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 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.
- 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.
Temporary health warnings
Ōpihi River at SH1 Bridge
Health New Zealand | Te Whatu Ora has issued a health warning for Ōpihi River at SH1 Bridge.
The warning follows finding moderate to high cover of potentially toxic harmful algae (benthic cyanobacteria) in the Ōpihi River at SH1 Bridge.
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 Ōpihi 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 with the water.
Find out more: Land, Air, Water Aotearoa (LAWA) - Opihi River at SH1 Bridge
Otaio River at Otaio Gorge and Waihao River at Gum Tree Road (Don’s Hole)
Health New Zealand | Te Whatu Ora has issued a health warning after high levels of faecal bacteria were found in samples taken from Otaio River at Otaio Gorge and Waihao River at Gum Tree Road (Don’s Hole).
Water quality at the affected sites is not considered suitable for recreational uses including swimming because of the risk to health from the bacteria and other pathogens.
Water contaminated by human or animal faecal matter may contain a range of disease-causing micro-organisms such as viruses, bacteria and protozoa.
Other popular swimming sites in South Canterbury may also have high levels of contamination after recent rainfall. People should avoid all rivers, lakes and beaches within 48 hours of significant rain.
Find out more: Land, Air, Water Aotearoa (LAWA) - Otaio River
Waihi River at Waihi Gorge
Health New Zealand has issued a health warning for Waihi River at Waihi Gorge.
The warning follows finding moderate to high cover of potentially toxic harmful algae (benthic cyanobacteria) in the Waihi River at Waihi Gorge.
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 Waihi River at Waihi Gorge 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.
Find out more: Land, Air, Water Aotearoa (LAWA) - Waihi River at Waihi Gorge
South Bank Tributary of the Waiau Uwha River above Waiau Bridge
Health warning
Health New Zealand has issued a health warning for the South Bank Tributary of Waiau Uwha River above Waiau Bridge.
The warning follows finding moderate to high cover of potentially toxic harmful algae (benthic cyanobacteria) in the South Bank Tributary of the Waiau Uwha River above Waiau Bridge.
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 South Bank Tributary of the Waiau Uwha River above Waiau Bridge 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.
Find out more: Land, Air, Water Aotearoa (LAWA) - South Bank Tributary of the Waiau Uwha River
Pareora River at Pareora Huts
Health New Zealand has issued a health warning for the Pareora River at Pareora Huts.
The warning follows finding moderate to high cover of potentially toxic harmful algae (benthic cyanobacteria) in the Pareora River 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.
Find out more: Land, Air, Water Aotearoa (LAWA) - Pareora River
Waihao River at Gum Tree Flat Road
Health New Zealand has issued a health warning for Waihao River at Gum Tree Flat Road (Don's Hole).
The warning follows finding moderate to high cover of potentially toxic harmful algae (benthic cyanobacteria) in the Waihao River at Gum Tree Flat Road (Don's Hole).
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 Waihao River at Gum Tree Flat Road 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.
Find out more: Land, Air, Water Aotearoa (LAWA) - Waihao River at Gum Tree Flat Road
