Cleaning up Lake Wānaka
Locals were shocked to find that Lake Wānaka is not as pristine as it looks, after discovering bacteria from sewage at a popular swimming spot. Now they're on a mission to clean it up.
Swimmers often emerge from the lake covered in mucus-like 'lake snow'.
Community groups and students from primary school to university are working on a range of projects to assess and improve the water quality in beautiful Lake Wānaka, with a focus on what’s coming down stormwater drains.
They’re finding that the lake is not as pristine as it looks in some areas, with a success story that’s stopped sewage discharging into the lake from a wrongly connected stormwater drain.
The cleanliness of the lake is important to wildlife as well as swimmers.
Down the Drain is a project that has evolved from the Wānaka Swimmers Participatory Science Project in 2017. It involves the whole community in managing the science of stormwater mitigation (limiting the amount of pollution carried by rain from the land into the lake) and ecosystem restoration (rebuilding the surrounding natural environment).
Students from Wānaka Primary School, Mount Aspiring College, Otago University and members of Wānaka Lake Swimmers are gathering information to determine where poor water quality spots are in and around the lake.
Project leader Chris Arbuckle of Touchstone says getting the community involved in identifying that stormwater drains contribute to poor quality water entering the lake will help with finding solutions. “Citizen science and community monitoring are valuable because people understand the issues more when they engage in the work. The impact on peoples’ understanding is actually quite significant.”
Bacteria discovered at swimming spot
A success story from this work was the discovery of bacteria in water at Stoney Creek which feeds into the lake at popular swimming area Roy’s Bay, where Wānaka lake swimmers use a 450m swim lane.
Swimmers had reported ‘stinky’ water, so they tested the water and the results showed that sewage was discharging directly into the lake through a stormwater pipe that had been mistakenly cross connected to a house sewerage pipe. The pipes have been rectified.
Chris says the project aims to identify where problems are, show that what goes down the drain causes water quality issues, change people’s behaviour, and eventually improve the stormwater drain system.
A beach survey at popular swimming spot Bremner Bay raised children’s awareness when they found plastics, rubbish and pollution, much of it caused by people putting things down their stormwater drains.
The students investigated the rubbish found in the lake, which came from litter in stormwater drains.
Children present to politicians
The children have since investigated types of devices that could stop pollution entering the lake. “We’re proving that these drains are a problem with water quality and the messaging has to be to stop people putting things down the drain.”
That includes educating decision-makers. Five students from Wānaka Primary presented their stories about creatures that live in the lake to the Wānaka Community Board, in a bid to raise awareness about the need to preserve the lake and fix stormwater drains. “The more people you get on board, the more can happen to fix things. That’s the whole point of Touchstone,” Chris says.
Wānaka Primary School students created a mock stormwater wetland as part of the project.
Chris explains that it’s important to involve younger generations in the work. “The kids are the ones that will be making the decisions in the future. The youth of today are having to fix things that my generation has stuffed up.”
He is also mentoring others to learn about the problems and spread the word. Two members of the swimming community presented about the water quality issues affecting Lake Wānaka at the 2018 New Zealand Freshwater Sciences Society Conference.
Fast development affecting water quality
Wānaka’s building boom is also sending sediment into rivers and lakes from building sites, Chris says. Mt Aspiring year 12 geography students are sampling water quality at three sites around the lake, analysing the data and changes in water quality with regard to clarity and conductivity, as well as temperature.
Members of Wānaka Lake Swimmers, who regularly swim long distances in the lake, are using baby wipes on their cheeks for analysis after swimming around Ruby Island to investigate the 'lake snow' phenomenon - the growth of sticky mucus-like blobs in the water - and will report to the Otago Regional Council (ORC) about the water quality in the lake.
Year 12 students at Mt Aspiring College are collecting and mapping data about the lake.
A second group of Mt Aspiring students are building water temperature sensors as a technology project. The sensors will feed back water temperature data to a Wānaka café that will be shared on a website.
Chris says he hopes these citizen science projects will engage and invigorate interest in water quality, and gather a big pot of knowledge to support a growing community of interest into what affects the water in Lake Wānaka.
And he says involving young people right through their school years and into university will be key to improving water quality in the future.
“We want to build capability and interest locally so that Lake Wānaka becomes not only pristine to look at, but also healthy and clean to swim in.”
Stormwater runoff (brown) contaminating Bremner Bay, Wānaka.
About the project
Down the Drain is run by Touchstone in partnership with the University of Otago Otago Regional Council Aspiring Environmental Queenstown Lakes District Council and the Wānaka Community Board, with support from the Otago Participatory Science Platform.
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