Fluctuating E coli levels in Queenstown’s Lake Wakatipu are going largely unexplained, prompting calls for more scientific research.
Tests found high levels of the bacteria at Queenstown Bay on Sunday, and the Queenstown Lakes District Council (QLDC) was advising people to avoid contact with the water until the levels subsided on Monday morning.
Swimmers were also advised to stay out of the water at Frankton Bay on two occasions last summer due to high E coli levels, which can cause people to become sick.
A regional council spokesperson says the increased E coli could be due to rainfall, water flow, bird activity, stock in waterways or the weather.
Following the latest incident, Queenstown Lakes District councillor Alexa Forbes says not enough is known about the health of the lakes, and not enough is being done to monitor what is causing sporadic bacterial problems.
“Queenstown’s really in the spotlight now and it’s very easy to point fingers at tourists or freedom campers or people who aren’t respecting where they need to go to the toilet or wash their clothes … but that’s not really fair,” she says.
“It’s really a much bigger systemic question than that, and that’s what we need to look at.”
She says the district council is testing the water more often than it used to, but is still unable to pinpoint the source of E coli outbreaks.
“So it’s pretty hard to say whether it’s common or it’s isolated,” she says.
Forbes says the district council and regional council should be working together and taking responsibility.
“We need to make sure that our activity as a local government isn’t impacting those lakes, and we need the Otago Regional Council to ensure that those lakes are healthy and that we are not damaging them.”
Neighbouring Lake Hayes has also had ongoing issues with high levels of E coli, and with Cyanobacteria algae blooms, prompting the formation of an environmental lobby group called Friends of Lake Hayes.
Its secretary, Richard Bowman, says he agrees bacterial issues make a “strong case for scientific investigation.”
“The tools are there. They need to be used to track down the sources and once you know what’s causing it, then you can deal with it.”
He says it’s a matter of prioritising public health and taking responsibility for clean waterways.
“People who use waterways for swimming and for recreation need to be safe doing it.”