Swimmers warned to take care after toxic algae found in Wellington region's rivers

Friday, 1 February 2019

Toxic Algae in the Hutt River

It is more deadly than cobra venom and it has returned to the Wellington region's rivers.

Toxic algae has pushed some of the region's rivers over the safe swimming limit and the Greater Wellington Regional Council says people should stay out of some altogether.

Swimmers should avoid the Hutt River between Moonshine Bridge and Fairway Drive Bridge, and the Pakuratahi River from SH2 to its confluence with the Hutt River in Kaitoke Regional Park, the council says.

Toxic to people and fatal to dogs, toxic algae is blooming in the Wellington region's rivers.

Children should be kept away from water in these sites and dogs should be kept on a lead.

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Swimmers have been warned to look out for toxic algae in the Wellington region's rivers before taking a dip. (File photo)

*** Toxic algae: more dangerous than cobra venom and deadly to dogs

* Dog owners and swimmers told to watch for toxic algae in rivers

Swimmers and dogs should keep away from sections of the Hutt River.

* Toxic algae outbreak in Wellington region's rivers**

Toxic algae occurs everywhere, but it is during hot weather and low water that the problems start.

It becomes dangerous when it comes loose from the riverbed and brown or black mats wash up on the banks or form floating rafts. A coin sized piece of algae could kill a 20kg dog.

Toxic algae cover is also rising at Greater Wellington's Waipoua, Waingawa and Ruamahanga river monitoring sites in Wairarapa, and in the Otaki and Waikanae rivers in Kāpiti, although these sites are currently below the council's 'no swim' trigger levels.

Senior Environmental Scientist Mark Heath said no detached mats of toxic algae had yet been seen at any of the monitored sites.

'However this could change rapidly, especially during warm weather, so we are urging people to be careful near all waterways throughout the region.'

The algae was more deadly than cobra venom.

Given the rapid growth of toxic algae, and its potential change in coverage between weekly monitoring points, the council urged people to know learn it looks like.

They should check information signs around popular swimming holes and visit Greater Wellington's Is it Safe to Swim? website and Facebook page for more information about toxic algae, as well as images.

WHERE IS THE TOXIC ALGAE?*

Kāpiti Coast: The Ōtaki and Waikanae Rivers both remain below guideline levels at approximately 5 per cent cover but council monitoring officers have noticed a significant increase in toxic algae coverage (approximately 15 per cent) and it has become concentrated in some areas.

Hutt River: Toxic algae exceed the 20 per cent cover guideline level at the Silverstream Bridge site. All other monitoring sites were below guideline levels.

Ruamahanga River: Toxic algae cover is at approximately 10 per cent cover at the Waipoua and Waingawa monitoring sites, while toxic algae at Ruamahanga River sites are at approximately 5 per cent cover.

Pakuratahi River: The Pakuratahi River at Kaitoke Forest Park has a significant toxic algal bloom (20 per cent cover).

Waipapa Stream: The Waipapa Stream near Red Rocks on Wellington's South Coast also has a significant bloom.

*Monitored January 29 to 31