Locals are demanding answers about a pollution incident in a usually pristine Derwent Valley river

Residents are concerned for their health after a waste spill in a normally crystal clear river that is home to numerous platypuses, with the incident also affecting a major tourism attraction.

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THE environmental watchdog is investigating a liquid waste spill that affected the Salmon Ponds in the Derwent Valley and contaminated a local water supply.

Residents living along the Plenty River described a large plume of foul smelling sludge that entered the river above the Salmon Ponds on Wednesday afternoon and moved downstream to the River Derwent.

Roderick Blair, who is one of a dozen property owners who source their drinking water directly from the Plenty River, said a neighbour alerted him about 2pm on Wednesday.

“He called and said ‘A large plume of sewage is heading your way’,” Mr Blair said.

By the time he arrived home about 5pm the sludge was covering an approximately 30m section of the river and Mr Blair said he could see fish pushed up against the riverbank attempting to get oxygen.

“It stank like treated sewage and moved as a plume. The horses wouldn’t drink from the water in that area,” he said.

A photo taken by local residents of polluted water in the usually pristine and crystal clear Plenty River.

The Environment Protection Authority (EPA) received a report from the Inland Fisheries Service, which runs the Salmon Ponds and hatchery, on Wednesday regarding “an incident of polluted water at the Salmon Ponds”, a spokeswoman said.

“The EPA has collected samples and is conducting an investigation into the cause of the incident,” she said.

One resident said she was concerned the samples taken by the EPA were collected from the Upper Plenty Bridge area, not the affected area near Plenty Bridge.

She said the pollution was foul smelling, with “white specked material” floating in it and there were concerns it had made its way to the Bryn Estyn Water Treatment plant, which is Hobart’s main water source.

However, TasWater said the Bryn Estyn plant was monitored 24 hours a day with regular sampling and there had been no indication of changes to water quality entering the system.

“Our Bryn Estyn water treatment plant uses chlorine dosing as the final disinfection process, and this system provides protection to ensure a safe supply of water for the customers of the greater Hobart area,” TasWater regional services manager Brendan Hanigan said.

“We are unaware of any notification of a recent incident. In the event of any incident we work closely with the EPA on any issues that could potentially pose a risk to drinking water.”

TasWater’s Brendan Hanigan said the organisation was unaware of any notification of a recent waste spill incident.

Mr Blair said locals were passionate about protecting the river, which is normally crystal clear and home to galaxias fish and platypuses.

“It must be investigated and I would like to see some results and some stringent action taken,” Mr Blair said.

“It’s a pristine environment that shouldn’t have potential hazards like this. It’s a small farming community and everyone looks after the environment.”

A Public Health spokesman said that although authorities had been alerted to the incident, they had not been advised of any water quality breaches.