Signs warning against swimming remain at Titahi Bay

The Team from Wellington Water

Wellington Water crews yesterday located a plumbing fault in the catchment feeding into Porirua’s Titahi Bay beach and are working to get this fixed. Recent regular monitoring at Titahi Bay beach showed high bacteria counts with signage going up last Thursday recommending against swimming there.
Work is continuing in the catchment to see if any other faults can be found, and water quality testing is continuing daily.

Sunday’s water quality results indicated lower levels of contamination at Titahi Bay Beach, but the warning signage will remain in place as a precaution while work continues to resolve the causes. Our normal protocol for lifting the warning is to have two consecutive days of results within the safe bathing guidelines.

Signs went up saying Titahi Bay Beach was not suitable for swimming or other recreational activity such as fishing or collecting seafood when Wellington Water’s regular monitoring programme returned high bacteria counts on Thursday 12 March.

This result triggered a response from Wellington Water’s operational team to investigate the catchment, looking for a potential source of pollution. This process involves collecting and analysing samples from key points in the stormwater network, and the team methodically working their way upstream from the beach, following the trail of contamination.

Causes such as cross-connections from wastewater to stormwater pipes or damaged pipes provide intermittent flows, so contamination is not constant. As a consequence, some issues can lie undetected for years, while tracking faults can take weeks and sometimes has to be delayed as more urgent repairs take priority.

As well as tracking down the sources in the catchment, sampling can only tell us one part of the story, and can change from tide to tide. As stormwater outlets run onto the beach, high tide can pull in the contaminants into the sea meaning we receive a high reading, and low tide can mean there is a lower result.

Late last month high levels of bacteria were found near one of the four stormwater outlets to Titahi Bay beach through Wellington Water’s regular water quality monitoring programme. A broken wastewater pipe connection was identified approximately a kilometre from the beach and fixed the following day, ahead of the Titahi Bay Beach festival.