Environment Protection Authority Victoria (EPA) has today published a snapshot of water quality in Port Phillip Bay and its catchments over the past financial year.
EPA Group Manager of Applied Sciences, Anthony Boxshall said that while overall water quality had marginally declined, it was pleasing to see improvements in some catchments and the continued good quality of Port Phillip Bay.
“The Yarra catchment’s water quality in particular has been improving for more than a decade, despite pressure from urbanisation and population growth,” Dr Boxshall said.
“More than one-third of Victoria's native plant and animal species live in this catchment and we know it’s popular for many recreational uses, so this result is very positive,” he said.
Dr Boxshall said that water quality in the Mornington catchment had also improved, with slightly lower levels of nutrients and improved dissolved oxygen levels.
Dry conditions also led to significantly reduced river flow and saw some small tributaries reduced to isolated pools, particularly in the Maribyrnong and Werribee catchments.
“This generally resulted in a decline in water quality. Reduced flow often results in low oxygen levels and increased salinity and algal blooms, all of which can cause stress to aquatic life,” Dr Boxshall said.
Called Report Card, the data is published on the Yarra and Bay website and was developed with input from Melbourne Water and the Department of Environment, Land, Water and Planning.
Report Cards dating back to 2012-13 are also available on the site.
Key indicators of water quality have been used to calculate an overall water quality score for each of the 102 catchments and eight marine sites in the 2015-16 Report Card.
Dr Boxshall said that government agencies, local councils and the community had taken many steps in recent years to improve water quality in the bay and its catchments.
“Native vegetation planting, the removal of silt and litter and efforts to reduce agricultural runoff are just some of the many initiatives helping to improve water quality,” he said.
“These steps are vitally important. The catchments and bay of the Port Phillip region are popular social and recreational areas, and are important to the livelihoods of farmers, fishers and businesses across Victoria.”
The Report Card provides examples of specific actions undertaken in each catchment that contribute to positive impacts on water quality.
Dr Boxshall said that everyone could make a difference to water quality in the bay and its catchments by being mindful of what enters the stormwater system.
“The stormwater drain in your street eventually flows to the nearest creek, river, lake or bay, so we must all be mindful of what enters these drains,” he said.
From 1 December, EPA will be issuing twice-daily water quality forecasts for 36 Port Phillip Bay Beaches and four locations in the Yarra River popular for water activities.
The forecasts will predict water quality based on the latest weather conditions, water quality history, recent bacterial sampling results and community pollution reports.
EPA advises against swimming for up to 48 hours after heavy rain because during this period there may be a higher risk of illness to swimmers from increased bacterial levels.
For further information visit the Yarra and Bay website at www.yarraandbay.vic.gov.au.
Photo: Volunteers cleaning up the Port Phillip Bay shoreline. Source: Melbourne Water