Algal Bloom Health Warning Issued for the Ashley/Rakahuri River

A health warning has been issued for the Ashley/Rakahuri River at the Rangiora-Loburn Bridge following the discovery of potentially toxic algae in the water.

The Community and Public Health division of Canterbury DHB has issued a health warning for the Ashley/Rakahuri River at the Rangiora-Loburn Bridge (also called the Cones Road Bridge) after identifying potentially toxic blue-green algae (benthic cyanobacteria) in this area.

People and animals, particularly dogs, should avoid the area of the Ashley/Rakahuri River at the Rangiora-Loburn Bridge until the health warning has been lifted.

There are also other access points along the Ashley River that may have cyanobacteria present, and people are advised to check for the presence of cyanobacteria and avoid contact.

The algae look like dark brown to black mats and can produce toxins harmful to people and animals. No one should drink water from the river at any time and pets that shown signs of illness after coming into contact with algal mats should be taken to the vet immediately.

Environment Canterbury are responsible for testing river water quality. They conduct weekly testing of the most popular swimming spots over summer and you can view the results and find out if it’s safe to swim here 

The site at Ashley/Rakahuri River at the Rangiora-Loburn Bridge is being monitoring on a weekly basis and the public will be advised of any changes in water quality.

Ashley Gorge, further up the river, remains suitable for swimming.

Facts about cyanobacteria:

  • The algae occur naturally but can increase rapidly during warmer months.
  • If the water is cloudy, discoloured, or has small globules suspended in it, avoid all contact.
  • Not all cyanobacterial blooms are visible to the naked eye and toxins can persist after the blooms disappear.
  • Cyanobacterial concentrations can change quickly with changing environmental conditions (e.g. wind). If a health warning is in place avoid contact with the water

Learn more:

Toxic Algae Information Brochure

Land Air Water Aotearoa – Canterbury region

Canterbury DHB – recreational water

For more information about Mahinga Kai: Mahinga kai.

Contact: Community and Public Health

Phone: (03) 364 1777