Current state of
The Department of Environment, Land, Water and Planning collects water quality data as part of a Regional Water Monitoring Partnership with 40 other organisations. The data is presented on the Water Measurement Information System and can be accessed by anyone on the internet at data.water.vic.gov.au
Some sites have monthly water quality data for the past 20 years.
The Water Measurement Information System holds a large amount of water quality data, including data on a number of indicators:
Most common indicators collected
Turbidity, pH, electrical conductivity, total suspended solids, nitrogen, phosphorus, dissolved oxygen, temperatureMetals
Arsenic, cadmium, chromium, copper, lead, manganese, mercury, nickel, zinc, iron
Less common indicators collected
Calcium, chloride, magnesium, potassium, sodium, sulphur, silica, alkalinity
Water quality indicators can be collected monthly, continuously every hour or day, or less often.
Water quality trends
The Victorian Water Quality Trends report is produced every five years. The analysis that informs the report helps us identify patterns of change in water quality over time. The latest report compares water quality from 2011 to 2016 with the historical record from 1991 to 2010.
During the historical period, most sites, when site-specific factors were taken into account, showed trends of declining turbidity and nutrients, declining dissolved oxygen levels and increasing electrical conductivity (salinity) from prolonged periods of low flow conditions.
The effect of reduced rainfall and river flows during the Millennium drought from 1996 to mid-2010 dominated water quality trends over the historical record from 1991 to 2010.
Record rainfall and flooding from late 2010 to 2012 caused by a La Niña weather pattern broke the Millennium drought and indicated a return to average conditions after 2012. These climate effects caused a shift in water quality conditions in the current data at most sites from 2011 to 2016.
During the current period, dissolved oxygen levels improved at most sites from increased flow in the rivers. Turbidity and nutrient levels increased with higher catchment runoff, although site-specific factors were at play.