On-site: Pranjip Creek is one of the three tributaries that flow into the Goulburn River. It is filled with blackwater, as seen in this photograph taken on Tuesday, January 18.
Photo by
Goulburn Valley Water
On Monday night Shepparton and Mooroopna residents received a text from Goulburn Valley Water stating that blackwater had contaminated drinking water.
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Blackwater occurs when river banks are flooded, due to heavy rain, and the leaves, organic cropping and grass on the sides are washed into the waterways.
Goulburn Valley Water water quality manager Mark Putman said this was what had happened to the smaller tributaries that flowed into the Goulburn River, where the city’s water came from.
“The high levels of organic matter in the waterways combined with the warmer weather means less oxygen in the waterways ... It can cause water levels to drop and it picks up natural taste and odour compounds and we call them MIB ... It can get released into the water and it’s hard to remove — but it’s harmless to drink,” Mr Putman said.
The heavy rainfall from the past week contributed to these build-ups of blackwater, which Mr Putman said was noticed on Saturday.
He said the levels of turbidity and absolute colour had peaked to higher levels than normal, indicating blackwater.
“Our two main target points (for blackwater) are more particulate matter like dirt in the water, and we call that turbidity. So, we would typically, prior to a rain event, be running 40 to 60 NTU in the water to measure turbidity. It peaked over the weekend to 130 NTU,” he said.
“Then we have what we call colour. An absolute colour prior to the weekend was 60 to 100 and on the weekend that peaked to 275. Today we are about 50 NTU and 125 colour so, we think we got over the worst of those washings and the water is certainly improving.”
It’s getting better: Raw water sourced from the Goulburn River. The container on the left holds water taken from the river on Monday; the middle container is Tuesday’s water; and the far right is the treated water distributed to homes.
Photo by
Goulburn Valley Water
Mr Putman said Goulburn Valley Water would monitor the water regularly and use a range of hand-held and online instrumentation to make the required adjustments as the water quality changed.
“The way we manage it is we increase our operation surveillance at the plant on a more regular basis and make small changes to the operation of the plant to ensure the water going into town is safe and the best it can be,” he said.
Mr Putman said the water was safe to drink and that if people could taste or smell it, there was a way to avoid it.
“One thing we have noticed that can help (get rid of any taste and odour) is to put an open jug of water in the fridge and that allows it to aerate and for the compounds to be released from the water, and also chilling it can help with the taste,” he said.
For more information on blackwater in the Shepparton area, visit the Goulburn Valley Water website.
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