Fitzroy Beach is New Plymouth's most popular swimming beach. Photo: RNZ / Robin Martin
Taranaki beaches, lakes and rivers will be back under the microscope this summer, with the Can I Swim Here? programme about to kick off.
Every Tuesday from 4 November until the end of March, Taranaki Regional Council staff would take water samples from 17 beach, 16 river and seven lake sites around the region to check for faecal contamination.
The water was tested for Escherichia coli (E coli) in freshwater and enterococci in coastal waters. These bacteria indicated the possible presence of disease-causing micro-organisms that could cause illnesses such as gastroenteritis, respiratory infections and skin irritations.
Results were usually available by Thursday evening on the Taranaki page of the Land, Air, Water Aotearoa (LAWA) website. Where water quality was poor with no clear explanation (such as heavy rain), the TRC would carry out further testing and investigations as to the cause of the contamination.
The council also monitored for toxic algae (benthic and planktonic cyanobacteria) at seven river and seven lake sites, updating the LAWA site with results.
The Can I Swim Here? programme was a collaboration between the TRC and Health New Zealand Te Whatu Ora, which was responsible for providing public health advice, as well as the region's three district councils who were tasked with signage and informing the public.
TRC water quality scientist Angela Collins said it had been monitoring recreational bathing spots for around 30 years, with the current all-weather monitoring programme now in its fifth year.
"We're proud of this mahi and it means a lot to us, not just from an environmental point of view, but because it helps keep our friends, neighbours and communities safe and well.
"Our goal is to arm people with the knowledge to make informed decisions when choosing where to swim this summer."
The nationwide programme used a traffic light system for results, where green was suitable for swimming, orange was caution advised and red was unsuitable for swimming.
Last summer 350 routine coastal samples were taken in Taranaki with 93 percent green and 4 percent red. Of the 475 routine freshwater samples, 54 percent were green and 27 percent red.
Collins said rivers could be more prone to contamination, as most bacteria comes from bird faeces and animal faeces washed from the land into waterways during rain.
And it could change quickly. While a river might have been suitable for swimming on a Tuesday when a sample was taken, three days of heavy rain following that could result in a higher risk of contamination by the weekend.
Collins said as well as checking LAWA, there were other things swimmers can do to minimise the risk.
"A general rule of thumb is to avoid swimming for three days after heavy or prolonged rain, particularly in rivers or beaches close to where rivers flow into the ocean. Look out for signage - some sites such as the Te Hēnui River mouth in New Plymouth have permanent no swimming signs.
"It's also about using common sense when something doesn't look or smell right. If the water is smellier, cloudier or greener than it usually is, you might want to find another swimming spot or stick to the shore that day.
"In rivers, also keep an eye out for thick black/brown mats of algae growing on rocks. Cyanobacteria mats can have a distinctive, unpleasant smell, often described as musty, earthy, or swampy. If you see any, stay out of the water and keep your pets well away as well."
For more information on what to look out for and to check the latest Can I Swim Here? results, go to LAWA's swimming data.
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