OPINION | Measuring the health of our waterways

Lake Wanaka | Photo: Wanaka Sun Archives

Victoria University scientist Dr Mike Joy is a member of the government’s Science and Technical Advisory Group, tasked with making recommendations to support future freshwater policy.  

At the recent water forum in Queenstown, Dr Mike Joy made clear his views that current State of the Environment testing carried out under the Resource Management Act is inadequate, outdated and not measuring the right things. The current approach also allows the sampling sites to be chosen by the agency doing the monitoring. Mike Joy is advocating for an independent body such as the Parliamentary Commissioner for the Environment to carry out testing and reporting across the country.  

The monthly water testing information published on ORC’s website for the Wanaka/Hawea lakes area covers nitrates/nitrogen, ammoniacal nitrogen, dissolved reactive phosphorus, E.coli and turbidity measured at five sites. Excessive amounts of nitrogen and phosphorous can cause water quality issues, particularly in lakes. Aquatic organisms are sensitive to ammoniacal nitrogen concentrations. Turbidity is the cloudiness or haziness of the water which can result from different factors, such as growth of phytoplankton or high sediment levels.

Two additional sites, Roys Bay and Lake Hawea Holiday Park, are tested weekly for E.coli over the summer months and the results are published on the LAWA website.  ORC has also been carrying out additional testing at Bullock Creek as a result of the ongoing sediment and stormwater runoff issues caused by adjacent development.

One of Mike Joy’s criticisms is that the current testing regime omits factors that would provide a fuller assessment of the health of our waterways and that monthly monitoring may not be effective at capturing the full range of indicators that can fluctuate day to day, depending on influences like rainfall.  For example, test results might show reduced nitrogen levels where there is excess algae growth.

ORC will soon be managing a single monitoring buoy on each of Lake Hayes, Lake Wanaka and Lake Wakatipu. Although limited in their depth capability, these buoys will enhance both the frequency and types of sampling being carried out on these lakes. Data will be collected every 15 minutes which will, over time, assist freshwater scientists to understand more about the lakes and eventually allow for future decision-making to be informed by science, to improve water quality management.    

The Wanaka Water Project is seeking community input for the development of an Integrated Catchment Management Plan for the catchments upstream of the confluence of Luggate Creek and Clutha River. If you would like to provide input as to how freshwater testing could be more effective in the Upper Clutha, please contact community@uppercluthalakestrust.org.  


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