Algal bloom leaves towns high and dry in Australia

by Leo Shanahan at theAge.com (Australia)

A toxic algal bloom has forced authorities to cut normal water supplies to towns along Victoria's Great Ocean Road, leaving locals reliant on daily deliveries by water trucks.

The latest outbreak comes as the head of a major regional water operator said he expected an increase in the number of blue-green algal blooms and follows an outbreak at Werribee South last month that affected farmers using recycled water to grow their crops.

At a cost of about $3000 a day to regional water supplier Barwon Water, 20 trucks a day are delivering water from Anglesea Reservoir to about 1400 Aireys Inlet and Fairhaven residents.

The algae, which has made the water unsafe to drink, was detected last Wednesday and has forced Barwon Water to shut down all supply from the Pan Reservoir that supplied the towns.

If consumed, blue-green algae can cause skin irritations, allergic reactions and nausea.

Barwon Water chairman Stephen Vaughan told theage.com.au the bloom was caused by a combination of warmer temperatures, prolonged drought and recent rain.

"It's mostly related to temperature and the unseasonably warm May," he said.

"It also occurs when reservoir levels are lower rather than fuller, and the third thing is the little bit of rain we had two weeks ago probably washed nutrients from the into the reservoir and then you get phosphorus and nitrogen ... that's enough to kick it off."

...Mr Vaughan said that while such outbreaks were likely to happen once every four to five years he warned that with warmer temperatures and drought, such algal blooms would be more common in all water supplies...