Water availability in NSW has always been highly variable - and this will continue. It is possible that extremes of wet and dry may become more pronounced and extreme events more frequent.
Our arrangements for sharing water are essential but highly contested. NSW has a well-established and secure system for planning, licensing, issuing entitlements and making allocations of water to different users - but these are put to the test during extreme drought.
We have learned that we can’t rely on our experience from the recent past to inform long- term water management decisions. In the years ahead, we will face the fundamental challenge of supporting the diverse aspirations of the people of NSW - for a better environment, a strong economy and thriving communities - with water resources that are finite and have clear limits on how much can be used for different purposes and where availability may be even more variable and unpredictable than in the past.
Variability of inflow means that the system needs to be able to capture water when it is available to manage reliability of supply over time, especially through prolonged periods of low flow that were experienced in the most recent drought. The Government’s priorities to progress the provision of new dams and other water infrastructure respond to this challenge. Meeting this challenge requires a much better understanding of plausible future climate conditions and how these may affect river flows, groundwater resources and the supply of water for communities, towns and cities, industry and the environment.
In NSW the recent impacts from extreme drought, bushfires and the global COVID-19 pandemic are all pressure points stretching water management capability and preparedness. The prospect of more frequent and extreme drought conditions in the future, together with reduced cool season rainfall in south-eastern Australia, should not come as a shock. We must plan and prepare for a future where we may need to deal with more extreme and more frequent droughts and floods than we have experienced in the past. This means that we need to reduce our reliance on traditional climate dependent water sources to supply our towns, cities and industry, while protecting the communities and natural environments sustained by our waterways.
The NSW Water Strategy acknowledges these challenges and sets a strategic and unified approach to water management issues to beyond 2040 - and to a future that may be quite different to the past.
Populations are growing and shifting
As NSW caters for a growing population, variable water reliability increases the risk to secure and sustainable water supplies.
By 2041, the population of NSW is projected to grow by 2.8 million to about 10.6 million. Growth will be centred in Greater Sydney, which is expected to grow by about 45% and be home to over 7 million people. Strong growth of more than 400,000 people is also forecast for regional NSW over the same period, driven by people moving from Greater Sydney. More people are also expected to move from rural and remote areas to larger regional centres. Predicted reductions in international migration, families having fewer children or delaying having children due to the COVID-19 pandemic and economic recession are likely to reduce but not stop this growth. It is likely to be more noticeable in the metropolitan areas than in regional NSW.
The climate is variable and changing
The NSW Government has invested in new modelling methods and datasets to develop a better understanding of both historical climate variability and likely future climate conditions. We are using new scientific methods that augment the observed historical record (about 130 years of rainfall, temperature and evaporation data) with paleoclimate data (data reconstructed from before instrumental records began, using sources such as tree rings, cave deposits and coral growth) and climate change projections. This greatly improves our ability to identify plausible climate impacts and risks, and it represents a significant and important advance in water planning for NSW.
The message from this work so far is that our water supplies in NSW could be less secure than we thought. This is because we now understand that droughts longer than those of the last 130 years are likely at some point, and that we could also see higher temperatures and less rainfall. Projected changes in rainfall patterns, warmer conditions and increased evaporation will impact future water availability. The frequency, intensity and duration of droughts are also predicted to increase, which may affect water quality and the ecology of our rivers.
Global climate models are useful for providing broad predictions of likely variations and changes in rainfall, rather than forecasting specific regional conditions. For NSW, these models indicate that there is unlikely to be much change in rainfall in the north of the state; however, in the south of the state, winter and spring rains are likely to be less.
Along the south coast, changes in the patterns of east coast lows are likely, with an increase in the intensity of rainfall. The risks that stem from such events are not confined to the loss of life and property; the gross domestic product of Australia was reduced by an estimated $30 billion due to the Queensland floods in 2010/11 [House of Representatives Standing Committee on Economics, June 2011].
Our new climate risk modelling means that we can now better understand the likely future climate characteristics of each region in NSW. We can better identify the potential risks to water security in different parts of the state and we can develop specific, targeted actions to mitigate these risks.
Pressure to adapt
A more variable and changing climate
Need to adapt