Sydney’s Water System Health Worsening Due to Climate Crisis, Study Shows

A recent study revealed that Sydney's water system is at risk of providing adequate and high-quality water due to the impact of climate change.

An audit report examined the health of the Sydney Drinking Water Catchment for four years, between 2019 and 2022, and was handed to the New South Wales government.

It shows that seven of the 18 main indicators of the water system's health were deteriorating.

Climate change was the "greatest driver of the catchment's overall health," citing the severe impact of occurrences such as the black summer bushfires, which burned nearly a third of the catchment area.

The catchment encompasses several important river systems, notably the Hawkesbury-Nepean, and gathers and stores drinking water for Sydney and the surrounding areas.

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What exactly climate change does to the catchment?

Climate change has increased the frequency and severity of natural disasters around the world.

According to the report by The Guardian, auditors discovered that ash and debris from the 2019 and 2020 fires had harmed water quality and the ecology of numerous areas of the landscape.

Heavy rains that followed the fires aided vegetation recovery but also caused soil erosion and landslides.

The assessment stated that there was an "increased likelihood of compounding effects of extreme rainfall following significant fire seasons due to climate change."

The report also indicated that two of three water quality indicators, raw water quality and nutrient concentrations, were decreasing in numerous streams.

The macroinvertebrate communities in the watershed were reported to be declining, owing in part to the loss of habitat and degrading wetlands.

" Further decline is likely due to climate change and increasing bushfires, especially in wetlands already under stress from impacts such as longwall mining or urban development," the audit said.

Recommendation to strengthen climate change policy

The audit advised that the New South Wales government evaluate its climate change mitigation plans.

It also suggests that more data be collected because modeling indicates that extreme weather will become more common.

The auditors described the catchment as a vital natural asset that supports Sydney's health, economy, and natural environment.

"Adverse impacts from climate-driven events are already observable in the catchment, although the thresholds to avoid serious and irreversible harm to catchment health from a changing climate are unclear," the report read.

It also offered sewage-related suggestions, encouraging the government to modernize treatment plants in the Wingecarribee area to avoid environmental harm as the population grows in the country.

They noted that the delays in upgrading sewage treatment plants risk increasing poor water quality outcomes and infringing on environmental protection licenses.

The Minister for Water, Rose Jackson said the advice to reduce greenhouse gases is consistent with the NSW government's net zero and climate adaptation policies, which intends to reduce the disturbance caused by more intense weather occurrences to management and monitoring.

"The negative impact of climate change is clear, which is why the NSW government has factored climate impacts into future water planning," she said.

The catchment is set to be re-evaluated in 2025.

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