River warnings

We monitor more than 100 popular recreational sites in Canterbury during summer. Health warnings are placed at sites where an increased risk of cyanobacteria or faecal contamination is present. Advisory notes may be present but are not an official public health warning.

Cyanobacteria can occur in any waterway, at any time, so it is important that you know what it looks like. Find out more about cyanobacteria in waterways and how you can protect yourself and your animals.

Faecal contamination poses a risk to health, check out LAWA’s swim smart checklist, to know what to check before you swim.

Kaiapoi Island at Smiths Stream

17 August 2021

Environment Canterbury advises that floating detached cyanobacteria mats have been detected in the Smiths Stream.

This area is popular with dog walkers in the Kaiapoi Island area of the Waimakariri River Regional Park.

If consumed by a dog, cyanobacteria can be deadly. We advise all dog walkers to not allow their dogs into or near Smiths Stream and the community should avoid contact with water in the stream.


Cust Main Drain at Skewbridge

10 May 2021

Canterbury DHB’s Community and Public Health unit has issued a health warning for the Cust Main Drain at Skewbridge.

The warning follows the finding of a high cover of potentially toxic algae (benthic cyanobacteria) at this site.

“Gathering of mahinga kai such as watercress/pūwhā should be avoided as exposure to the algae may cause skin rashes, nausea, stomach cramps, tingling and numbness around the mouth and fingertips," Dr Cheryl Brunton, Canterbury Medical Officer of Health said.

People should avoid the area and animals, particularly dogs, should not be allowed near the water until the health warning has been lifted. 

For more information about Mahinga Kai, use this CPH resource (PDF)