2020 August: Silvan Dam Loses Power (Melbourne) – Untreated water. 87 suburbs impacted

1/9/20 Untreated Silvan water pretty clean anyway, contrite supplier claims

The Age: https://www.theage.com.au/politics/victoria/untreated-silvan-water-pretty-clean-anyway-contrite-supplier-claims-20200901-p55r8d.html

Melbourne Water has apologised for a “rare event” that led to more than 270,000 Victorians being told to boil their drinking water for up to two days last week.

On Friday, Yarra Valley Water and South East Water were left scrambling to secure treated water supplies for 99 suburbs, after storms on Thursday night sparked power outages that allowed untreated water from Silvan Dam to enter the water supply.

Yarra Valley Water issued a warning to its customers on social media, directing customers to its website for more information about whether their suburb was affected.

Both providers’ websites crashed, amid widespread complaints from customers they weren’t told about the issue until after they’d drunk potentially contaminated water.

But Melbourne Water on Tuesday moved to assure customers that even untreated water from Silvan Reservoir is among the cleanest in the world.

Yarra Valley Water and South East Water buy bulk water from wholesaler Melbourne Water, which gets water from a range of water catchments.

The water released into parts of Melbourne’s water system on Thursday night came from Silvan Reservoir, where it is naturally filtered from forested catchments that are off limits to the public.

Melbourne Water says this water usually requires minimal chlorination treatment because of its high quality, and that untreated water is of low risk to the public.

Melbourne Water service delivery general manager Craig Dixon said a series of failures led to the water contamination.

“Thursday night’s severe storms caused a widespread power outage with the subsequent failure of the two – main and back-up – incoming power feeders causing the treatment process of water from Silvan Dam to go offline,” Mr Dixon said.

“The generator kicked in and, after successfully running for a number of hours, failed. This is a rare event.

“In the last 20 years this is only the second time in which the two main power feeders and the generator have failed at the same time at Silvan water treatment plant.”

Melbourne Water is still investigating the incident and said that it was working to lessen the impacts from future outages where possible.

Melbourne Water brought in backup generators on Friday, and restored one mains power feeder on Friday night. The second feeder was brought back online by Saturday morning, and water was again being treated later that day.

All of the Melbourne suburbs cautioned to boil their water due to a contamination scare were given the all-clear on Sunday.

28/8/20: Silvan Dam Loses Power – Untreated water enters system 87 Suburbs Impacted

Age 28/8/20

Melbourne residents are waiting to hear when they will no longer need to boil drinking water, as many gathered on Saturday at emergency tankers to fill bottles and pots and pans after a wild storm caused widespread blackouts and potentially contaminated drinking supplies across at least 100 suburbs.

More than 270,000 households were still being urged to boil their water on Saturday afternoon as they anticipated an update at 8pm. About 10,000 homes remained without power after the vicious winds and heavy rain that lashed the state on Thursday night knocked out power to more than 130,000 customers.

The Silvan Dam – one of the main water supplies for the city’s northern and eastern suburbs – lost power during the storm and a back-up generator also failed, allowing potentially contaminated water to be pumped into people’s homes.

But blackouts have made it impossible for some residents without a gas supply to boil their water.

Water tankers were sent to The Basin, Boronia, Ferntree Gully, Upper Ferntree Gully, Belgrave, Upwey, Croydon North and Mt Evelyn on Saturday for the second day, with residents encouraged to “bring your own bottles, pots [and] kettles to fill up from the tankers”.

Suburbs still affected by water contamination warning as of 10pm Saturday

Yarra Valley Water named 87 suburbs affected, including Doncaster, Reservoir and Eltham, while South East Water issued alerts for 13 suburbs still affected on Saturday morning.

Yarra Valley Water said it expected the water supply to back to normal by Saturday evening, but that confirmation may come at 8pm.

The company said it was conducting water quality tests to “ensure there is no risk”. Residents in affected suburbs will be notified as soon as the water is safe to drink again.

In the meantime, residents should bring their tap water to a “rolling boil” – a vigorous boil in which the bubbles do not lessen when the liquid is stirred – as a precaution for drinking, brushing teeth, food preparation, making baby formula, ice or bathing infants in the 100 affected suburbs including Epping, Doncaster, Croydon, Coburg North, Craigieburn, Mernda and Ringwood.

Chief Health Officer Professor Brett Sutton said he hoped the water boiling advisory would not be in place “for too long”, but if anyone drank the contaminated water they could get mild gastro-like symptoms such as vomiting, diarrhoea, cramps and headaches.

Thousands of homes across Melbourne’s eastern suburbs, the Yarra Yalley, South West Gippsland and Eastern Victoria were facing a third night without power on Saturday, with the suburbs Kilsyth, Ferntree Gully and The Basin worst affected.