All that water and nowhere to swim

Fifth consecutive summer swim ban at Pegasus Lake has locals hot and bothered.

The lake in the centre of a North Canterbury town is off limits for the fifth consecutive summer, and some residents are tiring of the ongoing health warnings.

This year’s alert for Pegasus Lake was issued by the Canterbury District Health Board on January 28, two weeks earlier than last year, after potentially toxic blue-green algae (planktonic cyanobacteria) was found.

A warning has been issued for the man-made lake every summer since 2014-15 and usually remains in place until April, by which time only the hardiest of swimmers would want to venture into the water.

Pegasus resident Jason Mooney said the lake was a key reason he moved to the North Canterbury town six years ago. It had been created as a central feature of the new town. ‘‘We actually bought here because the lake was something we could use all year round. The first year it wasn’t a problem, but it’s been getting worse the last few years.

‘‘It looks pretty, but it is unusable – unless you want to take photos of ducks from the shore.’’

Mooney said the boat ramps were also slippery because of the algae. He questioned whether the lake would keep being used for events such as dragon boating or triathlons if the water continued to pose a health hazard every summer.

Andrea Holley moved to Pegasus a few weeks ago and said the lake had been a drawcard for her too, but her dog, Bruno, ended up at the vets after jumping in.

‘‘Our dog is a water-loving labrador who loves a swim. We were hoping his new home would accommodate him.’’

Bruno’s treatment was just a precaution, but she feared a smaller dog may not have fared as well.

The lake’s owner is Todd Property Group, which took over from the initial developers Infinity Group in 2012.

Todd Property managing director Evan Davies said the lake was only designed and consented for secondary contact recreation, such as boating, kayaking, or model boating. ‘‘For most of the year, the lake also meets primary contact levels, which includes activities such as swimming.’’

He said there was always a risk of algal blooms occurring in waterways, as they were influenced by external elements like temperature, rainfall, and wind.

‘‘Pegasus Lake has shown a fairly consistent seasonal pattern since its completion.’’

The lake used solar-powered pumps that circulate water to help manage algae blooms, he said.

‘‘Pegasus Town has commissioned contractors to ensure all mechanisms associated with the lake are working appropriately.’’

The Waimakariri District Council will eventually take over ownership of the lake, the reserve surrounding the lake, and structures such as the bridges and jetties.

A council spokesman said the council was still working with Todd Property on the ownership transfer. ‘‘The focus of the discussion has been around assessment of options to mitigate the issue of toxic algae blooms. We do not have a time frame for the transfer at this stage.’’

The blooms look like dark brown or black mats and can produce harmful toxins. People and animals, particularly dogs, should avoid the affected areas until warnings have been lifted.

Exposure to the algae can cause skin rashes, nausea, stomach cramps, tingling and numbness around the mouth and fingertips.

‘‘It looks pretty, but it is unusable.’’ Pegasus resident Jason Mooney