High risk from toxic algae in Hutt River
River users should avoid parts of the Hutt River due to widespread growth of potentially toxic cyanobacteria.
Monitoring by Greater Wellington shows that coverage of cyanobacteria (also known as blue-green algae) is now high in the Hutt River from Birchville downstream. Detached algal mats are also present on the river’s edge. River users, particularly those with dogs, should avoid contact with these parts of the river.
Hutt City Council has posted warning signs at key access points along the river. See the Greater Wellington website for up-to-date information.
Cyanobacteria are naturally present in many New Zealand waters, and grow in dark brown or black coloured mats on rocks in the river bed. Some produce toxins that can be fatal to livestock and to dogs. Dogs are particularly susceptible to exposure because they like to scavenge near water. Contact with algae toxins may also cause vomiting, diarrhoea and skin irritations in humans.