River health warnings
We monitor river sites regularly over the summer to check for bacteria (faecal contamination) and toxic algae.
Each river site is given a long-term grade prior to the summer monitoring season for suitability for swimming and recreation. The grade is based on the last five years of bacteria sampling. Sites that are not recommended for swimming because of their long-term grade are red on the Land Air Water Aotearoa (LAWA) website and signage should be in place at the site.
Temporary Health warnings are issued when a site is graded as good to swim but there is now an increased risk of cyanobacteria or faecal contamination. Advisory notes may be present but are not an official public health warning.
Toxic algae (cyanobacteria) can occur in any waterway, at any time, so it is important that you know what it looks like. Find out more about toxic algae and how you can protect yourself and your animals.
Faecal contamination poses a risk to health, it can cause gastrointestinal illnesses, respiratory diseases, and eye, ear, nose, throat and skin infections.
Find out more about our monitoring programme.
Temporary health warnings
Waikirikiri/Selwyn River at Glentunnel
Water testing indicates moderate to high cover of toxic algae (benthic cyanobacteria) in the Waikirikiri/Selwyn River at Glentunnel.
People should avoid the area and animals, particularly dogs, should not be allowed near the water until the health warning has been lifted.
Other access points along the Waikirikiri/Selwyn River may have benthic cyanobacteria present. People are advised to treat every low-flowing river cautiously, check for the presence of benthic cyanobacteria and avoid contact.
Fish and shellfish can concentrate toxins and their consumption should be avoided. If fish are eaten, remove the gut and liver and wash in clean water. No one should drink the water from the river at any time. Boiling the water does not remove the toxin.
Exposure to cyanobacteria toxin may cause skin rashes, nausea, stomach cramps, tingling and numbness around the mouth and fingertips. If you experience any of these symptoms visit your doctor immediately and please let your doctor know if you have had contact with the lake water.
Animals that show signs of illness after coming into contact with algal mats or scums should be taken to a vet immediately.
We are monitoring the site and the public will be advised of any changes in water quality.
Rakahuri/Ashley River at SH1
Water testing indicates moderate to high cover of toxic algae (benthic cyanobacteria) in the Rakahuri/Ashley River at SH1.
People should avoid the area and animals, particularly dogs, should not be allowed near the water until the health warning has been lifted.
Other access points along the Rakahuri/Ashley River may have benthic cyanobacteria present. People are advised to treat every low-flowing river cautiously, check for the presence of benthic cyanobacteria and avoid contact.
Fish and shellfish can concentrate toxins and their consumption should be avoided. If fish are eaten, remove the gut and liver and wash in clean water. No one should drink the water from the river at any time. Boiling the water does not remove the toxin.
Exposure to cyanobacteria toxin may cause skin rashes, nausea, stomach cramps, tingling and numbness around the mouth and fingertips. If you experience any of these symptoms visit your doctor immediately and please let your doctor know if you have had contact with the lake water.
Animals that show signs of illness after coming into contact with algal mats or scums should be taken to a vet immediately.
We are monitoring the site and the public will be advised of any changes in water quality.
Opihi River at SH1
Water testing indicates moderate to high cover of toxic algae (benthic cyanobacteria) in the Opihi River at SH1.
People should avoid the area and animals, particularly dogs, should not be allowed near the water until the health warning has been lifted.
Other access points along the Opihi River may have benthic cyanobacteria present. People are advised to treat every low-flowing river cautiously, check for the presence of benthic cyanobacteria and avoid contact.
Fish and shellfish can concentrate toxins and their consumption should be avoided. If fish are eaten, remove the gut and liver and wash in clean water. No one should drink the water from the river at any time. Boiling the water does not remove the toxin.
Exposure to cyanobacteria toxin may cause skin rashes, nausea, stomach cramps, tingling and numbness around the mouth and fingertips. If you experience any of these symptoms visit your doctor immediately and please let your doctor know if you have had contact with the lake water.
Animals that show signs of illness after coming into contact with algal mats or scums should be taken to a vet immediately.
We are monitoring the site and the public will be advised of any changes in water quality.
Pareora River/Pureora at Pareora Huts
Water testing indicates moderate to high cover of toxic algae (benthic cyanobacteria) in the Pareora River/Pureora at Pareora Huts.
People should avoid the area and animals, particularly dogs, should not be allowed near the water until the health warning has been lifted.
Other access points along the Pareora River may have benthic cyanobacteria present. People are advised to treat every low-flowing river cautiously, check for the presence of benthic cyanobacteria and avoid contact.
Fish and shellfish can concentrate toxins and their consumption should be avoided. If fish are eaten, remove the gut and liver and wash in clean water. No one should drink the water from the river at any time. Boiling the water does not remove the toxin.
Exposure to cyanobacteria toxin may cause skin rashes, nausea, stomach cramps, tingling and numbness around the mouth and fingertips. If you experience any of these symptoms visit your doctor immediately and please let your doctor know if you have had contact with the lake water.
Animals that show signs of illness after coming into contact with algal mats or scums should be taken to a vet immediately.
We are monitoring the site and the public will be advised of any changes in water quality.
Waihao River at Bradshaws Bridge
Water testing indicates moderate to high cover of toxic algae (benthic cyanobacteria) in the Waihao River at Bradshaws Bridge.
People should avoid the area and animals, particularly dogs, should not be allowed near the water until the health warning has been lifted.
Other access points along the Waihao River may have benthic cyanobacteria present. People are advised to treat every low-flowing river cautiously, check for the presence of benthic cyanobacteria and avoid contact.
Fish and shellfish can concentrate toxins and their consumption should be avoided. If fish are eaten, remove the gut and liver and wash in clean water. No one should drink the water from the river at any time. Boiling the water does not remove the toxin.
Exposure to cyanobacteria toxin may cause skin rashes, nausea, stomach cramps, tingling and numbness around the mouth and fingertips. If you experience any of these symptoms visit your doctor immediately and please let your doctor know if you have had contact with the lake water.
Animals that show signs of illness after coming into contact with algal mats or scums should be taken to a vet immediately.
We are monitoring the site and the public will be advised of any changes in water quality.
Hae Hae Te Moana River at Gorge
Water testing indicates moderate to high cover of toxic algae (benthic cyanobacteria) in the Hae Hae Te Moana River.
People should avoid the area and animals, particularly dogs, should not be allowed near the water until the health warning has been lifted.
There are also other access points along the Hae Hae Te Moana River that may have benthic cyanobacteria present. People are advised to treat every low-flowing river cautiously, check for the presence of benthic cyanobacteria and avoid contact.
Fish and shellfish can concentrate toxins and their consumption should be avoided. If fish are eaten, remove the gut and liver and wash in clean water. No one should drink the water from the river at any time. Boiling the water does not remove the toxin.
Exposure to cyanobacteria toxin may cause skin rashes, nausea, stomach cramps, tingling and numbness around the mouth and fingertips. If you experience any of these symptoms visit your doctor immediately and please let your doctor know if you have had contact with the lake water.
Animals that show signs of illness after coming into contact with algal mats or scums should be taken to a vet immediately.
We are monitoring the site and the public will be advised of any changes in water quality.