As New Zealanders go on holiday breaks may will be asking where is it safe to swim this summer.
It's a pertinent question after Auckland Council's Safeswim website showed a 'high risk' of illness from swimming at dozens of beaches in the region over the weekend. Heavy rain had added significantly to the country's polluted waterways problem.
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Warnings are in place for Kohimarama Beach and St Heliers Beach in the central east, and several beaches in the Waitākere region are off limits. Earlier there were over 50 beaches with a red alert on the Safeswim website.
Water quality scientist Anna Madarasz-Smith, from Land Air Water Aotearoa, tells Jesse Mulligan the website has data from hundreds of lakes and rivers across the country enabling people to make safe choices on whether they should swim in these locations.
Madarasz-Smith says water quality models also featured on her organisation's website predict levels of faecal bacteria that exceed national guidelines for swimming.
Land, Air, Water Aeoteroa is a national water-quality monitoring body.
“We collect all of the environmental monitoring information, which is collected by regional authorities in New Zealand and it’s displayed on our website,” she says.
Auckland wasn’t the only region carrying out checks, with all regions being monitored and bacteria in the water identified.
“We have over 750 beaches, rivers and lagoons in our Can I Swim website and that data comes in from Auckland and Greater Wellington. It comes in from models and monitoring and from specifically going out and taking the water sample, getting it processed in the lab.”
In Auckland the data comes in about once every 15 minutes. For the rest of New Zealand, it could be weekly or fortnightly, so data from the main centres is more reliably up-to-date when making a decision on whether to swim or not. There is modelled data here offering information on storm water and waste water networks, tides, sunlight and rainfall.
“We sometimes might do a follow-up sample. So, if something seems out of the ordinary someone will go out and sample it again and that data comes through as soon as it’s available.”
The safety outlook for waterways was improving as rainfall receded, she says.
“It’s looking good at the moment, but we have to remember we’ve had a lot of rain between Christmas and New Year period unfortunately.
"We know when we get a lot of that heavy rain, it rushes through your gutters, it’s coming off the land into the water system, flowing into your lakes and rivers and ocean and that carries everything with it – anything on the roads and that can be litter, it can be faecal material from animals.
"So that’s why we say to stay out of the water for two or three days following heavy rain. We would have seen that in Auckland following those heavy downpours.”
She says water discoloration and thick algae are another classic signs of water contamination, and a signal to stay out. Other bacteria hotspots included lagoons, which in general weren't idea places to swim and usually posed a risk due to current flow and catchment area.
“These are areas where rivers come in and it becomes more slow-flowing. It’s gets a bit warmer and you may have a lot of ducks, birds, geese. They can be more susceptible to these higher levels of faecal-indicator bacteria’.”
The website is colour-code scheme on the website is based on The New Zealand Guidelines for recreational Water Quality, with green meaning the risk is acceptable, amber is higher, and red is unsuitable for swimming. Black signifies there has been a sewage overflow and the area is out of bounds.
Consult the website's data here to enhance your safety.