Results

The annual Water Quality Report Card uses key indicators of environmental water quality to calculate an overall annual score. The report card compiles results from July 2021 to June 2022, and presents a history over the last 20 years.

In 2021–2022, water quality in Port Phillip Bay and its waterways varied from Very Good in areas of the Bay and upper reaches of the catchment, to Very Poor in highly urbanised waterways, which is similar to previous years. Water quality was mostly Very Good or Good for rivers in the headwaters of catchments. Water quality generally declined to Poor or Very Poor as the rivers moved through rural, agricultural and low-lying urbanised areas in the foothills and coastal plains of the lowlands. In Port Phillip Bay, overall water quality was Good, which reduced water clarity resulted in a Poor rating for this parameter. In bays and lakes, water quality was Very Good or Good for areas that mix with the open ocean. Water quality was generally worse in areas of Port Phillip Bay adjacent to river entrances that transport sediments and nutrients from urban, industrial and agricultural areas.

Data from the Bureau of Meteorology shows that the climate in Victoria during 2021-2022 had an average rainfall across central Victoria but much higher in eastern Victoria compared with the long-term average. The summer months from December 2021 to March 2022, were notably drier in Western Port and Port Phillip Region and were similar to the long-term average. A weak La Niña event brought higher than average rainfall to some areas, which differed from the relatively drier conditions during the preceding 3 years.

The annual Water Quality Report Card has been available on Environment Protection Authority Victoria (EPA) website since 2019. Before that, results were published on the Yarra and Bay website.