Save Our Soils Water Watch

Findings from monthly water quality testing in the lower Werribee River.

Since 2008 The Werribee River Association has been undertaking monthly water quality testing at Bungees Hole as part of Melbourne Water’s Waterwatch program. The program asks local volunteers and community groups to collect water samples to test for nitrates, phosphates, pH levels and turbidity. With 15 years’ worth of data collected at the site, we now have extensive insight into the characteristics of the area, the common threats and priority areas for advocacy.

In 2022 we expanded our collection site into the lower Werribee River, to include three drain outlets in Werribee South. Aware of the important contribution Werribee South’s market gardens make to Melbourne’s food security, as well as the challenges many of the farms are facing in the current climate, we believe that this testing can help contribute to more economically viable and sustainable farming in the area.

Findings from four monthly tests from Nov 22-March 23 reveal that sediment is coming off the farms, but not on a regular basis. It seems to occur after rain, irrigation or a combination of those two. Sediment runoff is not desirable for waterways or the farms as it means topsoil, and the nutrients it carries with it, is washing into the river. The Werribee River Association will be undertaking extensive planting around more than one of the selected drain outlets later in 2023 and will monitor whether this reduces sediment run-off.

In most tests, phosphates are high. This is understandable in such an intensive farming area and is to be expected, and, the samples are taken from large areas of land and so may concentrate levels recorded. Through encouraging topsoil retention by revegetating, farmers could save costs as the level of fertiliser required may be able to be reduced. pH is generally neutral and are considered healthy, however is leaning towards alkaline, with findings of 7.4 or more in all three drains to date.

In addition to our monthly testing, we will be installing two Bio2Lab sensors that will provide real-time, accurate data that will deepen our understanding and add to our findings. As part of Save Our Soils we aim to work collaboratively with farmers, sharing results and knowledge to benefit our vital food bowl and local waterways.

For more information and to join our Water Watch program contact

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