Sewerage could still be leeching into the Taylor River from earthquake damaged pipes.
The popular river, that wends its way through the Blenheim town centre, is listed as unsuitable for swimming on the Land Air Water Aotearoa (LAWA) interactive swim map due to sewerage contamination.
Despite council plugging what was thought to be the main source of contamination, the Third Lane sewer main, other pipes are yet to be repaired.
Marlborough District Council team leader for water quality Peter Hamill says kilometres of sewerage pipes were damaged in the 2016 Kaikoura quake.
But council scientists say they’re seeing a slight improvement of water quality at the river with recent tests giving swimming the green light.
Peter says he would swim in the river; but only if it hadn’t rained recently.
“We want to make sure people can enjoy the amenities and we’re doing our best to make sure that happens,” Peter says.
The river has a long-term grade of poor, but latest tests say the quality is ‘good’ for swimming.
Peter says following the 2016 Kaikoura earthquake, kilometres of sewerage pipes were damaged causing spikes in e. coli in the waterway.
Escherichia coli (E. coli) is a bacteria commonly found in the gut of warm blooded organisms.
It can survive outside the body about four to six weeks in fresh water making it a useful indicator of faecal presence and the disease-causing organisms that may be present in faecal matter.
E. coli is relatively straightforward and inexpensive to measure, but the indicator bacteria isn’t particularly dangerous, Peter says.
“Campylobactor and giardia are expensive to measure,” he says.
Peter says the Taylor River is safe for dogs.
“What’s bad for humans isn’t necessarily going to have an effect on dogs.”
He says the biggest issue with the Taylor is what people put down their drain.
“Every stormwater grate along the roads – it goes into the Taylor River,” Peter says.
“Urban waterways are difficult, you don’t know what people are putting into their storm water drains.
“That’s why we put the blue fish – to remind people what goes down there ends up with the fish.”
Peter says the river looks to be improving.
“We want it to be available to swim all the time.
“Definitely we have an issue when we get rainfall,” Peter says.
It’s a wider issue for all Marlborough rivers, too.
He says excrement from sheep, goats, cows and even things in the bush like possums, are all washed into the region’s waterways following rain.
“That’s why we recommend people to not swim up to three days after rain,” he says.
Pelorus bridge is the only swimming spot with a long-term grade of ‘good’.
Ferry Bridge’s long-term grade is ‘fair’, while Craig Lochart has a ‘poor’ long-term status.
Peter says for swimmers, the thing to look at is the recent test results.
“At Ferry bridge, 92 per cent of the time it’s safe for swimming,” he says.
“Most of the time, our waterways are ok – it comes down to those rainfall events,” Peter says.
He says council is assisting farmers with fencing and planting and are constantly investigating contamination sources.
“We want people to be able to swim in the river,” he says.
“The council is constantly testing and looking for broken pipes – but it’s the general public that ultimately have the power over the cleanliness of our waterways.
“The key message is everyone in the community can make a difference.”