2010/11 + 2019: Red Cliffs (Victoria) – Blue Green Algae, Trihalomethanes

2019 December – Red Cliffs (Victoria) Blue Green Algae

Blue-green algae restricts water use for people in Red Cliffs near Mildura

https://www.abc.net.au/news/2019-12-16/blue-green-algae-restricts-water-use-for-town-in-mildura-region/11804070

Water use remains restricted for thousands of residents in Victoria’s Mallee region after warnings about blue-green algae were issued late last night.

A red alert was declared following blighting on the Murray River near Mildura, covering the stretch between Wentworth and Red Cliffs.

This afternoon, residents in Red Cliffs were told they no longer had to boil their drinking water, but a restriction on outdoor use has been extended to Mildura, Merbein and Irymple to give the town’s supplier enough time to build up a stockpile of disinfected water.

“It’s a very cautious approach, but we think it’s necessary at the moment given the challenges we’re having with our water production, and given the hot weather and the challenges we’re experiencing, we’re struggling to keep up with demand,” Lower Murray Water managing director Anthony Couroupis said.

The ban on outdoor use is all about restoring sufficient volumes in our storages so we can keep up with demand.”

With a heatwave forecast to hit the region this week — Mildura is tipped to exceed its December record with 47C on Friday — Lower Murray Water will be monitoring its urban water supply “almost on an hourly basis”, Mr Couroupis said.

“We’re not of the view that we’ll have to issue the same boil-water notice for Mildura, but we’re certainly experiencing the same challenges at our Mildura and Mildura West water treatment plants, [which] supply Merbein, Mildura and Irymple townships,” he said.

Blooming out of season

Joanne Farrell, executive officer of the Red Cliffs Community Resource Centre, said the restrictions initially caused some confusion, and that bottled water was “selling out fast” at local shops.

“We’re boiling water here and putting it in the fridge for people,” she said.

“There’s no taste difference or anything like that.”

Ms Farrell said the timing of the red alert was unusual for the region.

“We kind of expect it in about March, but this is quite a few months earlier,” she said.

“So that’s probably the biggest worry in people’s minds — that this is so much earlier in the piece.”

‘Not seen anything like it’

Experts have found both the timing of the outbreak, as well as the type of algae, unexpected.

“This is certainly a new strain for our staff,” Mr Couroupis said.

“We’ve got crews who have been on 24/7 over the past few days trying to work through this … people who have been dealing with blue-green algae for almost 30 years, and they have not seen anything like this.”

At time of publication, the Murray River algal bloom was not on Victoria’s emergency alert website, although an alert had been published for a bloom at Lake Charlegrark in the state’s west.

The situation is being monitored by Water NSW, which said it was unknown how long the bloom would last.

“It looks like it’s going to be a long summer for blue-green algae,” spokesman Tony Webber said.

“Certainly where the drought is biting in areas across the north, well north of the Murray region, water quality is diminishing and has certainly been in very, very poor quality for the last two years.

“But it remains to be seen what the situation is on the Murray as the summer progresses.”

Economic fears

The bloom has also sparked concerns that the Sunraysia region’s tourism industry could experience a lull over summer.

Authorities have warned people not to come in contact with the water in the Murray River there, because the algae can cause gastroenteritis, as well as skin and eye irritations.

Daryl Beasy, the owner of the Apex Riverbeach Holiday Park in Mildura, said high levels of algae had the potential to have a massive financial impact.

“Most people come here because of the river and the sandbar,” Mr Beasy said.

“They want to swim or ski, and if they can’t get in the water, we’ll lose lots of bookings.

“If we get any more warm weather, I think it will spread pretty fast and hang around for quite a while until we get cool weather or lots of rain to flush it out.”

Mildura Regional Development said it had a well-established action plan to help advise operators on dealing with the algal outbreak, such as providing visitors with information about travel and accommodation options.

Chief executive Brett Millington said visitors could be assured that paddleboat tours, recreational boating, kayaking and jet-skiing could all still be undertaken.

“We are working closely with Lower Murray Water who are monitoring these areas regularly, so that we can keep industry advised where water-skiing and swimming may still be accessible,” he said.

Red Cliffs (Victoria)

Highest Level Only

Red Cliffs 0.280mg/L THM’s 2010/11

Trihalomethanes Australian Guideline Level 250μg/L (0.25mg/L)

Why and how are THMs formed?
“When chlorine is added to water with organic material, such as algae, river weeds, and decaying leaves, THMs are formed. Residual chlorine molecules react with this harmless organic material to form a group of chlorinated chemical compounds, THMs. They are tasteless and odourless, but harmful and potentially toxic. The quantity of by-products formed is determined by several factors, such as the amount and type of organic material present in water, temperature, pH, chlorine dosage, contact time available for chlorine, and bromide concentration in the water. The organic matter in water mainly consists of a) humic substance, which is the organic portion of soil that remains after prolonged microbial decomposition formed by the decay of leaves, wood, and other vegetable matter; and b) fulvic acid, which is a water soluble substance of low molecular weight that is derived from humus”. Source: https://water.epa.gov/drink/contaminants/index.cfm