WAI Wānaka has engaged the National Institute of Water and Atmospheric Research (NIWA) to start a short-term study of currents in Lake Wānaka. 

The research, which will help identify where contaminated urban stormwater flows when it enters the lake, will be the first of its type on the deep-water lakes in the Upper Clutha.

WAI Wānaka trustee, Guardians of Lake Wānaka member and former NIWA scientist Dr. Don Robertson said the project represents the first step in developing the capability to predict the effects of currents on the dispersal and dilution of contaminants within Lake Wānaka.

‘While this is a small study, we hope that it will lead to better understanding of the effect of human activities on the quality of water in the lake,” he said.

Lake Wānaka is relied on for drinking water, tourism business, farming and recreation, and stormwater run-off into the lake brings with it nutrients, protozoa, bacterial and viral pathogens, organic matter, heavy metals silt, and other contaminants.

All of these things reduce water quality, Don said.

“We don’t know enough about the outcomes of using the lake this way to be able to protect it into the future,” he said.

The upcoming study will focus on Roys Bay south of a line between Damper Bay and Beacon Point – Wānaka’s main area for recreation and where the town’s main drinking water intakes are located. 

An image of a ‘drifter’ - which collects information about water quality - like the ones that will be located in Roys Bay. IMAGE: Supplied

Residents may see floating ‘drifters’ - which look like buoys from above the water but underneath feature spheres which house a number of sensors for measuring water quality and currents - around Roys Bay towards the end of April and during May.

NIWA freshwater centre chief scientist Dr Scott Larned said the study “will inform our understanding of contaminants as they come into this part of the lake”.

WAI Wānaka has been advocating research into the Upper Clutha deep-water lakes (Lake Hāwea and Lake Wānaka) since its inception in 2016. 

“WAI Wānaka hopes to continue to support research that will enable development of evidence-based management practices to maintain and improve water quality and lake biodiversity for the local community and future generations,” Don said.

There will be signs and information distributed about the drifters placed in Roys Bay for the duration of the May monitoring.