In a direct rebuke to the newly-formed Myall River Action Group, which wants the river mouth dredged, a government water scientist last week blamed careless practices for turning the lakes into incubators for algae.

“The way to minimise the risk of algal blooms is to reduce nutrient inputs from the catchment and not be distracted by the downstream issues,” Department of Environment and Climate Change water specialist Peter Scanes said.

“That’s why nutrient input at Myall, Smiths and Wallis Lakes has recently been the subject of a major investigation by DECC scientists.”

Department spokesman Lawrence Orel said human activity was making the water conducive to algae.

“Examples [of polluting practices] are poor grass cover in pastures, access to streams by cattle, stream bank erosion, poor fertiliser application practice and poor sewage and septic management,” he said.

The implications for tourism, fishing and anything involving the water are grim. A toxic bloom would rule out swimming in the water, let alone drinking it.

“Depending on the severity of the bloom, it would make the water unsuitable for human contact activities,” Mr Orel said.