix with seawater.
Stage one includes the $37 million work on the pipe, a new pumping station and installation of chlorination and odour-control facilities at the Tahuna plant, while stage two, due to begin later this year, is the installation of a $67 million secondary-treatment system at the plant.
It was originally expected stage one would be functioning from January, but weather delays meant that date was extended to April, then August.
While the pipe is in place under the water, a 15m section connecting to pipe on land - which needed two periods of work taking two days each - had not been possible.
"The weather slows things down."
Even on calm days, swells of up to 2m to 3m had been enough to stop work.
It could only be undertaken in swells of 1.5m or less, or there was a chance of injury to workers.
Mr Turner said completion of stage one would have to wait until conditions were suitable.
The delays were not affecting the contract price.
They did have indirect costs, though the project was still on budget.
