An audit report of Sydney’s drinking water catchment covering the period 2019-2022 has found climate change to be a threat to the city’s drinking water quality in the future, reports The Guardian.
The report, prepared by Eco Logical Australia and Restore Environmental Consultants for the New South Wales (NSW) Minister for Water, was recently tabled in the NSW Parliament. It assesses the health of the catchment in the context of long-term trends, as well as the main pressures on catchment health and responses needed.
According to the report, the evidence underscores the key role of climate in catchment health and suggests that, despite of good land management practices and pollution regulation, catchment health will not be maintained “unless substantial effort is also made to reduce greenhouse gas emissions and limit climate change impacts”.
The audit considered 18 indicators of catchment health, and found seven of them (ecosystem and raw water quality, fire, macroinvertebrates, nutrient load, soil erosion, surface water flow, and wetlands) followed a worsening trend.
The report’s recommendations relate to climate change, land management and pollution control, while it recognizes climate is “the greatest driver of overall health in the catchment”. While acknowledging that responses to climate change require a global effort, recommendations focus on what can be achieved within the catchment. In terms of minimising the impacts of climate driven events, it proposes the development of a disaster mitigation plan that identifies, maps and considers the resilience of critical water monitoring and management infrastructure, and using non-government bores to inform sustainable use of groundwater.
It was found that ash and debris from the 2019-20 bushfires affected water quality, ecological communities and constructed assets, while the heavy rain that followed resulted in soil erosion and landslips. The audit also concluded that, although adverse impacts from climate-driven events are already observable, “the thresholds to avoid serious and irreversible harm to catchment health from a changing climate are unclear”.
The report’s recommendation to reduce greenhouse gas emission is in line with the NSW government’s goal to achieve net zero emissions by 2050, said water minister Rose Jackson. “The negative impact of climate change is clear, which is why the NSW government has factored climate impacts into future water planning”, she noted, and added that safety barriers in place ensure “Sydney’s drinking water source is among the best protected in the world”.
