Checking the water at your favourite spots

As people hit their favourite beach and river spots this summer, Greater Wellington, local councils and Regional Public Health will be keeping a close eye on water quality.

During the bathing season (from mid November to the end of March) water quality is monitored at 20 river sites and 61 beach sites across the Wellington region.

Results are posted on Greater Wellington’s website www.gw.govt.nz/on-the-beaches, using a traffic light system. The health risk is determined from the number of bacteria found in water samples. A green light is for go and means the health risk is low.

Though past summer monitoring shows most beaches and river spots are fine most of the time, Greater Wellington advises people to wait for at least 48 hours after heavy rain before taking a dip.

“It pays to be careful for the first two days after heavy rain as rainfall can wash contaminants from agricultural and urban areas into our waterways and coasts,” Greater Wellington Senior Environmental Scientist Summer Greenfield says.

River users should also keep an eye out for potentially toxic cyanobacteria, a type of algae that grows in dark brown or black coloured mats on rocks in the river bed. Cyanobacteria can be fatal to dogs and livestock if eaten, and can make humans sick. Like other types of algae, cyanobacteria growth increases when river flows are low and stable and temperatures consistently warm. Users of the Hutt and Waikanae rivers and the Waipoua River near Masterton should be particularly careful as these rivers often experience cyanobacteria blooms during summer.

River users should check for warning signs and go to www.gw.govt.nz/toxic-algae for current warnings and further information about toxic algae.

If you see any exposed or easily accessible algal mats, contact Greater Wellington, P 04 384 5708 or your local council’s environmental health officer.