Some places, like the mouth of Te Henui Stream, are permanently unsuitable for swimming.
Some places, like the mouth of Te Henui Stream, are permanently unsuitable for swimming.
Swimmers are being warned to avoid waterways for a few days after heavy rain as Taranaki Regional Council begins its summer pollution testing.
The council’s weekly sampling programme is under way at 41 popular swimming spots at lakes, rivers and beaches but results take two days to come back from the lab and be posted online.
Water quality could change quickly so swimmers should take their own precautions to stay safe and protect whānau and pets, said TRC water quality scientist Angela Collins.
“The biggest one is to avoid swimming for three days after heavy or prolonged rainfall. That means any rain that leads to surface run-off, where you might see lots of water flowing in the gutters.
“Rain washes pollutants, including animal and bird faeces, from the land into rivers, lakes and the sea which can make them temporarily unsafe for swimming.”
Taranaki Regional Council takes weekly samples at 41 sites including Oākura River at Corbett Park.
Collins said three fine days usually brought water quality back to normal, but it was safest to stay out of the water whenever it didn’t look or smell right.
“If you can’t see your feet in knee-deep water, or if the water smells unpleasant, wait another day or two for the water to run clear before going for a dip. It’s just not worth the risk of getting sick.”
She said lake users should beware of green or brown particles in water, surface scum or green globules, while river swimmers need to watch out for dark brown and black mats forming on rocks and boulders, which can become exposed when river levels drop.
All these are signs of toxic blue-green algae that can make people and animals sick.
Some places with stubborn water quality problems are unsuitable for swimming even during fine weather, with permanent warnings at the likes of Te Hēnui Stream river mouth and the Waimōku Stream mouth on Oākura Beach.
District councils are responsible for signs at swim spots and Te Whatu Ora decides when to issue public health warnings
Until the end of March Taranaki Regional Council will test weekly for E. coli at rivers and lakes and for enterococci at beaches.
Fortnightly testing for blue-green cyanobacteria in rivers and lakes is upgraded to weekly when pollution guidelines are exceeded.
Results are posted to TRC’s Can I Swim Here? webpage, as well as www.lawa.org.nz on Thursday evening.
Any unexplained contamination sparks a follow-up sample on Friday, with results available on Monday.
Last September the council’s environmental quality director Abby Matthews confirmed that high E. coli levels at a few Taranaki estuaries were due to wild birds, but most testing sites were contaminated by farm animals.
Matthews said the Government’s National Policy Statement for Freshwater Management required that councils set limits on natural resource use, to reduce E. coli.
“Most of the actions are fairly well-known: keeping stock out of waterways, improving effluent discharges, looking at critical source areas on-farm – so dairy-shed effluent, laneways, places like that – are always going to be your best bang for buck.”
