23 January 2019

Working more closely together for water quality

Otago’s freshwater is among the best in New Zealand. The Otago Regional Council and Queenstown-Lakes District Council are collaborating more than ever before to ensure the quality of our waterways now and in the future.

Ensuring our water is safe to swim in, gather food from and supports healthy ecosystems is a key priority in our region. Otago Regional Council (ORC) and Queenstown-Lakes District Council (QLDC) are working together to strengthen their partnership to achieve these outcomes for lakes, rivers and other waterways in the area.

In this partnership each council has defined roles. ORC is responsible for managing the effects of using freshwater, managing rivers, mitigating soil erosion and flood control, while QLDC ensures the provision of water, sewerage and stormwater systems, environmental safety and health, and the effects of activities on the surface of lakes and rivers. ORC’s responsibilities also include the management of pest plants in lakes and waterways such as lagarosiphon, lake snow, toxic algae and didymo.

From testing, we know that the open parts of Lake Wakatipu have very high-quality water, whereas the areas closer to the shore can be more variable.

ORC takes weekly water samples from a range of locations around Otago during the summer, including two recreation sites on Lake Wakatipu, one site on Lake Wanaka and one site on Lake Hayes.

Every sample taken from these lakes is split and half is sent to Environmental Science and Research (ESR) for testing. If the routine E. coli test result is high, then ESR test for the source of the contamination.

Samples taken by ORC at Queenstown Bay in late 2018 reported fluctuating E. coli concentrations. When ESR undertook faecal source tracking, the result was clearly bird contamination which is consistent with the volume of birdlife in and around the district’s lakes. Fluctuations in results (reporting spikes in E. coli returning to very low levels in subsequent testing) can be quite common after heavy weather events rather than being a result of any infrastructure issues. QLDC is looking to undertake testing that differentiates between fluctuating and consistently elevated E. coli readings to reduce any unnecessary disruption to recreational enjoyment of the lakes whilst still keeping them safe.

ORC and QLDC have collaborated positively on water quality in recreation sites, and QLDC has recently agreed to take full responsibility for resampling any areas of concern daily until the levels of E. coli are low again, and to keep the public informed with signage if there is any health risk.

In another new initiative, QLDC has agreed to undertake more water sampling on behalf of ORC at sites 100m from the shore into the lake to further understand bacterial contamination in different weather conditions.

For up-to-date information on water quality at sites around New Zealand visit the LAWA website: www.lawa.org.nz

ENDS

Wider reading on E. coli:

https://www.nps.gov/indu/learn/nature/upload/Thinking-Differently-About-E-coli.pdf?fbclid=IwAR3cJqAc5-oH4onOocpuRIegUvAzbk0nBkTe6kKf-mgYF8tuQ7aYu22ko68

https://www.esr.cri.nz/assets/WATER-CONTENT/Images-and-PDFs/technical-report-faecal-source-tracking-avon-river-march-may-2009-screen-000809.pdf

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