Coogee and Malabar are among 11 beaches in the Sydney region to warrant a "poor" rating for water quality, with rainfall events the main factor, an annual survey found.
The state of the beaches report for 2015-16 found water quality had deteriorated in all three Sydney areas - north, central and south - in the past year. Contaminants include faecal material from animal and human sources.
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Storm clouds over Sydney
Fairfax photographer Nick Moir ventured out this morning to capture imagery of Sydney's wild weather.
Severe thunderstorms in November and December last year, and the wettest January in 28 years the following month contributed to the drop in quality.
"Rainfall is the major driver of pollution to recreational waters, generating stormwater runoff and triggering discharges from the wastewater treatment and transport systems," the report said.
![Coogee Beach is one of two ocean beaches in the Sydney area to get a "poor" rating.](/web/20161023041113im_/http://www.smh.com.au/content/dam/images/g/s/3/i/f/s/image.related.articleLeadwide.620x349.gs6h2f.png/1476945493815.jpg)
Between 83 per cent and 88 per cent of 96 sites around the city had good or very good ratings. Foreshores Beach in Botany Bay was again the only swimming spot to be rated "very poor".
"Microbial water quality [at Foreshores Beach] is highly influenced by faecal pollution, particularly after rainfall, and is very susceptible to faecal contamination from the sewage overflows which discharge into Mill Pond Creek," the report said.
Coogee and Malabar were the only ocean beaches among the 10 "poor" ranked sites, with the other eight all estuarine. Both beaches deteriorated in the past year.
While 94 per cent of dry weather samples at Coogee were within the safe swimming limits, levels of enterococci bacteria frequently exceeded those levels with just five millimetres or more of rain.
![Malabar Beach also got a 'poor' rating for water quality.](/web/20161023041113im_/http://www.smh.com.au/content/dam/images/g/s/6/i/7/n/image.related.articleLeadwide.620x349.gs6h2f.png/1476945493815.jpg)
For Malabar, the poor rating cames despite "significant improvements" since 2012-13 "due to the diversion of the large stormwater drain at the northern end of the beach". Only 76 per cent of samples taken during dry weather were within the safe swimming limit, the report said.
"Due to its topography Malabar beach takes longer to recover from stormwater events than surrounding areas," Rodd Kerr, strategy manager at Sydney Water, said. "Lower levels of flushing increase the time needed to disperse and dilute pollution inputs."
![Unusually heavy rain is blamed for worsening water quality at some Sydney beaches.](/web/20161023041113im_/http://www.smh.com.au/content/dam/images/g/s/6/i/e/f/image.related.articleLeadwide.620x349.gs6h2f.png/1476945493815.jpg)
Penny Sharpe, Labor's environment spokeswoman, said pollution of the city's beaches and waterways would get worse with climate change.
"The solution lies not in old-fashioned outflow pipes but investment in modern technology, partnerships with local government and waterside communities who are working every day to clean up our beaches," Ms Sharpe said.
NSW Water Minister Niall Blair said the report showed the region's world-class beaches "are in excellent shape".
The other beaches ranked as poor were at Narrabeen Lagoon, Bilarong Reserve, Bayview Baths and Barrenjoey Beach in the northern region, Davidson Reserve in the Sydney Harbour region, and the southern swimming sites at Yarra Bay, Gymea Bay Baths, and Gunnamatta Bay Baths, the report said.
'Resilient'
That 85 beaches should be gauged as having good or very good quality water was "a great result and testament to to the resilience of our beaches despite the intense rainfall", Mr Kerr said.
Bacteria found in tests were from all warm-blooded animals, including pets, native animals and birds.
"These are carried by stormwater off our roads, gardens and parks," Mr Kerr said.
Sydney Water, which has spent $1.8 billion since 2000 on wet weather overflows, will outlay another $129 million in 2016-17 to improve wastewater controls.
"Our gross pollutant traps alone stop 8,000 tonnes of rubbish and sediment entering our waterways every year, enough to fill 30,000 wheelie bins," Mr Kerr said.
Part of the current year's spending includes $45 million to separate Sydney's last remaining combined stormwater and wastewater system in Woolloomooloo, which will see an improvement across the harbour, he said.