The government of New South Wales (NSW) has developed a water strategy for Greater Sydney, to support population growth and adaption to a changing climate by 2040 and beyond, informs The Guardian. The draft strategy is part of a comprehensive set of water strategies to maintain the resilience of water services and resources in the Australian state for the coming decades, which includes 12 regional and two metropolitan water strategies.
By 2041, NSW’s population is projected to grow by 2.8 million to about 10.6 million. Most of that population will concentrate in Greater Sydney, expected to grow by about 45% to over 7 million people. To accommodate that growth, Greater Sydney will need to increase its water supply, at the same time as it adapts its rainfall-dependent water supply system.
The drought from 2017 to February 2020 brought to light the issue of water security in Greater Sydney. Drought conditions were more severe than anticipated in the 2017 Metropolitan Water Plan. Dam storage levels dropped by 50% of full dam capacity in two and a half years, much faster than in previous droughts. Lessons learned include the need to be prepared to respond timely, the importance of water conservation between droughts, and the interactions between water quality and drought – for example water quality is likely to deteriorate as dams approach low levels.
Looking ahead, the forecast long-term water yield is less than the annual demand. Greater Sydney’s drinking water system can provide between 515 and 540 GL/year, and estimates suggest that may be about 40 to 70 GL/year less than needed under a mid-case demand forecast in the short-term. The gap is estimated to increase to about 250 GL/year by 2060, again under a mid-case demand forecast (a “middle-range” population growth scenario).
The new draft water strategy provides guidance on how to bridge the gap between supply and demand, and will replace the 2017 Metropolitan Water Plan. Melinda Pavey, Minister of Water of NSW, said: “A secure water supply is vital and this plan ensures we are able to support economic growth as we recover from the pandemic and set the foundations for the future.”
The strategy proposes continuing investments in comprehensive water conservation and water efficiency initiatives, which are estimated to save up to 49 GL/year by 2040 at a relatively low cost.
On the supply side, the strategy contemplates additional rainfall independent sources of water. Options in the near term include optimizing de operation of the existing Sydney Desalination Plant to increase production by an extra 20 GL/year, and using alternate sources of water such as stormwater and recycled water to meet the water demand for greening and cooling, and potentially to be released as environmental flows. Other options to be further examined include expanding the Sydney Desalination Plant (providing an additional 90 GL/year), building a new one (also providing 90 GL/year), or purified recycled water schemes (capable of providing up to 140 GL/year).
The Greater Sydney Water Strategy also states it will consider actions to ensure water management supports Aboriginal rights, interest and access. These include strengthening the role of Aboriginal communities in water planning, management, governance and decision-making, and developing a state-wide Aboriginal Water Strategy in partnership with First Nations that will identify a program of measures to deliver on First Nations’ water rights and interests in water management.
