Algae issue back on agenda

Feb 10, 2010

The recent warm weather has caused the issue of algae to once again become problematic for the Wanaka water supply, Wanaka Community Board chairman Lyal Cocks said.

“In 2008 we had some issues with algae getting into the supply and the trend seems to accompany warm weather but is also the result of nutrients entering the lake over many years,” he said.

“You get the problem when the stuff dies off and then gets into the water system. It’s a nuisance as opposed to presenting any health risk,” Councillor Cocks said.

The installation of a finer mesh filter over the water intake last year had not entirely prevented algae from being drawn into the intake chambers of the reservoir.

“We are actively looking at the issue to see if we can come up with a more viable solution,” Queenstown Lakes District Council 3 waters manager Gerry Essenberg said.

Work being undertaken included a lake water sampling regime to understand when the algae occurred, the type and structure of the algae and the depth and temperature at which it grew. “We have identified 13 different types of algae to date,” Mr Essenberg said.

The Council needed to have detailed analysis of the problem before putting forward a ‘cost effective’ solution, which was likely to involve a more detailed filtration system. “In the interim we are continuing to flush mains in the areas that are experiencing problems to try and mitigate the issue, Mr Essenberg said.

The Council had received several calls from members of the Wanaka community with water pressure issues.

“Anyone with a reduced amount of water pressure should call a plumber and have their filter checked, although once you know how to do it, cleaning the filter is normally a relatively simple thing to do,” Mr Essenberg said. Another option that households could consider was the installation of a ‘primary filter’.

Mr Cocks said the situation was clearly not satisfactory but until a more effective solution could be introduced, households being affected would need to manage the situation. “And we do need a solution because unless we can address the flow of nutrients that are available to feed algae in our lake water it will be an ongoing problem,” Mr Cocks said.

Mr Essenberg encouraged anyone with a pressure or blockage issue to still report it to Council’s customer service team in order to help council monitor the problem.


For further information please contact Gerry Essenberg 03 441 0499 or Lyal Cocks 03 443 5750