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Wānaka Water Project

WAI Wānaka to start research into flow patterns in Lake Wānaka
We are excited to announce a project with the National Institute of Water and Atmospheric Research (NIWA) to start a short-term study of currents in Lake Wānaka. This is the first research of its type on the deep-water lakes in our area.

Early June 2022 you might spot floating ‘drifters’ (see image below) across Roys Bay. These devices are part of the WAI Wānaka project with NIWA to start to inform our understanding of water movement in the lake. Data from the study will help us understand where run-off of contaminated urban stormwater flows when it enters the lake. For example, does it reach the intakes for the Wānaka town drinking water supply or popular swimming areas.

‘Drifters’ to be released in Lake Wānaka – only the small orange buoy shows above the water.

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

As an indication of the cost associated with not understanding our lake water, $144 million was committed in 2008 for Rotorua Lakes clean-up projects over a 24-year period.

Dr. Don Robertson, trustee of WAI Wānaka, Guardian of Lake Wānaka and former NIWA scientist, says that 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.

“We rely on Lake Wānaka for drinking water, tourism business, farming and recreation. Urban and rural 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 which reduce water quality.

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

With rapid development around the lake, increased resident and visitor population, and the introduction of invasive weed pests, the ecosystem of Lake Wānaka is under pressure, but without research it’s difficult to know what steps are required to reduce the human impact on lake degradation. These concerns apply also to Otago’s two other deepwater lakes – Hāwea and Whakatipu.

The 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. Roys Bay is the recipient of multiple sources of contaminated stormwater runoff.

To understand what happens to these contaminants when they enter the lake, the currents in the lake need to be understood.

NIWA’s Freshwater Centre Chief Scientist Dr Scott Larned is heartened that work has been initiated.

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