State of the Derwent Report Card shows importance of high frequency data

Monitoring water quality can be challenging as programs are costly and do not capture incidents, variable pollutant sources, rainfall-runoff events and in-stream processes such as nutrient uptake. To address these challenges, we are trialling real-time water quality analysers in the Derwent River catchment.

Funding from The Ian Potter Foundation, Hydro Tasmania, TasWater, the Environment Protection Authority and Meadowbank Vineyard enabled us to purchase six Eco Detection real-time water quality monitoring systems to measure nitrate, nitrite, phosphate, chloride, carbonate, sulphate and fluoride, as well as other key parameters. The analysers work remotely and in near real-time, automatically taking measurements every 1–6 hours. Data is sent to the Cloud where it can be accessed from anywhere on mobile devices or computers.

The technology was developed by Professor Michael Breadmore’s team at the University of Tasmania and engineered for commercialisation by Melbourne-based company Eco Detection, with the goal to provide robust, autonomous and low cost systems that provide data in real-time allowing fast and smarter decisions regarding industry operations and waterway management.

Since May 2022, all six Eco Detection units have been operating in the River Derwent catchment. The six sites include two outfall locations (TasWater’s sewage treatment plant Turriff Lodge at New Norfolk, and Norske Skog outfall), as well as three tributaries (Clyde, Ouse, and Florentine rivers), and the River Derwent below Meadowbank Dam. We have also inherited an additional Eco Detection unit from the University of Tasmania located at Westerway (Tyenna river). This is the first water quality monitoring network on a catchment scale using this technology.

To validate the data generated by the analysers, traditional grab samples have been collected as part of a 12 monthly assessment with nutrients analysed at Analytical Services Tasmania. The laboratory results are compared to data produced by the in-situ Eco Detection units to ensure accuracy. Once the analyser validation is complete (June 2023), we will investigate nutrient loads at each site. With this high frequency data, we also gain an understanding of daily nutrient variability and rainfall-runoff dynamics, which is not possible with traditional monthly monitoring programs. Figure 5.4 shows an example for high frequency nitrate data at the Clyde (Hamilton), in relation to flow.

You can read the Report Card here.