Questions are being raised about the environmental impact of a sewer overflow in Kyneton after torrential rain overwhelmed part of the town’s sewerage network earlier this month.
Local resident and river pollution expert David Tiller has called on Coliban Water to release evidence supporting its assurances that the spill posed a low risk to the community and the environment.
Mr Tiller said that while the overflow was triggered by stormwater infiltrating the sewerage system, it would also have contained significant amounts of human sewage.
“The potential risks can only be assessed if pathogen testing, usually for E. coli, was undertaken,” he said.
“Coliban Water would no doubt have done this, so what were the results and do they back up their implied statements about there being little risk to human health? Disinfecting the spill area suggests there may have been potential risks.”
He also questioned Coliban Water’s explanation for frothy water seen in sections of the Campaspe River after the rain.
“Stormwater runoff will no doubt contain substances that cause foaming, but sewage also contains considerable amounts of surfactants, including household detergents,” he said.
“Sampling the overflow would provide evidence of the foaming agents present and therefore the likely source.”
Mr Tiller also asked whether the Environment Protection Authority had investigated the incident and called on Coliban Water to back its public statements with data collected during the spill.
The overflow occurred when intense rainfall inundated the Jeffrey Street sewer pump station, causing it and a nearby sewer access point to overflow.
Coliban Water said the discharge consisted largely of stormwater. Crews installed precautionary signage, cleaned and disinfected the affected area, carried out water quality testing and notified the Environment Protection Authority.
The authority also rejected suggestions the sewer spill caused frothy water in the Campaspe River.
“During heavy rainfall, runoff can wash accumulated organic matter, oils and tannins from roads, paths and nearby farmland into the Campaspe River,” a spokesperson said.
“This organic matter, combined with high water volumes, can create a frothy or bubbly appearance. This may have been visible at various points along the river and is unrelated to the sewer spill.”
Coliban Water confirmed the spill had been reported to the EPA and initial water quality testing had been completed.
“These results show the samples are not consistent with raw sewer contamination only,” the spokesperson said.
“The impacted land has been cleaned and disinfected. Further water quality testing will be carried out.”
The authority acknowledged community concerns about Kyneton’s ageing sewer infrastructure and confirmed a major upgrade of the Jeffrey Street pump station was due to begin in 2027. The project will include new underground storage tanks and replacement pumping equipment to improve capacity during future heavy rain events.
