Sewage spills into harbours
Some Auckland beaches will not be safe for swimming for up to five days after heavy rain caused sewage to overflow into the city’s harbours, a biologist says.
A Watercare spokeswoman said there were 41 wastewater overflow points in Auckland’s inner-city beaches, a number of which had been in use following heavy rain at the weekend.
‘‘This is due to significant amounts of stormwater entering the network following heavy rain.’’
Between 9am on Friday and 9am Saturday, Auckland recorded its wettest March day on record since 1959 with 100mm of rain falling due to a low pressure system dubbed the Tasman Tempest by Niwa.
Auckland Council recommends that people avoid swimming at beaches for up to 48 hours after heavy rain.
But wastewater biologist Gemma Tolich Allen said the 48 hour rule should be treated as a minimum amount of time following an extreme weather event such as the Tasman Tempest.
‘‘It is a guesstimate really. In some places I would say it would not be until four to five days until the contaminants are dispersed,’’ she said.
The main contaminants in wastewater were fecal matter, she said.
Tolich Allen said the main health risk from wastewater discharged at beaches came from consuming shellfish near the overflow points.
Swimming in a contaminated area could also cause gastroenteritis if water was ingested and bathers were at risk of eye and ear infections, she said.
Kerry Martin, who operates the Onehunga lagoon cable wakeboard park, filmed wastewater spewing out of a Watercare lagoon overflow site on Sunday.
‘‘The lid of the overflow was surfing around on the top of it, that has to be some pretty high pressure to make that happen,’’ Martin said.
Jim Jackson, chair of the Manukau Harbour Enhancement Society, said the overflows occurred because Auckland city had a combined stormwater and wastewater system.
On March 6 two out of 17 central Auckland beaches were deemed unsafe for swimming - Meola Reef and Cox’s Bay.
Turn to page 3 to read more about Auckland’s wastewater dilemma