The vast majority of beaches in Auckland are not suitable for swimming because of wastewater overflow following the recent stormy weather.
Auckland was hit with more than two months of rain in 24 hours yesterday, but many woke up this morning to calm, sunny conditions across the city.
Temperatures reached a high of 25C today, according to MetService, with the fine weather set to continue into Saturday.
However, Aucklanders have been warned against jumping in the ocean without first checking if it’s safe on Auckland Council’s Safeswim website.
“Water quality and conditions at beaches, lakes and rivers can change quickly and are not always visible from the shore,” the council said.
As at 5pm this afternoon, more than 30 beaches in Auckland have been designated as “do not swim” (illustrated by a black pin on Safeswim) because of wastewater overflow.
Some of the popular beaches with the warning include Mission Bay, Kohimarama, Herne Bay and Browns Bay.
Most of Auckland’s other beaches – from Ōrewa and Waiheke Island to Piha and Clarks Beach – have a “swimming not advised” warning (red pin), with only a handful of spots in the region deemed safe for swimming (green pin).
“Most parts of the Auckland region received more than 100mm of rain yesterday. However, we’re already seeing improvements in water quality across the region,” Holly Foreman, principal of Safeswim at Auckland Council, said.
“With the current weather forecast, many more beaches are expected to [be] swimmable again by Saturday, in time to make the most of the sunshine.”
Foreman said many Auckland beaches will remain unsafe for swimming until Sunday.
“Several beaches throughout the Waitematā Harbour and along the North Shore will continue to show a black pin until Sunday, indicating recent wastewater overflows.
“We encourage everyone to check the Safeswim website or app before heading out, in both wet and dry weather, to ensure they have the most up-to-date information.”
“The risk of illness from swimming is associated with levels of micro-organisms in the water, called Faecal Indicator Bacteria (FIB). FIB are bacteria that come from the gut of warm-blooded animals (including people),” the council said.
“They indicate the presence of faeces (poo) and are associated with the presence of disease-causing pathogens. The two common bacteria that are measured are E. coli, in freshwater, and Enterococci, in seawater.
“Guideline values for E.coli (freshwater) and Enterococci (seawater) are specified in the 2003 Microbiological Water Quality Guidelines for Marine and Freshwater Recreational Areas published by the Ministry for the Environment and Ministry of Health and have been selected to keep the risk of illness from swimming at less than 2%.
“The swimming guideline is based on the risk of getting sick from being immersed in the water for 10 minutes and putting your head under the water three times.”
During wet weather, stormwater (rain) can enter the wastewater network and overwhelm it, the council said.
“Rainwater can get into the wastewater network through cracks in pipes, flooded manholes or downpipes that are connected incorrectly.
“The wastewater network is designed to overflow through engineered overflow points and manholes. In particularly bad weather, it can also overflow through private gully traps. Overflows that occur during wet weather largely consist of rainwater – only a small volume is wastewater.
“This isn’t just an Auckland issue. Wastewater networks around the world are designed with overflow points to release discharges when capacity is reached, or a fault occurs. Without these overflow points, uncontrolled discharges can occur, including in our homes.”