The Water Corporation has issued a warning for people to avoid a one kilometre radius around the Cape Peron ocean outlet until further notice following a microbiology issue.
Elevated levels of microbiology in the marine environment off Cape Peron has prompted the Water Corp to issue the warning, urging people to avoid swimming, diving, kayaking or fishing within a one kilometre radius of the outlet.
The fishing restriction includes shell-fishing, crabbing and cray-fishing.
This outlet is four kilometres off shore from Cape Peron, in a channel 20 metres deep.
The elevated levels have been caused by a decline in the quality of treated wastewater leaving the Woodman Point Wastewater Treatment Plant since mid-February.
The drop in quality has resulted from work associated with the current major upgrade project under way at the Plant.
Since 1995, the Water Corporation's Perth long term ocean outlet monitoring program, has conducted an annual summer water quality monitoring survey.
Recent sampling results taken as part of this survey have shown elevated microbiology in the marine environment off Cape Peron.
As a precaution, Water Corporation has advised people to stop activities in the water near the zone, but Water Corporation spokesperson Clare Lugar said nearby beach areas are not affected.
Further sampling is under way and the results will assist Water Corporation to work with its regulators to determine when this precautionary advice can be lifted.
Water Corporation expects the quality of wastewater leaving the plant to significantly improve over the next month as the work that affected wastewater quality is completed.
The $158.5 million upgrade will increase the capacity of the wastewater treatment plant to safely treat up to 180 million litres of wastewater from homes and businesses south of the river each day. The project will be completed by October 2019.
Water Corporation’s Perth Long Term Ocean Outlet Monitoring Program focusses on the potential effects of ocean outlets from Perth’s major wastewater treatment plants on the marine environment.