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Vivienne Pearson

After floods and storms, is it safe to swim in beaches, lakes and rivers over Easter?

Jade contracted an ear and vaginal infection after swimming in Byron Bay.  (Supplied: Burak Polat)

It only took 15 minutes of swimming at Byron Bay's Belongil Beach, a week after February's devastating floods, for Jade to know something was amiss.

"The water looked okay, and other people convinced me it was fine, I but I felt a burning sensation so got out quickly," she remembers.

After a quick trip to the GP, Jade was confirmed to have an ear and vaginal infection.

The doctor said the clinic was seeing significant numbers of people with ear, eye, skin and – yes – genital infections after swimming or surfing.

These infections were caused by contact with polluted flood and storm water that had flowed into the sea.

With rain and storms seemingly endless across Australia's east coast over the past six weeks, how do you know when it's safe to get back in the water?

Belongil Beach at Byron Bay is usually great place to swim but flood and storm water has left it contaminated. (ABC News: file photo)

What's the deal with flood and stormwater?

The dirty water is coming from two places.

First, the heavy rainfall is sending larger than usual amounts of stormwater into drains and is not treated, or even necessarily even filtered, before it flows into creeks, rivers and oceans.

Secondly, these creeks and rivers are then overflowing, with the flood water inundating what is usually dry land.

Both stormwater (entering drains during heavy rainfall) and flood water (overflowing from rivers and lakes onto usually dry land) collect pollution from agriculture, urban environments and industry.

"Floodwater can contain hazardous substances, including raw sewage, chemicals and other contaminants," says Paul Douglas, the director of the North Coast Public Health Unit in NSW.

Extreme events — like the recent floods — can cause longer term problems for waterways.

A water treatment plan in the Lismore area was damaged beyond repair during the recent floods and is now sending four megalitres of raw sewage each day into the area's waterways and eventually out to sea.

The East Lismore sewage treatment plant hasn't been working since flooding in February. (ABC North Coast: Bruce MacKenzie)

Will I get sick if I swim?

Pollution becomes diluted as flood and stormwater flows through rivers and into the sea, but the impact remains significant.

Testing levels of Enterococci or E. coli bacteria is one way to check water quality.

The organism is typically found in the poo of virtually all birds and mammals, including humans.

"While Enterococci and E. coli are not typically a health risk in and of themselves, they're a useful indicator of faecal contamination in the water," says Dr Craig Evans from the School of Environmental and Life Sciences at The University of Newcastle. "Faeces often contains other organisms that do represent a health risk."

If you accidentally swallow a mouthful of water while swimming or surfing, bacterial or viral organisms in the dirty water can cause diarrhoea-type illnesses.

And if these organisms reach parts of the body where they don't normally belong, like ears, eyes or skin cuts, infection can set in.

These cattle swam through flood waters, contaminating it with faecal matter as they fled. (Supplied: Lee Challacombe)

Agh! How do I find water quality test results?

In NSW, local councils carry out water testing of rivers, harbours and oceans. The testing is usually in conjunction with Beachwatch, a Department of Planning and Environment program based on guidelines from the National Health and Medical Research Council (NHMRC).

Tom McAully Rix, an environmental officer with Ballina Shire Council, explains that river or sea water is collected from popular swimming spots. Samples are taken at knee-depth, sealed in 250ml jars and popped into an esky with ice before being sent off for testing.

There are several ways to report results.

One popular method is a star rating based on a scale of one to four.

Water samples that receive one or two stars on the scale indicates an increased risk of illness for everyone.

Three stars shows an increased risk, especially for those with lower immune function, the elderly and young children.

Four stars indicates the water has safe levels of bacteria.

Lighthouse Beach in Ballina, close to Byron Bay, was closed because the area's waterways were polluted by flooding. (ABC North Coast: Bruce Mackenzie)

Another method used to report water quality is a daily pollution forecast that is popular in the greater Sydney area including the Hunter, Central Coast and Illawarra.

The forecast, based on the most recent water quality test results plus recent weather, is communicated using an at-a-glance traffic light style system, rating water quality as red, amber or green.

Some regions test water only during the prime swimming months of December to February.

However, the recent flooding has sparked a change in the Ballina and Byron council areas where testing has restarted and expanded.

Test results are not instantaneous. Analysis takes at least 24 hours and weekly testing means results need to be interpreted along with knowledge of more recent weather and other local events.

There is no one-stop-shop app for water quality results — unlike the myriad of options available for tide, wave and weather forecasts — so it's not always easy to find information, especially while away on holiday.

Beachwatch's daily pollution forecast is available on a mobile-friendly website. Regional areas that are not included report their findings either via harder to find section of Beachwatch's website or their own websites or communication.

Should you swim?

The Easter holiday break is typically warm enough for most people to swim while on holiday but this year Ballina Shire Council is warning people not to swim.

"It could take several weeks before harmful bacteria and debris is flushed and will depend on further rainfall in the region," the alert says.

Byron Shire Council recently posted more variable results that range from safe to swim, to significant risk of illness.

It is an important example of the fact that testing results can vary widely, even within one geographical area.

"Pollution is affected by tide, swell, wind and onshore drifts and how these factors interact can be highly variable, even within the day," McAully Rix says.

What about foam?

Have you ever seen large amounts of dirty-looking foam building up in waterways, particularly on ocean beaches?

Some of this foam is caused by the natural breakdown of leaves and branches, says McAully Rix, who has a master's degree in marine science.

But the foam can also be contaminated. "I once accidentally swallowed some while surfing and it was rancid," he says.

Evans agrees it can be hard to tell the difference. "Foam due to natural organic matter is typically not slimly to the touch while sewage pollution may be," he says. "But I'm not suggesting you should necessarily be sticking your hands in it to find out!"

The Richmond River at Ballina is experiencing high levels of contamination in the wake of the floods, including untreated sewage which has flowed downriver from Lismore. (ABC News: Matt Coble)

How do I figure out whether it's safe to swim?

Unless pollution or other factors are severe enough to prompt closure of a beach — a decision made in consultation between councils and Surf Lifesaving NSW — the final call on whether to swim or surf is yours to make.

After regular heavy rainfall, Beachwatch's advice is to avoid swimming in the ocean for at least one day, or three days for harbour beaches. Things to watch for when making a decision are signs of pollution including water discolouration, oil or scum, or rubbish and debris collecting along the water or on the tideline.

After extreme weather events the wait to return to the water will most likely take weeks. If storms continue, or other circumstances are present, such as Lismore's damaged sewage treatment plant, that time frame could become even longer.

That's not great news for holiday makers or locals who rely on swimming for their physical or mental health.

Staying informed is the first step.

Seek out recent testing results from Beachwatch or local councils and combine that with common sense understanding about the most recent weather or local knowledge about other events.

If swimming seems like a possible option, Sonya Link from local company Surf Getaways, says physically assessing water conditions is the best strategy. If in doubt, stay out of the water.

This is advice that Jade will be following from here on.

"I went in against my better judgement because I'd had cabin fever for weeks stuck inside," she says. "I won't be swayed by others again. As a long-time local, I should have known better."

Decline in water quality after two major floods (ABC North Coast: Bruce Mackenzie)
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