Questions raised over threats to Sydney's water supply

Questions have been raised over the quality and security of Sydney's water supply following several reports and developments that highlight threats.

A recent audit by Alluvium Consulting Australia of Sydney's drinking water catchment, entitled "2016 Audit of the Sydney Drinking Water Catchment", and dated June 2017 found that Coal mining is affecting water flows in the catchment but its impact is unknown because of a lack of monitoring.

The audit, reviewed in an article in the Sydney Morning Herald, is produced every three years, and found "reduced water availability" compared with the 2013 report.

The audit found “an emerging issue of unquantified loss of surface flows associated with the cumulative impacts of underground coal mining activities."

It also noted that data and monitoring were inadequate, with datasets, such as those tracking native vegetation, not updated since 2013.

The audit was not available on the internet at the time of publication.

The release of the audit follows a decision by the NSW Court of Appeal to overturn a decision by the NSW Government to extend the Springvale colliery's underground operation by 13 years.

The decision was challenged by the 4Nature group, due to concerns that the expansion, located near to heritage-listed swamps in the Blue Mountains National Park, would pollute water entering catchments which feed into Sydney's water supply.

The mine, operated by Thai company Centennial Coal, supplies coal to the Mount Piper power station.

Meanwhile, research reported by the ABC shows that millions of litres of highly toxic water is escaping from a derelict coal mine into Sydney's drinking water catchment.

In the ABC's report, Dr Ian Wright of Western Sydney University tested waste water from the derelict Berrima Colliery, closed in 2013, and said pollution levels are the highest he's ever seen.

He said the contamination was "internationally significant", with heavy metals in the Wingecarribee River far exceeding safe environmental levels.

Key findings of the report were:

  • Median concentrations of nickel (430 ug/L), manganese (12667 ug/L) and zinc (1400 ug/L) are at extremely high levels

  • 89% of aquatic insects sampled in the vicinity of discharge have been wiped out (Ephemeropetera, Plecoptera and Trichoptera species)

  • Overall pollution has increased despite the mine's closure in 2013

  • Other contaminants include high levels of acidity, salinity, iron and sulfates.

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